A novel hybrid proline-rich type gene GsEARLI17 from Glycine soja participated in leaf cuticle synthesis and plant tolerance to salt and alkali stresses

Recent discoveries showed that hybrid proline rich type proteins were involved in plant responses to several environmental stresses. However, little is known about their roles in plant alkali stress adaptation, especially in wild soybean. Here, we isolated and characterized GsEARLI17, a novel the hybrid proline-rich protein type EARLI family gene from Glycine soja. Bioinformatic analysis showed that GsEARLI17 protein contained a conserved N-terminus hybrid proline-rich domain in and a C-terminus 8CM domain. Transcript abundance of GsEARLI17 was higher in young tissues than that in old tissues, and induced following exposure to salt and alkali treatments. GsEARLI17 overexpression in Arabidopsis influenced cuticles formation, as evidenced by thicker cuticles of transgenic lines, and enhanced plant tolerance to salt stress. Further observation was found that compared to the wild type Arabidopsis, overexpression of GsEARLI17 in Arabidopsis improved seed germination with higher leaf opening and greening rate during the early stages under alkali stress. GsEARLI17 exhibited enhanced alkaline tolerance with higher chlorophyll content, and lower malondialdehyde content at the adult developmental stage, and the expression levels of some alkali stress response marker genes NADP-ME, H (+) Ppase were higher in the GsEARLI17 overexpression lines than in wild-type plants. Taken together we suggest that GsEARLI17 reveal a positive role in enhancing plant tolerance of alkali stress in Arabidopsis.