3.2.3. Cyanobacteria

Clearly two distinct branches of common GMT sequences of betaine biosynthesis are found in *Cyanobacteria* (Figure 1). The most divergent branch in the tree is represented by the *Prochlorococcus* group, including *Synechoccoccus* WH8102 and *Prochlorococcus marinus*. The second major phylogenetic branch of *Cyanobacteria*, the *Halothece/Aphanothece* group, is represented by the most prominent member of halophilic *Cyanobacteria*, *Aphanothece*

*halophytica* (*Halothece* PCC7418), and several *Chroococcales*, including *Euhalothece natronophila* and *Rubidibacter lacunae*, but also *Dactylococcopsis salina,* which might be misclassified as a member of the *Synechococcales*.
