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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #384139
Research Project: Management of Pathogens for Strawberry and Vegetable Production Systems

Location: Crop Improvement and Protection Research

Title: Effector screening of secreted in xylem (SIX) genes from Fusarium oxysporum f. sp. lycopersici reveals several race 3 isolates containing AVR1

Author
item CARRILLO, J. - University Of Florida
item Martin, Frank
item VALLAD, G. - University Of Florida

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2021
Publication Date: 8/2/2021
Citation: Carrillo, J.D., Martin, F.N., Vallad, G.E. 2021. Effector screening of secreted in xylem (SIX) genes from Fusarium oxysporum f. sp. lycopersici reveals several race 3 isolates containing AVR1. American Phytopathological Society Annual Meeting, August 2-6, 2021 (virtual).

Interpretive Summary:

Technical Abstract: Fusarium wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici (FOL) is a soilborne disease present in many global production regions. Three FOL races are recognized, FOL3 is the predominant race in Florida, as most commercial varieties are resistant to FOL1 and FOL2. Specific secreted in xylem (SIX) genes that encode protein effectors corresponded to several immunity (I) genes and confer effective host resistance in tomato are associated with race designations. SIX4 (AVR1) is present in FOL1 isolates but absent in FOL2 and FOL3 and known to suppress I2 and I3 based host resistance. However, five recovered isolates from multiple production regions in Florida were identified as FOL3 through pathogenicity assays with tomato Fusarium wilt differentials, despite containing SIX4 as confirmed through sanger sequencing. Whole genome sequencing further confirmed the presence of SIX1-7 genes in two isolates in addition to SIX4. The sequences recovered from both approaches were 100% match to known FOL1 isolate IPO1530/B1 (Fol004). Further characterization is in progress. This is the first report of FOL3 isolates with this unique effector profile and emphasizes the need for continued monitoring and characterization of these evolving soilborne pathogens for resistance breeding, as well as for the development of reliable detection methods.