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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Research » Research » Research Project #429074

Research Project: Host-Pathogen Interactions in Fungal Diseases of Wheat and Barley

Location: Cereal Crops Research

Project Number: 3060-22000-050-00-D
Project Type: In-House Appropriated

Start Date: Mar 15, 2017
End Date: Mar 14, 2022

Objective:
Objective 1: Characterize the Septoria nodorum blotch of wheat interaction by identifying and characterizing necrotrophic effectors produced by Parastagonospora nodorum. Sub-objective 1.A.Generate a highly saturated genome wide single nucleotide polymorphism (SNP) and presence-absence variation (PAV) marker set using 1) predicted small secreted protein genes with presence-absence variation and 2) full genome resequencing of U.S. P. nodorum isolates collected from spring, winter, and durum wheat). Sub-objective 1.B. Collect disease data on wheat lines selected from different wheat classes including spring wheat, winter wheat, and durum wheat, and use this data in conjunction with subobjective 1A to identify genomic regions harboring virulence genes using a genome-wide association study (GWAS) analysis. Sub-objective 1.C. Identify and validate candidate virulence genes in the MTA regions identified in the data collected in sub objective 1B. Objective 2: Genetically characterize the mechanism of virulence used by Pyrenophora teres f. teres and P. teres f. maculata in causing barley net form and spot form net blotch, respectively. Sub-objective 2.A.Use a characterized bi-parental mapping population of P. teres f. teres to identify genes associated with virulence on barley lines Rika and Kombar. Sub-objective 2.B. Assemble, phenotype, and obtain whole genome sequences of a set of 124 P. teres f. teres isolates from the U.S., N. Africa, and Europe to be used in GWAS analysis to identify and characterize genomic regions associated with virulence/avirulence. Sub-objective 2.C. Use a P. teres f. maculata bi-parental mapping population to identify and characterize genomic regions and the underlying genes associated with virulence.

Approach:
Fungal diseases of small grains pose an economic threat to production throughout the US and the world. This project focuses on two fungal pathogens in an effort to better understand pathogenicity, virulence, and host resistance. It is our goal to identify and characterize pathogenicity/virulence factors of Pyrenophora teres f. teres (net form net blotch of barley), P. teres f. maculata (spot form net blotch of barley), and Parastagonospora nodorum (Septoria nodorum blotch of wheat), and evaluate their importance in each disease interaction. Our approach will be to: a) identify necrotrophic effectors and other components of virulence important in the Parastagonospora nodorum – wheat interaction using a genome wide association study (GWAS) approach involving full genome sequencing of a worldwide collection of P. nodorum isolates, b) Identify both virulence and avirulence factors in the P. teres f. teres – barley interaction by GWAS using a P. teres f. teres collection obtained from barley regions of the United States (North Dakota, Montana), Northern Europe, and North Africa (Morocco), and c) use previously characterized biparental mapping populations of both P. teres f. teres and P. teres f. maculata to identify and validate candidate genes that are associated with major virulence/avirulence QTL. These approaches will allow us to genetically characterize these interactions and will provide an opportunity to identify the genes underlying the virulence of each pathogen. Identification of virulence genes will allow us to better understand how these pathogens parasitize the plant. Understanding both how the pathogen infects the host and how the host defends itself are critical to defending against this disease.