| 1. |
- Abreu, Ilka, et al.
(författare)
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UHPLC-ESI/TOFMS Determination of Salicylate-like Phenolic Gycosides in Populus tremula Leaves
- 2011
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Ingår i: Journal of Chemical Ecology. - : Springer Science and Business Media LLC. - 0098-0331 .- 1573-1561. ; 37:8, s. 857-70
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Tidskriftsartikel (refereegranskat)abstract
- Associations of salicylate-like phenolic glycosides (PGs) with biological activity have been reported in Salix and Populus trees, but only for a few compounds, and in relation to a limited number of herbivores. By considering the full diversity of PGs, we may improve our ability to recognize genotypes or chemotype groups and enhance our understanding of their ecological function. Here, we present a fast and efficient general method for salicylate determination in leaves of Eurasian aspen that uses ultra-high performance liquid chromatography-electrospray ionization/time-of-flight mass spectrometry (UHPLC-ESI/TOFMS). The time required for the liquid chromatography separations was 13.5 min per sample, compared to around 60 min per sample for most HPLC protocols. In leaf samples from identical P. tremula genotypes with diverse propagation and treatment histories, we identified nine PGs. We found the compound-specific mass chromatograms to be more informative than the UV-visible chromatograms for compound identification and when quantitating samples with large variability in PG content. Signature compounds previously reported for P. tremoloides (tremulacin, tremuloidin, salicin, and salicortin) always were present, and five PGs (2'-O-cinnamoyl-salicortin, 2'-O-acetyl-salicortin, 2'-O-acetyl-salicin, acetyl-tremulacin, and salicyloyl-salicin) were detected for the first time in P. tremula. By using information about the formic acid adduct that appeared for PGs in the LTQ-Orbitrap MS environment, novel compounds like acetyl-tremulacin could be tentatively identified without the use of standards. The novel PGs were consistently either present in genotypes regardless of propagation and damage treatment or were not detectable. In some genotypes, concentrations of 2'-O-acetyl-salicortin and 2'-O-cinnamoyl-salicortin were similar to levels of biologically active PGs in other Salicaceous trees. Our study suggests that we may expect a wide variation in PG content in aspen populations which is of interest both for studies of interactions with herbivores and for mapping population structure.
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| 2. |
- Albrectsen, Benedicte Riber, 1960-, et al.
(författare)
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Disentangling functions of fungal endophytes in forest trees
- 2012
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Ingår i: Fungi. - : Nova Science Publishers, Inc.. - 9781619426719 - 9781619426856 ; , s. 235-246
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Bokkapitel (refereegranskat)abstract
- Endophytic fungi are known to be abundant colonizers of the internal tissues of forest trees, but their ecological functions are still largely unknown. Recent studies indicate that endophytes may associate with tree's resistance and tolerance properties, and they are thus potential bio-agents that could be utilized in sustainable forest protection and management. To gain a better understanding of the endophytes' potential role in shaping forest health we need more evidence in the form of ecological studies of endophyte communities, in various tissues, across space, and time. The recent advances in molecular methods have given us new and effective tools to obtain such data. Studies of endophyte functions are further facilitated with the development of new high through-put screening methods for substrate use and competitive ability. Fungi are known as chemical factories of natural compounds with biological properties. Beside their potential as antagonists against pests and diseases, the tree-associated endophytic fungi therefore also appear as an emerging source of novel biomolecules for industrial or clinical applications outside forestry. This chapter presents some of the current methodological approaches that are likely to be valuable in studies on endophyte diversity in forest trees, and discusses the goals and impacts of the studies that aim at disentangling the beneficial potential of fungal endophytes in trees. A new concept, bioactive symbiosis, is suggested as a general framework for these studies.
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| 3. |
- Albrectsen, Benedicte R., 1960-, et al.
