| 1. |
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| 2. |
- Agostinelli, Marta, et al.
(författare)
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Mycobiome of Fraxinus excelsior With Different Phenotypic Susceptibility to Ash Dieback
- 2021
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Ingår i: Frontiers in Forests and Global Change. - : Frontiers Media S.A.. - 2624-893X. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- For the last two decades, large-scale population decline of European ash (Fraxinus excelsior) has occurred in Europe because of the introduction of the alien fungal pathogen, Hymenoscyphus fraxineus, from East Asia. Since European ash is a keystone species having critical importance for biodiversity, and only a small percentage of the ash population appears to show some tolerance against the pathogen, the loss of ash trees means that other associated organisms, especially those with high or obligate associations to ash, are at risk of further species declines. In this study, we used high throughput DNA sequencing and multivariate analysis to characterize: (i) the mycobiome in aerial tissues (i.e., leaf, bark, and xylem) of ash trees showing different phenotypic response to ash dieback, (ii) the temporal variation in fungal communities across the growing season, and (iii) the similarity in fungal community structure between ash and other common trees species that may serve as an ecological niche substitute for ash microfungi. Results showed that fungal communities differed among the three tissue types, susceptibility classes, in time and between sites. Trophic analysis of functional groups using the FUNGuild tool indicated a higher presence of pathotrophic fungi in leaves than in bark and xylem. The share of pathotrophic fungi increased along a gradient of low to high disease susceptibility in both bark and xylem tissue, while the proportion of symbiotrophic fungi correspondingly decreased in both tissue types. Neighboring, alternative host trees did not share all the fungal species found in ash, however, most microfungi uniquely associated to ash in this study are generalists and not strictly host specific. The progressive disappearance of ash trees on the landscape imposes a high risk for extinction of Red-listed macrofungal species, and breeding for resistance against ash dieback should help sustain important biodiversity associated to ash. Microfungal diversity though may be less prone to such demise since most ash-associated endophytes appear to occur on a broad range of host species.
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| 3. |
- Agostinelli, Marta, et al.
(författare)
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Pedunculate Oaks (Quercus robur L.) Differing in Vitality as Reservoirs for Fungal Biodiversity
- 2018
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Ecological significance of trees growing in urban and peri-urban settings is likely to increase in future land-use regimes, calling for better understanding of their role as potential reservoirs or stepping stones for associated biodiversity. We studied the diversity of fungal endophytes in woody tissues of asymptomatic even aged pedunculate oak trees, growing as amenity trees in a peri-urban setting. The trees were classified into three groups according to their phenotypic vitality (high, medium, and low). Endophytes were cultured on potato dextrose media from surface sterilized twigs and DNA sequencing was performed to reveal the taxonomic identity of the morphotypes. In xylem tissues, the frequency and diversity of endophytes was highest in oak trees showing reduced vitality. This difference was not found for bark samples, in which the endophyte infections were more frequent and communities more diverse than in xylem. In general, most taxa were shared across the samples with few morphotypes being recovered in unique samples. Leaf phenolic profiles were found to accurately classify the trees according to their phenotypic vitality. Our results confirm that xylem is more selective substrate for endophytes than bark and that endophyte assemblages in xylem are correlated to the degree of host vitality. Thus, high vitality of trees may be associated with reduced habitat quality to wood-associated endophytes.
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| 4. |
- Albrectsen, Benedicte R, 1960-, et al.
(författare)
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Large scale geographic clines of parasite damage to Populus tremula L
- 2010
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Ingår i: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 33:3, s. 483-493
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Tidskriftsartikel (refereegranskat)abstract
- In conclusion, clines of Phyllocnistis were stronger and more persistent compared to Melampsora, which showed contrasting clines of varying strength. Our data thus support the assumption of the GMTC model that clines exist in the border between hot and cold spots and that they may be less persistent for parasites with an elevated gene flow, and/or for parasites which cover relatively larger hot spots surrounded by fewer cold spots.
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| 5. |
- Anderbrant, O., et al.
(författare)
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Feeding by Scolytus bark beetles to test for differently susceptible elm varieties
- 2017
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Ingår i: Journal of Applied Entomology. - : Wiley. - 0931-2048 .- 1439-0418. ; 141:5, s. 417-420
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Tidskriftsartikel (refereegranskat)abstract
- Dutch elm disease (DED), caused by the fungi Ophiostoma ulmi and O. novo-ulmi, has reduced elm populations severely in Europe and North America. Breeding programmes are in action to find less susceptible elm varieties suitable for re-establishing elm stands. Bark beetles, mainly Scolytus spp., are the only known natural vectors of DED. During twig feeding, beetles transfer Ophiostoma spores to healthy elms. Thus, less palatable elms should run a lower risk of DED infections. In feeding preference bioassays, we offered twigs from elms exhibiting different degree of susceptibility to O. novo-ulmi, together with non-host trees to Scolytus beetles. Scolytus multistriatus preferred wych elm, Ulmus glabra, to 100% in two-choice tests, whereas S. laevis did not discriminate between a tolerant and a susceptible variety of field elm, U. minor. We suggest that the feeding assay is useful as a low-tech method in breeding programmes for evaluating the suitability of promising elm genotypes to vector insects.
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| 6. |
- Benavent-Celma, Clara, et al.
(författare)
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Current practices and emerging possibilities for reducing the spread of oomycete pathogens in terrestrial and aquatic production systems in the European Union
- 2022
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Ingår i: Fungal Biology Reviews. - : Elsevier. - 1749-4613 .- 1878-0253. ; 40, s. 19-36
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Tidskriftsartikel (refereegranskat)abstract
- Diseases caused by oomycete pathogens are a global threat to forestry, agriculture and aquaculture. Because of their complex life cycles, characterised by dormant resting structures that enable their survival for years under hostile environmental conditions, reducing the spread of oomycetes is a challenging task. In this review, we present an overview of this challenge, starting from the need to understand the natural and anthropogenic dispersal pathways of these pathogens. Focusing on the European Union, we explore current legislation that forms a backbone for biosecurity protocols against the spread of oomycetes through trade and transport. We discuss the options for prevention, containment and long-term management of oomycetes in different production settings, emphasising the importance of prevention as the most cost-efficient strategy to reduce the spread of these pathogens. Finally, we highlight some of the new and emerging technologies and strategies as potential tools in the integrated pest management of animal and plant diseases caused by oomycetes. We emphasise the urgency of actions to halt the global spread of these pathogens.
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| 7. |
- Bengtsson, Therese, et al.
(författare)
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Activation of defence responses to Phytophthora infestans in potato by BABA
- 2014
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Ingår i: Plant Pathology. - : Wiley. - 0032-0862 .- 1365-3059. ; 63, s. 193-202
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Tidskriftsartikel (refereegranskat)abstract
- Late blight caused by Phytophthora infestans is one of the most devastating diseases of the potato crop. Resistance breeding and current fungicides are unable to control the rapidly evolving P. infestans and new control strategies are urgently needed. This study examined mechanisms of dl-β-aminobutyric acid (BABA)-induced resistance (IR) in the potato-P. infestans system. Leaves from two cultivars that differ in their degree of resistance, Bintje and Ovatio, were analysed after foliar treatment with BABA. Rapid activation of various defence responses and a significant reduction in P. infestans growth were observed in leaves treated with BABA. In the more resistant cultivar, Ovatio, the activation was both faster and stronger than in Bintje. Microscopic analysis of leaves treated with BABA revealed induction of small hypersensitive response (HR)-like lesions surrounded by callose, as well as production of hydrogen peroxide (H2O2). Molecular and chemical analyses revealed soluble phenols such as arbutin and chlorogenic acid and activation of PR-1. These results show a direct activation of defence responses in potato, rather than priming as reported for other plant species. They also show that the efficiency of BABA-IR differs between cultivars, which highlights the importance of taking all aspects into consideration when establishing new methods for disease management.
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| 8. |
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| 9. |
- Blumenstein, Kathrin, et al.
