Species delimitation within the group 16SrII phytoplasmas using genome analyses

Species delimitation is important because our understanding of an organism's biology and taxonomy are interdependent. Phytoplasmas are a group of phytopathogenic bacteria that have not yet been successfully cultured invitro. This has impeded the development of a cohesive and taxonomically significant system of classification for these bacteria. Instead, their taxonomy has largely focused on the 16S rRNA gene, which does not provide enough resolution to determin whether two individuals are distinct species. In this study, we used whole genome data to identify the species boundaries within the 16SrII phytoplasmas. Whole genome analyses were done using 42 phytoplasma strains classified into seven 16SrII subgroups, five 16SrII taxa without official 16SrII subgroup classifications, and one 16SrXXV-A phytoplasma used as the outgroup taxon.