(författare)
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Endophytic fungi in European aspen (Populus tremula) leaves - diversity, detection, and a suggested correlation with herbivory resistance
- 2010
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Ingår i: Fungal diversity. - : Springer Science and Business Media LLC. - 1560-2745 .- 1878-9129. ; 41:1, s. 17-28
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Tidskriftsartikel (refereegranskat)abstract
- According to the geographic mosaic theory of coevolution (GMTC), clines of traits reflecting local co-adaptation (including resistance genes) should be common between a host and its parasite and should persist across time. To test the GMTC-assumption of persistent clinal patterns we compared the natural prevalence of two parasites on aspen Populus tremula trees: mining moths of the genus Phyllocnistis and leaf rust Melampsora spp. Damage data were collated from the Swedish National Forest Damage Inventory (2004–2006). In addition, occurrence of the parasites was scored in field conditions in two common gardens in the north and south of Sweden over five growing seasons (2004–2008), then related to biomass (stem height and diameter) and to concentrations of eleven leaf phenolics. Phyllocnistis mainly occurred in the northern garden, a distribution range which was confirmed by the countrywide inventory, although Phyllocnistis was more abundant on southern clones, providing evidence for possible local maladaptation. Melampsora occurred all over the country and in both gardens, but built up more quickly on northern clones, which suggests a centre of local clone maladaptation in the north. Stem growth also followed a clinal pattern as did the concentration of three phenolic compounds: benzoic acid, catechin and cinnamic acid. However, only benzoic acid was related to parasite presence: negatively to Phyllocnistis and positively to Melampsora and it could thus be a potential trait under selection. 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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| 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. |
- Albrectsen, Benedicte R., et al.
(författare)
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The diversity and identification of eulophid parasitic wasps (Hymenoptera: Chalcidoidea: Eulophidae) on Phyllocnistis labyrinthella (Lepidoptera: Gracillariidae) from Västerbotten, Sweden.
- 2012
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Ingår i: Entomologisk tidskrift. - 0013-886X. ; 133:3, s. 111-118
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Tidskriftsartikel (refereegranskat)abstract
- Caterpillars of the mining micro-moth Phyllocnistis labyrinthella feed on leaves of aspen (Populus tremula) and are often parasitized by eulophid wasps. The parasitoids are a potential important cause of death for the miners. During 2009-2011 we collected mined leaves from an experimental stand of aspen trees in Västerbotten. Adults emerged from 17-35 percent of the mines and of these every second to third specimen appeared as wasps. These wasps represented seven species of eulophid parasitoids of which three were new to Västerbotten: Chrysocharis nitetis (Walker), Cirrospilus diallus (Walker) and Cirrospilus pictus (Nees). We include an identification key that may be used to identify these eulophid species.
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| 6. |
- Bernhardsson, Carolina, et al.
(författare)
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Geographic structure in metabolome and herbivore community co-occurs with genetic structure in plant defence genes
- 2013
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Ingår i: Ecology Letters. - Hoboken : Wiley-Blackwell. - 1461-023X .- 1461-0248. ; 16:6, s. 791-798
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Tidskriftsartikel (refereegranskat)abstract
- Plantherbivore interactions vary across the landscape and have been hypothesised to promote local adaption in plants to the prevailing herbivore regime. Herbivores that feed on European aspen (Populus tremula) change across regional scales and selection on host defence genes may thus change at comparable scales. We have previously observed strong population differentiation in a set of inducible defence genes in Swedish P. tremula. Here, we study the geographic patterns of abundance and diversity of herbivorous insects, the untargeted metabolome of the foliage and genetic variation in a set of wound-induced genes and show that the geographic structure co-occurs in all three data sets. In response to this structure, we observe local maladaptation of herbivores, with fewer herbivores on local trees than on trees originated from more distant localities. Finally, we also identify 28 significant associations between single nucleotide polymorphisms SNPs from defence genes and a number of the herbivore traits and metabolic profiles.
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| 7. |
- Caseys, Celine, et al.
(författare)
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Effects of interspecific recombination on functional traits in trees revealed by metabolomics and genotyping-by-resequencing
- 2012
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Ingår i: Plant Ecology & Diversity. - : Informa UK Limited. - 1755-0874 .- 1755-1668. ; 5:4, s. 457-471
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Tidskriftsartikel (refereegranskat)abstract
- Background: Understanding the potential and limits of recombination in adaptive evolution is of great interest to evolutionary biology. New (ultra-) high-throughput technologies in metabolomics and genomics hold great promise for addressing these questions, but their use in interspecific hybrids remains largely unexplored. Aims: Our goal was to test if recombination between the highly divergent genomes of Populus alba and P. tremula has the potential to contribute to the standing variation for functionally important chemical traits. Methods: We studied the metabolomes of interspecific hybrids by ultra-high-pressure liquid chromatography (UHPLC) coupled with quadrupole-time-of-flight (QTOF) mass spectrometry (MS) and initiated the characterisation of hybrid genomes by restriction site associated DNA (RAD) sequencing. Results: UHPLC-QTOF-MS indicated a complex 'mosaic' of chemical traits in recombinant hybrids and pointed to a heritable component for many of these. RAD sequencing confirmed the recombinant nature of natural hybrids previously characterised by microsatellites and suggested a complex history of recombination. Conclusions: It is likely that hybridisation has affected these species' genomes over several glacial cycles. Recombination holds great potential to create functionally relevant chemical variation in these trees. Nevertheless, correlations between chemical traits are not entirely broken up in recombinant hybrids, suggesting limits to adaptive evolution by genetic exchange.
