Effector Polymorphisms of the Sunflower Downy Mildew Pathogen Plasmopara halstedii and Their Use to Identify Pathotypes from Field Isolates.

PLoS One

Institut National de la Recherche Agronomique, INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR441, F-31326 Castanet-Tolosan, France.

Published: July 2016

AI Article Synopsis

  • Plasmopara halstedii, the pathogen causing downy mildew in sunflowers, has shown changes in virulence that have led to the breakdown of resistance in sunflower hybrids over the past 25 years.
  • Researchers identified 54 effector genes from Pl. halstedii, which are involved in its ability to infect host plants, and found that these genes are more diverse than non-effector genes.
  • A new set of 22 molecular markers was developed to classify Pl. halstedii pathotypes, providing a quicker and more effective way to diagnose sunflower downy mildew compared to traditional methods that use live spores.

Article Abstract

The obligate biotroph oomycete Plasmopara halstedii causes downy mildew on sunflower crop, Helianthus annuus. The breakdown of several Pl resistance genes used in sunflower hybrids over the last 25 years came along with the appearance of new Pl. halstedii isolates showing modified virulence profiles. In oomycetes, two classes of effector proteins, key players of pathogen virulence, are translocated into the host: RXLR and CRN effectors. We identified 54 putative CRN or RXLR effector genes from transcriptomic data and analyzed their genetic diversity in seven Pl. halstedii pathotypes representative of the species variability. Pl. halstedii effector genes were on average more polymorphic at both the nucleic and protein levels than random non-effector genes, suggesting a potential adaptive dynamics of pathogen virulence over the last 25 years. Twenty-two KASP (Competitive Allele Specific PCR) markers designed on polymorphic effector genes were genotyped on 35 isolates belonging to 14 Pl. halstedii pathotypes. Polymorphism analysis based on eight KASP markers aims at proposing a determination key suitable to classify the eight multi-isolate pathotypes into six groups. This is the first report of a molecular marker set able to discriminate Pl. halstedii pathotypes based on the polymorphism of pathogenicity effectors. Compared to phenotypic tests handling living spores used until now to discriminate Pl. halstedii pathotypes, this set of molecular markers constitutes a first step in faster pathotype diagnosis of Pl. halstedii isolates. Hence, emerging sunflower downy mildew isolates could be more rapidly characterized and thus, assessment of plant resistance breakdown under field conditions should be improved.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4742249PMC
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0148513PLOS

Publication Analysis

Top Keywords

halstedii pathotypes
16
downy mildew
12
effector genes
12
halstedii
9
sunflower downy
8
plasmopara halstedii
8
halstedii isolates
8
pathogen virulence
8
discriminate halstedii
8
pathotypes
6

Similar Publications

Two new downy mildew resistance genes, Pl and Pl, were introgressed from wild sunflower species into cultivated sunflower and mapped to sunflower chromosomes 4 and 2, respectively Downy mildew (DM), caused by the oomycete pathogen Plasmopara halstedii (Farl.) Berl. & de Toni, is known as the most prevalent disease occurring in global sunflower production areas, especially in North America and Europe.

View Article and Find Full Text PDF

Yield losses in sunflower crops caused by can be up to 100%, depending on the cultivar susceptibility, environmental conditions, and virulence of the pathogen population. The aim of this study was to investigate the genetic and phenotypic structure of a sunflower downy mildew agent at the field scale. The genetic diversity of 250 isolates collected from one field in southern France was assessed using single-nucleotide polymorphisms (SNPs) and single sequence repeats (SSR).

View Article and Find Full Text PDF

Characterization and mapping of a downy mildew resistance gene, , in sunflower ( L.).

Mol Breed

February 2022

USDA-Agricultural Research Service, Wheat, Sorghum and Forage Research Unit, 251 Filley Hall/Food Ind. Complex, Lincoln, NE 68583 USA.

Unlabelled: Downy mildew (DM) is one of the most serious diseases in sunflower-growing regions worldwide, often significantly reducing sunflower yields. The causal agent of sunflower DM, the oomycete pathogen , is highly virulent and aggressive. Studying regional disease spread and virulence evolution in the DM pathogen population is important for the development of new sunflower inbred lines with resistance to the existing DM pathogen.

View Article and Find Full Text PDF

Sustainable and efficient control of sunflower downy mildew by means of genetic resistance: a review.

Theor Appl Genet

November 2022

Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Alameda del Obispo s/n, 14004, Córdoba, Spain.

The breeding of sunflower (Helianthus annuus L.) for resistance to downy mildew (caused by the oomycete Plasmopara halstedii Farl. Berl.

View Article and Find Full Text PDF

Downy mildew of sunflower, caused by (Farl.) Berl. et de Toni, is a relevant disease of this crop.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!

A PHP Error was encountered

Severity: Notice

Message: fwrite(): Write of 34 bytes failed with errno=28 No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 272

Backtrace:

A PHP Error was encountered

Severity: Warning

Message: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/sessions)

Filename: Unknown

Line Number: 0

Backtrace: