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ARS Home » Plains Area » Lubbock, Texas » Cropping Systems Research Laboratory » Plant Stress and Germplasm Development Research » Research » Publications at this Location » Publication #403238
Research Project: Development of Economically Important Row Crops that Improve the Resilience of U.S. Agricultural Production to Present and Future Production Challenges

Location: Plant Stress and Germplasm Development Research

Title: Characterization of FOV4 and new Fusarium variants isolated from cotton roots in California

Author
item Jobe, Timothy
item GARCIA, JORGE - Fresno State University
item Ulloa, Mauricio
item ELLIS, MARGARET - Fresno State University
item HUTMACHER, ROBERT - University Of California, Davis

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/12/2023
Publication Date: 8/16/2023
Citation: Jobe, T.O., Garcia, J., Ulloa, M., Ellis, M.L., Hutmacher, R. 2023. Characterization of FOV4 and new Fusarium variants isolated from cotton roots in California. Plant Health 2023 Meeting.

Interpretive Summary:

Technical Abstract: While multiple races of Fusarium oxysporum f. sp vasinfectum (FOV) have been identified, FOV race 4 (FOV4) is considered to be the most virulent wilt pathogen in the U.S. disrupting cotton production in infested fields in California, far West Texas, and New Mexico. Preventing the spread of this pathogen and developing resistant cotton varieties to mitigate FOV4 losses are key goals of the cotton community. To meet these goals, there is an urgent need to improve our molecular understanding of FOV and identify key differences between FOV races. In the current study, Fusarium strains were isolated from symptomatic plant roots from field sites known to have FOV4 in California. Sites were chosen due to stand loss and early seedling death and other typical FOV symptoms on known commercial resistant varieties. Sequencing of the EF1-alpha gene confirmed the presence of FOV4 and FOV3-like isolates. Surprisingly, we also isolated FOV that could not be classified by race using the current suite of diagnostic markers and formed a new clade, diverging genetically from previous known FOV isolates. A screen for additional diagnostic markers of FOV4 identified a genetic locus present in all FOV4 tested, but not in other FOV races. The presence of this marker in the unclassified Fusarium isolates suggests these strains are either a new biotype of FOV4 or that horizontal gene transfer has occurred between FOV4 and a yet unclassified Fusarium. It is important to distinguish these existing and emerging genotypes for managing FOV and breeding more resistant and resilient varieties of cotton.