Pathogen diversity and screening for minor gene resistance to Pyrenophora teres f. teres in barley and its use for plant breeding

Wallwork, H.; Butt, M.; Capio, E.

doi:10.1007/s13313-016-0433-4

Cited by 18 publications

(24 citation statements)

References 8 publications

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“…Despite inferred high levels of gene flow in Ptt, the mechanism of the Maritime and Keel virulence introduction from WA to South Australia is unclear. Although the Maritime epidemic had a eastward trajectory as it moved rapidly from the far west coast of South Australia across the Eyre Peninsula and onto Yorke Peninsula [20], WA and South Australia is divided by the Nullarbor Plain, which is an arid region void of barley production. It is thus unlikely that natural dispersal of the pathogen resulted in the migration event, as dispersal distance is undoubtedly less than 500 km [1], a conservative estimate of the distance between the closest barley fields in WA and South Australia.…”

Section: Discussionmentioning

confidence: 99%

“…Ptt already poses a considerable threat to the barley industry because it is able to frequently defeat the resistance in barley varieties. In South Australia in 1994, Ptt re-emerged and rapidly defeated resistance in the Skiff variety, followed by the defeat of the resistance in Keel in 2007 and Maritime in 2009 [20]. It is unknown whether these virulences evolved locally or whether they were the result of pathogen migration from other barley growing regions in Australia.…”

Section: Introductionmentioning

confidence: 99%

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Host specialisation and disparate evolution of Pyrenophora teres f. teres on barley and barley grass

Linde

Smith

2019

BMC Evol Biol

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Background Pathogens evolve in an arms race, frequently evolving virulence that defeats resistance genes in their hosts. Infection of multiple hosts may accelerate this virulence evolution. Theory predicts that host diversity affects pathogen diversity, with more diverse hosts expected to harbour more diverse pathogens that reproduce sexually. We tested this hypothesis by comparing the microsatellite (SSR) genetic diversity of the barley leaf pathogen Pyrenophora teres f. teres (Ptt) from barley (monoculture) and barley grass (outbreeding). We also aim to investigate host specificity and attempt to track virulence on two barley cultivars, Maritime and Keel. Results Genetic diversity in barley Ptt populations was higher than in populations from barley grass. Barley Ptt populations also had higher linkage disequilibrium levels, indicating less frequent sexual reproduction, consistent with the Red Queen hypothesis theory that genetically diverse hosts should select for higher levels of sexual reproduction of the pathogen. SSR analyses indicate that host-associated Ptt populations do not share genotypes and have independent evolutionary histories. Pathogenicity studies showed host specificity as host-associated Ptt isolates could not cross-infect hosts. Minimum spanning network analyses indicated two major clusters of barley Ptt. One cluster represents Maritime virulent and isolates from Western Australia (WA). Low PhiPt population differentiation between WA populations and those from Maritime and Keel, indicated a WA origin of the Maritime and Keel virulences. The main minimum spanning network cluster is represented by a panmictic population structure, represented by isolates from all over Australia. Conclusions Although barley Ptt populations are more diverse than barley grass Ptt populations, this may be a result of the size and number of founder Ptt populations to Australia, with larger and more barley Ptt populations introduced. More frequent sexual reproduction of Ptt on barley grass support the Red Queen Hypothesis and suggest evolutionary potential of pathogens on diverse hosts are high. Extensive gene flow of Ptt between regions in Australia is suggested to maintain a panmictic population structure, with human-mediated dispersal aiding in virulence evolution of Ptt on barley. Electronic supplementary material The online version of this article (10.1186/s12862-019-1446-8) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Host specialisation and disparate evolution of Pyrenophora teres f. teres on barley and barley grass

Linde

Smith

2019

BMC Evol Biol

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“…Net form of net blotch (NFNB) caused by ascomycete fungus Pyrenophora teres f. teres ( Ptt ) is considered one of the most widespread and destructive diseases of barley ( Hordeum vulgare L.) crops worldwide. For susceptible cultivars, NFNB can result in yield losses up to 40% (Steffenson et al, 1991; Murray and Brennan, 2010), and under extreme epidemic conditions may cause even higher losses, up to 70% (Wallwork et al, 2016). Still, the most effective means of control is the use of resistant cultivars.…”

