Monitoring the Expression Pattern of Genes encoding S-adenosyl-L-methionine:phosphoethanolamine N-methyltransferase (PEAMT) enzyme in Arabidopsis under Drought Stress

In this study we use relative expression analysis via quantitative Real-Time PCR to evaluate the effects of drought on the expression pattern of genes coding for the enzyme S-adenosyl-L-methionine: phosphoethanolamine N-methyltransferase (PEAMT) in Arabidopsis thaliana. Tissues including fast-expanding leaves, fully expanded leaves, and roots have been considered. PEAMT plays a key role in the biosynthesis of phosphocholine. According to the Arabidopsis thaliana genome database (TAIR) there is one known gene At3g18000 (AtNMT1) and two putative genes At1g48600 (AtNMT2) and At1g73600 (AtNMT3) coding for the PEAMT enzyme. The tissue mRNA induction level of AtNMT1and AtNMT3 genes varied in response to drought levels, while AtNMT2 gene expression was affected negligibly by these factors. While withholding water for 12 days reduced the expression level of AtNMT1 in fast expanding and fully expanded leaves by about 0.8 folds, the expression level of the gene increased in roots by about 4.5 folds. In contrast, after 16 days without watering, the expression level of AtNMT1 rose about 2.5 folds and reduced to the level of control in fast expanding leaves and roots, respectively. The expression pattern of AtNMT3 suggests that AtNMT3 may be a drought responsive gene in roots. AtNMT3 expression in roots increased about 3.5 and 9 folds in response to 12 and 16 days of water deficit, respectively, despite the lack of changes and/or reduction in leaves. We conclude that the genes AtNMT1 and AtNMT3 may influence the response to drought stress in Arabidopsis.