ARS | Publication request: Biosynthesis of Gossypol in cotton: From Farnesyl Diphosphate to (+)- and(-)-Gossypol

Submitted to: Phytochemical Society of North America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: October 25, 2011
Publication Date: N/A

Technical Abstract: Gossypol is a dimeric sesquiterpene that occurs in some members of the Malvaceae family. It occurs as an enantiomeric mixture in the foliage, seeds and roots of the cotton plant (Gossypium). It provides protection from insect and animal herbivory. Early studies demonstrated that gossypol is the product of cyclization of E,E-farnesyl diphosphate to (+)-delta-cadinene, which is converted to 8-hydroxy-(+)-delta-cadinene. Proposed intermediates beyond 8-hydroxy-(+)-delta-cadinene include desoxyhemigossypol and hemigossypol. At the time of its first discovery, hemigossypol was proposed to be the immediate precursor of gossypol; it was subsequently shown that hemigossypol is converted into gossypol by peroxidase, and 30 years later that a peroxidase in concert with a flower petal dirigent protein provides a 56% enantiomeric excess of (+)-gossypol. To complete the last step in the gossypol biosynthesis, a temporal study has now identified hemigossypol in developing cottonseed.