Detection of novel QTLs for late blight resistance derived from the wild potato species Solanum microdontum and Solanum pampasense
Meade, Fergus ; Hutten, Ronald ; Wagener, Silke ; Prigge, Vanessa ; Dalton, Emmet ; Kirk, Hanne Grethe ; Griffin, Denis ; Milbourne, Dan - \ 2020
Genes 11 (2020)7. - ISSN 2073-4425 - p. 1 - 18.
Breeding - Late blight - Marker-assisted selection - Phytophthora infestans - Potato - QTL
Wild potato species continue to be a rich source of genes for resistance to late blight in potato breeding. Whilst many dominant resistance genes from such sources have been characterised and used in breeding, quantitative resistance also offers potential for breeding when the loci underlying the resistance can be identified and tagged using molecular markers. In this study, F1 populations were created from crosses between blight susceptible parents and lines exhibiting strong partial resistance to late blight derived from the South American wild species Solanum microdontum and Solanum pampasense. Both populations exhibited continuous variation for resistance to late blight over multiple field-testing seasons. High density genetic maps were created using single nucleotide polymorphism (SNP) markers, enabling mapping of quantitative trait loci (QTLs) for late blight resistance that were consistently expressed over multiple years in both populations. In the population created with the S. microdontum source, QTLs for resistance consistently expressed over three years and explaining a large portion (21–47%) of the phenotypic variation were found on chromosomes 5 and 6, and a further resistance QTL on chromosome 10, apparently related to foliar development, was discovered in 2016 only. In the population created with the S. pampasense source, QTLs for resistance were found in over two years on chromosomes 11 and 12. For all loci detected consistently across years, the QTLs span known R gene clusters and so they likely represent novel late blight resistance genes. Simple genetic models following the effect of the presence or absence of SNPs associated with consistently effective loci in both populations demonstrated that marker assisted selection (MAS) strategies to introgress and pyramid these loci have potential in resistance breeding strategies.
Governing a Collective Bad: Social Learning in the Management of Crop Diseases
Damtew, Elias ; Mierlo, Barbara van; Lie, Rico ; Struik, Paul ; Leeuwis, Cees ; Lemaga, Berga ; Smart, Christine - \ 2020
Systemic Practice and Action Research 33 (2020). - ISSN 1094-429X - p. 111 - 134.
Collective action - Communication - Crop disease - Late blight - Social learning
There has been strong research interest in designing and testing learning approaches for enhancing and sustaining the capacity of communities to manage collective action problems. Broadening the perspective from well-known social learning approaches in natural resource management, this study explores how social learning as a communicative process influences collective action in contagious crop disease management. A series of facilitated discussion and reflection sessions about late blight management created the social learning space for potato farmers in Ethiopia. Communicative utterances of participants in the sessions served as the units of analysis. The study demonstrates how and to what extent social learning, in the form of aligned new knowledge, relations and actions occurred and formed the basis for collective action in the management of late blight.
Introgression of Genes for Resistance against Phytophthora infestans in Diploid Potato
Su, Ying ; Viquez-Zamora, Marcela ; Uil, Danielle den; Sinnige, Jarno ; Kruyt, Hein ; Vossen, Jack ; Lindhout, Pim ; Heusden, Sjaak van - \ 2020
American Journal of Potato Research 97 (2020)1. - ISSN 1099-209X - p. 33 - 42.
Diploid potato - F1 hybrid potatoes - Late blight - Marker-assisted backcrossing
Potato is playing an increasingly important role in food production. The development of new varieties is slow due to the genetic complexity of potato and the inefficient breeding process. Modern techniques, such as hybrid breeding and the introduction of new traits in specific, existing elite material, have not been reported in the development of new and improved potato varieties. This paper describes the first example of marker-assisted introgression of four different Phytophthora infestans resistance genes in selected highly homozygous, diploid potato lines. After two backcrosses and one selfing, the original line can be recovered with Phytophthora resistance, thus providing added value. After crossing two diploid lines, each with a different resistance gene, hybrids were obtained and tested for resistance to Phytophthora in small field trials. In these experiments, the hybrids with two resistance genes were more resistant than the plants with only one of the two resistance genes.
