IDENTIFICATION AND CHARACTERIZATION OF A DIRIGENT PROTEIN THAT CONTROLS THE BIOSYNTHESIS OF (+)-GOSSYPOL IN COTTON
Insect Control and Cotton Disease Research Unit
2012 Annual Report
1a.Objectives (from AD-416):
1. Express cDNAs isolated from cotton that code for dirigent proteins in an insect/plant tissue culture system and assay for dirigent activity including the biosynthesis of (+)- or (-)-gossypol.
2. Transform cotton plants to optimize (+)-gossypol formation.
1b.Approach (from AD-416):
Cooperator will express appropriate cDNA sequences from cotton provided by the ARS cooperator in an insect/plant tissue culture system and test their activity for formation of (+)- or (-)-gossypol.
Gossypol is a compound that occurs naturally in cottonseed and is toxic to non-ruminant animals. Gossypol occurs in two forms; one is toxic and the other is relatively nontoxic. The goal of this project is to identify and characterize internal factors in the plant that control the production of the form that is minimally toxic to non-ruminant animals. Work during FY 2012 focused on analysis of flower petals of Gossypium hirsutum var. marie galante. Some of these plants produce gossypol with a high percentage of the nontoxic form [i.e., (+)-gossypol]. Flower petals were extracted to obtain DNA for analysis. Additional plants are being grown at College Station; these will provide genetic variation within the accessions of Gossypium hirsutum var. marie galante that can be used to further characterize the gene that controls this process. Ongoing work by this project will continue to make significant advances in understanding the genetic control of the (+)- and (-)-gossypol ratio in seed, and will provide foundational information for work to develop new cotton cultivars with low (-)-gossypol seed that can be safely fed to non-ruminant animals and thus expand utilization of cottonseed and enhance profitability of U.S. farmers.