TaFLZ54D enhanced salt stress tolerance of wheat by interacting with TaSGT1a and TaPP2Ca

FCS-like zinc finger (FLZ) gene family are C2-C2 zinc finger proteins taking part in seed dormancy, resistance to Myzus persicae 1, sucrose signaling and abiotic stresses. However, the function, especially the molecular mechanism of FLZs are not well understood now. In this study, we characterized 120 FLZs in wheat and revealed the function and mechanism of TaFLZ54D increasing salt stress tolerance in transgenic wheat. Expression analysis demonstrated TaFLZ54D was induced by NaCl treatment and has the highest expression level under NaCl treatment among 120 FLZs. Over-expression of TaFLZ54D increased wheat salt stress tolerance and the transgenic plants have higher level of SOD and POD enzyme activity, soluble sugar content, lower Na+/K+ ratio and MDA content than the wild type ones. Potassium ion transmembrane transporters and serine/threonine kinase inhibitor proteins showed differential expression between TaFLZ54D transgenic wheat and the wild type. Yeast two hybrid and luciferase complementation assay revealed TaSGT1a and TaPP2Ca were the direct interaction proteins of TaFLZ54D. To sum up, TaFLZ54D enhanced salt stress tolerance through interacting with TaSGT1a and TaPP2Ca to decrease Na+ absorption and mitigate oxidative stress. The interaction between TaFLZ54D and TaSGT1a or TaPP2Ca indicated a linker between salt stress tolerance of TaFLZ54D and the ubiquitination degradation of negative regulatory proteins.