(författare)
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Diversidad de endófitos del olmo y relación con la resistencia a la grafiosis
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Los endófitos activan en sus hospedantes mecanismos defensivos similares a los activados por patógenos. Se plantea la hipótesis de que estos mecanismos limitan el establecimiento de endófitos en olmos resistentes a la grafiosis. Asimismo, ciertos endófitos proporcionan a sus hospedantes mecanismos epigenéticos de protección ante patógenos. Planteamos como segunda hipótesis que determinados endófitos están implicados en la resistencia ambiental a la grafiosis. Se ha estudiado la frecuencia y diversidad de endófitos en olmos genéticamente resistentes a la grafiosis y se ha comparado con la encontrada en olmos susceptibles. Además, se han aislado endófitos de olmos que en campo muestran resistencia fenotípica a la grafiosis, pese a que son susceptibles a la enfermedad. Su antagonismo hacia la grafiosis se ha evaluado mediante ensayos in vitro e in vivo. Olmos resistentes muestran una menor frecuencia y diversidad de endófitos en el xilema, lo que confirma la primera hipótesis. Ciertos endófitos produjeron metabolitos extracelulares que inhibieron el crecimiento del hongo de la grafiosis in vitro. El efecto protector de los tratamientos con endófitos ante la grafiosis ha sido en general poco notable, si bien ciertas cepas mostraron un efecto significativo, aunque dependiente del genotipo de olmo.
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| 10. |
- Blumenstein, Kathrin, et al.
(författare)
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Nutritional niche overlap potentiates the use of endophytes in biocontrol of a tree disease
- 2015
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Ingår i: BioControl (Dordrecht). - : Springer Science and Business Media LLC. - 1386-6141 .- 1573-8248. ; 60:5, s. 655-667
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Tidskriftsartikel (refereegranskat)abstract
- Asymptomatic endophytic fungi are often regarded as potent biocontrol agents in plants, but the competitive interactions between endophytes and other microbes within the same host plant are poorly understood. We tested a hypothesis that as compared to asymptomatic endophytes, an aggressive pathogen inhabiting the same host is able to utilize carbon substrates more efficiently. Using phenotype microarray, we determined the carbon utilization profiles of the highly virulent Dutch elm disease (DED) pathogen Ophiostoma novo-ulmi, and four asymptomatic elm (Ulmus spp.) endophyte isolates that were selected based on their differential association to the DED-susceptibility pattern of the host elms. The competitive interactions between isolates were evaluated using a niche overlap index. In contrast to our hypothesis, the studied endophytes exhibited extensive niche overlap with the pathogen, suggesting that some endophyte strains might protect elms against DED-pathogen through competition for substrates and provide new tools for biocontrol of DED.
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| 11. |
- Blumenstein, Kathrin, et al.
(författare)
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Phenotype MicroArrays as a complementary tool to next generation sequencing for characterization of tree endophytes
- 2015
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- There is an increasing need to calibrate microbial community profiles obtained through next generation sequencing (NGS) with relevant taxonomic identities of the microbes, and to further associate these identities with phenotypic attributes. Phenotype MicroArray (PM) techniques provide a semi-high throughput assay for characterization and monitoring the microbial cellular phenotypes. Here, we present detailed descriptions of two different PM protocols used in our recent studies on fungal endophytes of forest trees, and highlight the benefits and limitations of this technique. We found that the PM approach enables effective screening of substrate utilization by endophytes. However, the technical limitations are multifaceted and the interpretation of the PM data challenging. For the best result, we recommend that the growth conditions for the fungi are carefully standardized. In addition, rigorous replication and control strategies should be employed whether using pre-configured, commercial microwell-plates or in-house designed PM plates for targeted substrate analyses. With these precautions, the PM technique is a valuable tool to characterize the metabolic capabilities of individual endophyte isolates, or successional endophyte communities identified by NGS, allowing a functional interpretation of the taxonomic data. Thus, PM approaches can provide valuable complementary information for NGS studies of fungal endophytes in forest trees.
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| 12. |
- Cleary, Michelle, et al.
(författare)
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First Report of Phytophthora gonapodyides Causing Stem Canker on European Beech (Fagus sylvatica) in Southern Sweden
- 2016
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Ingår i: Plant Disease. - 0191-2917 .- 1943-7692. ; 100, s. 2174-2175
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Tidskriftsartikel (refereegranskat)abstract
- Since 2010, extensive crown transparency of European beech (Fagus sylvatica) has been recorded in southern Sweden, with Phytophthora cambivora, P. plurivora, and P. cactorum as well as associated climatic triggers believed to be the major factors involved. In 2015, a different Phytophthora sp. was isolated from three F. sylvatica trees showing characteristic bleeding canker symptoms in Pildammsparken in Malmö, Sweden. Small sections of inner phloem were dissected at the interface between necrotic and healthy tissue, directly plated onto PAR(PH)-V8 selective medium containing 0.250 g/liter sodium ampicillin, 0.01 g/liter benomyl, 0.05 g/liter hymexazol, 0.1 g/liter PCNB, 0.05 g/liter pimaricin, and 0.01 g/liter rifamycin, and incubated at 20°C in darkness. Growing hyphae were later transferred to PDA and incubated at 20°C in the dark. The colony pattern was stellate. The average radial growth rate at 20°C was 0.6 cm/day. These morphological features are similar to that previously described for P. gonapodyides (Corcobado et al. 2010; Erwin and Ribeiro 1996; Jung et al. 1996). The isolates grown on PDA formed irregularly branched hyphae. Nonpapillate, elongated-ovoid to obpyriform sporangia (∼50 × 40 µm) were produced after 7 days by incubating on V8 agar culture (nonsterile soil water). DNA was extracted from mycelia and the identity of P. gonapodyides was confirmed by sequencing the internal transcribed (ITS) spacer region of the rDNA with the primers ITS4/ITS6 (GenBank accession nos. KX055998, KX055999, and KX056000). BLAST search showed 99 to 100% identity with reference sequences of P. gonapodyides deposited in GenBank. Pathogenicity on F. sylvatica was confirmed in a greenhouse experiment using two different isolates of P. gonapodyides. Mycelial plugs of 3-week-old cultures of each isolate grown on PDA were inoculated on the stems of 1-year-old seedlings at two locations, separated by 20 cm, by aseptically excising a small 5-mm flap of bark, inserting the mycelial plug along the cambium, and adding a droplet of Milliq H2O before sealing the wound with Parafilm. Ten seedlings were inoculated for each isolate. Controls consisted of stem-wound inoculation with a sterile plug of PDA, and no wounding at all. After 7 weeks, lesion length was measured. All seedlings inoculated with P. gonapodyides showed distinct necrotic lesions, whereas control treatments did not show any symptoms of disease. The average cumulative lesion length on seedlings inoculated with P. gonapodyides was significantly higher than on the wounded control treatment (25.4 mm ± 1.66 vs. 0.4 mm ± 0.01; P < 0.0001 for isolate 1 and 28.9 mm ± 1.42 vs. 0.4 mm ± 0.01; P < 0.001 for isolate 2). Koch's postulates were fulfilled by successfully reisolating the pathogen from infected seedlings. To our knowledge, this is the first report of P. gonapodyides causing disease on trees in Sweden. P. gonapodyides has been noted previously in Denmark (Erwin and Ribeiro 1996), and has been traditionally regarded as a weak parasite with saprophytic abilities, usually associated with aquatic environments such as rivers, riparian areas, and wetlands (Brasier et al. 2003). We cannot exclude that recent climatic triggers such as high summer precipitation coupled with mild winter temperatures have favored conditions to multicyclic spread of P. gonapodyides via zoospores, or that increased average age of beech stands has contributed to their higher susceptibility to weaker pathogens. Damage caused by P. gonapodyides however might be underestimated as it also can inhibit seed germination and is known to cause root rot and stem lesions in Quercus robur and Q. ilex (Corcobado et al. 2010; Jung et al. 1996). The newly reported damage caused by P. gonapodyides on F. sylvatica trees in southern Sweden is alarming particularly since beech is a dominant and ecologically important hardwood species that is widely used in forestry and as a planted ornamental in urban and landscape settings. Furthermore, other hosts such as Alnus glutinosa, Q. petraea, Q. robur (Jung et al. 1996), Picea abies, Betula spp., Acer spp., Tilia spp. (Jung et al. 2009), and Salix spp. (Brasier et al. 2003), also common in southern Sweden, may face an increased risk of damages caused by P. gonapodyides in the future.
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| 13. |
- Cleary, Michelle, et al.
