Using a limited mapping strategy to identify major QTLs for resistance to grapevine powdery mildew (Erysiphe necator) and their use in marker-assisted breeding

ABSTRACT Isolates of the causal ascomycete of grapevine powdery mildew, Erysiphe necator, correspond to two genetically differentiated groups (A and B) that coexist on the same host. This coexistence was analyzed by investigating temporal changes in the genetic and phenotypic structures of E. necator populations during three epidemics. Group A was present only at the start of the growing season, whereas group B was present throughout all three epidemics. Group A was less aggressive in terms of germination and infection efficiency but was more aggressive than group B in terms of the latency period, lesion diameter, and spore production. Our results are consistent with a temporal differentiation of niches, preventing recombination, and suggest an association between the disease level and the frequencies of genetic groups.

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No Indication of Strict Host Associations in a Widespread Mycoparasite: Grapevine Powdery Mildew (Erysiphe necator) Is Attacked by Phylogenetically Distant Ampelomyces Strains in the Field

Phytopathology ◽

10.1094/phyto-10-11-0270 ◽

2012 ◽

Vol 102 (7) ◽

pp. 707-716 ◽

Cited By ~ 17

Author(s):

Alexandra Pintye ◽

Zsolt Bereczky ◽

Gábor M. Kovács ◽

László G. Nagy ◽

Xiangming Xu ◽

...

Keyword(s):

Powdery Mildew ◽

Environmental Fate ◽

Phylogenetic Analyses ◽

Inter Simple Sequence Repeat ◽

Issr Markers ◽

Genetic Distances ◽

Nuclear Ribosomal Dna ◽

Erysiphe Necator ◽

Grapevine Powdery Mildew ◽

Powdery Mildew Fungi

Pycnidial fungi belonging to the genus Ampelomyces are common intracellular mycoparasites of powdery mildews worldwide. Some strains have already been developed as commercial biocontrol agents (BCAs) of Erysiphe necator and other powdery mildew species infecting important crops. One of the basic, and still debated, questions concerning the tritrophic relationships between host plants, powdery mildew fungi, and Ampelomyces mycoparasites is whether Ampelomyces strains isolated from certain species of the Erysiphales are narrowly specialized to their original mycohosts or are generalist mycoparasites of many powdery mildew fungi. This is also important for the use of Ampelomyces strains as BCAs. To understand this relationship, the nuclear ribosomal DNA internal transcribed spacer (ITS) and partial actin gene (act1) sequences of 55 Ampelomyces strains from E. necator were analyzed together with those of 47 strains isolated from other powdery mildew species. These phylogenetic analyses distinguished five major clades and strains from E. necator that were present in all but one clade. This work was supplemented with the selection of nine inter-simple sequence repeat (ISSR) markers for strain-specific identification of Ampelomyces mycoparasites to monitor the environmental fate of strains applied as BCAs. The genetic distances among strains calculated based on ISSR patterns have also highlighted the genetic diversity of Ampelomyces mycoparasites naturally occurring in grapevine powdery mildew. Overall, this work showed that Ampelomyces strains isolated from E. necator are genetically diverse and there is no indication of strict mycohost associations in these strains. However, these results cannot rule out a certain degree of quantitative association between at least some of the Ampelomyces lineages identified in this work and their original mycohosts.

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Overwintering form of Erysiphe necator, the causal agent of grapevine powdery mildew in southern Syria

Journal of Plant Protection Research ◽

10.1515/jppr-2017-0017 ◽

2017 ◽

Vol 57 (2) ◽

pp. 129-135 ◽

Cited By ~ 1

Author(s):

Nujoud Alimad ◽

Walid Naffaa ◽

Fawaz Azmeh

Keyword(s):

