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POSTERS: Disease Detection and Diagnosis I

P-191 - A qPCR detection assay for Fusarium oxysporum f. sp. vasinfectum race 4 from artificially infested cotton seeds.

Monday, August 4, 2025
3:45 PM - 4:30 PM HST
Location: Exhibit Hall 3

    Author(s)

  • MU

    Michael Urner

    California State University, Fresno
    Fresno, California, United States

    • Presenting Author(s)

  • ME

    Margaret Lee Ellis

    Associate Professor
    California State University, Fresno
    Fresno, California, United States

    • Author(s)

  • MU

    Mauricio Ulloa

    USDA-ARS, Plains Area, Cropping Systems Research Lab, Plant Stress and Germplasm Development Research
    Lubbock, Texas, United States

Abstract Text: Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4), a causal agent of Fusarium wilt, has negatively impacted California cotton (Gossypium spp.) production for over two decades. FOV4 is a soilborne pathogen, but it has also been reported to be detected from cotton seed. Therefore, improved diagnostic methods for FOV4 are critical to help prevent the spread of FOV4 and to improve management practices. In this study, a protocol to detect FOV4 from artificially contaminated cotton seed was developed. Infestation rates of 10, 5, 1, 0.5, 0.25 and 0.125% were prepared by inoculating cotton seed of a susceptible Pima variety and mixing the FOV4-infested seed with non-infested seed. DNA extracted from cotton seeds at each infestation rate and DNA from non-infested seed was evaluated using a SYBR Green qPCR assay. The non-infested cotton seed was negative with no FOV4 DNA being detected. FOV4 DNA was detected from all artificially infested cotton seed rates of 0.125 to 10%. FOV4 DNA was detected as low as 6.0 x 10-3 ng from the 0.125% FOV4 infection rate treatment. The protocol developed in this study has potential utility in research and industry for detecting FOV4 infestations in cotton seed. Future studies are needed to establish the limits of FOV4 DNA detection, and to validate the protocol by testing potentially naturally infested seeds from cotton plants grown in fields with confirmed FOV4 infestation.