A Gram-negative, non-spore-forming, non-pigmented, strictly aerobic and non-motile short rod bacterium, designated NCCP-1258T, was isolated from Cholistan desert soil, Bahawalpur, Pakistan. Growth of strain NCCP-1258T was observed at pH range 6.5-9.5 (optimum 7.5-8.5) and temperature range 20-45 °C (optimum 40 °C), and it tolerated 0-2 % NaCl (optimum 0.5 %, w/v). Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that strain NCCP-1258T belongs to genus Microvirga and is most closely related to Microvirga lotononidis (98.0 %), Microvirga vignae (97.4 %), Microvirga lupini (97.2 %), Microvirga zambiensis (97.2 %) and Microvirga flocculans (97.1 %). Analysis of the concatenated sequences of four housekeeping gene loci (dnaK, gyrB, recA and rpoB) also confirmed the placement of strain NCCP-1258T within the genus Microvirga. DNA-DNA relatedness values of NCCP-1258T with above-mentioned type strains were less than 42 %. The DNA G+C content of strain NCCP-1258T was 64.3 mol%. Chemotaxonomic data (predominant menaquinone system was Q-10; major fatty acids were C16:0, C18:1 ω7c and C19:0 cyclo ω8c; the polar lipid profile contained diphosphatidylglycerol, phosphatidylcholine, phosphatidyl dimethyl ethanolamine and phosphatidyl ethanolamine) also supported the affiliation of strain NCCP-1258T to the genus Microvirga. On the basis of physiological and biochemical characteristics, phylogenetic analyses and DNA-DNA relatedness, strain NCCP-1258T can be distinguished from the closely related taxa and thus represents a novel species of the genus Microvirga, for which the name Microvirga pakistanensis sp. nov. is proposed with the type strain NCCP-1258T (=CGMCC 1.15074T = KCTC 42496T).
Keywords: Cholistan desert; Microvirga pakistanensis; Moderately thermotolerant.