| 1. |
- Araujo Sandroni, Murilo, et al.
(författare)
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Plant resistance inducers (PRIs): perspectives for future disease management in the field
- 2020
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Ingår i: Cab Reviews: Perspectives In Agriculture, Veterinary Science, Nutrition And Natural Resources. - 1749-8848. ; 15, s. 10-
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Forskningsöversikt (refereegranskat)abstract
- Plants are confronted with numerous biotic stresses that may affect productivity. Besides their constitutive defence, plants can activate specific metabolic processes to enhance resistance upon stress detection. These defence mechanisms can also be activated through the recognition of plant resistance inducers (PRIs). This review highlights some of the current challenges that prevent the adoption of PRIs in agriculture, and explore research topics and knowledge gaps to be addressed for bringing PRIs closer to practice. First, we present studies on the variance of induced defence responses and examine the possibility of employing inducibility in breeding strategies as well as the possible role of epigenetics. We also discuss the efficiency of PRIs in future climate and knowledge gaps on this subject. Remote sensing, high-throughput phenotyping and modelling in combination with PRIs as part of decision support systems and integrated pest management are further possibilities to advance the use of PRIs. Finally, we discuss the challenges which need to be addressed to make PRIs available for small-scale farmers in low-income countries. Although PRIs have successfully presented significant rates of disease prevention under controlled conditions, converting these findings into field application still depends on more studies, e.g. on how they can be integrated into disease management programmes. Better mechanistic understanding of IR together with the coupling of PRIs to new disease monitoring and protection strategies can give PRIs a stronger role in future agricultural practice.
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| 2. |
- Brouwer, Sophie, et al.
(författare)
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Transcriptome Analysis of Potato Infected with the Necrotrophic Pathogen Alternaria solani
- 2021
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Ingår i: Plants. - : MDPI AG. - 2223-7747. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Potato early blight is caused by the necrotrophic fungus Alternaria solani and can result in yield losses of up to 50% if left uncontrolled. At present, the disease is controlled by chemical fungicides, yet rapid development of fungicide resistance renders current control strategies unsustainable. On top of that, a lack of understanding of potato defences and the quantitative nature of resistance mechanisms against early blight hinders the development of more sustainable control methods. Necrotrophic pathogens, compared to biotrophs, pose an extra challenge to the plant, since common defence strategies to biotic stresses such as the hypersensitive response and programmed cell death are often beneficial for necrotrophs. With the aim of unravelling plant responses to both the early infection stages (i.e., before necrosis), such as appressorium formation and penetration, as well as to later responses to the onset of necrosis, we present here a transcriptome analysis of potato interactions with A. solani from 1 h after inoculation when the conidia have just commenced germination, to 48 h post inoculation when multiple cell necrosis has begun. Potato transcripts with putative functions related to biotic stress tolerance and defence against pathogens were upregulated, including a putative Nudix hydrolase that may play a role in defence against oxidative stress. A. solani transcripts encoding putative pathogenicity factors, such as cell wall degrading enzymes and metabolic processes that may be important for infection. We therefore identified the differential expression of several potato and A. solani transcripts that present a group of valuable candidates for further studies into their roles in immunity or disease development.
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| 3. |
- Karlsson Green, Kristina, et al.
(författare)
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Långliggande fältförsök för rot och knölväxter – behov och möjligheter identifierade genom intervjuer
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I den här rapporten presenteras en utredning om behov och möjligheter för långliggande fältförsök för rot- och knölgrödor. Utredningen baseras huvudsakligen på intervjuer med representanter från universitet, näring, rådgivning och finansiärer, och även på en mindre uppföljande enkät till de intervjuade. Intervjuerna visar på att det finns ett brett intresse av långliggande fältförsök med frågeställningar som explicit rör rot- och knölgrödor. Frågeställningar som anses särskilt viktiga rör markbearbetning, växtskydd och växtföljd men även andra aspekter föreslås. Det finns ett intresse av att samarbeta om den här typen av försök men för många aktörer är det viktigt att man då kan få ut även kortsiktigare resultat och att dessa ska vara användbara för organisationen. Den främsta utmaningen kan vara att säkra långsiktig finansiering men även experimentdesign och organisation runt försöken är viktiga att beakta för att de ska ha ett långsiktigt värde.
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| 4. |
- Lankinen, Åsa, et al.
(författare)
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Challenges and opportunities for increasing the use of low-risk plant protection products in sustainable production. A review
- 2024
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Ingår i: Agronomy for Sustainable Development. - : Springer. - 1774-0746 .- 1773-0155. ; 44:2
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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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| 5. |
- Lankinen, Åsa, et al.
