Molecular characterization and expression profiles of GRAS genes in response to abiotic stress and hormone treatment in Tamarix hispida

GRAS (GAI, RGA and SCR) domain proteins are plant-specific transcriptional regulators that play roles in developmental processes and stress responses. However, the function and molecular regulatory networks of woody plant GRAS under various physiological conditions are still unclear. As a step toward understanding the GRAS function in plants under diverse environmental stimuli, a total of 12 GRAS genes from Tamarix hispida were identified and characterized. Sequence analysis showed that most of these ThGRASs contained a complete GRAS DNA-binding domain and a variable N-terminal region. Phylogenetic analysis revealed that these GRAS members were divided into PAT1, SHR, LISCL, DLT and DELLA groups. The expressions of each individual GRAS under various abiotic stress conditions or hormone treatments were investigated by real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR). qRT-PCR results showed that these ThGRASs were all differentially expressed in the roots or leaves of T. hispida under abiotic stress and hormone treatment, especially ThGRAS3, ThGRAS5, ThGRAS6, ThGRAS7 and ThGRAS10 genes, indicating that these genes were involved in abiotic stress responses and signaling pathways. This study provides a basis for the elucidation of the function of GRAS genes for future works.