GT Transcription Factors of Rosa rugosa Thunb. Involved in Salt Stress Response.

Rosa rugosa was a famous aromatic plant while poor salt tolerance of commercial cultivars has hindered its culture in saline-alkali soil. In many plants, the roles of GT (or trihelix ) genes in salt stresses responses have been emerging. In the wild R. rugosa, a total of 37 GTs ( RrGTs ) were grouped into GT-1, GT-2, GTγ, SH4, and SIP1 lineages. SIP1 lineage expanded by transposition. The motifs involved in the binding of GT cis-elements were conserved. Four RrGTs ( RrGT11/14/16/18 ) significantly differentially expressed in roots or leaves under salt stress. The responsive patterns within 8 h NaCl treatment indicated that RrGTγ-4 ( RrGT18 ) and RrGT-1 ( RrGT16 ) were significantly induced by salt in roots of R. rugosa . Subcellular localizations of RrSIP1 ( RrGT11 ) and RrGTγ-4 were on chloroplasts while RrGT-1 and RrSIP2 ( RrGT14 ) located on cell nucleus. Regulation of ion transport could be the most important role of RrSIPs and RrGTγ-4 . And RrGT-1 could be a halophytic gene with higher transcription abundance than glycophytic GT-1 . These results provide key clue for further investigations of roles of RrGTs in salt stress response and would be helpful in the understanding the salt tolerance regulation mechanism of R. rugosa .