A Novel WRKY Transcription Factor, ( Lam. Verdc.) Enhances Drought Stress Tolerance in Transgenic Groundnut ( L.) Plants.

Drought stress has adverse effects on growth, water relations, photosynthesis and yield of groundnut. WRKY transcription factors (TFs) are the plant-specific TFs which regulate several down-stream stress-responsive genes and play an essential role in plant biotic and abiotic stress responses. We found that gene is highly up-regulated under drought stress conditions and therefore isolated a new gene from a drought-adapted horsegram ( Lam. Verdc.). Conserved domain studies revealed that protein encoded by this gene contains highly conserved regions of two WRKY domains and two C2H2 zinc-finger motifs. The fusion protein localization studies of transient 3-YFP revealed its nuclear localization. Overexpression of TF gene in groundnut ( L.) showed increased tolerance to drought stress compared to wild-type (WT) plants. groundnut transgenics displayed lesser and delayed wilting symptoms than WT plants after 10-days of drought stress imposition. The transgenic groundnut plants expressing showed less accumulation of malondialdehyde, hydrogen peroxide (HO), and superoxide anion (O), accompanied by more free proline, total soluble sugar content, and activities of antioxidant enzymes than WT plants under drought stress. Moreover, a series of stress-related , and genes found up-regulated in the transgenic groundnut plants. The study demonstrates that nuclear-localized TF regulates the expression of stress-responsive genes and the activity of ROS scavenging enzymes which results in improved drought tolerance in groundnut. We conclude that may serve as a new putative candidate gene for the improvement of stress resistance in plants.