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

A Gram-negative-staining bacterium, designated strain 25BT, 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 25BT grew optimally at 37 degrees C and pH 7.0. The predominant fatty acids of this soil isolate were C18:1omega7c, C19:0 cyclo omega8c and C16:0. Phylogenetic analysis based on the almost-complete 16S rRNA gene sequence showed that strain 25BT 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 25BT was also readily distinguishable from Microvirga subterranea DSM 14364T 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 25BT (=CGMCC 1.7666T=JCM 15710T).