Three sequences (KX768754, KX810197, KX810198), assembled from metagenomic data, were obtained by sequencing DNA from the New Zealand native fuchsia psyllid, Ctenarytaina fuchsiae (family Aphalaridae). Phylogenetic analysis of these three sequences from the 16S rRNA operon, the rplJ - rplL region and the DNA-directed RNA polymerase α subunit, indicated the presence of a novel species of Candidatus Liberibacter, for which the binomial ‘Candidatus Liberibacter ctenarytainae’ is proposed.
The genus Liberibacter includes five unculturable species assigned Candidatus (Ca.) status: The pathogenic L. solanacearum, L. asiaticus, L. americanus, L. africanus and the endophytic L. europaeus; and one culturable, non-pathogenic, species assigned full status, L. crescens. The five Ca. Liberibacter species are vectored by/associated with psyllid species in the Psyllidae and Trizoidae families of the Psylloidea superfamily. In 2015, a new species, ‘Ca. L. carribeanus’, was reported from the psyllid, Diaphorina citri and citrus samples from Columbia based on 92-96% similarity of 16S rRNA sequence from this new species to that of other Ca. Liberibacter species. Further, in 2015 sequences with 99% identity to Ca. Liberibacter 16S rRNA sequences were found in the Australian native psyllid Acizzia solanicola and ‘Ca. L. brunswickensis’ proposed as the name for this species.
The three C. fuchsiae metagenomic sequences had significant similarities to (Ca.) Liberibacter sequences: the 1.4 kbp 16S rRNA sequence was 95.6% similar to the same region of Ca. L. europaeus. Maximum likelihood phylogenetic analyses revealed that these new sequences were not derived from any currently known species, have distinct lineages and most likely originate from a new-to-science Liberibacter species. This is the first report of Ca. Liberibacter sequences in a psyllid species that is not a member of either the Psyllidae or Triozidae families providing initial evidence that this bacterial genus may be more widely distributed in the Psylloidea superfamily than is currently recognised.