GsVAMP72, a novel Glycine soja R-SNARE protein, is involved in regulating plant salt tolerance and ABA sensitivity

Abiotic stress, especially high salinity, is a major threat to agricultural production. It has been well established that SNARE proteins sustain directed vesicle traffic to underpin plant growth and development, yet little is known about the role of SNARE protein in the capacity to withstand abiotic stress, especially in wild soybeans. Here we identified and characterized a GsCBRLK interacting protein, GsVAMP72, which is a putative vesicle-associated membrane protein in Glycine soja. GsVAMP72 protein has a longin domain at its N-terminus, belonging to R-SNARE family. Quantitative real-time (RT) PCR and beta-glucuronidase (GUS) activity assays revealed that the expression of GsVAMP72 was highly and rapidly induced by both high salt and ABA treatments. Overexpression of GsVAMP72 in Arabidopsis significantly reduced salt tolerance by modifying the ionic content and down-regulating expression of stress-responsive genes, including RD29A, COR47, KIN1, COR15A and RAB18. On the other hand, GsVAMP72 overexpression increased plant ABA sensitivity and altered the expression levels of ABA-responsive genes. Subcellular localization analysis showed that eGFP-GsVAMP72 fusion protein was observed on the plasma membrane-like and endosome-like structures but eGFP alone was distributing throughout the cytoplasm in Arabidopsis protoplasts and onion epidermal cells. GsVAMP72 promoter-controlled GUS activity was detected in both vegetative and reproductive organs, and was strongly induced by salt and ABA. In summary, we demonstrated that GsVAMP72 is a novel Glycine soja vesicle-associated membrane protein and is highly involved in regulating plant responses to salt and ABA stresses.