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

Abstract

Microvirga guangxiensis sp. nov., a novel alphaproteobacterium from soil, and emended description of the genus Microvirga A Gram-negative-staining bacterium, designated strain 25B T , 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 25B T grew optimally at 37 6C and pH 7.0. The predominant fatty acids of this soil isolate were C 18 : 1 v7c, C 19 : 0 cyclo v8c and C 16 : 0 . Phylogenetic analysis based on the almostcomplete 16S rRNA gene sequence showed that strain 25B T 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 25B T was also readily distinguishable from Microvirga subterranea DSM 14364 T 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 25B T (5CGMCC 1.7666 T 5JCM 15710 T ).The genus Microvirga was established by Kanso & Patel (2003) to accommodate strictly aerobic, Gram-negative, non-sporulating, motile and rod-shaped bacteria from free-flowing geothermal waters of a bore tapping the Great Artesian Basin of Australia, which grew optimally at 41 u C and pH 7.0 and had an absolute requirement for yeast extract. The genus currently encompasses a single species with a validly published name, Microvirga subterranea, and is assigned to the class Alphaproteobacteria, phylum Proteobacteria (Garrity & Holt, 2001;Garrity et al., 2005a), almost equidistant from Methylobacterium species (Patt et al., 1976;Urakami et al., 1993) Egli et al., 1988) and Bosea thiooxidans (Das et al., 1996), its nearest phylogenetic relatives, with a mean similarity value of 93 %., Chelatococcus asaccharovorans (AulingA sampling campaign during an ecological survey of soil bacteria in China led to the isolation of a pink-pigmented bacterium, designated strain 25B T . The soil sample (10 cm in depth, pH 6.2) was collected from a rice field in Guangxi Province. A glucose-yeast extract-malt extract (GYM) agar plate (comprising, l 21 : 4 g D-glucose, 4 g yeast extract, 10 g malt extract, 15 g agar; pH 7.3) was inoculated with a suspension of the soil and incubated at 37 u C for 7 days. The isolate that was obtained, strain 25B T , was maintained on LB agar (l 21 : 10 g tryptone, 5 g yeast extract, 10 g NaCl, 15 g agar; pH 7.0) at 4 u C and as glycerol suspensions (20 %, v/v) at 220 u C. Biomass for the chemotaxonomic and molecular systematic studies was prepared as described previously (Zhang et al., 2002) with the modification that the strain was grown in shake flasks of LB broth.Micromorphological and colonial properties of strain 25B T were examined on LB agar, Rourf's agar (Mulder & Deinema, 1992) and ...

Bacillus oceanisediminis sp. nov., isolated from marine sediment

“…To characterize strain H2 T phenotypically, standard phenotypic tests were performed according to procedures described elsewhere (Gordon et al, 1973(Gordon et al, , 1977Smibert & Krieg, 1994;Zhang et al, 2008Zhang et al, , 2009. Cellular morphology was examined by light microscopy (BH-2; Olympus).…”

“…A standard dilution-plating technique was used to isolate the strain on marine agar 2216 (MA; Difco) at 37 u C for 3 days. Strain H2 T was maintained on LB agar (10 g tryptone, 5 g yeast extract, 10 g NaCl, 1 l distilled water; pH 7.0) at 4 u C and stored in 20 % (v/v) glycerol suspensions at 220 u C.To characterize strain H2 T phenotypically, standard phenotypic tests were performed according to procedures described elsewhere (Gordon et al, 1973(Gordon et al, , 1977Smibert & Krieg, 1994;Zhang et al, 2008Zhang et al, , 2009. Cellular morphology was examined by light microscopy (BH-2; Olympus).…”

The Family Methylobacteriaceae

“…Other media used have been half-strength lupin agar (½ LA; Yates et al 2007), and R2A agar (described above). Glucose, yeast extract-malt extract media, and Luria Broth also support growth (Zhang et al 2009). …”

“…The original genus description (Kanso and Patel 2003) has been subject to two emendations to date, as new species were characterized (Weon et al 2010;Zhang et al 2009) and can now be updated as below.…”

“…Only the root nodule . Microvirga species have been isolated from water (a thermal spring and a thermal aquifer), air, and soil and as endosymbionts of the legumes Listia (formerly Lotononis) and Lupinus (Ardley et al 2012;Kanso and Patel 2003;Takeda et al 2004;Weon et al 2010;Zhang et al 2009). The type species, Mv subterraneae, came from free-flowing geothermal water from a borehole (source depth, 295 m; Kanso and Patel 2003).…”