Comprehensive genome-wide identification and expression analysis of the SAMS gene family in peanut (Arachis hypogaea L.)

Background -adenosyl-L-methionine synthetase (SAMS) catalyzes the synthesis of S -adenosylmethionine (SAM), a universal methyl donor, and regulate plant growth, development, and stress responses. Although SAMS genes have been functionally characterized in several plant species, their roles in peanut ( Arachis hypogaea L.) remain unclear. Results Here, we conducted a genome-wide identification and characterization of the SAMS gene family in peanut. Nine AhSAMS genes were identified and mapped to five chromosomes. Phylogenetic analysis clustered these genes into five groups, revealing close evolutionary relationships with soybean SAMS homologs. Conserved domain and motif analyses indicated that all AhSAMS proteins share highly conserved functional features. Expression profiling revealed tissue-specific patterns, AhFJ1AK4 was highly expressed, while AhRG5YED and AhPNM9T4 were preferentially expressed in reproductive organs. Promoter analysis identified abundant cis -regulatory elements related to stress and hormone responses. Upon Ralstonia solanacearum infection and treatments with salicylic acid, abscisic acid, and methyl jasmonate, AhRG5YED and Ah6Q1KS5 were significantly induced in the resistant cultivar H108, suggesting their potential involvement in stress response pathways. Conclusions This study provides the first comprehensive analysis of the AhSAMS gene family in peanut, offering insights into their functional diversification. In particular, AhRG5YED and Ah6Q1KS5 are highlighted as promising candidates for improving bacterial wilt resistance in peanut through molecular breeding.