title: Molecular basis for resistance to ACCase-inhibiting fluazifop in Eleusine indica from Malaysia.
abstract: Eleusine indica (goosegrass) populations resistant to fluazifop, an acetyl-CoA carboxylase (ACCase: EC6.4.1.2)-inhibiting herbicide, were found in several states in Malaysia. Dose-response assay indicated a resistance factor of 87.5, 62.5 and 150 for biotypes P2, P3 and P4, respectively. DNA sequencing and allele-specific PCR revealed that both biotypes P2 and P3 exhibit a single non-synonymous point mutation from TGG to TGC that leads to a well known Trp-2027-Cys mutation. Interestingly, the highly resistant biotype, P4, did not contain any of the known mutation except the newly discovered target point Asn-2097-Asp, which resulted from a nucleotide change in the codon AAT to GAT. ACCase gene expression was found differentially regulated in the susceptible biotype (P1) and highly resistant biotype P4 from 24 to 72h after treatment (HAT) when being treated with the recommended field rate (198gha(-1)) of fluazifop. However, the small and erratic differences of ACCase gene expression between biotype P1 and P4 does not support the 150-fold resistance in biotype P4. Therefore, the involvement of the target point Asn-2097-Asp and other non-target-site-based resistance mechanisms in the biotype P4 could not be ruled out.
authors.affiliation: School of Fundamental Science, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia; Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia. Electronic address: cha_ts@umt.edu.my.
authors.forename: Thye San
authors.initials: TS
authors.lastname: Cha
authors.affiliation: School of Fundamental Science, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia.
authors.forename: Mohamed Ghazani
authors.initials: MG
authors.lastname: Najihah
authors.affiliation: School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.
authors.forename: Ismail Bin
authors.initials: IB
authors.lastname: Sahid
authors.affiliation: School of Food Science and Technology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia. Electronic address: chuahts@umt.edu.my.
authors.forename: Tse Seng
authors.initials: TS
authors.lastname: Chuah
mesh_terms: D000103:Acetyl-CoA Carboxylase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D004095:Dihydropyridines / Q000494:pharmacology*; D031748:Eleusine / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D053209:Herbicide Resistance; D006540:Herbicides / Q000494:pharmacology*; D008296:Malaysia; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D004095:Dihydropyridines; D004791:Enzyme Inhibitors; D006540:Herbicides; D010940:Plant Proteins; C050582:fluazifop; D000103:Acetyl-CoA Carboxylase
keywords: ACCase gene expression; Goosegrass; Herbicide resistance; Mutation