|Stipanovic, Robert - Bob|
Submitted to: World Cotton Research Conference Proceedings
Publication Type: Review Article
Publication Acceptance Date: 8/14/2007
Publication Date: N/A
Technical Abstract: Annual, worldwide cottonseed output can potentially provide the protein requirements of half a billion people if it could be used directly as food. However, the presence of gossypol within seed-glands renders cottonseed toxic to humans and monogastric animals. Therefore, elimination of gossypol from cottonseed has been a long-standing goal of geneticists. The "glandless cotton" developed by breeders in the 1950s to meet this objective was commercially unviable because of the increased susceptibility of the plant to insect pests due to the systemic absence of glands that contain gossypol and other protective terpenoids. Thus, the promise of cottonseed in contributing to the food requirements of the burgeoning world population remained unfulfilled. We have demonstrated that RNA interference (RNAi) can be employed to disrupt gossypol production in a tissue (seed)-specific manner in cotton. Targeted engineering of the gossypol biosynthetic pathway by inhibiting the expression of a key gene encoding delta-cadinene synthase during seed development resulted in a significant reduction in cottonseed-gossypol levels. This trait was heritable and stable. Results from molecular and enzyme analyses on developing, transgenic embryos were consistent with the observed phenotype in the mature seeds. Most importantly, the levels of gossypol and related terpenoids in the foliage and floral parts were not diminished and thus remain available for plant defense against insects and diseases. This overcomes the major weakness of "glandless cotton". The use of reduced gossypol cottonseed either directly as food or indirectly as feed for the more efficient monogastric animals has the potential to significantly impact global food security.