Genome-wide characterization of MATE family members in Cucumis melo L.and their expression profiles in response to abiotic and biotic stress

The multidrug and toxic compound extrusion(MATE) family plays pivotal roles in the detoxification process in plants, while no information has been provided for this gene family in melon(Cucumis melo L.) thus far, limiting our understanding of its functions in melon acclimation to stressful environments. In this study, a total of 39 MATEs(CmMATE1–CmMATE39) were observed in the melon genome;these were unevenly distributed in all chromosomes, with the most on Chromosome 1. Based on their orthologous relationship with those from Arabidopsis, rice, and sorghum, melon MATEs were clustered into three subfamilies of Clades Ⅰ, Ⅱ, and Ⅲ, wherein 23, 9, and 7 members were included, respectively.Variable exon number was observed in CmMATEs, and the most were harbored by CmMATE8. Gene ontology(GO) term and cis-regulatory element(CRE) analyses pointed to the potential roles of CmMATEs in both the regulation of melon development and acclimation to various abiotic and biotic stressors. The RNA-seq and qRT-PCR(quantitative real-time PCR) results demonstrated that under normal growth conditions, CmMATEs were expressed in a tissue-and development-specific manner, while their abundance apparently varied in a stress-dependent manner when melon plants were exposed to unfavorable environmental conditions. Altogether, these observations could expand our knowledge about the plant MATE family and benefit functional genomics analysis for CmMATEs in the future.