Homothallism in <i>Pseudoperonospora humuli</i>

Gent, David H.; Cohen, Yigal; Runge, Fabian

doi:10.1111/ppa.12689

Cited by 20 publications

(14 citation statements)

References 55 publications

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“…Pseudoperonospora humuli , the causal organism of hop downy mildew (DM), is an obligate biotrophic oomycete pathogen and has been a serious threat in recent years (Gent, Cohen, & Runge, 2017; Neve, 1991). Especially in humid hop‐growing areas, it is one of the most severe diseases that lead to losses in yield and quality, and current control of DM mainly depends on the use of pesticides or copper, as well as the planting of resistant genotypes.…”

Section: Introductionmentioning

confidence: 99%

Downy mildew resistance is genetically mediated by prophylactic production of phenylpropanoids in hop

Feiner

Pitra²,

Matthews³

et al. 2020

Plant Cell & Environment

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Downy mildew in hop (Humulus lupulus L.) is caused by Pseudoperonospora humuli and generates significant losses in quality and yield. To identify the biochemical processes that confer natural downy mildew resistance (DMR), a metabolome-and genomewide association study was performed. Inoculation of a high density genotyped F1 hop population (n = 192) with the obligate biotrophic oomycete P. humuli led to variation in both the levels of thousands of specialized metabolites and DMR. We observed that metabolites of almost all major phytochemical classes were induced 48 hr after inoculation. But only a small number of metabolites were found to be correlated with DMR and these were enriched with phenylpropanoids. These metabolites were also correlated with DMR when measured from the non-infected control set. A genome-wide association study revealed co-localization of the major DMR loci and the phenylpropanoid pathway markers indicating that the major contribution to resistance is mediated by these metabolites in a heritable manner. The application of three putative prophylactic phenylpropanoids led to a reduced degree of leaf infection in susceptible genotypes, confirming their protective activity either directly or as precursors of active compounds.

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Section: Introductionmentioning

confidence: 99%

Downy mildew resistance is genetically mediated by prophylactic production of phenylpropanoids in hop

Feiner

Pitra²,

Matthews³

et al. 2020

Plant Cell & Environment

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“…Oospore density was determined microscopically using a procedure modified from Spring and Zipper (2000) and Gent et al . (2017). Briefly, 1 g of leaf material was blended in a small stirrer (T‐line 101; Talboys Engineering) in 25 ml deionized water.…”

Section: Methodsmentioning

confidence: 99%

Temporal disease dynamics and relative importance of sexual and asexual reproduction of grape downy mildew (Plasmopara viticola) in an isolated vineyard in the North Georgia Mountains, USA

et al. 2020

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The North Georgia Mountains are the southernmost region along the United States East Coast where European wine grapes (Vitis vinifera) are grown commercially. Epidemics of downy mildew, caused by Plasmopara viticola, are frequent and severe, but little is known about the epidemiology and population biology of the pathogen in this region. Disease monitoring in an experimental vineyard from 2015 to 2017 indicated that times of disease onset and progress rates were highly variable across years and cultivars. Oospores were observed microscopically, and simulation with a process‐based model indicated presence of conditions favourable for oospore germination in the spring and early summer each year. A total of 409 P. viticola isolates collected over three years were genotyped with seven microsatellite markers, revealing very high genotypic diversity, which when combined with the observation of oospores is indicative of a sexually reproducing population. Among the 409 isolates, 225 multilocus genotypes (MLGs) were identified, of which 164 were detected only once and 61 were repeated (clonal). Eight MLGs (represented by 28 isolates) were detected across years, suggesting the possibility of asexual overwintering of P. viticola in this region. Across sampling dates, the percentage of isolates belonging to nonrepeated (unique) MLGs ranged from 27.3% to 63.2%. Even towards the end of the annual epidemic, the percentage of isolates in nonrepeated MLGs was still relatively high, around 30%. These MLGs may have originated from oospores germinating late during the growing season, although incomplete sampling at earlier dates and contribution by immigration cannot be fully excluded.

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“…However, more recent detailed studies using multilocus sequence analysis (nrITS, B-tub, coxII, and ypt1), provided strong support for retaining P. humuli and P. cubensis as separate taxa (Runge et al, 2011;Kitner et al, 2015). This coroborates with significant differences in sexual reproduction, where P. cubensis was heterothallic (Cohen and Rubin, 2012), whereas P. humuli was homothallic (Gent et al, 2017). Nevertheless, under laboratory conditions of artificial inoculation, some isolates of P. cubensis can infect hop and have limited sporulation and conversely, P. humuli can infect cucumber with limited success (Mitchell et al, 2011;.…”

Section: A Biological Featuresmentioning

confidence: 96%

Biological Characteristics and Assessment of Virulence Diversity in Pathosystems of Economically Important Biotrophic Oomycetes

Spring

Gómez-Zeledón

Hadziabdic

et al. 2018

Critical Reviews in Plant Sciences

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Plant biotrophic oomycetes cause significant production problems and economic losses in modern agriculture and are controlled by fungicide applications and resistance breeding. However, high genetic variability and fast adaptation of the pathogens counteract these measures. As a consequence of the "arms race," new pathogen phenotypes recurrently occur and may rapidly dominate the population when selected through the pressure of control measures. Intensive monitoring with fast and reliable identification of virulence phenotypes is essential to avoid epidemics and the economic consequences in agriculture. For some of the most important downy mildews and white blister rusts, bioassay-based differentiation has been established to classify infectivity of field isolates or cultivated strains on hosts of defined resistance. However, the testing is laborious, time-consuming, logistically demanding, and prone to impreciseness. Alternatively, host independent classification could overcome these problems and enable fast assessment of the infection risk when monitoring the local pathogen population. The prerequisite would be the identification of pathogen characters correlating with the infection behavior. This review examines the current situation of bioassay-based pathotyping in six of the most important biotrophic oomycetes (Plasmopara viticola, Plasmopara halstedii, Pseudoperonospora cubensis, Peronospora tabacina, Bremia lactucae, and Albugo candida) and gives an overview on attempts and progress to identify genetic markers of the pathogens that correlate with their infection behavior.

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Homothallism in Pseudoperonospora humuli

Cited by 20 publications

References 55 publications

Downy mildew resistance is genetically mediated by prophylactic production of phenylpropanoids in hop

Downy mildew resistance is genetically mediated by prophylactic production of phenylpropanoids in hop

Temporal disease dynamics and relative importance of sexual and asexual reproduction of grape downy mildew (Plasmopara viticola) in an isolated vineyard in the North Georgia Mountains, USA

Biological Characteristics and Assessment of Virulence Diversity in Pathosystems of Economically Important Biotrophic Oomycetes

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