Overexpression of OsNAC17 Enhances Drought Tolerance in Rice

Abstract

Drought stress reduces crop production yields. Plant specific NAC transcription factors in rice are known to play an essential roles in stress resistance transcriptional regulation. However, It is still remains how each NAC genes involve transcriptional regulation in response to drought stress in rice. Here, we show that the rice (Oryza stiva L japonica) NAM, AFTF and CUC transcription factor OsNAC17, which is predominantly induced by abiotic stress in leaf, contributes to the drought tolerance in transgenic rice plants. We generate transgenic plants overexpressing OsNAC17 using constitutive (PGD1) promoter. Ectopic overexpression of OsNAC17 improved drought resistance phenotype at the vegetative stage. Agronomic traits such as grain yield, grain filling rate, and total grain weight improved by 22~64% over wild type plants under drought conditions during the reproductive stage. DEG profiling experiment identified 119 up-regulated genes by more than twofold (P<0.01). Differentially expressed genes include UDP-glycosyltransferase family protein, similar to 2-alkenal reductase (NADPH-dependent oxireductase), similar to retinol dehydrogenase 12, Lipoxygenase, and NB-ARC domain containing protein related in cell death. OsNAC17 acts as a transcriptional activator in transcriptional activation assay, which has an activation domain in C-terminal region. Furthermore, it was proved that OsNAC17 is localized in the nucleus. These result suggest that the overexpression of OsNAC17 improve drought tolerance by regulating ROS related enzymes and by reducing stomatal density.