Transcriptional Activation of Glutamate Decarboxylase and F-Box DUF Protein-Encoding Genes Promote Enhanced Abiotic Stress Tolerance and Improved Agronomic Traits in Indica Rice

Abstract

In the present study, an activation-tagged (AT) rice line T8-Ds-RFP3 developed has been tested for its ability to combat drought and salinity stress conditions besides analysis of its genes associated with improved productivity traits. TAIL-PCR analysis revealed the integration site of Ds element at LOC_Os03g51080 locus in the genome of the AT line. qRT-PCR analysis of glutamate decarboxylase (GAD) and F-box DUF protein-encoding genes showed more than 10- and 14-fold increased expression levels in the AT line when compared to that of wild-type (WT) plants. AT plants subjected to drought and salinity stresses exhibited enhanced stress tolerance compared to WT plants besides increased root length, tiller number and number of grains per plant. Additionally, AT plants also disclosed increased accumulation of osmolytes and antioxidants under salt and drought stress conditions owing to their enhanced ROS detoxification ability. Furthermore, AT plants also disclosed improved plant water status, photosynthetic efficiency, stomatal conductance and water use efficacy confirming their explicit stress tolerance compared to WT plants. The overall results suggest the underlying coordinated expressions of F-box DUF and GAD genes contribute to the elevated stress tolerance as well as increased productivity of the AT plants. Accordingly, the T8-Ds-RFP3 AT line can serve as a potent genetic resource for optimizing rice cultivars with increased yield potential.