Robertmurraya mesotrionivorans sp. nov., a mesotrione-degrading strain isolated from farmland soil

A Gram-stain-positive, aerobic, rod-shaped and non-motile bacterium, designated strain P23^T, was isolated from farmland soil in Nanchang, Jiangxi Province, China. Growth was observed at 4-42 °C (optimum 37 °C), pH 5.0-9.0 (optimum pH 7.0) and salinity of 0-4.0% (w/v, optimum 1.0%). Strain P23^T could completely degrade 30 mg l^-1 of mesotrione within 48 h of incubation. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain P23^T belongs to the genus Robertmurraya and showed the highest sequence similarity to Robertmurraya beringensis BR035^T (98.8%) and Robertmurraya korlensis ZLC-26^T (98.6%). The draft genome of strain P23^T was ~5.2 Mb with a 38.2mol% G+C content. The average nucleotide identity values between P23^T and its most closely related type strains R. beringensis BR035^T and R. korlensis ZLC-26^T were 91.5% and 87.4%, respectively, and the digital DNA-DNA hybridization values between them were 48.8% and 38.0%, respectively. The predominant fatty acids (≥5% of the total) of strain P23^T were iso-C_{15 : 0}, anteiso-C_{15 : 0}, iso-C_{15 : 1} F, C_{16 : 0} and iso-C_{17 : 0}. The major isoprenoid quinone was MK-7. The major polar lipids of strain P23^T were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and three unidentified phospholipids. Based on phenotypic, genotypic and phylogenetic evidence, strain P23^T represents a novel species in the genus Robertmurraya, for which the name Robertmurraya mesotrionivorans sp. nov. is proposed. The type strain is P23^T (=GDMCC 1.4869^T=KCTC 43732^T=KACC 23834^T).