title: Cross-resistance patterns to acetolactate synthase (ALS)-inhibiting herbicides of flixweed (Descurainia sophia L.) conferred by different combinations of ALS isozymes with a Pro-197-Thr mutation or a novel Trp-574-Leu mutation.
abstract: Acetolactate synthase (ALS) is the common target of ALS-inhibiting herbicides, and target-site ALS mutations are the main mechanism of resistance to ALS-inhibiting herbicides. In this study, ALS1 and ALS2 genes with full lengths of 2004bp and 1998bp respectively were cloned in individual plants of susceptible (S) or resistant (R) flixweed (Descurainia sophia L.) populations. Two ALS mutations of Pro-197-Thr and/or Trp-574-Leu were identified in plants of three R biotypes (HB24, HB30 and HB42). In order to investigate the function of ALS isozymes in ALS-inhibiting herbicide resistance, pHB24 (a Pro-197-Thr mutation in ALS1 and a wild type ALS2), pHB42 (a Trp-574-Leu mutation in ALS1 and a wild type ALS2) and pHB30 (a Trp-574-Leu mutation in ALS1 and a Pro-197-Thr mutation in ALS2) subpopulations individually homozygous for different ALS mutations were generated. Individuals of pHB30 had mutations in each isozyme of ALS and had higher resistance than pHB24 and pHB42 populations containing mutations in only one ALS isozyme. Moreover, the pHB24 had resistance to SU, TP and SCT herbicides, whereas pHB24 and pHB42 had resistance to these classes of herbicides as well as IMI and PTB herbicides. The sensitivity of isolated ALS enzyme to inhibition by herbicides in these populations correlated with whole plant resistance levels. Therefore, reduced ALS sensitivity resulting from the mutations in ALS was responsible for resistance to ALS-inhibiting herbicides in flixweed.
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 of Yuan Ming Yuan Xilu, Haidian District, Beijing 100193, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Deng
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 of Yuan Ming Yuan Xilu, Haidian District, Beijing 100193, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 of Yuan Ming Yuan Xilu, Haidian District, Beijing 100193, China.
authors.forename: Yongzhi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 of Yuan Ming Yuan Xilu, Haidian District, Beijing 100193, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Jiao
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 of Yuan Ming Yuan Xilu, Haidian District, Beijing 100193, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Mei
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 of Yuan Ming Yuan Xilu, Haidian District, Beijing 100193, China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 of Yuan Ming Yuan Xilu, Haidian District, Beijing 100193, China. Electronic address: mqzheng@cau.edu.cn.
authors.forename: Mingqi
authors.initials: M
authors.lastname: Zheng
mesh_terms: D000095:Acetolactate Synthase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D001577:Benzophenones / Q000633:toxicity; D019607:Brassicaceae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D053209:Herbicide Resistance / Q000235:genetics*; D006540:Herbicides / Q000633:toxicity; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D057685:Plant Weeds / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D036226:Seedlings / Q000187:drug effects / Q000235:genetics; D013457:Sulfur Compounds / Q000633:toxicity
chemical_list: D001577:Benzophenones; D006540:Herbicides; D007527:Isoenzymes; D010940:Plant Proteins; D013457:Sulfur Compounds; C454324:benzophenone O-(2,6-bis(4,6-dimethoxypyrimidin-2-yloxy)benzoyl)oxime; D000095:Acetolactate Synthase
keywords: ALS; Cross-resistance; Flixweed; Trp-574-Leu mutation