Expression Analysis of the Bet Locus Encoding the Glycine Betaine Biosynthesis Pathway in Sinorhizobium meliloti

Glycine betaine can be used both as an osmoprotective molecule and as carbon and nitrogen source for growth by S. meliloti. It is synthetized from choline by a two-step pathway catalyzed by the enzymes choline dehydrogenase (CDH) and betaine aldehyde dehydrogenase (BADH) encoded by the genes betA and betB, respectively (Smith et al., 1988; Pocard et al., 1997).