The Involvement of DNA Methylation in Plant Growth Regulators-Mediated Growth in Tomato (Solanum lycopersicum) Seedlings.

DNA methylation is a kind of epigenetic modification regulated by DNA methyltransferases and DNA demethylases. Here, the influences of DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-azadC) combined with plant hormones [abscisic acid (ABA), methyl jasmonate (MeJA), and gibberellic acid (GA₃)] and small gaseous signal molecules [(nitric oxide (NO), hydrogen sulfide (H₂S), and hydrogen gas (H₂)] on the tomato (Solanum lycopersicum) seedlings growth were explored. Moreover, the expression levels of DNA methyltransferases and demethylases under plant hormones and small gaseous molecules were detected. We found that ABA and MeJA restrained tomato seedling growth, and GA₃, NO, H₂S, and H₂ promoted seedling growth. Nevertheless, 5-azadC treatment retarded the effects of these plant growth regulators mentioned above. Moreover, ABA boosted SlDRM5 expression, whereas GA₃ and MeJA treatments inhibited the expression. Sodium hydrosulfide and hydrogen-rich water treatments affected SlDRM5 expression. Moreover, MeJA increased the quantity of SlDML1 transcripts from 3 to 24 h, while other therapies decreased the quantity. It is interesting to note that GA₃ expressively induced SlMET1 and SlDML2 expression. Hence, DNA methylation may be essential for plant growth and is controlled by phytohormones and gaseous signal channels. The findings above offer fresh perspectives on how DNA methylation inhibitor reacts to different plant growth regulators. [ABSTRACT FROM AUTHOR]