Identification and expression pattern analysis of BpGRAS gene family in Bergenia purpurascens and functional characterization of BpGRAS9 in salt tolerance.

Abstract

Bergenia purpurascens is an important medicinal, edible, and ornamental plant. It generally grows in extreme environments with complex stresses. The GRAS transcription factors play a crucial role in regulating plant stress tolerance and growth-development. There is no research on GRAS transcription factors in B. purpurascens. In this study, 29 B. purpurascens GRAS (BpGRAS) genes were identified based on B. purpurascens transcriptome data. These BpGRAS genes were classified into seven subfamilies according to phylogenetic analysis, while BpGRAS1 was not classified into any other subfamilies. The motif analysis showed that the protein motifs in the same subfamily were relatively conserved. The expression pattern analysis of BpGRAS genes in different tissues and under salt stress showed that eight BpGRAS genes were differentially expressed under salt stress. The expression profiles showed that BpGRAS9 might play an important role in salt response and the transgenic Arabidopsis thaliana lines with overexpressed BpGRAS9 showed the enhanced salt tolerance. Root length and fresh weight were significantly increased in transgenic lines under salt conditions. The studies enhanced our comprehension of the function of BpGRAS and established a more foundation for exploring the molecular mechanisms underlying plant salt tolerance.