title: Chiral triazole fungicide difenoconazole: absolute stereochemistry, stereoselective bioactivity, aquatic toxicity, and environmental behavior in vegetables and soil.
abstract: In this study, the systemic assessments of the stereoisomers of triazole fungicide difenoconazole are reported for the first time, including absolute stereochemistry, stereoselective bioactivity toward pathogens (Alternaria sonali, Fulvia fulva, Botrytis cinerea, and Rhizoctonia solani), and toxicity toward aquatic organisms (Scenedesmus obliquus, Daphnia magna, and Danio rerio). Moreover, the stereoselective degradation of difenoconazole in vegetables (cucumber, Cucumis sativus and tomato, Lycopersicon esculentum) under field conditions and in soil under laboratory-controlled conditions (aerobic and anaerobic) was investigated. There were 1.33-24.2-fold and 1.04-6.78-fold differences in bioactivity and toxicity, respectively. Investigations on the stereoselective degradation of difenoconazole in vegetables showed that the highest-toxic and lowest-bioactive (2S,4S)-stereoisomer displays a different enrichment behavior in different plant species. Under aerobic or anaerobic conditions, (2R,4R)- and (2R,4S)-difenoconazole were preferentially degraded in the soil. Moreover, difenoconazole was configurationally stable in the test soil matrices. On the basis of biological activity, ecotoxicity, and environmental behavior, it is likely that the use of pure (2R,4S)-difenoconazole instead of the commercial stereoisomer mix may help to increase the bioactivity and reduce environmental pollution.
authors: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
authors: Fengshou
authors: F
authors: Dong
authors: Jing
authors: J
authors: Li
authors: Bezhan
authors: B
authors: Chankvetadze
authors: Yongpu
authors: Y
authors: Cheng
authors: Jun
authors: J
authors: Xu
authors: Xingang
authors: X
authors: Liu
authors: Yuanbo
authors: Y
authors: Li
authors: Xiu
authors: X
authors: Chen
authors: Carlo
authors: C
authors: Bertucci
authors: Daniele
authors: D
authors: Tedesco
authors: Riccardo
authors: R
authors: Zanasi
authors: Yongquan
authors: Y
authors: Zheng
mesh_terms: D000332:Aerobiosis / Q000187:drug effects; D000693:Anaerobiosis / Q000187:drug effects; D000818:Animals; D059001:Aquatic Organisms / Q000187:drug effects*; D002851:Chromatography, High Pressure Liquid; D004148:Dioxolanes / Q000737:chemistry* / Q000633:toxicity*; D004784:Environmental Monitoring; D005658:Fungi / Q000187:drug effects; D005659:Fungicides, Industrial / Q000737:chemistry / Q000633:toxicity*; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D012987:Soil / Q000737:chemistry*; D013237:Stereoisomerism; D013997:Time Factors; D018675:Toxicity Tests; D014230:Triazoles / Q000737:chemistry* / Q000633:toxicity*; D014675:Vegetables / Q000737:chemistry*
chemical_list: D004148:Dioxolanes; D005659:Fungicides, Industrial; D012987:Soil; D014230:Triazoles; C115058:difenoconazole