Microvirga guangxiensis sp. nov., a novel alphaproteobacterium from soil, and emended description of the genus Microvirga

A Gram-negative-staining bacterium, designated strain 25B^T, was isolated from a soil sample from a rice field in Guangxi Province, China, and its taxonomic position was investigated by using a polyphasic approach. Cells were rod-shaped, non-spore-forming, non-motile and strictly aerobic. Strain 25B^T grew optimally at 37°C and pH 7.0. The predominant fatty acids of this soil isolate were C_18:ω7c, C_19:0 cyclo ω8c and C_16:0. Phylogenetic analysis based on the almostcomplete 16S rRNA gene sequence showed that strain 25B^T formed a monophyletic clade with the type strain of Microvirga subterranea; the two organisms shared 97.2% 16S rRNA gene sequence similarity. However, the two strains shared low DNA-DNA relatedness. Strain 25B^T was also readily distinguishable from Microvirga subterranea DSM 14364^T by various phenotypic characteristics. The combination of genotypic and phenotypic data suggests that the isolate represents a novel species of the genus Microvirga, for which the name Microvirga guangxiensis sp. nov. is proposed. The type strain is 25B^T (=CGMCC 1.7666^T=JCM 15710^T).