(författare)
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Increasing understanding of alien species through citizen science (Alien-CSI)
- 2018
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Ingår i: Research Ideas and Outcomes. - : Pensoft Publishers. - 2367-7163. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- There is no sign of saturation in accumulation of alien species (AS) introductions worldwide, additionally the rate of spread for some species has also been shown to be increasing. However, the challenges of gathering information on AS are recognized. Recent developments in citizen science (CS) provide an opportunity to improve data flow and knowledge on AS while ensuring effective and high quality societal engagement with the issue of IAS (Invasive Alien Species). Advances in technology, particularly on-line recording and smartphone apps, along with the development of social media, have revolutionized CS and increased connectivity while new and innovative analysis techniques are emerging to ensure appropriate management, visualization, interpretation and use and sharing of the data. In early July 2018 we launched a European CO-operation in Science and Technology (COST) Action to address multidisciplinary research questions in relation to developing and implementing CS, advancing scientific understanding of AS dynamics while informing decision-making specifically implementation of technical requirements of relevant legislation such as the EU Regulation 1143/2014 on IAS. It will also support the EU biodiversity goals and embedding science within society. The Action will explore and document approaches to establishing a European-wide CS AS network. It will embrace relevant innovations for data gathering and reporting to support the implementation of monitoring and surveillance measures, while ensuring benefits for society and citizens, through an AS CS European network. The Action will, therefore, increase levels of participation and quality of engagement with current CS initiatives, ensuring and evaluating educational value, and improve the value outcomes for potential users including citizens, scientists, alien species managers, policy-makers, local authorities, industry and other stakeholders.
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| 14. |
- Cleary, Michelle, et al.
(författare)
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Oomycetes in rhizosphere soil of ornamental plants from retail nurseries in Southern Sweden
- 2021
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Ingår i: Forest Pathology. - : John Wiley & Sons. - 1437-4781 .- 1439-0329. ; 51:2
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Tidskriftsartikel (refereegranskat)abstract
- Trade of herbaceous and woody ornamental plants is recognized as a principal pathway for the introduction of alien plant pathogens, such as soil-borne Phytophthora and Pythium species (oomycetes). The rhizosphere soil of container-grown plants obtained from 13 nurseries and garden centres in southern Sweden were sampled and the presence of Phytophthora and Pythium species determined using traditional baiting and isolation. DNA sequencing of isolates revealed five Phytophthora taxa including P. cinnamomi, P. citricola s.l., P. plurivora, P. undulata and a non-identified Phytophthora sp., as well as Phytopythium cf. citrinum and several species of Pythium. Phytophthora cinnamomi was detected on two different ornamental plants at the same nursery and is a first record of P. cinnamomi in Sweden. The survey revealed that a diversity of potentially pathogenic oomycetes is associated with ornamental plants available for sale in Sweden and emphasizes the need to recognize potential risks if these organisms get introduced in nature.
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| 15. |
- Cleary, Michelle, et al.
(författare)
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Pine Pitch Canker and Insects: Regional Risks, Environmental Regulation, and Practical Management Options
- 2019
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Ingår i: Forests. - : MDPI AG. - 1999-4907. ; 10
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Forskningsöversikt (refereegranskat)abstract
- Pine pitch canker (PPC), caused by the pathogenic fungus Fusarium circinatum (Nirenberg and O' Donnell), is a serious threat to pine forests globally. The recent introduction of the pathogen to Southern Europe and its spread in Mediterranean region is alarming considering the immense ecological and economic importance of pines in the region. Pines in forests and nurseries can be infected, resulting in severe growth losses and mortality. The pathogen is known to spread in plants for planting and in seeds, and results from recent studies have indicated that F. circinatum may also spread through phoretic associations with certain insects. With this review, we aim to expand the current understanding of the risk of insect-mediated spread of PPC in different parts of Europe. Through the joint action of a multinational researcher team, we collate the existing information about the insect species spectrum in different biogeographic conditions and scrutinize the potential of these insects to transmit F. circinatum spores in forests and nurseries. We also discuss the impact of environmental factors and forest management in this context. We present evidence for the existence of a high diversity of insects with potential to weaken pines and disseminate PPC in Europe, including several common beetle species. In many parts of Europe, temperatures are projected to rise, which may promote the activity of several insect species, supporting multivoltinism and thus, further amplifying the risk of insect-mediated dissemination of PPC. Integrated pest management (IPM) solutions that comply with forest management practices need to be developed to reduce this risk. We recommend careful monitoring of insect populations as the basis for successful IPM. Improved understanding of environmental control of the interaction between insects, the pathogen, and host trees is needed in order to support development of bio-rational strategies to safeguard European pine trees and forests against F. circinatum in future.
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| 16. |
- Cleary, Michelle, et al.
(författare)
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Potential Interactions between Invasive Fusarium circinatum and Other Pine Pathogens in Europe
- 2020
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Ingår i: Forests. - : MDPI AG. - 1999-4907. ; 11
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Forskningsöversikt (refereegranskat)abstract
- Pines are major components of native forests and plantations in Europe, where they have both economic significance and an important ecological role. Diseases of pines are mainly caused by fungal and oomycete pathogens, and can significantly reduce the survival, vigor, and yield of both individual trees and entire stands or plantations. Pine pitch canker (PPC), caused by Fusarium circinatum (Nirenberg and O'Donnell), is among the most devastating pine diseases in the world, and is an example of an emergent invasive disease in Europe. The effects of microbial interactions on plant health, as well as the possible roles plant microbiomes may have in disease expression, have been the focus of several recent studies. Here, we describe the possible effects of co-infection with pathogenic fungi and oomycetes with F. circinatum on the health of pine seedlings and mature plants, in an attempt to expand our understanding of the role that biotic interactions may play in the future of PPC disease in European nurseries and forests. The available information on pine pathogens that are able to co-occur with F. circinatum in Europe is here reviewed and interpreted to theoretically predict the effects of such co-occurrences on pine survival, growth, and yield. Beside the awareness that F. circinatum may co-occurr on pines with other pathogens, an additional outcome from this review is an updating of the literature, including the so-called grey literature, to document the geographical distribution of the relevant pathogens and to facilitate differential diagnoses, particularly in nurseries, where some of them may cause symptoms similar to those induced by F. circinatum. An early and accurate diagnosis of F. circinatum, a pathogen that has been recently introduced and that is currently regulated in Europe, is essential to prevent its introduction and spread in plantings and forests.
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| 17. |
- Cleary, Michelle, et al.
(författare)
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Susceptibility of common tree species in Sweden to Phytophthora cactorum, P. cambivora and P. plurivora
- 2017
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Ingår i: Forest Pathology. - : Wiley. - 1437-4781 .- 1439-0329. ; 47
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Tidskriftsartikel (refereegranskat)abstract
- In Sweden, invasive Phytophthora pathogens have been recognized as a growing threat to urban and production forests, calling for an urgent update of regeneration strategies for infested areas. Stem inoculation tests were performed to test the relative susceptibility of common conifer and broadleaved tree species Pinus sylvestris, Picea abies, Larix x eurolepis, Betula pendula, Quercus robur, Fagus sylvatica, Populus trichocarpa and Tilia cordata to the root pathogens Phytophthora cactorum, P. cambivora and P. plurivora commonly isolated from Swedish soils. Results indicate that all the species tested were susceptible and formed lesions following stem inoculation with all three Phytophthora species, but to varying degrees. Of particular interest are the high levels of susceptibility in P. trichocarpa to all three Phytophthora species compared to other tested tree species.
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| 18. |
- Davydenko, Kateryna, et al.
(författare)
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Forewarned is forearmed: harmonized approaches for early detection of potentially invasive pests and pathogens in sentinel plantings
- 2019
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Ingår i: NeoBiota. - : Pensoft Publishers. - 1619-0033 .- 1314-2488. ; , s. 95-123
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Tidskriftsartikel (refereegranskat)abstract
- The number of invasive alien pest and pathogen species affecting ecosystem functioning, human health and economies has increased dramatically over the last decades. Discoveries of invasive pests and pathogens previously unknown to science or with unknown host associations yet damaging on novel hosts highlights the necessity of developing novel tools to predict their appearance in hitherto naive environments. The use of sentinel plant systems is a promising tool to improve the detection of pests and pathogens before introduction and to provide valuable information for the development of preventative measures to minimize economic or environmental impacts. Though sentinel plantings have been established and studied during the last decade, there still remains a great need for guidance on which tools and protocols to put into practice in order to make assessments accurate and reliable. The sampling and diagnostic protocols chosen should enable as much information as possible about potential damaging agents and species identification. Consistency and comparison of results are based on the adoption of common procedures for sampling design and sample processing. In this paper, we suggest harmonized procedures that should be used in sentinel planting surveys for effective sampling and identification of potential pests and pathogens. We also review the benefits and limitations of various diagnostic methods for early detection in sentinel systems, and the feasibility of the results obtained supporting National Plant Protection Organizations in pest and commodity risk analysis.