Diagnosis of management of bacterial wilt and late blight in potato in Ethiopia : A systems thinking perspective
Damtew, E. ; Tafesse, Shiferaw ; Lie, R. ; Mierlo, B. van; Lemaga, B. ; Sharma, K. ; Struik, P.C. ; Leeuwis, C. - \ 2018
NJAS Wageningen Journal of Life Sciences 86-87 (2018). - ISSN 1573-5214 - p. 12 - 24.
Bacterial wilt - Complex problems - Disease management - Late blight - Potato - Systems thinking
Potato is one of the most important food crops for smallholder farmers in the Ethiopian highlands. Diseases, particularly bacterial wilt (caused by Ralstonia solanacearum) and late blight (caused by Phytophthora infestans), are among the major constraints of potato production, despite continuous efforts to control them. Bacterial wilt and late blight are complex problems with multiple technical and institutional features, involving multiple actors with different perceptions and understanding, not only of the problem but also of possible solutions. Appreciating such complexity, this study adopted a systems thinking perspective. It aimed to explore actors’ understanding of the complex problem situation and its implication for the management of the diseases at a collective level. Using a multi-stakeholder workshop and in-depth interviews, a qualitative study was conducted with actors that are directly or indirectly involved in the management of the two diseases. Results showed that actors essentially overlooked key systemic problems in the management of the two diseases. This is mainly reflected in actors’ tendency to give event-level responses, shift responsibilities and engage in a mutual blaming to the problem of bacterial wilt and late blight. Lack of a preventive disease management culture, limited recognition of interdependencies among activities of actors, power inequalities, and top-down and linear approaches in information and knowledge sharing are identified as key structural problems that are underrated by the actors. We contend that the most appropriate way forward towards the management of both diseases is designing and implementing management strategies that, on the one hand, are preventive of disease epidemics, and, on the other hand, foster horizontal information sharing, learning and collective action among the local actors in the system. Digital platforms, particularly mobile-based technologies, can play a role in catalyzing new forms of information sharing, broader learning, and collaboration among farmers and local actors.
Farmers’ knowledge and practices of potato disease management in Ethiopia
Tafesse, Shiferaw ; Damtew, E. ; Mierlo, B. van; Lie, R. ; Lemaga, B. ; Sharma, K. ; Leeuwis, C. ; Struik, P.C. - \ 2018
NJAS Wageningen Journal of Life Sciences 86–87 (2018). - ISSN 1573-5214 - p. 25 - 38.
Bacterial wilt - Disease management - Farmers’ knowledge - Farmers’ practices - Late blight - Phytophthora infestans - Potato diseases - Ralstonia solanacearum
Effective management of potato diseases such as bacterial wilt and late blight depends to a large extent on farmers’ knowledge of the diseases as well as on the integration of recommended management methods in their daily practices. Late blight has continued to be a dominant potato disease for many decades in Ethiopia, whereas bacterial wilt has emerged more recently with a devastating impact on the country's potato production systems. A survey of 261 randomly selected farmers was carried out in three major potato growing districts in the central highlands of Ethiopia to examine farmers’ knowledge and management practices of the two diseases, and to analyze the role of relevant knowledge in their practices. Considering their different characteristics, three groups of farmers were distinguished: producers of quality declared seed, producers of normal seed and producers of ware. The study shed light on the vital role the lack of knowledge about the diseases plays in shaping farmers’ daily potato production practices. Most farmers could recognize symptoms of the diseases on infected leaves and stems. However, they had very limited knowledge of the diseases including their causal agents, spreading mechanisms, and effective management methods, although they knew a little bit more about late blight than about bacterial wilt. Therefore, to effectively manage the diseases, farmers need to learn about the diseases and how to manage them in their local context applying a feasible combination of management options through a community-based approach. The effectivity of such an approach could be enhanced by stipulating operational standards in bylaws and through continuous monitoring of changes in farmers’ practices and environmental monitoring for disease occurrence by leveraging an interactive mobile-based platform.
