Genetic Manipulation of Peanut for Enhancing Abiotic Stress Tolerance

Abstract

Transgenic plants of peanut var. JL 24, carrying the stress inducible drought responsive element (DRE), rd29A:DREB1A , from newlineArabidopsis thaliana , were successfully evaluated and screened for the induced drought tolerance using a lysimetric system-based drydown procedure. These transgenic events, which were in T3 generation, newlinewere advanced to T8 during this study, while confirming the presence and induced expression of the rd29A:DREB1A transgene at each of the advanced generations. Successive lysimetric system-based drydown experiments were carried in the P2-level contained greenhouse conditions during the post-rainy seasons of 2006, 2007 and 2008, while the first ever confined outdoor event selection trial under field conditions in the lysimeters was conducted during the post-rainy season of 2009. Lysimeters were used for growing the plants while terminal / intermittent drought stress (DS) was imposed at mid-flowering and peak pod-filling stage of the crop through the gradual drydown procedure. In each of the trials, six transgenic events, with varying transpiration efficiency (TE) were evaluated for their genotypic response in terms of changes in water uptake, i.e., transpiration (T), newlineaccumulated biomass, comprehensive root traits and ultimately pod yield, under the imposed DS relative to that under control well-watered (WW) conditions. Lysimeters made feasible the complete extraction of roots leading to detailed analysis of root architecture as well as measurements of yield components viz., T, TE and harvest newlinex index (HI), crucial for drought tolerance studies, simultaneous.