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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 #410578

Research Project: Development of Climate Resilient Germplasm and Management Tools for Sustainable Row Crop Production

Location: Plant Stress and Germplasm Development Research

Title: A secreted in xylem (six) gene is highly conserved in fusarium oxysporum f. Sp. Vasinfectum race 4

item Jobe, Timothy
item URNER, MICHAEL - Fresno State University
item Ulloa, Mauricio
item Broders, Kirk
item HUTMACHER, ROBERT - University Of California, Davis
item ELLIS, MARGARET - Fresno State University

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/30/2023
Publication Date: 1/3/2024
Citation: Jobe, T.O., Urner, M., Ulloa, M., Broders, K.D., Hutmacher, R., Ellis, M.L. 2024. A secreted in xylem (six) gene is highly conserved in fusarium oxysporum f. Sp. Vasinfectum race 4. National Cotton Council Beltwide Cotton Conference.

Interpretive Summary:

Technical Abstract: Diseases such as Fusarium wilt (Fusarium oxysporum f. sp vasinfectum (FOV)) represent extreme threats to cotton production. FOV is a widespread soilborne pathogen that causes vascular plant disease in cotton and is responsible for substantial crop and economic losses worldwide. There are six numbered FOV races currently recognized, which are FOV1, FOV2, FOV3/5, FOV4/7, FOV6, and FOV8. Of these, FOV1, FOV2, FOV3, FOV4, and FOV8 have been reported in the US. In addition, two biotypes (VCG01111 and VCG01112) of FOV are specific to the continent of Australia. Single gene molecular markers aimed at quickly identifying and differentiating FOV races have been developed. These markers are useful for classifying new FOV isolates into races as each race has been associated with unique polymorphisms. However, multigene phylogenies using different combinations of the EF1-a, mitochondrial small subunit ribosomal DNA (mtSSU rDNA), nitrate reductase (NIR), phosphate permease-like protein (PHO), and beta-tubulin (BT) gene sequences often lead to conflicting results. It is currently unclear which method best reflects the evolutionary history of the organism. More importantly, none of these marker genes can be linked to the variable pathogenicity of the races. Additional genetic markers linked to FOV race pathogenicity are needed to better assess the threat of novel isolates to cotton production. Thus, in this study, a collection of Fusarium oxysporum isolates composed primarily of FOV races was screened for the presence or absence of fourteen SIX effector genes (SIX1-SIX14). These genes have been linked to pathogenicity in other formae speciales but have not been evaluated in FOV to date. Our results show that the most virulent FOV races, FOV4 & FOV7, share a common SIX effector. This effector is largely absent in other races of FOV in North America making it a potential target for rapid detection of these highly virulent FOV strains and enabling race specific FOV quantification in infected cotton plants.