Powdery Mildew ◽

Winter Season ◽

Causal Agent ◽

Bud Break ◽

Erysiphe Necator ◽

First Report ◽

Primary Inoculum ◽

Grapevine Powdery Mildew ◽

Histopathological Studies ◽

Grapevine Buds

AbstractThe main aims of this study were to determine the overwintering form and the primary inoculum ofErysiphe necator,the causal agent of grapevine powdery mildew in southern Syria. Eleven vineyards located at five different geographical sites were visited every week from March to November in 2014 and 2015. The results of field and histopathological studies showed thatE. necatorsurvived as mycelium in dormant grapevine buds during the winter season. The first flag shoots were observed shortly after bud break in spring. The number of flag shoots varied greatly according to vineyards, cultivars and years, being present on 27.4 to 61.9% of the grapevines in 2014, and on 5.2 to 40% of the grapevines in 2015. The percentage of flag shoots on the same grapevine also varied according to the year, cultivar and location. It was between 4.3 to 9.4% in 2014, and 2.1 to 3.6% in 2015. The disease was observed only on Balady and Black cultivars. Conidia were released from the second week of May to early September. The first conidia were trapped around mid-May, and the first secondary symptoms were observed on leaves from mid-May to early June according to the site. Chasmothecia were observed on leaves in 45.5% of the studied vineyards. The first observation of chasmothecia on leaves was in July, and their numbers varied greatly between vineyards and years. Chasmothecia were not detected on bark, nor were ascospores trapped at the beginning of the season. These results confirmed that the ascospores did not have any role in the initiation of spring infection. To the best of our knowledge, this is the first report of the overwintering form ofE. necatorin Syria.

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Sporulation rate in culture and mycoparasitic activity, but not mycohost specificity, are the key factors for selecting Ampelomyces strains for biocontrol of grapevine powdery mildew (Erysiphe necator)

European Journal of Plant Pathology ◽

10.1007/s10658-015-0834-1 ◽

2015 ◽

Vol 144 (4) ◽

pp. 723-736 ◽

Cited By ~ 8

Author(s):

Sara Elisabetta Legler ◽

Alexandra Pintye ◽

Tito Caffi ◽

Szilvia Gulyás ◽

Gyula Bohár ◽

...

Keyword(s):

Powdery Mildew ◽

Key Factors ◽

Erysiphe Necator ◽

Grapevine Powdery Mildew ◽

Sporulation Rate

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Isolation and identification of three new mycoparasites of Erysiphe necator for biological control of grapevine powdery mildew

Australasian Plant Pathology ◽

10.1007/s13313-019-00636-0 ◽

2019 ◽

Vol 48 (4) ◽

pp. 351-367

Author(s):

Shashikant B. Ghule ◽

Indu S. Sawant ◽

Sanjay D. Sawant ◽

Sujoy Saha ◽

R. M. Devarumath

Keyword(s):

Biological Control ◽

Powdery Mildew ◽

Isolation And Identification ◽

Erysiphe Necator ◽

Grapevine Powdery Mildew

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Grapevine powdery mildew (Erysiphe necator): a fascinating system for the study of the biology, ecology and epidemiology of an obligate biotroph

Molecular Plant Pathology ◽

10.1111/j.1364-3703.2011.00728.x ◽

2011 ◽

Vol 13 (1) ◽

pp. 1-16 ◽

Cited By ~ 95

Author(s):

DAVID M. GADOURY ◽

LANCE CADLE-DAVIDSON ◽

WAYNE F. WILCOX ◽

IAN B. DRY ◽

ROBERT C. SEEM ◽

...

Keyword(s):

Powdery Mildew ◽

Erysiphe Necator ◽

Grapevine Powdery Mildew ◽

Obligate Biotroph

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Occurrence of Erysiphe necator Chasmothecia and Their Natural Parasitism by Ampelomyces quisqualis

Phytopathology ◽

10.1094/phyto-99-6-0704 ◽

2009 ◽

Vol 99 (6) ◽

pp. 704-710 ◽

Cited By ~ 13

Author(s):

Dario Angeli ◽

Elisabetta Pellegrini ◽

Ilaria Pertot

Keyword(s):

Powdery Mildew ◽

Northern Italy ◽

Development Pattern ◽

Erysiphe Necator ◽

Ampelomyces Quisqualis ◽

Grapevine Powdery Mildew ◽

Severity Of The Disease ◽

Organically Grown ◽

Natural Parasitism

In northern Italy, Erysiphe necator overwinters almost exclusively as chasmothecia. From 2004 to 2008, we investigated the occurrence of natural parasitism of grapevine powdery mildew chasmothecia by Ampelomyces quisqualis in the Trentino-Alto Adige region, in northern Italy. The survey was conducted in 18 vineyards in autumn 2004 and 2005 and in 45 vineyards in autumn 2006 and 2007. The incidence of powdery mildew signs (white powdery mycelia and conidia), the number of chasmothecia and their development pattern, and the incidence of parasitism by A. quisqualis were assessed. The production of E. necator chasmothecia on leaves is related to the incidence and severity of the disease on leaves at the end of the season and is not correlated with the elevation of the vineyard, which is inversely related to the temperature. A limited amount of natural parasitism of E. necator by Ampelomyces spp. (0.17 to 3.51%) was observed in all of the years of the survey. Pycnidia and conidia of Ampelomyces spp. parasitizing E. necator chasmothecia were found in conventional, organically grown, and untreated vineyards. Some of the isolated Ampelomyces strains have conidia that are shaped differently than those of the commercial A. quisqualis strain (AQ10) and are phylogenetically different from AQ10.

