ARS | Publication request: RNAi-mediated elimination of toxic gossypol from cottonseed: A powerful model demonstrating the effectiveness of molecular tools to enhance global food security

Submitted to: American Society of Plant Biologists
Publication Type: Abstract Only
Publication Acceptance Date: July 18, 2009
Publication Date: July 22, 2009
Citation: Rathore, K.S., Sundaram, S., Sunilkumar, G., Campbell, L.M., Puckhaber, L.S., Stipanovic, R.D. 2009. RNAi-mediated elimination of toxic gossypol from cottonseed: A powerful model demonstrating the effectiveness of molecular tools to enhance global food security [abstract]. Proceedings of the American Society of Plant Biologists, July 18-22, 2009, Honolulu, Hawaii. p. 54.

Technical Abstract: Cottonseed, a byproduct of lint production, remains an abundant but greatly underutilized source of protein because of the presence of toxic gossypol. Annual, worldwide production of 44 million metric tons (MMT) of cottonseed contains ~10 MMT of protein, enough to meet the basic protein requirements of 500 million people. We utilized RNA interference to inhibit the expression of the <delta>-cadinene synthase gene in a seed-specific manner, thereby disrupting a key step in the biosynthesis of gossypol in cotton [Gossypium hirsutum L. Compared to an average gossypol value of 10 <mu>g/mg in wild-type seeds, seeds from RNAi lines showed values as low as 0.2 <mu>g/mg. Importantly, the levels of gossypol and related terpenoids that are derived from the same pathway were not diminished in the foliage and floral parts of mature plants and thus remain available for plant defense against insects and diseases. Further, we found that the germinating, RNAi seedlings are capable of launching terpenoid-based defense pathway when challenged with a pathogen. Thus, the silenced state of the <delta>-cadinene synthase gene that existed in the seed, does not leave a residual effect that can interfere with the normal functioning of the cotton seedling during germination. Evidence will be presented showing that transgene-encoded RNAi can be restricted in a spatial and temporal manner in cotton plants.