Effects of Salinity, Drought and Osmotic Stress on Expression Pattern of Choline Monooxygenase (CMO) in Arabidopsis

Choline Monooxygenase (CMO) enzyme is a key component of glycine betaine (GB) biosynthesis pathway, playing important role in plant's biochemical adaptation to abiotic stresses. In plants, GB is synthetized by a two-step oxidation of choline (Cho) catalyzed by the CMO enzyme in the first step. According to the Arabidopsis thaliana genome database (TAIR) there is an AtCMO-like gene probably encoding for the Cho oxidizing enzyme to the GB. In this study, we used relative expression analysis via quantitative Real-Time PCR (qRT-PCR) to evaluate the effects of salinity stress, drought stress, and osmotic stress on the expression pattern of the gene in Arabidopsis thaliana tissues including fast-expanding leaves, fully expanded leaves, and roots. In general, the expression pattern of AtCMO-like gene varied through studied tissues in response to the different abiotic stresses. While the gene expression was affected mostly as the lack of changes and/or down-regulation; the only prominent up-regulation observed in fast expanding leaves and roots by about 3 and 1.9 folds, respectively, in response to the first level of salinity stress. We conclude that the AtCMO-like gene seems to negligibly influence the response to salinity stress, drought stress, and osmotic stress in Arabidopsis.