Person: Hovmoller, M.S.
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Hovmoller
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M.S.
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Hovmoller, M.S.
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0000-0002-4432-88987 results
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- First Report of Ug99 Wheat Stem Rust Caused by Puccinia graminis f. sp. tritici in South Asia(American Phytopathological Society, 2024) Patpour, M.; Baidya, S.; Basnet, R.; Justesen, A.F.; Hodson, D.P.; Thapa, D.B.; Hovmoller, M.S.
Publication - Distribution of Puccinia striiformis f. sp. tritici races and virulence in wheat growing regions of Kenya from 1970 to 2014(American Phytopathological Society, 2022) Wamalwa, M.; Wanyera, R.; Rodriguez-Algaba, J.; Boyd, L.; Owuoche, J.O.; Ogendo, j.; Bhavani, S.; Uauy, C.; Justesen, A.F.; Hovmoller, M.S.
Publication - MARPLE, a point-of-care, strain-level disease diagnostics and surveillance tool for complex fungal pathogens(BioMed Central, 2019) Radhakrishnan, G.V.; Cook, N.M.; Bueno Sancho, V.; Lewis, C. M.; Persoons, A.; Debebe, A.; Heaton, M.; Davey, P.E.; Abeyo Bekele Geleta; Alemayehu, Y.; Badebo, A.; Barnett, M.; Bryant, R.; Chatelain, J.; Xianming Chen; Suomeng Dong; Henriksson, T.; Holdgate, S.; Justesen, A.F.; Kalous, J.; Zhensheng Kang; Laczny, S.; Legoff, J.P.; Lesch, D.; Richards, T.; Randhawa, H.S.; Thach, T.; Meinan Wang; Hovmoller, M.S.; Hodson, D.P.; Saunders, D.G.O.Background: Effective disease management depends on timely and accurate diagnosis to guide control measures. The capacity to distinguish between individuals in a pathogen population with specific properties such as fungicide resistance, toxin production and virulence profiles is often essential to inform disease management approaches. The genomics revolution has led to technologies that can rapidly produce high-resolution genotypic information to define individual variants of a pathogen species. However, their application to complex fungal pathogens has remained limited due to the frequent inability to culture these pathogens in the absence of their host and their large genome sizes. Results: Here, we describe the development of Mobile And Real-time PLant disEase (MARPLE) diagnostics, a portable, genomics-based, point-of-care approach specifically tailored to identify individual strains of complex fungal plant pathogens. We used targeted sequencing to overcome limitations associated with the size of fungal genomes and their often obligately biotrophic nature. Focusing on the wheat yellow rust pathogen, Puccinia striiformis f.sp. tritici (Pst), we demonstrate that our approach can be used to rapidly define individual strains, assign strains to distinct genetic lineages that have been shown to correlate tightly with their virulence profiles and monitor genes of importance. Conclusions: MARPLE diagnostics enables rapid identification of individual pathogen strains and has the potential to monitor those with specific properties such as fungicide resistance directly from field-collected infected plant tissue in situ. Generating results within 48 h of field sampling, this new strategy has far-reaching implications for tracking plant health threats.
