3.2.6. Chlorobiaceae

Among the green sulfur bacteria, betaine biosynthesis is found only in *Chloroherpeton thalassium*. The GMT sequence forms a separate line that associates distantly with those of the halophilic *Chromatiales* and *Actinobacteria* (Figure 1). Both methyltransferase genes are found in a small cluster together with the BetT transport system (Table 1).
