Genome-wide bioinformatics analysis revealed putative substrate specificities of SABATH and MES family members in silver birch (Betula pendula)

Plant SABATH family members catalyze the methylation of many hormones, signaling molecules, and floral scent metabolites, including salicylic acid (SA), jasmonic acid (JA), and indol-3 acetic acid (IAA). Demethylation of resulting methyl esters was executed by members of the MES family. Members of both families are significantly involved in plant developmental processes. Here, using different bioinformatics tools, we studied the evolutionary relationship and characterized the putative functions of the family members in silver birch (Betula pendula). It is a socio-ecologically important tree species and plays a vital role in reforestation. Ten and twelve members of the SABATH (BpSABATH1-10) and MES (BpMES1-12) family were identified in silver birch, respectively at the gene and enzyme levels. The BpSABATH and BpMES genes were distributed on seven of fourteen chromosomes, indicating the occurrence of moderate duplication events important for the expansion of both families. Phylogenetic clustering and the gene ontology database suggest, BpSA-BATH8 is involved in the methylation of indole-3-acetic acid (IAA), while BpSABATH5, BpSABATH6, and BpSABATH7 methylate JA to methyl jasmonate (MeJA). BpSABATH9 was alone in the phylogenetic functional group 1 and prefers SA as a substrate to synthesize methyl salicylate (MeSA). Likewise, BpMES5 and BpMES12 are possibly involved in the demethylation of the methyl ester of IAA, while BpMES6, BpMES7, and BpMES8 are responsible for the demethylation of MeJA. BpMES9 clustered with MES and prefers MeSA as a substrate. The current analysis helped to select candidate genes that could be subjected to further molecular breeding of birch varieties adapted to biotic and abiotic stress conditions.