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

The taxonomic positions of two Gram-negative strains, SV1470T and SV2184PT, 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 SV1470T was found to be closely related to Microvirga vignae BR3299T (98.8 %), Microvirga flocculans TFBT (98.3 %) and Microvirga lupini Lut6T (98.2 %), whilst similarity to other type strains of the genus ranged from 97.8 to 96.3 %; strain SV2184PT was found to be closely related to Microvirga aerilata 5420S-16T (98.0 %), Microvirga zambiensis WSM3693T (97.8 %) and M. flocculans ATCC BAA-817T (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 SV1470T and 62.1 mol % for strain SV2184PT. Both strains were found to have the same quinone system, with Q-10 as the major ubiquinone. The polar lipid profile of strain SV1470T was found to consist of phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and one unidentified aminolipid, while that of strain SV2184PT 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 SV1470T = DSM 25394T = KCTC 23863T = NRRL-B 24875T) and Microvirga arabica sp. nov. (type strain SV2184PT = DSM 25393T = KCTC 23864T = NRRL-B 24874T) are proposed.