Rice Product Quality Inspection and Supervision Center, China National Rice Research Institute, Hangzhou, China.
Microbiol Spectr. 2021 Oct 31;9(2):e0039821. doi: 10.1128/Spectrum.00398-21. Epub 2021 Sep 29.
Quinclorac (QNC) is a persistent, highly selective, hormonal herbicide of low toxicity. QNC accumulates in soil and affects the growth and development of crops planted subsequent to its application. In this study, we isolated and screened a QNC-degrading bacterial strain, strain D, from rice paddy soil. Morphological analysis, physiological and biochemical tests, and 16S rRNA gene sequencing led us to identify strain D as a Cellulosimicrobium cellulans strain. We investigated the characteristics of strain D in relation to QNC degradation. Under optimal culture conditions, the QNC degradation rate was 45.9% after 21 days of culture. QNC degradation by strain D in the field was modeled and quantified by a pot experiment. The results show that strain D promotes rice growth and degrades QNC. This research has identified a new bacterial species that degrades QNC, providing a foundation for further research into QNC remediation. QNC-degrading bacteria have been isolated from different environments, but there are no reports of Cellulosimicrobium cellulans strains that degrade QNC. In this study, a previously unidentified bacterial strain that degrades QNC, strain D, was screened from paddy soil. The characteristics of strain D that relate to QNC degradation were investigated in detail. The results showed that strain D effectively degraded QNC. Two degradation products of QNC formed by strain D that have not been reported previously, i.e., 3-pyridylacetic acid ( 138.0548) and 3-ethylpyridine ( 108.0805), were identified using high-performance liquid chromatography-quadrupole time of flight mass spectrometry. Strain D has the capacity to degrade QNC in a QNC-polluted paddy.
双氯喹啉酸（QNC）是一种持久性、高选择性、低毒性的激素型除草剂。QNC 在土壤中积累，并影响其施用后种植的作物的生长和发育。在这项研究中，我们从稻田土壤中分离和筛选出一种能降解 QNC 的细菌菌株，菌株 D。通过形态分析、生理生化试验和 16S rRNA 基因测序，我们将菌株 D 鉴定为纤维单胞菌属菌株。我们研究了菌株 D 与 QNC 降解相关的特性。在最佳培养条件下，培养 21 天后 QNC 的降解率为 45.9%。通过盆栽试验对田间菌株 D 降解 QNC 的特性进行了模拟和量化。结果表明，菌株 D 促进了水稻的生长并降解了 QNC。本研究鉴定了一种能降解 QNC 的新细菌物种，为进一步研究 QNC 的修复提供了基础。已经从不同的环境中分离出了能降解 QNC 的细菌，但尚未有报道称纤维单胞菌属菌株能降解 QNC。在这项研究中，从稻田土壤中筛选出了一种以前未鉴定的能降解 QNC 的细菌菌株 D。详细研究了菌株 D 与 QNC 降解相关的特性。结果表明，菌株 D 能有效地降解 QNC。通过高效液相色谱-四极杆飞行时间质谱鉴定了菌株 D 生成的两种以前未报道过的 QNC 降解产物，即 3-吡啶基乙酸（138.0548）和 3-乙基吡啶（108.0805）。菌株 D 具有在 QNC 污染稻田中降解 QNC 的能力。
