Metabacillus mesotrionivorans sp. nov., a Mesotrione‑Degrading Bacterium Isolated from Cornfield Soil

A Gram-stain-positive, aerobic, rod-shaped and non-motile bacterium, designated strain JX24^T, was isolated from cornfield soil in Jiangxi Province, China. Growth was observed at 20-50 °C (optimum 37 °C), pH 6.0-10.0 (optimum pH 8.0) and salinity of 0-8.0% (w/v; optimum 2.0%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JX24^T belongs to the genus Metabacillus and exhibits the highest sequence similarity to Metabacillus indicus LMG 22858^T (99.9%) and Metabacillus idriensis SMC 4352-2^T (98.2%). The draft genome of strain JX24^T was approximately 4.2 Mb with a 44.3% G + C content. The average nucleotide identity values between JX24^T and the most closely related type strains M. indicus LMG 22858^T and M. idriensis SMC 4352-2^T were 93.1% and 77.2%, respectively, and the digital DNA-DNA hybridization values between them were 50.8% and 21.1%, respectively. The predominant fatty acids (≥ 5% of the total) of strain JX24^T were iso-C_15:0, anteiso-C_15:0, iso-C_16:0, iso-C_17:0 and anteiso-C_17:0. The major isoprenoid quinone was MK-7. The major polar lipids of strain JX24^T were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, two unidentified glycolipids, phospholipid and aminophosphoglycolipid. Based on phenotypic, genotypic and phylogenetic evidence, strain JX24^T represents a novel species in the genus Metabacillus, for which the name Metabacillus mesotrionivorans sp. nov. is proposed. The type strain is JX24^T (= GDMCC 1.4914^T = KCTC 43837^T = KACC 24116^T). Furthermore, a NADPH-dependent nitroreductase MnrC, which efficiently transformed mesotrione to AMBA was identified in strain JX24^T.