Date of Award
Doctor of Philosophy (PhD)
Plant and Environmental Science
Fusarium wilt of cotton (Gossypium hirsutum and G. barbadense), caused by Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4), is the most threatening disease faced by today’s cotton breeders. During the past 20 years, over $7 million have been dedicated to efforts in breeding upland cotton for resistance to FOV4 while yielding little to no results. To counteract this, we conducted a study in Clint, TX, that utilized control plots and geostatistical methods to adjust phenotypic data for the heterogeneous distribution of FOV4 in the field, improving the accuracy of genetic resistance assessments. Concurrently, early-generation genetic mapping in the FOV4-resistant upland cotton cultivar U1 identified two glutamate receptor-like (GLR) genes, which contribute to FOV4 resistance through a mechanism that potentially increases calcium influx, thus activating an array of immune responses and defense pathways. Unique genetic variations in the GLR genes are implicated in developing an initial barrier to pathogen invasion and regulating subsequent defense mechanisms. Further, we performed transcriptomic analysis of pima cotton ‘DP348RF’, which possesses resistance to FOV4 and is incorporated as a field control for FOV4 screening programs. This analysis revealed a unique biofortification of the Casparian strip, a potentially crucial structural barrier against vascular colonization by FOV4. This multifaceted approach outlined in the following research combined spatial adjustment of field data with genetic and molecular profiling to unravel the complex interactions governing resistance to FOV4 in cotton, identifying novel models of pathogen resistance, and suggesting a comprehensive strategy for enhancing crop resilience to pathogens.
Parris, Stephen, "Integrated Techniques to Identify and Characterize Resistance to Fusarium Wilt Caused by Fusarium Oxysporum, F. SP. Vasinfectum Race 4 in Two Domesticated Gossypium Species" (2023). All Dissertations. 3534.
Author ORCID Identifier
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