Microvirga calopogonii sp. nov., a novel alphaproteobacterium isolated from a root nodule of Calopogonium mucunoides in Southwest China

In this study, a Gram-negative, rod-shaped, and non-spore-forming bacterium, which was designated as strain CCBUA 65841T, was isolated from a root nodule of Calopogonium mucunoides grown in Yunan Province of China. The sequence alignment results of 16S rRNA and four housekeeping genes (including gyrB, recA, dnaK and rpoB) indicated the isolated strain is a member of the genus Microvirga, closely related to Microvirga lotononidis WSM3557T. In addition, results of genome average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) had revealed the lower values (ANI ≤ 88.72%, dDDH ≤ 39.5%) between strain CCABU 65841T and other related Microvirga species. The genome of the novel strain exhibits a G + C content of 64.48% and contains 7296 protein-coding genes and 93 RNA genes. The major polar lipids were found to be phosphatidylcholine and phosphatidylethanolamine. The predominant cellar fatty acids were identified to be C16:0, C18:0, C19:0 cyclo ω8c, summed feature 2, summed feature 3 and summed feature 8. Moreover, menaquinone 8 (MK-8) was detected to be the predominant quinone. Based on the phylogenetic and phenotypic dissimilarity, a novel species Microvirga calopogonii sp. nov. is proposed with the type strain CCABU 65841T (= LMG 25488 T = HAMBI 3033T).