The timetree of phytoplasmas reveals new insights into the relationships with their insect and plant hosts

Phytoplasmas are a diverse monophyletic group of phytopathogenic bacteria. No attempts have yet been made to the estimate the divergence times of phytoplasma lineages. Reltime molecular divergence time analyses using 16S rRNA gene sequence data of Acholeplasmataceae was performed. The timetree of phytoplasmas, provided here for the first time, and based on prior divergence time estimates for two nodes within the Mollicutes, estimates the split between phytoplasma and Acholeplasma at about 663 million years ago (Ma), and initial diversification of the crown phytoplasma clade at about 330 Ma. Overall, these results suggest that phytoplasmas have been associated with insect and plant hosts at least since the carboniferous period.