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Transcriptomic analysis for differentially expressed genes in response to the phytoalexin gossypol in Fusarium oxysporum f. sp. vasinfectum

Ambika Pokhrel: Auburn University

<div><em>Fusarium oxysporium</em> f.sp <em>vasinfectum</em> (FOV) is a soilborne filamentous fungus that causes vascular wilt in cotton. In response to pathogens including FOV, cotton plants produce the phytoalexin gossypol as a defense mechanism. This research aims to explore the molecular mechanisms utilized by FOV to tolerate the antimicrobial action of gossypol during infection and colonization of cotton. To identify these mechanisms candidate genes that could be responsible for gossypol tolerance were identified through RNA sequencing. Four RNA samples were extracted from germlings of a virulent race 4 genotype FOV isolate, grown in minimal medium before and after treatment of 80 ug/mL of gossypol at 1, 2 and 4 hours. RNA sequence data showed upregulation of ABC and major facilitator transporters and several classes of dehydrogenases when compared with the non-treated FOV control RNA sample. The last phase of this work involves validation of genes identified through RNA sequencing in gossypol tolerance. This will be done through generation of mutants using CRISPR-Cas9 technology. The research findings will help to understand how a pathogen can develop mechanisms to overcome these plant antimicrobial compounds.</div>