title: Target-site basis for resistance to imazethapyr in redroot amaranth (Amaranthus retroflexus L.).
abstract: Experiments were conducted to confirm imazethapyr resistance in redroot amaranth (Amaranthus retroflexus L.) and study the target-site based mechanism for the resistance. Whole-plant response experiments revealed that the resistant (R) population exhibited 19.16 fold resistance to imazethapyr compared with the susceptible (S) population. In vitro ALS activity assay demonstrated that the imazethapyr I50 value of the R population was 21.33 times greater than that of the S population. However, qRT-PCR analysis revealed that there is no difference in ALS gene expression between the R and S populations. Sequence analysis revealed an Asp-376-Glu substitution in ALS in the R population. In order to verify that the imazethapyr resistance was conferred by Asp-376-Glu mutation, the ALS-R and ALS-S genes were fused to the CaMV 35S promoter and introduced into Arabidopsis respectively. The expression of ALS-R in transgenic Arabidopsis plants exhibited 13.79 fold resistance to imazethapyr compared to ALS-S transgenic Arabidopsis.
authors.affiliation: Key Laboratory of Weed and Rodent Biology and Management, Institute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS), China.
authors.forename: Zhaofeng
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Key Laboratory of Weed and Rodent Biology and Management, Institute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS), China.
authors.forename: Jinyi
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Weed and Rodent Biology and Management, Institute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS), China. Electronic address: cxzhang@ippcaas.cn.
authors.forename: Chaoxian
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Weed and Rodent Biology and Management, Institute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS), China.
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Huang
authors.affiliation: Key Laboratory of Weed and Rodent Biology and Management, Institute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS), China.
authors.forename: Shouhui
authors.initials: S
authors.lastname: Wei
authors.affiliation: Institute for the Control of Agrochemicals, Ministry of Agriculture, China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Weed and Rodent Biology and Management, Institute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS), China.
authors.forename: Jingchao
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Weed and Rodent Biology and Management, Institute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS), China.
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
mesh_terms: D027721:Amaranthus / Q000187:drug effects* / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression; D009539:Nicotinic Acids / Q000494:pharmacology*; D030821:Plants, Genetically Modified
chemical_list: D009539:Nicotinic Acids; C093630:imazethapyr
keywords: Acetolactate synthase (ALS); Arabidopsis; Herbicide resistance; Imazethapyr