Section: Introductionmentioning

confidence: 99%

“…Ptt is a highly diverse pathogen (Khan and Tekauz, 1982; Steffenson and Webster, 1992; Robinson and Jalli, 1997; Afanasenko, 2001; Serenius, 2006; Liu et al, 2012). However, the measure of virulence diversity is limited by the number of differential genotypes used in the tests (Wallwork et al, 2016). The barley cultivar, Canadian Lake Shore (CLS), has been used in numerous studies examining the virulence of local Ptt isolates in different barley growing regions around the world (Gray, 1966; Gacek, 1985; Steffenson, 1988; Steffenson and Webster, 1992; Afanasenko et al, 1995; Minarikova, 1995; Minarikova and Polisenska, 1999; Gupta and Loughman, 2001).…”

Section: Introductionmentioning

confidence: 99%

Genetic Characterization of Resistance to Pyrenophora teres f. teres in the International Barley Differential Canadian Lake Shore

et al. 2019

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Genetic resistance to net form of net blotch in the international barley differential Canadian Lake Shore (CLS) was characterized and mapped. A doubled haploid (DH) population generated from a cross between CLS and susceptible cultivar Harrington was evaluated at the seedling stage using eight diverse Pyrenophora teres f. teres ( Ptt ) isolates and at the adult stage in the field using natural inoculum. To effectively map the CLS resistance, comparative marker frequency analysis (MFA) was performed using 8,762 polymorphic DArT-seq markers, where ‘resistant’ and ‘susceptible’ groups each comprised 40 DH lines displaying the most extreme phenotypes. Five DArTseq markers were consistently detected in eight disease assays, which was designated qPttCLS and deemed to harbor the locus underpinning CLS resistance. Four of these markers were present onto the barley DArTseq physical map and spans a region between 398203862 and 435526243 bp which were found to consist several genes involved in important plant functions such as disease response and signaling pathways. While MFA only detected the 3H region, genetic analyses based on segregation patterns were inconsistent, suggesting complex inheritance or variation in phenotypic expression of qPttCLS , particularly in the field. This study represents progress toward connecting Ptt pathotype surveys with the corresponding resistance genes in barley differentials. The markers associated with qPttCLS are useful for marker-assisted selection in breeding programs.

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“…() utilized greenhouse accelerated growth conditions to screen for novel APR phenotypes in wheat to leaf rust ( P. triticina ). Similar methodology was used by Wallwork, Butt, and Capio () to screen a significant number of barley accessions in the greenhouse under accelerated growth conditions to assess APR responses to Pyrenophora teres f. sp. teres , the causal agent of net form net blotch.…”

Section: Introductionmentioning

confidence: 99%

Rapid phenotyping of adult plant resistance in barley (Hordeum vulgare) to leaf rust under controlled conditions

et al. 2018

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Breeding for adult plant resistance (APR) is currently impeded by the low frequency of annual field‐based testing and variable environmental conditions. We developed and implemented a greenhouse‐based methodology for the rapid phenotyping of APR to leaf rust in barley to improve the efficacy of gene discovery and cloning. We assessed the effects of temperature (18 and 23°C) and growth stage (1–5 weeks) on the expression of APR in the greenhouse using 28 barley genotypes with both known and uncharacterized APR. All lines were susceptible in week 1, while lines carrying Rph20 and several with uncharacterized resistance expressed resistance as early as week 2. In contrast, lines lacking Rph20 and carrying either Rph23 and/or Rph24 expressed resistance from week 4. Resistant phenotypes were clearest at 18°C. A subset of 16 of the 28 lines were assessed for leaf rust across multiple national and international field sites. The greenhouse screening data reported in this study were highly correlated to most of the field sites, indicating that they provide comparable data on APR phenotypes for screening purposes.

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Pathogen diversity and screening for minor gene resistance to Pyrenophora teres f. teres in barley and its use for plant breeding

Cited by 18 publications

References 8 publications

Host specialisation and disparate evolution of Pyrenophora teres f. teres on barley and barley grass

Host specialisation and disparate evolution of Pyrenophora teres f. teres on barley and barley grass

Genetic Characterization of Resistance to Pyrenophora teres f. teres in the International Barley Differential Canadian Lake Shore

Rapid phenotyping of adult plant resistance in barley (Hordeum vulgare) to leaf rust under controlled conditions

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