Sexual Recombinants Make a Significant Contribution to Epidemics Caused by the Wheat Pathogen <i>Phaeosphaeria nodorum</i>

Sommerhalder, Rubik J.; McDonald, Bruce A.; Mascher, Fabio; Zhan, Jiasui

doi:10.1094/phyto-100-9-0855

Cited by 35 publications

(29 citation statements)

References 57 publications

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“…Sexual reproduction, which gives rise to windborne ascospores, could explain the current epidemics of brown spot needle blight in Switzerland, Germany and Austria (Angst 2011;Blaschke 2002;Hintsteiner et al 2012). Ascospore dissemination thus probably plays a major role in the long distance dispersal of L. acicola within Europe (Wingen et al 2013) as has also been seen for the wheat pathogen Phaeosphaeria nodorum (Sommerhalder et al 2010). Sexual reproduction allows for the formation of new haplotypes, while asexual reproduction can enhance fast multiplication of advantageous haplotypes.…”

Section: Reproductive Modementioning

confidence: 91%

Genetic Analyses Suggest Separate Introductions of the Pine Pathogen Lecanosticta acicola Into Europe

et al. 2016

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Lecanosticta acicola is a heterothallic ascomycete that causes brown spot needle blight on native and nonnative Pinus spp. in many regions of the world. In this study we investigated the origin of European L. acicola populations and estimated the level of random mating of the pathogen in affected areas. Part of the elongation factor 1-α gene was sequenced, 11 microsatellite regions were screened, and the mating type idiomorphs were determined for 201 isolates of L. acicola collected from three continents and 17 host species. The isolates from Mexico and Guatemala were unique, highly diverse and could represent cryptic species of Lecanosticta. The isolates from East Asia formed a uniform and discrete group. Two distinct populations were identified in both North America and Europe. Approximate Bayesian computation analyses strongly suggest independent introductions of two populations from North America into Europe. Microsatellite data and mating type distributions indicated random recombination in the populations of North America and Europe. Its intercontinental introduction can most likely be explained as a consequence of the movement of infected plant material. In contrast, the spread of L. acicola within Europe appears to be primarily due to conidial dispersion and probably also ascospore dissemination.

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Section: Reproductive Modementioning

confidence: 91%

Genetic Analyses Suggest Separate Introductions of the Pine Pathogen Lecanosticta acicola Into Europe

et al. 2016

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“…From the epidemiological perspective, determining the prevalent inoculum associated with epidemics is important for disease management and policy‐making. If sexual reproduction can occur then ascospores may play an important role in epidemics, serving as initial and secondary inoculum as well as contributing to the long distance dispersal of the pathogen, as demonstrated in other pathosystems (Shaw & Royle, ; Sommerhalder et al ., ).…”

Section: Introductionmentioning

confidence: 97%

Yellow sigatoka epidemics caused by a panmictic population of Mycosphaerella musicola in Brazil

Gomes

Douhan²,

Lehner

et al. 2017

Plant Pathology

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The genetic structure of Mycosphaerella musicola has never been investigated in Brazil to address epidemiologically related questions associated with yellow sigatoka. A total of 223 single‐conidium isolates from four regions (North, South, Zona da Mata and Triângulo Mineiro) of Minas Gerais State, Brazil, were used to assess the population genetic structure of M. musicola. Isolates were characterized regarding the frequency of the MAT1‐1‐1 or MAT1‐2‐1 idiomorphs and polymorphism at nine microsatellite loci. The mating‐type ratio in three of the four subpopulations was c. 1:1. A total of 87 alleles and 216 multilocus genotypes were identified. The overall population was in linkage equilibrium. Most (93.9%) genetic variation was detected within the subpopulations and there was weak differentiation between them. In total, eight genetic groups were detected and isolates of seven groups were present in all regions. The population of M. musicola in Minas Gerais seems to have high evolutionary potential: it is panmictic and both sexual reproduction and gene flow affect genetic variability. Strategies to avoid fungicide resistance should be enforced and breeding programmes need to consider quantitative resistance in the banana cultivars.

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“…The increase in the array of molecular techniques and computing technologies, offers endless possibilities of conducting mark-release-recapture experiments that allow tracking of inoculum sources during disease development and thus determines the inoculum origin (Bardin et al 2014;Sommerhalder et al 2010;Zhan et al 1998;Zhan and McDonald 2013). Mark-release-recapture experiments have been reported for the wheat pathogen Phaeosphaeria nodorum (Bennet et al 2007;Shah et al 1995) and other pathogens (Zhan and McDonald 2013).…”

Section: Introductionmentioning

confidence: 99%

Relative Contribution of Seed Tuber- and Soilborne Inoculum to Potato Disease Development and Changes in the Population Genetic Structure of Rhizoctonia solani AG 3-PT under Field Conditions in South Africa

et al. 2018

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Understanding the contribution of seed tuber-and soil-borne inocula of Rhizoctonia solani AG 3-PT in causing potato disease epidemics is an important step in implementing effective management strategies for the pathogen. A two-year study was conducted to evaluate the contribution of each source of inoculum using an integrative experimental approach combining field trials and molecular techniques. Two distinct sets of genetically-marked isolates were used as seed tuber-borne and soil-borne inocula in a mark-release-recapture experiment. Disease assessments were done during tuber initiation and at tuber harvest Both inoculuma sources were found to be equally important in causing black scurf disease, whereas soil-borne inocula appeared to be more important for root and stolon infection, and seed-borne inocula contributed more to stem canker. However, seed tuber transmitted genotypes accounted for 60% of the total recovered isolates when genotyped using three PCR-RFLP markers. The changes in population structure of the experimental 1 R. solani population over the course of the growing season and across two growing seasons were investigated using eight microsatellite markers. The populations at different sampling times were somewhat genetically differentiated as indicated by Nei's gene diversity (0.24 -0.27) and the fixation index (F ST ) . The proportion of isolates with genotypes that differed from the inoculants ranged from 13% to 16% in 2013 and 2014, respectively, suggesting the possibility of emergence of new genotypes in the field. Because both soilborne and tuber-borne inocula are critical, it is important to ensure the use of pathogen-free seed tubers to eliminate seed tuber-borne inoculum and the introduction of new genotypes of R. solani for sustainable potato production in South Africa.

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Sexual Recombinants Make a Significant Contribution to Epidemics Caused by the Wheat Pathogen Phaeosphaeria nodorum

Cited by 35 publications

References 57 publications

Genetic Analyses Suggest Separate Introductions of the Pine Pathogen Lecanosticta acicola Into Europe

Genetic Analyses Suggest Separate Introductions of the Pine Pathogen Lecanosticta acicola Into Europe

Yellow sigatoka epidemics caused by a panmictic population of Mycosphaerella musicola in Brazil

Relative Contribution of Seed Tuber- and Soilborne Inoculum to Potato Disease Development and Changes in the Population Genetic Structure of Rhizoctonia solani AG 3-PT under Field Conditions in South Africa

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