Ventosimonas gracilis gen. nov., sp. nov., a member of the Gammaproteobacteria isolated from Cephalotes varians ant guts representing a new family, Ventosimonadaceae fam. nov., within the order 'Pseudomonadales'.

Cephalotes 'turtle' ants are known to harbor a core group of gut symbionts, including members belonging to the Gammaproteobacteria. Here, we describe the cultivation and characterization of strain CV58T, a novel member of the Gammaproteobacteria order Pseudomonadales isolated from the guts of the ant Cephalotes varians. Strain CV58T was rod-shaped, Gram-stain-negative, non-motile and formed pale-yellow colonies on trypticase soy agar. Optimum growth occurred under an atmosphere of 4-20 % (v/v) O2. Growth was possible for strain CV58Tat NaCl concentrations of 0-1.5 % (w/v), temperatures of 23-40 °C, and pH values of 5.5-8.5. The G+C content of the genomic DNA was 54.9 mol% and the major fatty acids were C18 : 1ω7c, C16 : 0, C16 : 1ω7c/C16 : 1ω6c, C12 : 0 and C12 : 03OH. The only respiratory quinone detected was ubiquinone-9 (Q-9) and the major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Based on phylogenetic analysis of the 16S rRNA gene sequence, strain CV58T shared an 88.3 % nucleotide identity with its closest cultivated neighbor, Pseudomonas putida R43. We believe that this, combined with the housekeeping gene phylogeny, differences in phenotypic characteristics and cellular fatty acid compositions of other cultivated members indicates that strain CV58T represents a novel species occupying a novel genus and family within the order Pseudomonadales. Thus, we propose the name Ventosimonadaceae fam nov., followed by Ventosimonas gracilis gen. nov., sp. nov., to classify strain CV58T (=NCIMB 15011T =DSM 100910T).