title: Mutations and amplification of EPSPS gene confer resistance to glyphosate in goosegrass (Eleusine indica).
abstract: Field-evolved resistance of goosegrass to glyphosate is due to double or single mutation in EPSPS , or amplification of EPSPS leads to increased transcription and protein levels. Glyphosate has been used widely in the south of China. The high selection pressure from glyphosate use has led to the evolution of resistance to glyphosate in weeds. We investigated the molecular mechanisms of three recently discovered glyphosate-resistant Eleusine indica populations (R1, R2 and R3). The results showed that R1 and R2 had double Thr102Ile and Pro106Ser mutation and a single mutation of Pro106Leu in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene, respectively. Escherichia coli containing the mutated EPSPS genes was tolerant to glyphosate. EPSPS activity in R1 and R2 plants was higher than in the sensitive plants. There was no amino acid substitution in EPSPS gene in R3. However, expression of EPSPS in R3 plants was higher than in glyphosate-susceptible (S) population (13.8-fold) after glyphosate treatment. EPSPS enzyme activity in both R3 and S plants was inhibited by glyphosate, while shikimate accumulation in R3 was significantly lower than for the S population. Further analysis revealed that the genome of R3 contained 28.3-fold more copies of the EPSPS gene than that of susceptible population. EPSPS expression was positively correlated with copy number of EPSPS. In conclusion, mutation of the EPSPS gene and increased EPSPS expression are part of the molecular mechanisms of resistance to glyphosate in Eleusine indica.
authors.affiliation: Key Laboratory of Weed and Rodent Biology and Management, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors.forename: Jingchao
authors.initials: J
authors.lastname: Chen
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Huang
authors.forename: Chaoxian
authors.initials: C
authors.lastname: Zhang
authors.forename: Shouhui
authors.initials: S
authors.lastname: Wei
authors.forename: Zhaofeng
authors.initials: Z
authors.lastname: Huang
authors.forename: Jinyi
authors.initials: J
authors.lastname: Chen
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
mesh_terms: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase / Q000235:genetics*; D031748:Eleusine / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005998:Glycine / Q000031:analogs & derivatives*; D053209:Herbicide Resistance / Q000235:genetics*; D006540:Herbicides; D009154:Mutation; D012765:Shikimic Acid / Q000378:metabolism; D000097797:Glyphosate
chemical_list: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D005998:Glycine; D006540:Herbicides; D012765:Shikimic Acid; D000097797:Glyphosate