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| 19. |
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| 20. |
- Engman, Mattias, et al.
(författare)
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Towards streamlined bank vole odor preference evaluation using Y-mazes
- 2020
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Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 65, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Seed consumption by rodents causes substantial economic losses in agriculture and forest restoration. Rodents rely on their sensitive sense of smell to gather information about their environment. However, comparably little is known about how rodents use olfaction to locate food. We used bank voles to measure attraction to acorn odors in a Y-maze. Preferences were measured using two behaviors: approaching (time spent in odor preference zones) and investigation (numbers of nose pokes in odor nozzle), which yielded similar results. Shorter time intervals (15 and 30 s) in the preference zones were at least as good as the longer time interval (60 s) for detecting differences in approaching behavior. In this way, it is possible to reduce the measurement time with approximately 50%. Investigation, which was evaluated using only one time interval (180 s), yielded longer measurement time. Acorns were as preferred as the familiar, standard food (rodent chow) while an acorn aeration extract did not produce any response. We conclude that short measurement times for the evaluation of attractive odors makes it possible to efficiently assay the wide range of volatile compounds from bank voles' natural foods which may be important in studies wishing to develop new rodent control methods.
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| 21. |
- Farnier, Kevin, et al.
(författare)
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Novel bioassay demonstrates attraction of the white potato cyst nematode Globodera pallida (Stone) to non-volatile and volatile host plant cues
- 2012
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Ingår i: Journal of Chemical Ecology. - : Springer. - 0098-0331 .- 1573-1561. ; 38:6, s. 795-801
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Tidskriftsartikel (refereegranskat)abstract
- Potato cyst nematodes (PCNs) are a major pest of solanaceous crops such as potatoes, tomatoes, and eggplants and have been widely studied over the last 30 years, with the majority of earlier studies focusing on the identification of natural hatching factors. As a novel approach, we focused instead on chemicals involved in nematode orientation towards its host plant. A new dual choice sand bioassay was designed to study nematode responses to potato root exudates (PRE). This bioassay, conducted together with a traditional hatching bioassay, showed that biologically active compounds that induce both hatching and attraction of PCNs can be collected by water extraction of incised potato roots. Furthermore, our results demonstrated that PCN also were attracted by potato root volatiles. Further work is needed to fully understand how PCNs use host plant chemical cues to orientate towards hosts. Nevertheless, the simple attraction assay used in this study provides an important tool for the identification of host-emitted attractants.
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| 22. |
- Felton, Adam, et al.
(författare)
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Forest biodiversity and ecosystem services from spruce-birch mixtures : The potential importance of tree spatial arrangement
- 2022
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Ingår i: Environmental Challenges. - : Elsevier BV. - 2667-0100. ; 6
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Forskningsöversikt (refereegranskat)abstract
- There is increasing empirical support for the biodiversity and ecosystem service (ES) benefits of mixed-species production forests. However, few studies control for the spatial arrangement of the trees within mixtures to determine the influence that clustering the tree species (patch scale mixtures), versus evenly dispersing them (intimate scale mixtures), may have for biodiversity and ES outcomes. To highlight the potential implications of altering tree spatial arrangement in mixtures, and the need to fill related knowledge gaps, here we provide a qualitative multi-disciplinary overview of ecological and socio-economic drivers with the potential to alter biodiversity, ecosystem services, and management-related outcomes from patch versus intimate scale mixtures. We focused our overview on even-aged mixtures of Norway spruce (Picea abies) and birch (Betula pendula or B. pubescens) in Sweden, which enabled us to contrast findings within a biogeographical and silvicultural setting. Specifically, we targeted implications for biodiversity (understory vascular plants, epiphytic lichens, saproxylic beetles, birds), biomass production, harvesting costs, management ease, recreation and aesthetics, cervid game, as well as abiotic and biotic risks (wind, fire, pathogens, pests, browsing damage). In the absence of direct empirical evidence, we primarily relied on expert inference from theory and relevant empirical studies sourced from the Fennoscandian region, and further afield if needed. Collectively these efforts allowed us to develop a number of informed hypotheses indicating that for spruce-birch mixtures in this region, patch scale mixtures may have the potential to favour the diversity of several forest dependant taxonomic groups, cervid game and reduce harvesting costs, whereas intimate mixtures may have the potential to reduce pathogen and pest damage, and likewise, potentially benefit production outcomes. Current knowledge was too limited, inconsistent or context dependant to even tentatively infer outcomes for fire risk, wind damage, browsing damage, management ease, recreational and aesthetic outcomes. We emphasize that our hypotheses require testing, but are sufficient to (1) highlight the likely importance of spatial-scale to biodiversity and ecosystem services outcomes in mixed-species production forests, (2) caution against generalization from mixture studies that lack scale considerations, and (3) motivate the targeted consideration of spatial grain in future mixture studies.
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| 23. |
- Felton, Adam, et al.
(författare)
-
The tree species matters : Biodiversity and ecosystem service implications of replacing Scots pine production stands with Norway spruce.
- 2020
-
Ingår i: Ambio. - : Springer. - 0044-7447 .- 1654-7209. ; 49:5, s. 1035-1049
-
Forskningsöversikt (refereegranskat)abstract
- The choice of tree species used in production forests matters for biodiversity and ecosystem services. In Sweden, damage to young production forests by large browsing herbivores is helping to drive a development where sites traditionally regenerated with Scots pine (Pinus sylvestris) are instead being regenerated with Norway spruce (Picea abies). We provide a condensed synthesis of the available evidence regarding the likely resultant implications for forest biodiversity and ecosystem services from this change in tree species. Apart from some benefits (e.g. reduced stand-level browsing damage), we identified a range of negative outcomes for biodiversity, production, esthetic and recreational values, as well as increased stand vulnerability to storm, frost, and drought damage, and potentially higher risks of pest and pathogen outbreak. Our results are directly relevant to forest owners and policy-makers seeking information regarding the uncertainties, risks, and trade-offs likely to result from changing the tree species in production forests.
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| 24. |
- Franic, Iva, et al.
(författare)
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Climate, host and geography shape insect and fungal communities of trees
- 2023
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Non-native pests, climate change, and their interactions are likely to alter relationships between trees and tree-associated organisms with consequences for forest health. To understand and predict such changes, factors structuring tree-associated communities need to be determined. Here, we analysed the data consisting of records of insects and fungi collected from dormant twigs from 155 tree species at 51 botanical gardens or arboreta in 32 countries. Generalized dissimilarity models revealed similar relative importance of studied climatic, host-related and geographic factors on differences in tree-associated communities. Mean annual temperature, phylogenetic distance between hosts and geographic distance between locations were the major drivers of dissimilarities. The increasing importance of high temperatures on differences in studied communities indicate that climate change could affect tree-associated organisms directly and indirectly through host range shifts. Insect and fungal communities were more similar between closely related vs. distant hosts suggesting that host range shifts may facilitate the emergence of new pests. Moreover, dissimilarities among tree-associated communities increased with geographic distance indicating that human-mediated transport may serve as a pathway of the introductions of new pests. The results of this study highlight the need to limit the establishment of tree pests and increase the resilience of forest ecosystems to changes in climate.
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| 25. |
- Franic, Iva, et al.
(författare)
-
Worldwide diversity of endophytic fungi and insects associated with dormant tree twigs
- 2022
-
Ingår i: Scientific Data. - : Nature Publishing Group. - 2052-4463. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- International trade in plants and climate change are two of the main factors causing damaging tree pests (i.e. fungi and insects) to spread into new areas. To mitigate these risks, a large-scale assessment of tree-associated fungi and insects is needed. We present records of endophytic fungi and insects in twigs of 17 angiosperm and gymnosperm genera, from 51 locations in 32 countries worldwide. Endophytic fungi were characterized by high-throughput sequencing of 352 samples from 145 tree species in 28 countries. Insects were reared from 227 samples of 109 tree species in 18 countries and sorted into taxonomic orders and feeding guilds. Herbivorous insects were grouped into morphospecies and were identified using molecular and morphological approaches. This dataset reveals the diversity of tree-associated taxa, as it contains 12,721 fungal Amplicon Sequence Variants and 208 herbivorous insect morphospecies, sampled across broad geographic and climatic gradients and for many tree species. This dataset will facilitate applied and fundamental studies on the distribution of fungal endophytes and insects in trees.
