title: Enantiomeric resolution and growth-retardant activity in rice seedlings of uniconazole.
abstract: The increasing application of chiral pesticides has enhanced interest in their enantioselectivity. However, little relevant information is currently available for enantioselective activity of chiral plant growth regulators. In an attempt to screen active enantiomers of uniconazole, this work investigated enantiomeric separation and the enantioselective effect of uniconazole on the growth of rice seedlings and cyanobacteria. Baseline resolution of uniconazole enantiomers was achieved on a Chiralpak AD column by chiral high-performance liquid chromatography (HPLC). The relationship among circular dichroism (CD), optical rotation (OR), and absolute configuration was successfully established by coupling of CD and OR detection. The t test at the 95% level of confidence indicated significant differences between the enantiomers in their retardant activity toward growth of rice seedlings and stimulation effect on growth of cyanobacteria, the natural biofertilizers in rice paddy fields. The S-(+)-enantiomer was more active than the R-(-)-enantiomer in retarding growth of rice seedlings and stimulating growth of  Microcystis aeruginosa . This special enantiomeric selectivity was further elucidated by probing the binding mode of enantiomers to gibberellin (GA) 20-oxidase by molecular docking. The S-(+)-enantiomer was found to bind tightly with GA 20-oxidase. The results suggested that the S-(+)-enantiomer instead of a racemate of uniconazole should be used to improve rice seedling quality.
authors.affiliation: Research Center of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Sun
authors.forename: Anping
authors.initials: A
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Xuemei
authors.initials: X
authors.lastname: Xie
authors.forename: Weiping
authors.initials: W
authors.lastname: Liu
mesh_terms: D000458:Cyanobacteria / Q000187:drug effects; D015394:Molecular Structure; D012275:Oryza / Q000737:chemistry* / Q000254:growth & development / Q000382:microbiology; D010937:Plant Growth Regulators / Q000737:chemistry* / Q000494:pharmacology; D036226:Seedlings / Q000737:chemistry / Q000254:growth & development / Q000382:microbiology; D013237:Stereoisomerism; D014230:Triazoles / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D010937:Plant Growth Regulators; D014230:Triazoles; C092705:uniconazole