Two different R gene loci co-evolved with Avr2 of Phytophthora infestans and confer distinct resistance specificities in potato
Aguilera-Galvez, C. ; Champouret, N. ; Rietman, H. ; Lin, X. ; Wouters, D. ; Chu, Z. ; Jones, J.D.G. ; Vossen, J.H. ; Visser, R.G.F. ; Wolters, P.J. ; Vleeshouwers, V.G.A.A. - \ 2018
Studies in Mycology 89 (2018). - ISSN 0166-0616 - p. 105 - 115.
Avr gene - Co-evolution - Late blight - Phytophthora infestans - Potato - R gene - Resistance - Solanum
Late blight, caused by the oomycete pathogen Phytophthora infestans, is the most devastating disease in potato. For sustainable management of this economically important disease, resistance breeding relies on the availability of resistance (R) genes. Such R genes against P. infestans have evolved in wild tuber-bearing Solanum species from North, Central and South America, upon co-evolution with cognate avirulence (Avr) genes. Here, we report how effectoromics screens with Avr2 of P. infestans revealed defense responses in diverse Solanum species that are native to Mexico and Peru. We found that the response to AVR2 in the Mexican Solanum species is mediated by R genes of the R2 family that resides on a major late blight locus on chromosome IV. In contrast, the response to AVR2 in Peruvian Solanum species is mediated by Rpi-mcq1, which resides on chromosome IX and does not belong to the R2 family. The data indicate that AVR2 recognition has evolved independently on two genetic loci in Mexican and Peruvian Solanum species, respectively. Detached leaf tests on potato cultivar ‘Désirée’ transformed with R genes from either the R2 or the Rpi-mcq1 locus revealed an overlapping, but distinct resistance profile to a panel of 18 diverse P. infestans isolates. The achieved insights in the molecular R – Avr gene interaction can lead to more educated exploitation of R genes and maximize the potential of generating more broad-spectrum, and potentially more durable control of the late blight disease in potato.
Reduced efficacy of fluazinam against Phytophthora infestans in the Netherlands
Schepers, H.T.A.M. ; Kessel, G.J.T. ; Lucca, F. ; Förch, M.G. ; Den Bosch, G.B.M. van; Topper, C.G. ; Evenhuis, A. - \ 2018
European Journal of Plant Pathology 151 (2018)4. - ISSN 0929-1873 - p. 947 - 960.
AUDPC - Clonal lineage - Control strategy - Fungicides - Late blight - Potato - Shirlan
Phytophthora infestans is the causal organism of potato late blight, the most important disease in potato, the second most important arable crop in Europe. The P. infestans population in Europe is well known for its sudden changes in composition. Currently it is composed of a wide variety of genotypes, some of which are dominant clonal lines while others are rare or even unique to a year or location. Fungicides play a crucial role in the integrated control of late blight. Since its introduction in the Netherlands in 1992, fluazinam has been used in late blight control strategies in ware and starch potatoes. It has a broad spectrum of activity and is effective against a range of diseases including potato late blight. Fluazinam interrupts the pathogen cell’s energy production process by an uncoupling effect on oxidative phosphorylation. It is considered to have a low resistance risk. Until recently, reduced efficacy against fluazinam was not detected in P. infestans surveys in Europe. In this paper we present the finding of a new clonal lineage (EU_33_A2) of P. infestans in the Netherlands and the reduced efficacy of fluazinam to control one of the EU_33_A2 isolates in field experiments carried out in 2011 and 2015 under high disease pressure. The potential effects of this finding on practical late blight control strategies are discussed.
Assessing changes in potato canopy caused by late blight in organic production systems through UAV-based pushbroom imaging spectrometer
Domingues Franceschini, Marston ; Bartholomeus, H. ; Apeldoorn, D. van; Suomalainen, J. ; Kooistra, L. - \ 2017
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Science 42 (2017)2W6. - ISSN 1682-1750 - p. 109 - 112.
