An isoleucine-leucine substitution in chloroplastic acetyl-CoA carboxylase from green foxtail (Setaria viridis L. Beauv.) is responsible for resistance to the cyclohexanedione herbicide sethoxydim.
The cDNAs encoding chloroplastic acetyl-CoA carboxylase (ACCase, EC 6.4.1.2) from three lines of Setaria viridis (L. Beauv.) resistant or sensitive to sethoxydim, and from one sethoxydim-sensitive line of Setaria italica (L. Beauv.) were cloned and sequenced. Sequence comparison revealed that a single isoleucine-leucine substitution discriminated ACCases from sensitive and resistant lines. Using near-isogenic lines of S. italica derived from interspecific hybridisation, we demonstrated that the transfer of the S. viridis mutant ACCase allele into a sethoxydim-sensitive S. italica line conferred resistance to this herbicide. We confirmed this result using allele-specific polymerase chain reaction and showed that a single copy of the mutant allele is sufficient to confer resistance to sethoxydim. We conclude that a mutant allele of chloroplastic ACCase encoding a leucine residue instead of an isoleucine residue at position 1780 is a major gene of resistance to sethoxydim.
Délye
Christophe
C
Institut National de la Recherche Agronomique, Laboratoire de Malherbologie et Agronomie, Dijon, France. delye@dijon.inra.fr
Wang
Tianyu
T
Darmency
Henri
H
D000103:Acetyl-CoA Carboxylase / Q000235:genetics* / Q000378:metabolism; D000483:Alleles; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D002736:Chloroplasts / Q000187:drug effects / Q000201:enzymology*; D003512:Cyclohexanones / Q000494:pharmacology*; D004351:Drug Resistance / Q000235:genetics; D005799:Genes, Dominant; D006540:Herbicides / Q000494:pharmacology*; D007532:Isoleucine / Q000235:genetics; D007930:Leucine / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D006109:Poaceae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D017354:Point Mutation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D003512:Cyclohexanones; D006540:Herbicides; D007532:Isoleucine; C049437:sethoxydim; D000103:Acetyl-CoA Carboxylase; D007930:Leucine