Marine Agriculture Research Center, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, Shandong, 266101, China.
Department of Research & Development, Biotechnology, Uttaranchal University, Dehradun, 248007, India.
Ecotoxicol Environ Saf. 2020 Jan 30;188:109826. doi: 10.1016/j.ecoenv.2019.109826. Epub 2019 Nov 13.
Quinclorac (QNC) is an effective but environmentally persistent herbicide commonly used in rice production. However, few studies have investigated its environmental behavior and degradation. In the present study, we carried out microbial cultures in the presence of QNC to observe changes in soil microbiota and to identify species capable of QNC degradation by using high-throughput sequencing of the 16S rRNA. Pseudomonas was the dominant genus, and Pseudomonas putida II-2 and other species were found to be capable of mineralizing QNC as a source of carbon and energy. However, this degradation rate was slow, only reaching 51.5 ± 1.6% for 7 days at 30 °C on QNC + minimal salt medium. Achromobacter sp. QC36 co-metabolized QNC when rice straw was added into the mineral salt medium containing QNC, and a mixed culture of both strains could mineralize approximately 92% of the 50 mg/L QNC after 5 days of cultivation in the presence of rice straw, at 25-35 °C and pH 6.0-8.0. Non-phytotoxicity of tobacco after degradation of QNC by mixed strains was evidenced in a pot experiment. These results suggest that this mixed culture may be useful in QNC bioremediation and can be used as a bio-formulation for agro-economical and industrial application.
双草醚（QNC）是一种高效但在环境中持久存在的除草剂，常用于水稻生产。然而，很少有研究调查其环境行为和降解情况。在本研究中，我们在存在 QNC 的情况下进行微生物培养，以观察土壤微生物群落的变化，并通过 16S rRNA 的高通量测序来鉴定能够降解 QNC 的物种。假单胞菌是主要的属，发现假单胞菌属和其他物种能够将 QNC 矿化为碳和能源的来源。然而，这种降解速度很慢，在 30°C 下，在含有 QNC 和最小盐培养基中仅 7 天就达到 51.5±1.6%。在含有 QNC 的无机盐培养基中添加稻草时，无色杆菌 QC36 共代谢 QNC，两种菌株的混合培养物在 25-35°C 和 pH 6.0-8.0 下，在存在稻草的情况下培养 5 天后，能够矿化约 92%的 50mg/L QNC。在盆栽试验中，混合菌株降解 QNC 后烟草无毒性。这些结果表明，这种混合培养物可能在 QNC 生物修复中有用，并可作为农用和工业应用的生物制剂。
