Tuesday, September 11, 2007

Alternative Respiration during Cotton Growth & Development

Dr. Hirut Kebede, Dr. Debjani Tripathy, Dr. Sangjoon Hwang, Dr. Norma Trolinder, and Dr. Robert Wright. Texas Tech University, Dept of Plant and Soil Science, Box 42122, Lubbock, TX 79409

The inability of varieties to reach their genetic potential is largely due to late season cool weather. Cool temperature during boll and fiber maturation greatly slows the deposition of cellulose in the secondary cell wall. The ultimate result can be immature fibers and lower yield.  In “voodoo lily” (Sauromatum guttatum) an increase in temperature of the floral tissue serves to volatilize aromatic compounds that attract pollinators. This stress response is regulated by the alternative oxidase enzyme (AOX). Unlike the lily, cotton does not need to attract pollinators, but an increase in temperature in the boll during exposure to low temperature would serve to provide a more optimum and stable environment for fiber development. Agrobacterium mediated transformation was used to created 31 independent transgenic lines that express the tobacco Aox1 gene.  Molecular analysis of several sequential generations putatively identified 13 single copy lines.  The spatial and temporal expression of two lines verified as single copy homozygotes was increased by 100 fold in stem, root and bolls (8-10 and 20-25 DPA) when compared to the null line.