Function Analysis Of Na~+/H~+ Transport-related Protein OXHS6 In Rice

The soil salinization is one of the worst abiotic stress factors,which constrains seriously growth of crops leading to the reduced production.Therefore,cultivating salt-tolerant rice varieties has very important practical significance.Previouly,we cloned a salt stress-induced gene OXHS6 which codes a typical XHS protein including conserved domains XH,XS,and Zf-XS,however,its detailed biological function is largely unclear.Here,we plan to investigate the phenotype of OXHS6transgenic plants in salt stress,promoter analysis,and identification of down-regulated genes and interacting proteins of OXHS6 to research the function of OXHS6 on salt tolerance in rice.The main results are as follows:?1?The full-length CDS sequence of OXHS6 was constructed into the prokaryotic expression vector pET-28a and transformed into the expression strain BL21.One80KD protein was expressed in E.coli and identified to be the target protein OXHS6by western blot.?2?Partial cDNA sequence of OXHS6 was cloned into the RNAi vector ds1301 and transformed into japonica rice Zhonghua 11 by Agrobacterium.T₀ plants that the expression level of OXHS6 was suppressed significantly were identified by Real-Time PCR.?3?The OXHS6 over-expression and RNAi transgenic lines were identified through qPCR to conduct salt stress testing under different pH.The results showed that RNAi plants had higher sensitivity to salt stress,but overexpression of OXHS6 could increase the tolerance of rice to salt stress.The qPCR results showed that the expression level of OsHKT3,which involved in Na⁺transport,was up-regulated obviously in OXHS6 overexpression plants under salt treatment with different pH,whereas other OsHKT genes showed the opposite results compared to OsHKT3.These results indicated that OXHS6 could mediate salt resistance of rice through regulating OsHKT genes.?4?Gene OXHS6 was cloned into bait vector pDEST32,and 3 interacting protein were screened in rice cDNA library using yeast two hybrid after assessment of self-activation and determination of the 3-AT concentration.Our result would provide important clues to further research the molecular mechanism of OXHS6 on salt tolerance.