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| 26. |
- Grenville-Briggs, Laura J, et al.
(författare)
-
Draft genome of the oomycete pathogen Phytophthora cactorum strain LV007 isolated from European beech (Fagus sylvatica)
- 2017
-
Ingår i: Genomics Data. - : Elsevier. - 2213-5960. ; 12, s. 155-156
-
Tidskriftsartikel (refereegranskat)abstract
- Phytophthora cactorum is a broad host range phytopathogenic oomycete. P. cactorum strain LV007 was isolated from a diseased European Beech (Fagus sylvatica) in Malmö, Sweden in 2016. The draft genome of P. cactorum strain LV007 is 67.81 Mb. It contains 15,567 contigs and 21,876 predicted protein-coding genes. As reported for other phytopathogenic Phytophthora species, cytoplasmic effector proteins including RxLR and CRN families were identified. The genome sequence has been deposited at DDBJ/ENA/GenBank under the accession NBIJ00000000. The version described in this paper is version NBIJ01000000.
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| 27. |
- Gunulf, Anna, et al.
(författare)
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Risk of False Positives during Sampling for Heterobasidion annosum s.l.
- 2016
-
Ingår i: Plant Disease. - : Swedish University of Agricultural Sciences (APS). - 0191-2917 .- 1943-7692. ; 100, s. 175-179
-
Tidskriftsartikel (refereegranskat)abstract
- A standard method to detect infection by Heterobasidion annosum sensu lato (s.l.) in stumps or stems is to cut a disc and examine it under a microscope. Concerns have been raised that spores can be transferred from the bark to the cut surface, thus contaminating the sample. The aims of this study were to test whether viable basidiospores of H. annosum s.l. can be transferred from the bark onto disc surfaces by a chainsaw and to investigate the impacts of different sampling procedures on the extent of contaminations. Logs were cut with or without adding basidiospores to the bark prior to the cut. Infection measurements were significantly greater for discs with treated bark (100% infected, infection coverage 40 cm(2) dm(-2) of disc area) compared with control discs (47% infected, infection coverage 0.2 to 0.3 cm(2) dm(-2)). In addition, trees were sampled under authentic field conditions using different procedures. The infection measurements differed significantly depending on the procedure; sampling involving debarking or disinfection of the bark with 70% ethanol prior to cutting had lower measurements (6 to 19% and 13% infected, respectively) compared with leaving the bark on untreated (63 to 75% infected). Consideration of the contamination risk is warranted when evaluating the results of earlier studies and when planning new experiments.
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| 28. |
- Hjältén, Joakim, et al.
(författare)
-
Unintentional changes of defence traits in GM trees can influence plant-herbivore interactions
- 2007
-
Ingår i: Basic and Applied Ecology. - : Elsevier BV. - 1439-1791. ; 8:3, s. 434-443
-
Tidskriftsartikel (refereegranskat)abstract
- GM trees hold promises of increased quality and yield and reduced use of herbicides and pesticides but could also have ecological consequences. We investigated whether modification of a non-defensive trait unintentionally influenced plant traits important for plant-herbivore interactions. We found that over-expression of sucrose phosphate synthase (SPS), which is known to increase mesophyll sucrose content and biomass production in GM aspens, also unintentionally induced changes in the concentration of plant phenolics and nitrogen. One of the GM lines, SPS33A, had higher concentrations of salicin, tremuloidin, condensed tannins and nitrogen and lower concentrations of coumaric acid and four flavonoids compared with the isogenic wild type. Line SPS33A was also utilized less by the leaf-beetle Phratora vitellinae than the isogenic wild type. Ecological consequences such as this are not specific to GM trees or GM plants but can occur as a result of the introduction of all introduced new varieties of crops or trees. Nevertheless, the results underline the need to consider these unexpected effects when evaluating both the potential benefits and the potential risks with GM plants, and highlight the need to establish and implement comprehensive product-by-product evaluation protocols for GM plants.
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| 29. |
- Hultberg, Tove, et al.
(författare)
-
Ash dieback risks an extinction cascade
- 2020
-
Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 244
-
Tidskriftsartikel (refereegranskat)abstract
- Large-scale decline in populations of European ash (Fraxinus excelsior) are occurring throughout Europe due to the invasive fungus Hymenoscyphus fraxineus. This has grave ecological implications not only for ash trees, but also for the biodiversity supported by, and in some cases solely dependent on ash. Here we used data on the tree-species associations of biodiversity in Sweden, to predict extinction risks for ash-associated organisms, and the potential for combinations of other tree species to sustain ash-associated biodiversity. Of the 483 ash-associated species identified, 11% are exclusive to ash, and a further 23% prefer mainly ash. Notably, many ash-associated species are shared with wych elm (Ulmus glabra) which is similarly threatened by an invasive fungus. Considering the level of host association and the species' conservation status, 115 species were deemed at high risk of regional extinction. Using a mathematical optimization model we found that up to nine additional tree species would be needed to sustain all non-obligate ash dependent/preferring species in the absence of ash and elm. We discuss mitigation and adaption options to reduce the potential for an extinction cascade and conserve ash-associated biodiversity, but all pose unique challenges.
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| 30. |
- Jensen, Anna M., et al.
(författare)
-
Effects of competition and indirect facilitation by shrubs on Quercus robur saplings
- 2012
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Ingår i: Plant Ecology. - : Springer. - 1385-0237 .- 1573-5052. ; 213:4, s. 535-543
-
Tidskriftsartikel (refereegranskat)abstract
- Indirect facilitation by shrubs has been suggested as a cost-effective way of regenerating oaks in forests of conservation interest. In this study, we tested whether shrubs can enhance growth in pedunculate oak (Quercus robur) by suppressing herbaceous competitors. We studied interactions between young oaks, shrubs, and/or herbaceous vegetation in an open-field experiment, in southern Sweden, over the first 3 years after planting. Oak saplings were grown in four competition treatments: no competing vegetation; with herbaceous vegetation; with shrubs; and with both herbaceous vegetation and shrubs. Competition from shrubs and herbaceous vegetation both reduced stem diameter and biomass accumulation, but they affected biomass partitioning differently. Saplings grown with competition from shrubs partitioned biomass primarily into height growth, while those saplings exposed to competition from herbaceous vegetation invested a relatively higher proportion in root growth. Competition between shrubs and herbaceous vegetation reduced the above-ground biomass of the herbaceous vegetation, resulting in an indirect facilitative effect for the oaks during the first 2 years after planting. However, during the third year, shrubs had a negative effect on biomass accumulation. In summary, results from this study suggest that shrubs indirectly facilitate biomass accumulation of oak saplings by suppressing herbaceous vegetation, possibly by reducing competition for below-ground resources. However, owing to the relatively short duration of positive net outcome for the oak, we recommend that a longer-term assessment of the interaction between oak regeneration and neighboring shrubs be made before the outcome of this study is applied to practical forestry.
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| 31. |
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| 32. |
- Lankinen, Åsa, et al.
(författare)
-
Challenges and opportunities for increasing the use of low-risk plant protection products in sustainable production. A review
- 2024
-
Ingår i: Agronomy for Sustainable Development. - : Springer. - 1774-0746 .- 1773-0155. ; 44:2
-
Forskningsöversikt (refereegranskat)abstract
- Plant production systems worldwide are struggling to meet the diverse and increasing needs of humankind while also facing challenges such as climate change and biodiversity loss. This, combined with the desirable transition from the use of conventional pesticides to more sustainable plant protection solutions, has led to an urgent, and increasing, need for low-risk plant protection products (PPPs) to be developed, applied, and integrated into management practices across all types of plant production systems. Despite a high demand from end users and consumers together with joint political goals at the EU level to replace conventional pesticides, the number of low-risk PPPs on the European market remains low, in comparison to synthetic agrochemicals. In this review, we summarize knowledge about the policy, technical, and administrative issues hampering the process of bringing new low-risk PPPs to the European market. We present an overview of the challenges in using the low-risk PPPs that are currently available within the EU agricultural, horticultural, and forestry sectors. We describe the variation in modes of action and the limitations associated with different application techniques and give concrete examples of problems and solutions from Swedish plant production sectors, in contrast to global perspectives as demonstrated by examples from African agriculture. Finally, we conclude that trans-sectoral, multi-actor approaches are required and provide suggestions on how to address the remaining knowledge gaps related to efficiency, application, and economics of low-risk PPP use in Integrated Pest Management (IPM) solutions for plant protection to improve future food security in Europe.
