The Role of ABFs and CBFs in Abiotic Stress Tolerance

Though climatic conditions fluctuate from year to year, extreme drought and protracted periods of higher than normal temperatures, as were experienced this last summer, not only necessitate more irrigation to maintain a healthy cotton crop, but leads to elevated levels of abiotic stress, potentially reducing yield and quality. To combat these, and the corresponding aquifer depletion, our goal is to characterize a suite of genes which play a significant role in in drought and temperature stress response, and develop lines which are better able to withstand these stressors.

  Of the many gene families involved in abiotic stress response, the ABA-responsive element binding factors (ABFs) and C-repeat binding factors (CBFs) are of particular interest for their role in drought and temperature stress, respectively. In addition, these families have recently been shown to interact. Previous work has shown the constitutive overexpression of Arabidopsis ABF3 in cotton to confer a high level of water deficit tolerance, though this benefit was offset by delayed reproductive transition. Analyses of endogenous cotton ABF and CBF gene expression in cotton have, thus far, shown differential, marked increases and decreases of both of these families of genes under both water deficit and extreme temperatures. Though still in the early stages, we believe the overexpression select ABFs or CBFs in cotton will lead to the development of viable transgenics for commercialization.