(författare)
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Whole-genome sequencing elucidates the species-wide diversity and evolution of fungicide resistance in the early blight pathogen Alternaria solani
- 2022
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Ingår i: Evolutionary applications. - : Wiley. - 1752-4571. ; 15, s. 1605-1620
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Tidskriftsartikel (refereegranskat)abstract
- Early blight of potato is caused by the fungal pathogen Alternaria solani and is an increasing problem worldwide. The primary strategy to control the disease is applying fungicides such as succinate dehydrogenase inhibitors (SDHI). SDHI-resistant strains, showing reduced sensitivity to treatments, appeared in Germany in 2013, shortly after the introduction of SDHIs. Two primary mutations in the SDH complex (SdhB-H278Y and SdhC-H134R) have been frequently found throughout Europe. How these resistances arose and spread, and whether they are linked to other genomic features, remains unknown. For this project, we performed whole-genome sequencing for 48 A. solani isolates from potato fields across Europe to better characterize the pathogen's genetic diversity in general and understand the development and spread of the genetic mutations that lead to SDHI resistance. The isolates can be grouped into seven genotypes. These genotypes do not show a geographical pattern but appear spread throughout Europe. We found clear evidence for recombination on the genome, and the observed admixtures might indicate a higher adaptive potential of the fungus than previously thought. Yet, we cannot link the observed recombination events to different Sdh mutations. The same Sdh mutations appear in different, non-admixed genetic backgrounds; therefore, we conclude they arose independently. Our research gives insights into the genetic diversity of A. solani on a genome level. The mixed occurrence of different genotypes, apparent admixture in the populations, and evidence for recombination indicate higher genomic complexity than anticipated. The conclusion that SDHI tolerance arose multiple times independently has important implications for future fungicide resistance management strategies. These should not solely focus on preventing the spread of isolates between locations but also on limiting population size and the selective pressure posed by fungicides in a given field to avoid the rise of new mutations in other genetic backgrounds.
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| 6. |
- Liljeroth, Erland, et al.
(författare)
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Automatic late blight lesion recognition and severity quantification based on field imagery of diverse potato genotypes by deep learning
- 2021
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Ingår i: Knowledge-Based Systems. - : Elsevier BV. - 0950-7051. ; 214
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Tidskriftsartikel (refereegranskat)abstract
- The plant pathogen Phytophthora infestans causes the severe disease late blight in potato, which can result in huge yield loss for potato production. Automatic and accurate disease lesion segmentation enables fast evaluation of disease severity and assessment of disease progress. In tasks requiring computer vision, deep learning has recently gained tremendous success for image classification, object detection and semantic segmentation. To test whether we could extract late blight lesions from unstructured field environments based on high-resolution visual field images and deep learning algorithms, we collected similar to 500 field RGB images in a set of diverse potato genotypes with different disease severity (0%-70%), resulting in 2100 cropped images. 1600 of these cropped images were used as the dataset for training deep neural networks and 250 cropped images were randomly selected as the validation dataset. Finally, the developed model was tested on the remaining 250 cropped images. The results show that the values for intersection over union (IoU) of the classes background (leaf and soil) and disease lesion in the test dataset were 0.996 and 0.386, respectively. Furthermore, we established a linear relationship (R-2 = 0.655) between manual visual scores of late blight and the number of lesions detected by deep learning at the canopy level. We also showed that imbalance weights of lesion and background classes improved segmentation performance, and that fused masks based on the majority voting of the multiple masks enhanced the correlation with the visual disease scores. This study demonstrates the feasibility of using deep learning algorithms for disease lesion segmentation and severity evaluation based on proximal imagery, which could aid breeding for crop resistance in field environments, and also benefit precision farming. (C) 2021 Elsevier B.V. All rights reserved.
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| 7. |
- Liljeroth, Erland, et al.
(författare)
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Phosphite Integrated in Late Blight Treatment Strategies in Starch Potato Does Not Cause Residues in the Starch Product
- 2020
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Ingår i: Plant Disease. - 0191-2917 .- 1943-7692. ; 104, s. 3026-3032
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Tidskriftsartikel (refereegranskat)abstract
- Currently available fungicides against potato late blight are effective but there are concerns about the sustainability of frequent applications and the risks of fungicide resistance. Therefore, we investigated how potassium phosphite can be integrated into late blight control programs with reduced fungicides in field trials. Phosphite was somewhat less effective than the conventional fungicides at suppressing late blight in the foliage, and the tubers contained less starch. However, when we reduced the amount of phosphite and combined it with reduced amounts of conventional fungicides, we observed no differences in disease suppression, total yields, and tuber starch contents compared with the full treatments with conventional fungicides. The amount of phosphite detected in the harvested tubers was linearly associated with the amount of phosphite applied to the foliage. Our analyses indicate that phosphite could replace some fungicides without exceeding the current European Union standards for the maximum residue levels in potato tubers. No phosphite was detected in the starch from the tubers. In 1 of 2 years, early blight (caused by Alternaria solani) was less severe in the phosphite treatments than in the treatments without phosphite. The integration of phosphite into current treatment strategies would reduce the dependence on conventional fungicides.
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| 8. |
- Mostafanezhad, Hadis, et al.