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| 33. |
- Lankinen, Åsa, et al.
(författare)
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Fokusprojekt Lågriskmedel i växtskyddet
- 2019
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Rapport (populärvet., debatt m.m.)abstract
- Fokusgruppens syfte har varit att definiera kunskapsluckor avseende den praktiska användningen och implementeringen av alternativa medel med låg risk för bekämpning av skadegörare och sjukdomar inom jordbruk, trädgårdsodling och skogsbruk. Vi har utgått från en bred definition av medel med låg risk, som har omfattat både allmänkemikalier och växtskyddsmedel med låg risk (enligt gällande EU-lagstiftning). Trots att det idag finns ett ökat behov av alternativa verktyg inom växtskyddet och politiska mål om minimerad användning av kemiska medel, så är användningen av alternativa bekämpningsmedel i fältodlade grödor mycket begränsad. • En viktig faktor som styr och begränsar tillgängligheten av alternativa medel är EU-lagstiftningen för godkännande av dessa medel. För att kunna registrera ett medel behövs en investering från det företag som ansöker om godkännande, vilket kan vara en anledning till att medel inte blir tillgängliga på marknaden. En annan lagteknisk begränsning är ogynnsamma skatteregler för dessa medel. • Från ett användarperspektiv är bristande kunskap om hur effektiva dessa medel är, hur man bäst applicerar dem samt hur de kan integreras i befintliga växtskyddsstrategier en bidragande orsak till att de inte används fullt ut. • Rådgivningen pekar också på en otydlighet om vilka medel som får användas speciellt i ekologisk produktion och att användningen missgynnas av höga priser i kombination med en osäkerhet om hur effektiva dessa medel är. • I Jordbruksverkets rapport ”Hinder för ökad användning av alternativa bekämpningsmedel” (SJV, Rapport 2019:3), som medlemmar av fokusgruppen har varit med att skriva, är ett av förslagen en utökad rådgivningsverksamhet. Detta eftersom informationsinsatser och aktiv rådgivning kan påverka hur snabbt odlare accepterar och börjar använda ett växtskyddsmedel, speciellt om det har nya egenskaper (och en ny verkningsmekanism). Forskning visar att en ny åtgärd/metod inte bara ska Sammanfattning och slutsatser 5 passa in i befintliga verksamheter utan också passa med attityd och värderingar hos användaren. • Från ett forskningsperspektiv kan vi se ett klart behov av tillämpningsnära forskning framför allt för att få en ökad kunskap om hur alternativa bekämpningsmedel kan integreras i befintliga växtskyddsstrategier. En utmaning är den begränsade mängd forskningsmedel som finns att söka för denna typ av forskning. • Forskningen är ofta väldigt uppdelad mellan agrikultur, hortikultur och skogsbruk. Här skulle man kunna dra nytta av kunskap inom respektive system eftersom vissa aspekter är generella mellan olika system, åtminstone för vissa grödor/träd. • Från ett internationellt perspektiv kan vi se vinster med ett bättre samarbete med närliggande länder, tex Plant Biologicals Network (PBN) som koordineras från Danmark, men även engagemang inom det vidare EUperspektivet (bla lagar). • Ytterligare en slutsats från fokusgruppens arbete är att växtskyddsforskningen på SLU behöver samordnas bättre, tex genom att knyta samman de kompetenscentrum som finns idag – CBC och CKB – med nya strukturer som skulle kunna fokusera på i) analys av växtskadegörare och ii) lågrisk-metoder och hur dessa kan spela en roll i integrerat växtskydd (IPM). • ygarbeta tillsammans för att få till en bra samverkan och kunskapsutbyte.
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| 34. |
- Löf, Magnus, et al.
(författare)
-
Restoring forests: regeneration and ecosystem function for the future
- 2019
-
Ingår i: New Forests. - : Springer Science and Business Media LLC. - 0169-4286 .- 1573-5095. ; 50, s. 139-151
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Tidskriftsartikel (refereegranskat)abstract
- Conventions and policies for biodiversity conservation and climate change mitigation state the need for increased protection, restoration and climate change adaptation of forests. Much degraded land may be targeted for large-scale forest restoration, yet challenges include costs, a shortage of regeneration material and the need for restored forests to serve as a resource for communities. To ensure ecosystem function for the future, forest restoration programs must: (1) learn from the past; (2) integrate ecological knowledge; (3) advance regeneration techniques and systems; (4) overcome biotic and abiotic disturbances and (5) adapt for future forest landscapes. Historical forest conditions, while site-specific, may help to identify the processes that leave long-term legacies in current forests and to understand tree migration biology/population dynamics and their relationship with climate change. Ecological theory around plant-plant interactions has shown the importance of negative (competition) and positive (facilitation) interactions for restoration, which will become more relevant with increasing drought due to climate change. Selective animal browsing influences plant-plant interactions and challenges restoration efforts to establish species-rich forests; an integrated approach is needed to simultaneously manage ungulate populations, landscape carrying capacity and browse-tolerant regeneration. A deeper understanding of limiting factors that affect plant establishment will facilitate nursery and site preparation systems to overcome inherent restoration challenges. Severe anthropogenic disturbances connected to global change have created unprecedented pressure on forests, necessitating novel ecological engineering, genetic conservation of tree species and landscape-level approaches that focus on creating functional ecosystems in a cost-effective manner.
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| 35. |
- Macaya-Sanz, David, et al.
(författare)
-
Core endophytic mycobiome in Ulmus minor and its relation to Dutch elm disease resistance
- 2023
-
Ingår i: Frontiers in Plant Science. - : Frontiers Media S.A.. - 1664-462X. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- The core microbiota of plants exerts key effects on plant performance and resilience to stress. The aim of this study was to identify the core endophytic mycobiome in U. minor stems and disentangle associations between its composition and the resistance to Dutch elm disease (DED). We also defined its spatial variation within the tree and among distant tree populations. Stem samples were taken i) from different heights of the crown of a 168-year-old elm tree, ii) from adult elm trees growing in a common garden and representing a gradient of resistance to DED, and iii) from trees growing in two distant natural populations, one of them with varying degrees of vitality. Endophyte composition was profiled by high throughput sequencing of the first internal transcribed spacer region (ITS1) of the ribosomal DNA. Three families of yeasts (Buckleyzymaceae, Trichomeriaceae and Bulleraceae) were associated to DED-resistant hosts. A small proportion (10%) of endophytic OTUs was almost ubiquitous throughout the crown while tree colonization by most fungal taxa followed stochastic patterns. A clear distinction in endophyte composition was found between geographical locations. By combining all surveys, we found evidence of a U. minor core mycobiome, pervasive within the tree and ubiquitous across locations, genotypes and health status.
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| 36. |
- Martín, Juan A, et al.
(författare)
-
Resistance to Dutch elm disease reduces presence of xylem endophytic fungi in Elms (Ulmus spp.)
- 2013
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:2
-
Tidskriftsartikel (refereegranskat)abstract
- Efforts to introduce pathogen resistance into landscape tree species by breeding may have unintended consequences for fungal diversity. To address this issue, we compared the frequency and diversity of endophytic fungi and defensive phenolic metabolites in elm (Ulmus spp.) trees with genotypes known to differ in resistance to Dutch elm disease. Our results indicate that resistant U. minor and U. pumila genotypes exhibit a lower frequency and diversity of fungal endophytes in the xylem than susceptible U. minor genotypes. However, resistant and susceptible genotypes showed a similar frequency and diversity of endophytes in the leaves and bark. The resistant and susceptible genotypes could be discriminated on the basis of the phenolic profile of the xylem, but not on basis of phenolics in the leaves or bark. As the Dutch elm disease pathogen develops within xylem tissues, the defensive chemistry of resistant elm genotypes thus appears to be one of the factors that may limit colonization by both the pathogen and endophytes. We discuss a potential trade-off between the benefits of breeding resistance into tree species, versus concomitant losses of fungal endophytes and the ecosystem services they provide.
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| 37. |
- Martinez-Arias, Clara, et al.
