Genome-Wide Identification and Characterisation of Wheat MATE Genes Reveals Their Roles in Aluminium Tolerance

The Multidrug and toxin efflux (MATE) gene family plays crucial roles in plant growth and development and response to adverse stresses. This work investigated the structural and evolutionary characteristics, expression profiling and potential functions involved in aluminium (Al) tolerance from a genome-wide level. In total, 211 wheat MATE genes were identified, which were classified into four subfamilies and unevenly distributed on chromosomes. Duplication analysis showed that fragments and tandem repeats played the main roles in the amplification of TaMATEs, and Type II functional disproportionation had a leading role in the differentiation of TaMATEs. TaMATEs had abundant Al resistance and environmental stress-related elements, and generally had a high expression level in roots and leaves and in response to Al stress. The 3D structure prediction by AlphaFold and molecular docking showed that six TaMATE proteins localised in the plasmalemma could combine with citrate via amino acids in the citrate exuding motif and other sites, and then transport citrate to soil to form citrate aluminium. Meanwhile, citrate aluminium formed in root cells might be transported to leaves by TaMATEs to deposit in vacuoles, thereby alleviating Al toxicity.