(författare)
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Rapid emergence of boscalid resistance in Swedish populations of Alternaria solani revealed by a combination of field and laboratory experiments
- 2022
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Ingår i: European Journal of Plant Pathology. - : Springer Science and Business Media LLC. - 0929-1873 .- 1573-8469. ; 162, s. 289-303
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Tidskriftsartikel (refereegranskat)abstract
- Early blight, caused by Alternaria solani, is a common potato disease worldwide. Reduced field efficacy of the fungicide boscalid against this disease has been reported in several countries. Boscalid resistance has been mostly studied with in-vitro and/or greenhouse experiments. Field studies validating this phenomenon are largely missing. Here, for the first time in Scandinavia, we validated boscalid resistance in a Swedish population of A. solani both in the field and in the laboratory. Field trials between 2014 and 2017 in Nymo showed significant efficacy reduction by year. The target regions of the A. solani genes encoding the succinate dehydrogenase subunits (Sdh) B, C and D of samples collected from Nymo, and additional fields in south-eastern and central Sweden, were analysed for substitutions associated with loss of boscalid sensitivity. In 2014, the SdhC-H134R mutation was found at several sites at a low frequency, while, in 2017, the majority of the samples had either the SdhB-H278Y or the SdhC-H134R substitution. No mutations were detected in the gene encoding the SdhD subunit. Spore germination tests showed a high sensitivity (EC50 < 1 mu g mL(-1)) of isolates lacking the substitutions. This was supported by a significant decrease in their radial growth rate, from 0.1 to 10 mu g mL(-1) boscalid. However, the mutated isolates had EC50 > 100 mu g mL(-1) and their growth rates hardly decreased at concentrations above 1-10 mu g mL(-1). These results add to the current knowledge of fungicide resistance development in field and indicate that early blight management in southeast Sweden should no longer rely on boscalid.
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| 9. |
- Odilbekov, Firuz, et al.
(författare)
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Intact salicylic acid signalling is required for potato defence against the necrotrophic fungus Alternaria solani
- 2020
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Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 104, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- Key Message Using disease bioassays and transcriptomic analysis we show that intact SA-signalling is required for potato defences against the necrotrophic fungal pathogenAlternaria solani. Early blight, caused by the necrotrophic fungusAlternaria solani,is an increasing problem in potato cultivation. Studies of the molecular components defining defence responses toA. solaniin potato are limited. Here, we investigate plant defence signalling with a focus on salicylic acid (SA) and jasmonic acid (JA) pathways in response toA. solani. Our bioassays revealed that SA is necessary to restrict pathogen growth and early blight symptom development in both potato foliage and tubers. This result is in contrast to the documented minimal role of SA in resistance ofArabidopsis thalianaagainst necrotrophic pathogens. We also present transcriptomic analysis with 36 arrays ofA. solaniinoculated SA-deficient, JA-insensitive, and wild type plant lines. A greater number of genes are differentially expressed in the SA-deficient mutant plant line compared to the wild type and JA- insensitive line. In wild type plants, genes encoding metal ion transporters, such as copper, iron and zinc transporters were upregulated and transferase-encoding genes, for example UDP-glucoronosyltransferase and Serine-glyoxylate transferase, were downregulated. The SA-deficient plants show upregulation of genes enriched in GO terms related to oxidoreductase activity, respiratory chain and other mitochondrial-related processes.Pathogenesis-relatedgenes, such as genes encoding chitinases and PR1, are upregulated in both the SA-deficient and wild type plants, but not in the JA-insensitive mutants. The combination of our bioassays and the transcriptomic analysis indicate that intact SA signalling, and not JA signalling, is required for potato defences against the necrotrophic pathogenA. solani.
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| 10. |
- Odilbekov, Firuz, et al.
(författare)
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QTL Mapping for resistance to early blight in a tetraploid potato population
- 2020
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Ingår i: Agronomy. - : MDPI AG. - 2073-4395. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Early blight of potato, caused by Alternaria solani, is an economically important foliar disease in most potato-growing regions. Growing cultivars with higher levels of resistance to early blight can reduce tuber yield losses and the need for fungicide applications. In this research, a bi-parental tetraploid potato population, segregating for resistance to early blight in leaves and tubers, was characterized to identify novel quantitative trait loci (QTL) associated with foliar and tuber early blight resistance. Assessment of the disease resistance in the foliage was performed by field evaluation and in tuber under controlled conditions. Results from this study revealed significant differences (P < 0.001) in resistance to A. solani among potato clones both in the leaves and in tubers. There was no statistically significant correlation (r = 0.06, P = 0.35) between the resistance scores from leaves and tubers. Several clones exhibited; however, high levels of resistance both in leaves and tubers and are; thus, promising candidates for breeding for early blight resistance. Linkage mapping revealed several QTL for early blight affecting both foliage and tubers. QTL associated with disease resistance in the tuber were found on chromosomes 1, 2, 3, 4, 8, 11 and 12. QTL associated with disease resistance in foliage were also examined for independence from defoliation, and independent QTL were; thus, found on chromosomes 5 and 11.
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