Characterization of wheat (Triticum aestivum) TIFY family and role of Triticum Durum TdTIFY11a in salt stress tolerance

The TIFY proteins constitute a plant-specific super-family and they are involved in regulating many plant processes, such as development, defences and stress responses. The Jasmonate-ZIM-Domain (JAZ) proteins, the best-characterized sub-group of the TIFY family are key regulator of the jasmonic acid (JA) signalling pathway. Jasmonates regulate several aspects of plant development, and play a primary role in defence mechanisms as well as in plant responses to abiotic stresses. The TIFY family is well studied in dicots but poorly investigated in monocots. The present study reports an extensive genomic identification of TIFY proteins from Triticum aestivum. We identified 49 TIFY genes, which were annotated according to three sub-genomes (AABBDD) of T. aestivum. Following their clustering with Oryza sativa and Brachypodium distachyon, the 49 genes were grouped in 18 different TIFY homeologous subsets. Expression analyses of 6 representative TIFY genes on Tunisian durum wheat seedlings revealed their differential regulation by various stress treatment, including JA, ABA and salt stress. TIFY11a was specifically induced after salt treatment. Transgenic lines over-expressing TdTIFY11a showed higher germination and growth rates under high salinity conditions, compared to wild type plants. In summary, our results outline a relevant role of wheat TIFY proteins in promoting germination under salt stress.