(författare)
-
Beneficial and pathogenic plant-microbe interactions during flooding stress
- 2022
-
Ingår i: Plant, Cell and Environment. - : John Wiley & Sons. - 0140-7791 .- 1365-3040. ; 45:10, s. 2875-2897
-
Tidskriftsartikel (refereegranskat)abstract
- The number and intensity of flood events will likely increase in the future, raising the risk of flooding stress in terrestrial plants. Understanding flood effects on plant physiology and plant-associated microbes is key to alleviate flooding stress in sensitive species and ecosystems. Reduced oxygen supply is the main constrain to the plant and its associated microbiome. Hypoxic conditions hamper root aerobic respiration and, consequently, hydraulic conductance, nutrient uptake, and plant growth and development. Hypoxia favours the presence of anaerobic microbes in the rhizosphere and roots with potential negative effects to the plant due to their pathogenic behaviour or their soil denitrification ability. Moreover, plant physiological and metabolic changes induced by flooding stress may also cause dysbiotic changes in endosphere and rhizosphere microbial composition. The negative effects of flooding stress on the holobiont (i.e., the host plant and its associated microbiome) can be mitigated once the plant displays adaptive responses to increase oxygen uptake. Stress relief could also arise from the positive effect of certain beneficial microbes, such as mycorrhiza or dark septate endophytes. More research is needed to explore the spiralling, feedback flood responses of plant and microbes if we want to promote plant flood tolerance from a holobiont perspective.
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| 38. |
- Nordin, Annika, et al.
(författare)
-
Nitrogen deposition and the biodiversity of boreal forests : implications for the nitrogen critical load.
- 2005
-
Ingår i: Ambio. - : Royal Swedish Academy of Science. - 0044-7447 .- 1654-7209. ; 34:1, s. 20-24
-
Tidskriftsartikel (refereegranskat)abstract
- The critical load concept is used to establish the deposition levels which ecosystems can tolerate without significant harmful effects. Here we summarize work within the Swedish research program Abatement Strategies for Transboundary Air Pollution (ASTA) assessing the critical load of N for boreal forests. Results from both field experiments in an area with low background N deposition in northern Sweden, and from a large-scale monitoring study, show that important vegetational changes start to take place when adding low N doses and that recovery of the vegetation after ceasing N input is a very slow process. The data presented indicate that changes in key ecosystem components occur even at a lower rate of N input than the present recommended empirical critical load for boreal forest understorey vegetation of 10-15 kg N ha-1 yr-1. Based on the data presented, we suggest that the critical load should be lowered to 6 kg N ha-1 yr-1.
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| 39. |
- Normark, Erik, et al.
(författare)
-
Nya och gamla skogsskötselstrategier och skogsskador
- 2022
-
Ingår i: Kungl. Skogs- och lantbruksakademiens tidskrift. - : Kungl. Skogs- och lantbruksakademien. - 0023-5350. ; 161:7, s. 40-43
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- I avsnittet diskuteras möjligheten att påverka skogens hälsa genom aktiv skogsskötsel som bland annat omfattar val av föryngringsmaterial, trädslag och gallringar som påverkar stamtätheten. Diskussionen sammanfattar resultate från KSLA:s Skogsskadeekonomiska workshop "Skogsskötsel för skogens hälsa" som organiserades i november 2021
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| 40. |
- Olofsson, Johan, et al.
(författare)
-
Gray-sided voles increase the susceptibility of northern willow, Salix glauca, to invertebrate herbivory
- 2007
-
Ingår i: Ecoscience. - 1195-6860. ; 14:1, s. 48-54
-
Tidskriftsartikel (refereegranskat)abstract
- The relationships between grey-sided vole (Clethrionomys rufocanus) densities, levels of invertebrate herbivory on Northern willow (Salix glauca) leaves, and chemical quality of the willows was studied on 8 islands and 2 mainland sites with contrasting vole densities in northernmost Norway. These variables were measured at each of the study sites to determine the degree and nature of the effects of browsing-induced alterations in plant quality on subsequent invertebrate herbivory. The level of invertebrate herbivory was positively correlated with vole density, as were the number of leaves per shoot, leaf size, and leaf nitrogen content, while leaf C/N ratios were negatively correlated with vole density. The level of herbivory increased from > 1% on the vole-free island to < 4% on the island with the highest vole density. The plant character that explained most of the variance in the level of invertebrate herbivory was leaf size. Since the vole densities have been altered by human intervention and their numbers are largely governed by predation rather than food quality, the positive correlation between vole densities and level of invertebrate herbivory is probably due to a facilitative effect of voles on invertebrate herbivores, mediated through changes in plant chemistry. We suggest that voles affect susceptibility of willows to invertebrate herbivory both directly by winter browsing and indirectly by reducing the abundance of competing plants.
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| 41. |
- Pettersson, Viktoria, 1976-, et al.
(författare)
-
Rates of insect herbivory on Silene dioica change across primary successional zones.
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The strengths and directions of herbivore-host plant interactions are strongly shaped by environmental conditions that also affect a number of plant traits (density, size, nutritional quality). We studied spatio-temporal patterns in attack rates of two specialist herbivores Delia criniventris and Caryocolum viscariella that utilize the same food resource, the floral stems, of their shared host plant Silene dioica across young, intermediate and old successional zones in the primary succession in a Bothinan archipelago. Our data from nine islands collected during seven consecutive years showed that attack rates were consistently higher in the youngest zone and decreased in parallel to progressing succession. This zonal pattern of decreasing attack rates correlated with several plant attributes, a decrease in plant size and nitrogen content, and an increased content of secondary compounds, but not to host plant density. We failed to come up with a simple explanation for the spatial structure with chronic high attack rates in the younger zones. However, the consistent patterns in attack rate suggest that a suite of abiotic and biotic factors interact and reinforce the strength and direction of selection.
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| 42. |
- Pettersson, Viktoria, 1976-, et al.
(författare)
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Sex-biased herbivory in Silene dioica. : Which sex is the better resource?
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In cases when sexual dimorphic traits form the target resource of a particular herbivore we would expect the herbivore to select the best resource. We studied the interaction between to specialist insect herbivores Delia criniventris and Caryocolum viscariella that share the same food resource, the floral stems, of their host plant the perennial and dioecious herb, Silene dioica. We studied the interaction on nine islands in a Bothinan archipelago over seven consecutive years. Both herbivores attacked female plants more than male plants (D. criniventris, 32.8% females, 30.7% males; C. viscariella, 4% females, 2% males). The pattern was consistent over years and islands. We also found a number of sexually dimorphic traits suggesting females to be the better resource. We have presented evidence that female-biased herbivory does occur in dioecious plants and, as with male-biased herbivory, it may occur because herbivores utilise the better resource which will vary depending upon feeding strategy. We conclude that in dioecious species we need identify the dimorphism responsible for the sex sustaining the greatest attack rates and avoid being blinded by the expectation of male herbivory.
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| 43. |
- Pötzelsberger, Elisabeth, et al.
(författare)
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Biotic threats for 23 major non-native tree species in Europe
- 2021
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Ingår i: Scientific Data. - : Nature Publishing Group. - 2052-4463. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- For non-native tree species with an origin outside of Europe a detailed compilation of enemy species including the severity of their attack is lacking up to now. We collected information on native and non-native species attacking non-native trees, i.e. type, extent and time of first observation of damage for 23 important non-native trees in 27 European countries. Our database includes about 2300 synthesised attack records (synthesised per biotic threat, tree and country) from over 800 species. Insects (49%) and fungi (45%) are the main observed biotic threats, but also arachnids, bacteria including phytoplasmas, mammals, nematodes, plants and viruses have been recorded. This information will be valuable to identify patterns and drivers of attacks, and trees with a lower current health risk to be considered for planting. In addition, our database will provide a baseline to which future impacts on non-native tree species could be compared with and thus will allow to analyse temporal trends of impacts.
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| 44. |
- Riit, Taavi, et al.
(författare)
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Oomycete Soil Diversity Associated with Betula and Alnus in Forests and Urban Settings in the Nordic–Baltic Region
- 2023
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Ingår i: Journal of Fungi. - : MDPI. - 2309-608X. ; 9:9
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to determine the differences and drivers of oomycete diversity and community composition in alder- and birch-dominated park and natural forest soils of the Fennoscandian and Baltic countries of Estonia, Finland, Lithuania, Norway, and Sweden. For this, we sequenced libraries of PCR products generated from the DNA of 111 soil samples collected across a climate gradient using oomycete-specific primers on a PacBio high-throughput sequencing platform. We found that oomycete communities are most affected by temperature seasonality, annual mean temperature, and mean temperature of the warmest quarter. Differences in composition were partly explained by the higher diversity of Saprolegniales in Sweden and Norway, as both total oomycete and Saprolegniales richness decreased significantly at higher longitudes, potentially indicating the preference of this group of oomycetes for a more temperate maritime climate. None of the evaluated climatic variables significantly affected the richness of Pythiales or Peronosporales. Interestingly, the relative abundance and richness of Pythiales was higher at urban sites compared to forest sites, whereas the opposite was true for Saprolegniales. Additionally, this is the first report of Phytophthora gallica and P. plurivora in Estonia. Our results indicate that the composition of oomycetes in soils is strongly influenced by climatic factors, and, therefore, changes in climate conditions associated with global warming may have the potential to significantly alter the distribution range of these microbes, which comprise many important pathogens of plants.
