Systematic Comparisons of Orthologous Selenocysteine Methyltransferase and Homocysteine Methyltransferase Genes from Seven Monocots Species

Identifying and manipulating genes underlying selenium metabolism could be helpful for increasing selenium content in crop grain, which is an important way to overcome diseases resulted from selenium deficiency. A reciprocal smallest distance algorithm (RSD) approach was applied using two experimentally confirmed Homocysteine S-Methyltransferases genes (HMT1 and HMT2) and a putative Selenocysteine Methyltransferase (SMT) from dicots plant Arabidopsis thaliana , to explore their orthologs in seven sequenced diploid monocot species: Oryza sativa , Zea mays , Sorghum bicolor, Brachypodium distachyon, Hordeum vulgare , Aegilops tauschii (the D-genome donor of common wheat) and Triticum urartu (the A-genome donor of common wheat). HMT1 was apparently diverged from HMT2 and most of SMT orthologs were the same with that of HMT2 in this study, leading to the hypothesis that SMT and HMT originate from one common ancestor gene. Identifying orthologs provide candidates for further experimental confirmation; also it could be helpful in designing primers to clone SMT or HMT orthologs in other crops.