Gen. Nov., Sp. Nov., a New Member of the Isolated from the Gut of the Cockroach

A novel bacterium designated G55GP and pertaining to the family was isolated from the gut of the Madagascar hissing cockroach . The Gram-negative cells were rod-shaped and non-motile. The complete 16S rRNA sequence of the strain G55GP showed the highest pairwise similarity to CFN-Cf-55T (95.35 %), suggesting it represents a potential new genus of the family . Phylogenetic analysis based on 16S rRNA gene and 106 orthologous housekeeping protein sequences revealed that G55GP forms a monophyletic clade with the genus , which thus far has also been isolated exclusively from insects. The G55GP genome size was 2.70 Mbp, and the G+C content was 45.4 mol%, which is lower than most acetic acid bacteria (51-68 mol%) but comparable to AH83 (45.1 mol%) and higher than A911 (36.8 mol%). Overall genome relatedness indices based on gene and protein sequences strongly supported the assignment of G55GP to a new genus within the family . The percentage of conserved proteins, which is a useful metric for genus differentiation, was below 54 % when comparing G55GP to type strains of acetic acid bacteria, thus strongly supporting our hypothesis that G55GP is a member of a yet-undescribed genus. The fatty acid composition of G55GP differed from that of closely related acetic acid bacteria, particularly given the presence of C 9/11 and the absence of C and C 2-OH fatty acids. Strain G55GP also differed in terms of metabolic features such as its ability to produce acid from d-mannitol, and its inability to produce acetic acid from ethanol or to oxidize glycerol to dihydroxyacetone. Based on the results of combined genomic, phenotypic and phylogenetic characterizations, isolate G55GP (=LMG 31394=DSM 111244) is considered to represent a new species in a new genus, for which we propose the name gen. nov., sp. nov.