Hyperspectral imagery - Late blight - Organic potato production - Vis-NIR spectroscopy
Productivity of cropping systems can be constrained simultaneously by different limiting factors and approaches allowing to indicate and identify plants under stress in field conditions can be valuable for farmers and breeders. In organic production systems, sensing solutions are not frequently studied, despite their potential for crop traits retrieval and stress assessment. In this study, spectral data in the optical domain acquired using a pushbroom spectrometer on board of a unmanned aerial vehicle is used to evaluate the potential of this information for assessment of late blight (Phytophthora infestans) incidence on potato (Solanum tuberosum) under organic cultivation. Vegetation indices formulations with two and three spectral bands were tested for the complete range of the spectral information acquired (i.e., from 450 to 900 nm, with 10 nm of spectral resolution). This evaluation concerned the discrimination between plots cultivated with only one resistant potato variety in contrast with plots with a variety mixture, with resistant and susceptible cultivars. Results indicated that indices based on three spectral bands performed better and optimal wavelengths (i.e., near 490, 530 and 670 nm) are not only related to chlorophyll content but also to other leaf pigments like carotenoids.
Filamentous actin accumulates during plant cell penetration and cell wall plug formation in Phytophthora infestans
Kots, Kiki ; Meijer, Harold J.G. ; Bouwmeester, Klaas ; Govers, Francine ; Ketelaar, Tijs - \ 2017
Cellular and Molecular Life Sciences 74 (2017)5. - ISSN 1420-682X - p. 909 - 920.
Actin cytoskeleton - Appressorium - Late blight - Lifeact - Oomycete - Plant pathogen
The oomycete Phytophthora infestans is the cause of late blight in potato and tomato. It is a devastating pathogen and there is an urgent need to design alternative strategies to control the disease. To find novel potential drug targets, we used Lifeact-eGFP expressing P. infestans for high resolution live cell imaging of the actin cytoskeleton in various developmental stages. Previously, we identified actin plaques as structures that are unique for oomycetes. Here we describe two additional novel actin configurations; one associated with plug deposition in germ tubes and the other with appressoria, infection structures formed prior to host cell penetration. Plugs are composed of cell wall material that is deposited in hyphae emerging from cysts to seal off the cytoplasm-depleted base after cytoplasm retraction towards the growing tip. Preceding plug formation there was a typical local actin accumulation and during plug deposition actin remained associated with the leading edge. In appressoria, formed either on an artificial surface or upon contact with plant cells, we observed a novel aster-like actin configuration that was localized at the contact point with the surface. Our findings strongly suggest a role for the actin cytoskeleton in plug formation and plant cell penetration.
Silencing of six susceptibility genes results in potato late blight resistance
Sun, Kaile ; Wolters, Anne-Marie A. ; Vossen, Jack H. ; Rouwet, Maarten E. ; Loonen, Annelies E.H.M. ; Jacobsen, Evert ; Visser, Richard G.F. ; Bai, Yuling - \ 2016
Transgenic Research 25 (2016)5. - ISSN 0962-8819 - p. 731 - 742.
Late blight - Potato - Resistance - RNAi - Susceptibility gene
Phytophthora infestans, the causal agent of late blight, is a major threat to commercial potato production worldwide. Significant costs are required for crop protection to secure yield. Many dominant genes for resistance (R-genes) to potato late blight have been identified, and some of these R-genes have been applied in potato breeding. However, the P. infestans population rapidly accumulates new virulent strains that render R-genes ineffective. Here we introduce a new class of resistance which is based on the loss-of-function of a susceptibility gene (S-gene) encoding a product exploited by pathogens during infection and colonization. Impaired S-genes primarily result in recessive resistance traits in contrast to recognition-based resistance that is governed by dominant R-genes. In Arabidopsis thaliana, many S-genes have been detected in screens of mutant populations. In the present study, we selected 11 A. thalianaS-genes and silenced orthologous genes in the potato cultivar Desiree, which is highly susceptible to late blight. The silencing of five genes resulted in complete resistance to the P. infestans isolate Pic99189, and the silencing of a sixth S-gene resulted in reduced susceptibility. The application of S-genes to potato breeding for resistance to late blight is further discussed.