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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Research » Research » Research Project #431199

Research Project: Net Blotch of Barley, Identification and Characterization of Host Resistance Genes and the Interacting Pathogen Effectors

Location: Cereal Crops Research

Project Number: 3060-22000-050-38-T
Project Type: Trust Fund Cooperative Agreement

Start Date: May 15, 2016
End Date: May 14, 2021

Objective:
Use Pyrenophora teres f. teres mapping populations to identify and characterize genomic regions associated with virulence on barley.

Approach:
Identification of pathogen effectors using pathogen-mapping populations. Segregating pathogen populations, like barley mapping populations, can be used to characterize traits of interest. In previous work funded by the NDBC, we crossed two P. teres f. teres isolates (6A and 15A) that produce virulence factors that target the barley 6H region. Isolate 6A induces disease on the cultivar Rika by interacting with rpt.r and isolate 15A induces disease on the cultivar Kombar by interacting with rpt.k, therefore, progeny from the genetic cross of 15A and 6A can be used to characterize the virulence that targets the 6H region in both Rika and Kombar. Additionally, we identified 468 SNP markers and used these markers to generate a genetic map for the characterization of pathogen virulence. Four major virulence loci were identified including two conferring virulence on Kombar and two conferring virulence on Rika. These virulences correspond to the susceptibility genes on barley chromosome 6H. Using the current 15A × 6A genetic map in conjunction with additional next generation long read (PAC BIO) sequencing we have assembled the genomic regions around these virulence genes and identified candidates for validation. In the coming year, validation and characterization of the candidate genes will be initiated. Currently, eight candidates have been prioritized with strong potential as virulence factors. Criteria used for prioritizing these candidates include size (<50kDa), harboring a secretion signal sequence, cysteine rich (this is a character of many effectors), and lack of homology to other known fungal genes. Validation of these eight genes will be done by transformation of the genes into avirulent P. teres isolates as well as by site directed gene disruption in virulent isolates (Liu and Friesen 2012) followed by evaluation of the change in virulence of each transformed pathogen strain using the barley lines Rika and Kombar.