Overexpression of MtWRKY76 increases both salt and drought tolerance in Medicago truncatula

WRKY transcription factors have been studied in a wide range of plant species, but have remained largely uncharacterized in legumes. To obtain insight into the functions of WRKY in legumes, we isolated and characterized one WRKY family member from Medicago truncatula, MtWRKY76, which belongs to sub-group II. Expression analysis showed that MtWRKY76 was rapidly induced by abiotic stresses. MtWRKY76 overexpression markedly enhanced the salt and drought tolerance of transgenic M. truncatula and triggered abiotic inducible genes. MtWRKY76 was located in the nucleus and interacted with Medtr1g098680.1 that was deduced as ASR protein, which acted as a component of a transcription-regulating complex involved in abiotic stress signalling pathways. Interestingly, MtWRKY76 was found to be involved in regulated abiotic pathways via Solexa/Illumina digital gene expression (DGE) analysis. In conclusion, we demonstrated that MtWRKY76 was a multifunctional abiotic stress response gene in M. truncatula.