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| 45. |
- Romeralo, Carmen, et al.
(författare)
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Consistency of impact assessment protocols for non-native species
- 2019
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Ingår i: NeoBiota. - : Pensoft Publishers. - 1619-0033 .- 1314-2488. ; , s. 1-25
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Tidskriftsartikel (refereegranskat)abstract
- Standardized tools are needed to identify and prioritize the most harmful non-native species (NNS). A plethora of assessment protocols have been developed to evaluate the current and potential impacts of non-native species, but consistency among them has received limited attention. To estimate the consistency across impact assessment protocols, 89 specialists in biological invasions used 11 protocols to screen 57 NNS (2614 assessments). We tested if the consistency in the impact scoring across assessors, quantified as the coefficient of variation (CV), was dependent on the characteristics of the protocol, the taxonomic group and the expertise of the assessor. Mean CV across assessors was 40%, with a maximum of 223%. CV was lower for protocols with a low number of score levels, which demanded high levels of expertise, and when the assessors had greater expertise on the assessed species. The similarity among protocols with respect to the final scores was higher when the protocols considered the same impact types. We conclude that all protocols led to considerable inconsistency among assessors. In order to improve consistency, we highlight the importance of selecting assessors with high expertise, providing clear guidelines and adequate training but also deriving final decisions collaboratively by consensus.
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| 46. |
- Romeralo, Carmen, et al.
(författare)
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Pine species determine fungal microbiome composition in a common garden experiment
- 2022
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Ingår i: Fungal ecology. - : Elsevier. - 1754-5048 .- 1878-0083. ; 56
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Tidskriftsartikel (refereegranskat)abstract
- The factors shaping the composition of microbial communities in trees remain poorly understood. We evaluated whether the core and satellite fungal communities in five pine species (Pinus radiata, Pinus pinaster, Pinus sylvestris, Pinus nigra, and Pinus uncinata) were shaped by the host species identity. Because the trees had earlier been inoculated with a fungal pathogen (Fusarium circinatum), we also explored the possibilities to detect its presence and potential co-occurrence networks. We found interspecific variation in the fungal community composition and abundance among the different tree species and the existence of a core microbiome that was independent of the host species. The presence of F. circinatum was confirmed in some samples through qPCR but the pathogen did not co-occur with a specific fungal community. The results highlight the importance of host species as a determinant of microbiome assembly in common environments.
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| 47. |
- Schiebe, Christian, et al.
(författare)
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Inducibility of chemical defenses in Norway spruce bark is correlated with unsuccessful mass attacks by the spruce bark beetle
- 2012
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 170:1, s. 183-198
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Tidskriftsartikel (refereegranskat)abstract
- Secondary attraction to aggregation pheromones plays a central role in the host colonization behavior of the European spruce bark beetle Ips typographus. However, it is largely unknown how the beetles pioneering an attack locate suitable host trees, and eventually accept or reject them. To find possible biomarkers for host choice by I. typographus, we analyzed the chemistry of 58 Norway spruce (Picea abies) trees that were subsequently either (1) successfully attacked and killed, (2) unsuccessfully attacked, or (3) left unattacked. The trees were sampled before the main beetle flight in a natural Norway spruce-dominated forest. No pheromones were used to attract beetles to the experimental trees. To test the trees' defense potential, each tree was treated in a local area with the defense hormone methyl jasmonate (MeJ), and treated and untreated bark were analyzed for 66 different compounds, including terpenes, phenolics and alkaloids. The chemistry of MeJ-treated bark correlated strongly with the success of I. typographus attack, revealing major chemical differences between killed trees and unsuccessfully attacked trees. Surviving trees produced significantly higher amounts of most of the 39 analyzed mono-, sesqui-, and diterpenes and of 4 of 20 phenolics. Alkaloids showed no clear pattern. Differences in untreated bark were less pronounced, where only 1,8-cineole and (-)-limonene were significantly higher in unsuccessfully attacked trees. Our results show that the potential of individual P. abies trees for inducing defense compounds upon I. typographus attack may partly determine tree resistance to this bark beetle by inhibiting its mass attack.
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| 48. |
- Schlyter, Fredrik, et al.
(författare)
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Forests : carbon sources in peril
- 2009
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Ingår i: Public Service Review: Science & Technology. - 1757-2770. ; 3, s. 136-137
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 49. |
- Srivastava, Vaibhav, et al.
(författare)
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Downregulation of high-isoelectric-point extracellular superoxide dismutase mediates alterations in the metabolism of reactive oxygen species and developmental disturbances in hybrid aspen
- 2007
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Ingår i: The Plant Journal. - : Blackwell Publishing. - 0960-7412 .- 1365-313X. ; 49:1, s. 135-148
-
Tidskriftsartikel (refereegranskat)abstract
- Transgenic hybrid aspen (Populus tremula L. x P. tremuloides Michx.) plants expressing a high-isoelectric-point superoxide dismutase (hipI-SOD) gene in antisense orientation were generated to investigate its function. Immunolocalization studies showed the enzyme to be localized extracellularly, in the secondary cell wall of xylem vessels and phloem fibers. The antisense lines of hipI-SOD exhibited a distinct phenotype; growth rate was reduced, stems were thinner and leaves smaller than in wild-type (WT) plants. The abundance of hipI-SOD was reduced in the bark and xylem of plants from these antisense lines. The vascular tissue of transgenic lines became lignified earlier than in WT plants and also showed an increased accumulation of reactive oxygen species (ROS). Xylem fibers and vessels were shorter and thinner in the transgenic lines than in WT plants. The total phenolic content was enhanced in the antisense lines. Furthermore, microarray analysis indicated that several enzymes involved in cell signaling, lignin biosynthesis and stress responses were upregulated in apical vascular tissues of transgenic plants. The upregulation of selected genes involved in lignin biosynthesis was also verified by real-time PCR. The results suggest that, in the transgenic plants, a premature transition into maturation occurs and the process is discussed in terms of the effects of increased accumulation of ROS due to reduced expression of hipI-SOD during development and differentiation.
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| 50. |
- Stenberg, Johan A, et al.
(författare)
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Tall herb herbivory resistance reflects historic exposure to leaf beetles in a boreal archipelago age-gradient.
- 2006
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 148:3, s. 414-425
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we introduce the coevolution-by-coexistence hypothesis which predicts that the strength of a coevolutionary adaptation will become increasingly apparent as long as the corresponding selection from an interacting counterpart continues. Hence, evolutionary interactions between plants and their herbivores can be studied by comparing discrete plant populations with known history of herbivore colonization. We studied populations of the host plant, Filipendula ulmaria (meadow sweet), on six islands, in a Bothnian archipelago subject to isostatic rebound, that represent a spatio-temporal gradient of coexistence with its two major herbivores, the specialist leaf beetles Galerucella tenella and Altica engstroemi. Regression analyses showed that a number of traits important for insect-plant interactions (leaf concentrations of individual phenolics and condensed tannins, plant height, G. tenella adult feeding and oviposition) were significantly correlated with island age. First, leaf concentrations of condensed tannins and individual phenolics were positively correlated with island age, suggesting that plant resistance increased after herbivore colonization and continued to increase in parallel to increasing time of past coexistence, while plant height showed a reverse negative correlation. Second, a multi-choice experiment with G. tenella showed that both oviposition and leaf consumption of the host plants were negatively correlated with island age. Third, larvae performed poorly on well-defended, older host populations and well on less-defended, younger populations. Thus, no parameter assessed in this study falsifies the coevolution-by-coexistence hypothesis. We conclude that spatio-temporal gradients present in rising archipelagos offer unique opportunities to address evolutionary interactions, but care has to be taken as abiotic (and other biotic) factors may interact in a complicated way.
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