Overexpression of ZmDUF1644 from Zoysia matrella enhances salt tolerance in Arabidopsis thaliana

The DUF1644 family is a highly conserved and functionally unknown protein family and it has been demonstrated that it significantly improved the salt tolerance of rice (non-halophytes). However, little is understood about the function of the DUF1644 gene in halophytes. This study aimed to investigate whether the DUF1644 gene has a similar function in non-halophytes as in halophytic species. The functions of ZmDUF1644 transferred from the halophytic Zoysia matrella into non-halophytic Arabidopsis thaliana were investigated under salt stress (150 mM NaCl). Phylogenetic analysis clustered ZmDUF1644 and OsSDIP361 in the same group, which function as salt-tolerant genes in rice. The obtained results exhibited that the ZmDUF1644 gene significantly alleviated the adverse effects of salt stress on transgenic Arabidopsis thaliana seedlings. The maximum root length, fresh weight, and photosynthetic pigment content of the transgenic seedlings were obviously better than that of the wild type. The relative electrolyte leakage rate, Na+ content, and Na+/K+ ratios were relatively lower in the transgenic line than in the wild type under salt stress. Moreover, the expression of AtSOS2 gene was also significantly higher than that of wild-type under salt stress. The study concluded that the ZmDUF1644 gene was significantly overexpressed in salt-stressed Arabidopsis thaliana, enhancing its salt tolerance. It is the first report on the functions of ZmDUF1644 from halophytic Zoysia matrella which has a similar function in glycophytic species or non-halophytic species.