Investigating the roles of an atlatoxin resistance-associated protein in maize using RNAi

Aflatoxins are carcinogens produced by Aspergillus flavus and A. parasiticus during infection of susceptible crops such as maize. Although resistant maize genotypes and resistance-associated proteins (RAPs) have been identified, the direct involvement of these proteins in resistance has been difficult to demonstrate until the recent discovery of a sequence-specific gene silencing phenomena called RNA interference (RNAi). In this study, RNAi technology is used to specifically silence a RAP gene and the resulting changes of kernel resistance in the silenced transformants will be evaluated. As a first step, a binary RNAi vector is being constructed with Gateway technology to eliminate several cloning steps. Afterwards, immature maize embryos will be transformed with the newly constructed RNAi vector through collaboration with Iowa State University. These RNAi studies should uncover the roles of RAP gene(s) in kernel resistance. Genes confirmed as important to resistance can then serve as markers for marker-assisted breeding.