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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Improvement Research » Research » Publications at this Location » Publication #424074
Research Project: Improvement of Disease and Pest Resistance in Barley, Durum, Oat, and Wheat Using Genetics and Genomics

Location: Cereal Crops Improvement Research

Title: Identification of a novel genetic locus conferring virulence in the wheat tan spot pathogen Pyrenophora tritici-repentis

Author
item GUO, JINGWEL - NORTH DAKOTA STATE UNIVERSITY
item SHI, GONGJUN - NORTH DAKOTA STATE UNIVERSITY
item ISLAM, MD. MUKUL - NORTH DAKOTA STATE UNIVERSITY
item KARIYAWASAM, GAYAN - NORTH DAKOTA STATE UNIVERSITY
item MOOLHUIJZEN, PAULA - CURTIN UNIVERSITY
item SEE, PAO-THEEN - CURTIN UNIVERSITY
item ZHONG, SHAOBIN - NORTH DAKOTA STATE UNIVERSITY
item ABOUKHADDOUR, REEM - AGRICULTURE AND AGRI-FOOD CANADA
item FARIS, JUSTIN
item FRIESEN, TIMOTHY
item LIU, ZHAUHUI - NORTH DAKOTA STATE UNIVERSITY

Submitted to: Fungal Genetics and Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2025
Publication Date: 5/16/2025
Citation: Guo, J., Shi, G., Islam, M., Kariyawasam, G., Moolhuijzen, P., See, P., Zhong, S., Aboukhaddour, R., Faris, J.D., Friesen, T.L., Liu, Z. 2025. Identification of a novel genetic locus conferring virulence in the wheat tan spot pathogen Pyrenophora tritici-repentis. Fungal Genetics and Biology. https://doi.org/10.1016/j.fgb.2025.104002.
DOI: https://doi.org/10.1016/j.fgb.2025.104002

Interpretive Summary: Tan spot is a leaf disease of wheat caused by a fungal pathogen that secretes specific proteins during infection. The fungal-produced proteins cause the plant to be susceptible to tan spot. To date, three such fungal proteins produced by the tan spot pathogen have been identified. In this study, researchers conducted genetic analyses on different fungal strains to identify a gene that produces a disease-inducing protein different from the previously identified proteins. This work provides knowledge regarding the mechanisms that plant pathogens use to cause disease and will lead to the development of new strategies for controlling yield losses attributed to tan spot.

Technical Abstract: The ascomycete Pyrenophora tritici-repentis (Ptr) is the causal agent of tan spot, a common and economically important wheat disease worldwide. Three necrotrophic effectors (NE), including Ptr ToxA, Ptr ToxB and Ptr ToxC, have been identified from the fungal pathogen acting as important virulence factors. However, many studies have suggested that the fungal pathogen produces additional NEs. To identify new NE gene (s) from race 2 isolate 86-124, we developed a biparental fungal population from a cross between this isolate and race 5 isolate DW5 using genetically modified heterothallic strains. The fungal population, designated 86-124/DW5, was subjected to genotyping with SNP and SSR markers as well as ToxA, mating type genes and six ToxB loci. Each progeny was phenotyped onto the hard red spring wheat line CDC-Osler which is insensitive to both Ptr ToxA and Ptr ToxB, but is highly susceptible to 86-124. The constructed genetic map consisted of 11 linkage groups which largely corresponded to the 11 chromosomes (chr) of Ptr reference genome. ToxA and mating type genes were mapped to the expected positions. Five of six ToxB copies are tightly linked with each other residing at the distal end of chr 11 while the sixth copy was located to the distal end of chr 5. Composite interval mapping revealed a major QTL on a distal end of chr 2 conferring virulence toward CDC-Osler by 86-124, designated as VirOsler1. Genomic sequence alignment at the locus showed the absence of approximate 900 kb region at the end of chr 2 in DW5. The identification of the VirOsler1 locus provides convincing evidence that the wheat tan spot system involves additional virulence factors that act on unidentified host susceptibility factor.