Comparative genomic analysis of sp. nov. isolated from the International Space Station.

A single strain from the family was isolated from the wall behind the Waste Hygiene Compartment aboard the International Space Station (ISS) in April 2018, as part of the Microbial Tracking mission series. This strain was identified as a gram-positive, rod-shaped, oxidase-positive, catalase-negative motile bacterium in the genus , designated as F6_2S_P_1. The 16S sequence of the F6_2S_P_1 strain places it in a clade with and , which were originally isolated from plant tissue or rhizosphere environments. The closest 16S and gyrB matches to strain F6_2S_P_1 are to with 98.84 and 93.99% sequence similarity, while a core single-copy gene phylogeny from all publicly available genomes places it as more closely related to . Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values to any described species are <89 and <22%, respectively. The major fatty acids for strain F6_2S_P_1 are anteiso-C (51.7%), iso-C (23.1%), and iso-C (10.5%), and it is able to metabolize a wide range of carbon compounds. Given the results of the ANI and dDDH analyses, this ISS strain is a novel species within the genus for which we propose the name , with the type strain F6_2S_P_1 (=NRRL B-65657 and DSMZ 115098). Because no closely related genomes were available, this study generated the whole-genome sequences (WGSs) of the type strains for and . Phylogenetic and pangenomic analysis reveals that F6_2S_P_1, , and , along with two uncharacterized strains, possess a shared set of 332 gene clusters which are not shared with any other WGS of species, and form a distinct clade branching off from . Functional traits were predicted for the genomes of strain F6_2S_P_1 and other members of this clade.