Genome-Wide Identification of MATE Gene Family in Potato (Solanum tuberosum L.) and Expression Analysis in Heavy Metal Stress

A genome-wide identification and expression analysis of multidrug and toxic compound extrusion (MATE) gene family in potato was carried out to explore the response of MATE proteins to heavy meta stress. In this study, we identified 64 MATE genes from potato genome, which are located on 12 chromosomes, and are divided into I–IV subfamilies based on phylogenetic analysis. According to their order of appearance on the chromosomes, they were named from StMATE1–64. Subcellular location prediction showed that 98% of them are located on the plasma membrane as transporters. Synteny analysis showed that five pairs of collinearity gene pairs belonged to members of subfamily I and subfamily II had two pairs indicating that the duplication is of great significance to the evolution of genes in subfamilies I and II. Gene exon–intron structures and motif composition are more similar in the same subfamily. Every StMATE gene contained at least one cis-acting element associated with regulation of hormone transport. The relative expression levels of eight StMATE genes were significantly upregulated under Cu(2+) stress compared with the non-stress condition (0 h). After Cd(2+) stress for 24 h, the expression levels of StMATE33 in leaf tissue were significantly increased, indicating its crucial role in the process of Cd(2+) stress. Additionally, StMATE18/60/40/33/5 were significantly induced by Cu(2+) stress, while StMATE59 (II) was significantly induced by Ni(2+) stress. Our study initially explores the biological functions of StMATE genes in the regulation of heavy metal stress, further providing a theoretical basis for studying the subsequent molecular mechanisms in detail.