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| 8. |
- Gundale, Michael, et al.
(författare)
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Variation in protein complexation capacity among and within six plant species across a boreal forest chronosequence
- 2010
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Ingår i: Plant Ecology. - : Springer. - 1385-0237 .- 1573-5052. ; 211:2, s. 253-266
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Tidskriftsartikel (refereegranskat)abstract
- We investigated among and within species variation in several litter chemical properties, including protein complexation capacity (PCC), for six plant species across a boreal forest chronosequence in northern Sweden across which stand fertility declines sharply with stand age. We hypothesized (1) that evergreen species which dominate in late-successional stands would exhibit higher PCCs than deciduous species that dominate in young stands, (2) that individual species would increase their PCCs in response to nutrient limitation as succession proceeds, and (3) that differences in PCC among litter types would determine their interactive effects with proteins on soil N and C mineralization. The data demonstrated a high PCC, but a low PCC per unit of soluble phenol, for two deciduous species that dominate in early-successional high fertility stands, providing mixed support for our first hypothesis. No species demonstrated a significant correlation between their PCC and stand age, which did not support our second hypothesis. Finally, a soil incubation assay revealed that litter extracts for three of the six species had negative interactive effects with added proteins on N mineralization rates, and that all six species demonstrated positive interactive effects with protein on C mineralization. This pattern did not provide strong support for our third hypothesis, and suggests that N immobilization was likely a more important factor regulating N mineralization than stabilization of proteins into tannin complexes. These data suggest that multiple interactive mechanisms between litter extracts and proteins likely occur simultaneously to influence the availability of N in soils.
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| 9. |
- Keefover-Ring, Ken, et al.
(författare)
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2 '-(Z)-Cinnamoylsalicortin : A novel salicinoid isolated from Populus tremula
- 2014
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Ingår i: Phytochemistry Letters. - : Elsevier BV. - 1874-3900 .- 1876-7486. ; 7, s. 212-216
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Tidskriftsartikel (refereegranskat)abstract
- Using a combination of NMR and mass spectroscopic techniques, we have isolated a new salicinoid from the foliage of European aspen (Populus tremula) and identified it as 2'-(Z)-cinnamoylsalicortin. The relatively high amounts in foliage and the similarity in structure to bioactive salicinoids isolated from other salicaceous trees indicates that this compound may have implications for the study of P. tremulaherbivore interactions.
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| 10. |
- Keefover-Ring, Ken, et al.
(författare)
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No evidence of geographical structure of salicinoid chemotypes within Populus tremula
- 2014
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Ingår i: PLOS ONE. - : Public library science. - 1932-6203. ; 9:10, s. e107189-
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Tidskriftsartikel (refereegranskat)abstract
- Salicinoids are well-known defense compounds in salicaceous trees and careful screening at the population level is warranted to fully understand their diversity and function. European aspen, Populus tremula, is a foundation species in Eurasia and highly polymorphic in Sweden. We exhaustively surveyed 102 replicated genotypes from the Swedish Aspen collection (SwAsp) for foliar salicinoids using UHPLC-ESI-TOF/MS and identified nine novel compounds, bringing the total to 19 for this species. Salicinoid structure followed a modular architecture of a salicin skeleton with added side groups, alone or in combination. Two main moieties, 2'-cinnamoyl and 2'-acetyl, grouped the SwAsp population into four distinct chemotypes, and the relative allocation of salicinoids was remarkably constant between different environments, implying a highly channeled biosynthesis of these compounds. Slightly more than half of the SwAsp genotypes belonged to the cinnamoyl chemotype. A fraction synthesized the acetyl moiety alone (similar to 7%) or in combination with cinnamoyl (similar to 2%), and close to forty percent lacked either of the two characteristic moieties, and thus resemble P. tremuloides in their salicinoid profile. The two most abundant chemotypes were evenly distributed throughout Sweden, unlike geographical patterns reported for SwAsp phenology traits, plant defense genes, and herbivore community associations. Here we present the salicinoid characterization of the SwAsp collection as a resource for future studies of aspen chemical ecology, salicinoid biosynthesis, and genetics.
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