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Oral: Translational Research for the Management of Complex Diseases


Accelerating the selection of candidate genes to control mycotoxin contamination of maize through host-induced gene silencing (HIGS)
B. BLUHM (1), J. Smith (2), Y. Ramegowda (2), B. Dhillon (2), W. Shim (3), C. Woloshuk (4) (1) University of Arkansas, U.S.A.; (2) University of Arkansas, U.S.A.; (3) Texas A&M University, U.S.A.; (4) Purdue University, U.S.A.

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The maize ear rot pathogens Fusarium verticillioides and Aspergillus flavus contaminate grain with fumonisins and aflatoxins, respectively. Both categories of toxins pose severe health risks and limit grain marketability. Despite extensive breeding efforts in maize, adequate resistance to mycotoxin accumulation has not been developed. Additionally, current tools available to control mycotoxin contamination in maize are limited in number and efficacy. Recently, host-induced gene silencing (HIGS) utilizing hairpin RNA (hpRNA) has been advanced as an approach to silence genes underlying plant pathogenesis in filamentous fungi. We developed an efficient process to select and evaluate fungal gene targets for HIGS. In this approach, hpRNA constructs are evaluated for their ability to suppress target gene expression in fungi before transgenic maize plants are created. Our strategy to create hpRNA constructs minimizes cloning steps, thus accelerating the evaluation of candidate genes and creation of transgenic maize plants. To date, constructs have been created that target fumonisin and aflatoxin biosynthetic genes, as well as global regulators of mycotoxin biosynthesis. Advanced lines of transgenic maize plants are currently being tested for suppression of mycotoxin biosynthesis.