Gynumella flava gen. nov., sp. nov., isolated from the rhizosphere of rice (Oryza sativa L.) managed under a no-tillage regime.

A bacterial strain designated YC6842T, isolated from the rhizosphere of rice (Oryza sativa L.) managed under no-tillage practice in Jinju, Korea, was characterized using polyphasic taxonomic approach. Cells of the strain were Gram-negatively stained, aerobic, rod-shaped and motile by multiple polar flagella. It grew at a temperature of 20 to 40 degrees C (optimum at 28 degrees C). Growth occurred between pH 6.0 and 10.0, with an optimum of pH 7.0-8.0. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the strain represented a separate clade within the family Xanthomonadaceae. It showed the highest 16S rRNA gene sequence similarity with Dyella yeojuensis R2A16-10T (93.6 %). The DNA G+C content was 62.6 mol%. Q-8 was the major quinone. Major polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylcholine (PC) and phosphatidylglycerol (PG). Phylogenetic analysis, biochemical and physiological characteristics strongly supported the genotypic and phenotypic differentiation of the strain YC6842T from the validly published genera of the family Xanthomonadaceae. Therefore, it is proposed that the strain YC6842T represents a novel species within a novel genus, with the name Gynumella flava gen. nov., sp. nov. The type strain is YC6842T (= KCTC 22443T = DSM 21636T).