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Genome Sequence Resource for Erysiphe necator NAFU1, a Grapevine Powdery Mildew Isolate Identified in Shaanxi Province of China

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-03-21-0061-a ◽

2021 ◽

Author(s):

Xingyuan Zhang ◽

Bo Mu ◽

Kaicheng Cui ◽

Min Liu ◽

Guihua Ke ◽

...

Keyword(s):

Powdery Mildew ◽

Genome Sequence ◽

Genome Assembly ◽

Gene Prediction ◽

Molecular Genetic ◽

Shaanxi Province ◽

Erysiphe Necator ◽

Protein Coding ◽

Sequencing Technologies ◽

Grapevine Powdery Mildew

Erysiphe necator is an economically important biotrophic fungal pathogen responsible for powdery mildew disease on grapevine. Currently, genome sequences are available for only a few Erysiphe necator isolates from USA. Based on the combination of Nanopore and Illumina sequencing technologies, we present here the complete genome assembly for an isolate of E. necator NAFU1 identified in China. We acquired a total of 15.93 Gb raw reads. These reads were processed into a 61.12 Mb genome assembly containing 73 contigs with the N50 of 2.06 Mb and a maximum length of 6.05 Mb. Combining the results of three gene-prediction modules, i.e. an evidence-based gene modeler (EVidenceModeler or EVM), an ab initio gene modeler, and a homology-based gene modeler, we predicted 7235 protein-coding genes in the assembled genome of E. necator NAFU1. This information will facilitate studies of genome evolution and pathogenicity mechanisms of E. necator and other powdery mildew species through comparative genome sequence analysis and other molecular genetic tools.

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Initiation and development of Erysiphe necator chasmothecia and their role in the epidemiology of grapevine powdery mildew in southern Syria

Acta Mycologica ◽

10.5586/am.1088 ◽

2016 ◽

Vol 51 (2) ◽

Cited By ~ 1

Author(s):

Nujoud Alimad ◽

Walid Naffaa ◽

Fawaz Azmeh

Keyword(s):

Powdery Mildew ◽

Microscopic Examination ◽

Fungal Disease ◽

Erysiphe Necator ◽

Initial Development ◽

First Report ◽

Primary Inoculum ◽

Grapevine Powdery Mildew ◽

Sudden Reduction

Powdery mildew caused by <em>Erysiphe necator</em> is the most important fungal disease of grapevine in southern Syria. The purpose of this study was to determine the development of chasmothecia and their role as a primary inoculum in spring. Leaves and/or branches were examined by a stereo binocular from July to December 2014 and 2015. The number of chasmothecia was estimated on both surfaces of the leaves, and their viability was estimated by microscopic examination. During 2 years of survey chasmothecia were detected in 45.5% of vineyards. The initial development of chasmothecia on infected leaves was observed in the second half of July. Their numbers increased from July to October, and the sudden reduction at the beginning of November was noted. Chasmothecia were formed on 38.7% of infected leaves, with 12.5%, 18.4%, and 7.5% on the upper, under and on both surfaces of infected leaves respectively. Chasmothecia were more frequent on the leaf under side (0.6 / leaf) than on the leaf upper side (0.4 / leaf), but their occurrence on both sides together was relatively low (0.2 / leaf), and their numbers were highly variable between vineyards and years. Microscopic examination showed that chasmothecia contained 1–5 (usually three) asci with 1–4 (usually three) ascospores in each asci, and 65.6% of chasmothecia were empty. Their viability decreased between December and February, with an average viability of 1.2% and 0.2% in March and April, respectively. Chasmothecia were not detected on bark and ascospores were not trapped at the beginning of the season. These results indicate that the ascospores have no or little role in the initiation of spring infection. To the best of our knowledge, this is the first report of <em>E. necator</em> chasmothecia development and their role in the initiating infection on grapevine in Syria.

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