Heterologous expression of the halophyte Zoysia matrella H⁺-pyrophosphatase gene improved salt tolerance in Arabidopsis thaliana.

Abstract A number of vacuolar H + -pyrophosphatase (VP) family genes play important roles in plant growth under salt stress condition. Despite their biological importance in plant salt-stress regulation, there is no report about VP in the halophytic turfgrass Zoysia matrella . Here, we isolated ZmVP1 , a type I VP homologues gene encoding 768 amino acids by using the degenerated PCR and RACE PCR methods from Zoysia matrella . The expression level of ZmVP1 was significantly induced by salinity, drought and cold, but not by heat. ZmVP1 can restore the salt-tolerant ability of a salt-sensitive yeast strain. Overexpression of ZmVP1 in Arabidopsis thaliana resulted in more vigorous growth under salt stress. Moreover, the transgenic Arabidopsis accumulated more Na + and K + in the leaves compared to that of wild type plants under salt stress, had higher activities of V-ATPase and V-PPase, and showed higher relative gene expression levels of 5 stress-related genes ( AtNHX1 , AtLEA , AtP5CS , AtMn-SOD , AtAPX1 ). These results demonstrated that ZmVP1 from Z. matrella was a functional tonoplast H + -pyrophosphatase contributing to salt tolerance potentially through regulating the Na + compartment in vacuole, K + assimilation, osmotic regulation and antioxidant response.