Genome-Wide Dissection of MATE Gene Family in Cultivated Peanuts and Unveiling Their Expression Profiles Under Aluminum Stress

Peanut faces yield constraints due to aluminum (Al) toxicity in acidic soils. The multidrug and toxic compound extrusion (MATE) family is known for extruding organic compounds and transporting plant hormones and secondary metabolites. However, the MATE transporter family has not yet been reported in peanuts under the Al stress condition. In this genome-wide study, we identified 111 genes encoding MATE proteins from the cultivated peanut genome via structural analysis, designated as <i>AhMATE1</i>-<i>AhMATE111</i>. Encoded proteins ranged from 258 to 582 aa residues. Based on their phylogenetic relationship and gene structure, they were classified into six distinct groups. Genes were distributed unevenly on twenty peanut chromosomes. Chr-05 exhibited the higher density of 12%, while chr-02 and chr-11 have the lowest 1% of these loci. Peanut MATE genes underwent a periodic strong to moderate purifying selection pressure during evolution, exhibiting both tandem and segmental duplication events. Segmental duplication accounted for 82% of the events, whereas tandem duplication represented 18%, with both events predominantly driving their moderate expansion. Further investigation of seven <i>AhMATE</i> genes expression profiles in peanut root tips resulted in distinct transcriptional responses at 4, 8, 12, and 24 h post-Al treatment. Notably, <i>AhMATE</i> genes exhibited greater transcriptional changes in the Al-tolerant cultivar 99-1507 compared to the Al-sensitive cultivar ZH2 (Zhonghua No.2). Our findings provide the first comprehensive genome-wide analysis of the MATE family in cultivated peanuts, highlighting their potential roles in response to Al stress.