Flexivirga oryzae sp. nov., isolated from soil of a rice paddy, and emended description of the genus Flexivirga Anzai et al. 2012

Abstract

A Gram-staining-positive, strictly aerobic bacterium, designated R1T, was isolated from a rice paddy in South Korea. Cells were non-motile cocci showing oxidase-negative and catalase-positive activities. Growth of strain R1T was observed at 10-37 °C (optimum, 30 °C) and pH 5.0-9.0 (optimum, pH 7.0). Strain R1T contained iso-C16 : 0, summed feature 9 (comprising iso-C17 : 1ω9c/10-methyl C16 : 0), anteiso-C17 : 0, iso-C17 : 0 and anteiso-C17 : 1ω9c as the major fatty acids and MK-8 (H4) and MK-8 (H6) as the isoprenoid quinones. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, three unidentified phospholipids, four unidentified aminolipids, one unidentified glycolipid and four unidentified lipids. The peptidoglycan type was A4α with an l-Lys-l-Ser2-d-Glu interpeptide bridge containing a Gly residue. The G+C content of the genomic DNA was 64.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain R1T was most closely related to the members of the genus Flexivirga, Flexivirga endophytica YIM 7505T (97.7 %), Flexivirga luteaTBS-100T (97.5 %) and Flexivirga alba ST13T (97.2 %). On the basis of phenotypic, chemotaxonomic and molecular properties, it is clear that strain R1T represents a novel species of the genus Flexivirga, for which the name Flexivirga oryzae sp. nov. is proposed. The type strain is R1T (=KACC 18597T=JCM 31060T). An emended description of the genus Flexivirga is also proposed.

Endophytic Bacterium Flexivirga meconopsidis sp. nov. with Plant Growth-Promoting Function, Isolated from the Seeds of Meconopsis integrifolia

“…Genomic ANI and dDDH analyses, together with physiological and biochemical analyses, confirmed that strain Q11 T is a novel species of the genus Flexivirga. Compared with the reported strains of the genus Flexivirga [1][2][3][4][5][6], strain Q11 T has the abilities of nitrogen fixation (181.80 IU/L), IAA production (3.26 mg/L in 2 days), and plant growth promotion, this last function being described for the first time for the genus Flexivirga. Previous research showed that endophytes promote plant growth through nitrogen fixation, phosphorus dissolution, and growth hormone production [12,79].…”

“…The genus Flexivirga, a member of the Phylum Actinobacteria, was first described by Anzai et al [1]. The List of Prokaryotic Names with Standing in Nomenclature (https://lp sn.dsmz.de/search?word=Flexivirga, accessed on 8 October 2023) contains six species with legitimately recognized names, i.e., Flexivirga alba [1], Flexivirga endophytica [2], Flexivirga lutea [3], Flexivirga oryzae [4], Flexivirga caeni [5], and Flexivirga aerilata [6], which were isolated from the leaves of basil [2], the feces of ibis [3], the soil of a rice paddy [4], activated sludge [5], and an automobile air conditioning system [6], respectively. All members of the genus Flexivirga are described as Gram-positive bacteria, aerobic, non-motile, and with a high G + C content in their DNA (~67 mol%).…”