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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #402393
Research Project: Disease Management and Improved Detection Systems for Control of Pathogens of Vegetables and Strawberries

Location: Crop Improvement and Protection Research

Title: Fusarium oxysporum f. sp. fragariae race 2 in California did not evolve through a single mutation in the AvrFW1 avirulence gene

Author
item Henry, Peter
item DILLA-ERMITA, CHRISTINE - University Of California
item PENNERMAN, KAYLA - Oak Ridge Institute For Science And Education (ORISE)

Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/17/2023
Publication Date: 8/20/2023
Citation: Henry, P.M., Dilla-Ermita, C., Pennerman, K.K. 2023. Fusarium oxysporum f. sp. fragariae race 2 in California did not evolve through a single mutation in the AvrFW1 avirulence gene. International Congress of Plant Pathology, August 20-25, 2023, Lyon, France.

Interpretive Summary:

Technical Abstract: In the fall of 2022, Fusarium oxysporum f. sp. fragariae (Fof) race 2 was discovered for the first time in California. This new race was comprised of a single strain that caused severe Fusarium wilt of strawberry and was present in multiple fields at the time of its discovery. The resistance gene it overcame, called FW1, was fortuitously present in commercially available strawberry cultivars at the time of Fof race 1’s discovery in 2006 and was a critical tool for managing disease caused by Fof race 1. This presentation will review what is known about the emergence of this new pathogen, gene-for-gene interactions between Fof and FW1-resistant strawberry cultivars, and new insights about the evolutionary mechanisms that led to the emergence of Fof race 2 in California. Knocking out a single avirulence gene from Fof race 1 confers pathogenicity on FW1-resistant varieties, but FW1-resistant varieties retain quantitative resistance to the Fof race 2 strains generated by single-gene knockouts. By contrast, wild Fof race 2 isolates collected from diseased strawberry plants in Japan and California are equally virulent on FW1-resistant and fw1-susceptible cultivars. These wild Fof race 2 isolates share several potentially important pathogenicity factors that are absent in other Fof race 1 strains. These data suggest that a fully virulent race 2 phenotype cannot be gained by a single mutation in an avirulence gene; acquisition of other virulence factors is also necessary.