Ethanolamine induced modification in glycine betaine and proline metabolism in Nicotiana rustica under salt stress

The present study aimed to investigate the effects of ethanolamine on glycine betaine and proline metabolism in Nicotiana rustica under salt stress. The in vitro grown tobacco (Nicotiana rustica) plants were pretreated with ethanolamine (at concentrations 70, 130, 270, and 530 μM for biochemical analysis and only at the concentration of 530 μM for molecular analysis) and then transferred to Murashige and Skoog medium containing 200 mM NaCl for 3 weeks. Our results showed that ethanolamine promoted glycine betaine biosynthesis by an increase in betaine aldehyde dehydrogenase (BADH) gene expression and BADH enzymatic activity. Moreover, ethanolamine pretreatment possibly reduced proline content in salt stressed plants via its negative effect on Δ-pyrroline-5-carboxylate synthase (P5CS) gene expression and P5CS enzymatic activity and its positive effect on proline dehydrogenase (PDH) gene expression and PDH activity.