Function of wheat Ta-UnP gene in enhancing salt tolerance in transgenic Arabidopsis and rice

Based on microarray analysis results of the salt tolerant wheat mutant, we identified and cloned an unknown salt-induced gene Ta-UnP (Triticum aestivum unknown protein). Quantitative PCR results revealed that Ta-UnP expression was induced not only by salt but also by polyethylene glycol, abscisic acid, and other environmental stress factors. Under salt stress, transgenic Arabidopsis plants that overexpressed Ta-UnP showed superior physiological properties (content of proline, soluble sugar, MDA, and chlorophyll) compared with the control. Subcellular localization demonstrated that Ta-UnP was mainly localized on the cell membrane. The expressions of nine salt tolerance-related genes of Arabidopsis in Ta-UnP-overexpressed Arabidopsis were analyzed via qPCR, and the results revealed that the expressions of SOS2, SOS3, RD29B, and P5CS were significantly up-regulated, whereas the other five genes only slightly changed. The results of the salt tolerance analysis indicated that Ta-UnP can enhance the salt tolerance of transgenic rice plants, and RNAi transgenic rice plants became highly susceptible to salt stress. The results from this study indicate that this novel Ta-UnP may be useful in improving of plant tolerance to salt stress.