Microvirga makkahensis sp nov., and Microvirga arabica sp nov., isolated from sandy arid soil

Abstract

The taxonomic positions of two Gram-negative strains, SV1470(T) and SV2184P(T), isolated from arid soil samples, were determined using a polyphasic approach. Analysis of the 16S rRNA gene and the concatenated sequences of three housekeeping gene loci (dnaK, rpoB and gyrB) confirmed that the strains belong to the genus Microvirga. Strain SV1470(T) was found to be closely related to Microvirga vignae BR3299(T) (98.8 %), Microvirga flocculans TFBT (98.3 %) and Microvirga lupini Lut6(T) (98.2 %), whilst similarity to other type strains of the genus ranged from 97.8 to 96.3 %; strain SV2184P(T) was found to be closely related to Microvirga aerilata 5420S-16(T) (98.0 %), Microvirga zambiensis WSM3693(T) (97.8 %) and M. flocculans ATCC BAA-817(T) (97.4 %), whilst similarity to other type strains of the genus ranged from 97.2 to 95.9 %. The G + C content of the genomic DNA was determined to be 61.5 mol % for strain SV1470(T) and 62.1 mol % for strain SV2184P(T). Both strains were found to have the same quinone system, with Q-10 as the major ubiquinone. The polar lipid profile of strain SV1470(T) was found to consist of phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and one unidentified aminolipid, while that of strain SV2184P(T) consisted of phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, one unidentified aminolipid, one unidentified aminophospholipid and two unidentified phospholipids. DNA-DNA relatedness studies showed that the two strains belong to different genomic species. The strains were also distinguished using a combination of phenotypic properties. Based on the genotypic and phenotypic data, the novel species Microvirga makkahensis sp. nov. (type strain SV1470(T) = DSM 25394(T) = KCTC 23863(T) = NRRL-B 24875(T)) and Microvirga arabica sp. nov. (type strain SV2184P(T) = DSM 25393(T) = KCTC 23864(T) = NRRL-B 24874(T)) are proposed.