Publication - Potential for re-emergence of wheat stem rust in the United Kingdom(Nature Research, 2018) Lewis, C. M.; Persoons, A.; Bebber, D.; Kigathi, R.; Maintz, J.; Findlay, K.; Bueno Sancho, V.; Corredor-Moreno, P.; Harrington, S.A.; Ngonidzashe Kangara; Berlin, A.; Garcia, R.; German, S.E.; Hanzalova, A.; Hodson, D.P.; Hovmoller, M.S.; Huerta-Espino, J.; Imtiaz, M.; Mirza, J.I.; Justesen, A.F.; Niks, R.; Ali Omrani; Patpour, M.; Pretorius, Z.; Ramin Roohparvar; Sela, H.; Singh, R.P.; Steffenson, B.; Visser, B.; Fenwick, P.; Thomas, J.; Wulff, B.B.H.; Saunders, D.G.O.Wheat stem rust, a devastating disease of wheat and barley caused by the fungal pathogen Puccinia graminis f. sp. tritici, was largely eradicated in Western Europe during the mid-to-late twentieth century. However, isolated outbreaks have occurred in recent years. Here we investigate whether a lack of resistance in modern European varieties, increased presence of its alternate host barberry and changes in climatic conditions could be facilitating its resurgence. We report the first wheat stem rust occurrence in the United Kingdom in nearly 60 years, with only 20% of UK wheat varieties resistant to this strain. Climate changes over the past 25 years also suggest increasingly conducive conditions for infection. Furthermore, we document the first occurrence in decades of P. graminis on barberry in the UK . Our data illustrate that wheat stem rust does occur in the UK and, when climatic conditions are conducive, could severely harm wheat and barley production.
Publication - Yellow Rust epidemics worldwide were caused by Pathogen Races from divergent genetic lineages(Frontiers, 2017) Ali, S.; Rodriguez-Algaba, J.; Thach, T.; Sorensen, C.K; Hansen, J.; Lassen, P.; Nazari, K.; Hodson, D.P.; Justesen, A.F.; Hovmoller, M.S.We investigated whether the recent worldwide epidemics of wheat yellow rust were driven by races of few clonal lineage(s) or populations of divergent races. Race phenotyping of 887 genetically diverse Puccinia striiformis isolates sampled in 35 countries during 2009–2015 revealed that these epidemics were often driven by races from few but highly divergent genetic lineages. PstS1 was predominant in North America; PstS2 in West Asia and North Africa; and both PstS1 and PstS2 in East Africa. PstS4 was prevalent in Northern Europe on triticale; PstS5 and PstS9 were prevalent in Central Asia; whereas PstS6 was prevalent in epidemics in East Africa. PstS7, PstS8 and PstS10 represented three genetic lineages prevalent in Europe. Races from other lineages were in low frequencies. Virulence to Yr9 and Yr27 was common in epidemics in Africa and Asia, while virulence to Yr17 and Yr32 were prevalent in Europe, corresponding to widely deployed resistance genes. The highest diversity was observed in South Asian populations, where frequent recombination has been reported, and no particular race was predominant in this area. The results are discussed in light of the role of invasions in shaping pathogen population across geographical regions. The results emphasized the lack of predictability of emergence of new races with high epidemic potential, which stresses the need for additional investments in population biology and surveillance activities of pathogens on global food crops, and assessments of disease vulnerability of host varieties prior to their deployment at larger scales.
Publication - Emergence of virulence to SrTmp in the Ug99 race group of wheat stem rust, Puccinia graminis f. sp. tritici, in Africa(American Phytopathological Society (APS), 2016) Patpour, M.; Hovmoller, M.S.; Justesen, A.F.; Newcomb, M.; Olivera Firpo, P.D.; Yue Jin; Szabo, L.J.; Shahin, A.; Wanyera, R.; Habarurema, I.; Wobibi, S.; Hodson, D.P.The Ug99 race (TTKSK) of wheat stem rust was first detected in Uganda in 1998 (Pretorius et al. 2000) and since then seven additional variants have been reported, i.e., TTKSF, TTKST, TTTSK, TTKSP, PTKSK, PTKST, and TTKSF+ (Pretorius et al. 2012). In this study, 84 stem rust samples from the 2014 surveys of wheat fields in Africa (Kenya, 9; Uganda, 28; Rwanda, 41; and Egypt, 6) were sent to the Global Rust Reference Center (GRRC, Denmark) for race analysis. Puccinia graminis f. sp. tritici (Pgt) samples were recovered on cv. Morocco, and resulting urediniospores of 53 single-pustule isolates were inoculated onto 20 North American stem rust differential lines using standard procedures (Jin et al. 2008). The pathotyping was repeated in two or three independent experiments. Twelve of the derived isolates were also typed at the USDA-ARS Cereal Disease Laboratory (USA) for an independent confirmation. Among the Kenyan samples, four collected from Njoro (Central Rift, cvs. Robin and Kwale) and two from Ntulumeti and Olgilai (South Rift, cv. Robin), were typed as TTKTK. Race TTKTK was similar to TTKSK except for additional virulence to SrTmp (Infection Type 4). An additional single-pustule isolate derived from one sample from Njoro showed a high infection type on LcSr24Ag and CnsSrTmp, testers for Sr24 and SrTmp, respectively, and was typed as TTKTT. These isolates were also tested on Siouxland (PI 483469, Sr24+Sr31), Sisson (PI 617053, Sr31+Sr36), and Triumph 64 (CI 13679, donor of SrTmp) to confirm their virulence/avirulence combinations to Sr24, Sr31, Sr36, and SrTmp. Race TTKTK was also detected at two locations in Uganda (Rubaya and Muko in Kabale region) and at five locations in Rwanda (Kinigi, Rwerere, Rufungo, Gatebe and Kamenyo). Three isolates derived from stem rust samples collected on cv. PBW343 (carrying Sr31) in Sakha in the Nile Delta region in Egypt were also typed as TTKTK. In addition, DNA from isolates of race TTKTK were analyzed using a diagnostic qPCR assay (Ug99 RG stage-1, Szabo unpublished data), which confirmed that these samples belong to the Ug99 lineage. The identification of SrTmp virulence in the Ug99 race group in several countries in one year emphasizes the relevance of coordinated international surveillance efforts and utilization of diverse sources of resistance to control stem rust in wheat. Further studies are in progress to determine the detailed relationship of the newly emerged races and other Pgt isolates identified in the Ug99 group.
Publication - Phenotypic and genotypic characterization of Race TKTTF of Puccinia graminis f. sp. tritici that caused a Wheat Stem Rust Epidemic in Southern Ethiopia in 2013–14(American Phytopathological Society (APS), 2015) Olivera Firpo, P.D.; Newcomb, M.; Szabo, L.J.; Rouse, M.N.; Johnson, J.W.; Gale, S.; Luster, D.G.; Hodson, D.P.; Cox, J.A.; Burgin, L.; Hort, M.C.; Gilligan, C.A.; Patpour, M.; Justesen, A.F.; Hovmoller, M.S.; Woldeab, G.; Hailu, E.; Kotu, B.H.; Tadesse, K.; Pumphrey, M.; Singh, R.P.; Yue JinA severe stem rust epidemic occurred in southern Ethiopia during November 2013 to January 2014, with yield losses close to 100% on the most widely grown wheat cultivar, ‘Digalu’. Sixty-four stem rust samples collected from the regions were analyzed. A meteorological model for airborne spore dispersal was used to identify which regions were most likely to have been infected from postulated sites of initial infection. Based on the analyses of 106 single-pustule isolates derived from these samples, four races of Puccinia graminis f. sp. tritici were identified: TKTTF, TTKSK, RRTTF, and JRCQC. Race TKTTF was found to be the primary cause of the epidemic in the southeastern zones of Bale and Arsi. Isolates of race TKTTF were first identified in samples collected in early October 2013 from West Arsi. It was the sole or predominant race in 31 samples collected from Bale and Arsi zones after the stem rust epidemic was established. Race TTKSK was recovered from 15 samples from Bale and Arsi zones at low frequencies. Genotyping indicated that isolates of race TKTTF belongs to a genetic lineage that is different from the Ug99 race group and is composed of two distinct genetic types. Results from evaluation of selected germplasm indicated that some cultivars and breeding lines resistant to the Ug99 race group are susceptible to race TKTTF. Appearance of race TKTTF and the ensuing epidemic underlines the continuing threats and challenges posed by stem rust not only in East Africa but also to wider-scale wheat production.
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