Phylogenetics And Expression Of Methyltransferases And Demethylases In Potato

DNA methylation is a stable epigenetic mark. Methylation and demethylation play important role in diverse biological processes, including gene and transposon silencing, imprinting and X chromosome inactivation. These processes are involved in the growth and development of plant. Methyltransferases maintain and establish methylation, while demethylases catalyze the process of demethylation.As the third most important food crop in the world, potato has not been well studied in its DNA methylation, and the putative methyltransferases and demethylases have not been characterized. In this study, we analyzed sequence homology in order to predict potato methyltransferases and demethylases, made amino acid alignment of these two enzymes across12different species, built evolutionary trees and investigated the protein domains of these genes. There were9methyltransferase and4demethylase genes in the potato genome. We analyzed the relative transcript levels of methyltransferase and demethylase genes in the root, stem, leaf, flower, stolon and tuber of cultivar Atlantic with real-time PCR. Moreover, we used zebularine, a DNA methylation inhibitor, to treat test-tube plantlet, to understand the impact of application on the plant growth and the gene express of methyltransferases and demethylases. The results indicated that two putative chromomethylases CMT1.1and CMT1.2and one demethylase DMEb did not express in all the tissues. Zebularine did not activate CMT1.1, CMT1.2and DMEb, suggesting nonfunctional of these sequences. In the mature tuber of Atlantic, most genes of methyltransferases and demethylases had lower expression levels, implying that the pattern of methylation during tuber formation was different with those in other tissues.