Identification of SABATH Family Members in Solanum lycopersicum and Their Expression Patterns Under Abiotic/Biotic Stresses

The SABATH family proteins catalyse S-adenosyl-l-methionine-dependent methylation of hormones, signal molecules and other metabolites in plants, and they play an important role in various processes of plant development, especially in plant resistance. Solanum lycopersicum is an important model plant and provides fleshy fruits that are widely used. To date, the SABATH family has not been investigated in Solanum lycopersicum. Here, a total of 20 SABATH amino acid sequences were identified and characterized in S. lycopersicum (SlSABATH). Phylogenetic analysis of different species indicated that these proteins could be classified into 3 groups, and proteins with similar functions were classified into the subclades. Chromosomal mapping showed that SlSABATH proteins were distributed on 7 chromosomes. Conserved domain and motif analysis revealed that these proteins shared homology in 10 motifs, and motifs 2 and 5 were the specific binding sites for S-adenosyl-l-methionine. The structural features of each SlSABATH member showed that those in the same subgroup containing the same exon-intron patterns generally catalysed the same substrate. There were 7 pairs in the SlSABATH family that were produced from the tandem duplication of genes and 2 pairs that were produced during the segmental duplication of genes; these were primary driving forces in the evolution of SlSABATH family. Plant hormone-responsive, stress-inducible and defence-related elements and light-responsive elements accounted for most of the cis regulatory-elements. Gene expression profiling revealed that most of the SlSABATH members were expressed in tissues, Solyc01g080970 was significantly expressed in fully opened flowers and Solyc09g091550 was abundantly expressed in stems. Many SlSABATH genes were significantly up- or downregulated by stress treatments (Pseudomonas syringae pv. tomato DC3000, cold and drought). The above results provide references to further study the function of SlSABATH family members in S. lycopersicum.