new amino acid substitution (Ala-205-Phe) in acetolactate synthase (ALS) confers broad spectrum resistance to ALS-inhibiting herbicides

• Published in: Planta 2016-01, Vol.243 (1), p.149-159
• Main Authors: Brosnan, James T, Vargas, Jose J, Breeden, Gregory K, Grier, Logan, Aponte, Raphael A, Tresch, Stefan, Laforest, Martin
• Format: Article
• Language: English
• Subjects: acetolactate synthase; Acetolactate Synthase - genetics; Acetolactate Synthase - metabolism; Agriculture; Alanine - metabolism; Amino Acid Substitution; Amino acids; Base Sequence; Biomedical and Life Sciences; Carbonyl compounds; D1 protein; Ecology; Forestry; genes; golf courses; Herbicide Resistance; Herbicides; Herbicides - pharmacology; homozygosity; Homozygote; lawns and turf; Life Sciences; Molecular Sequence Data; Mutation; Nucleic acids; Original; ORIGINAL ARTICLE; Phenylalanine - metabolism; photosystem II; Plant Sciences; Poa - drug effects; Poa - enzymology; Poa - genetics; Poa annua; point mutation; Recombinant Proteins; Sequence Analysis, DNA; Simazine; Turf
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-015-2399-9

MAIN CONCLUSION : This is a first report of an Ala-205-Phe substitution in acetolactate synthase conferring resistance to imidazolinone, sulfonylurea, triazolopyrimidines, sulfonylamino-carbonyl-triazolinones, and pyrimidinyl (thio) benzoate herbicides. Resistance to acetolactate synthase (ALS) and photosystem II inhibiting herbicides was confirmed in a population of allotetraploid annual bluegrass (Poa annua L.; POAAN-R3) selected from golf course turf in Tennessee. Genetic sequencing revealed that seven of eight POAAN-R3 plants had a point mutation in the psbA gene resulting in a known Ser-264-Gly substitution on the D1 protein. Whole plant testing confirmed that this substitution conferred resistance to simazine in POAAN-R3. Two homeologous forms of the ALS gene (ALSa and ALSb) were detected and expressed in all POAAN-R3 plants sequenced. The seven plants possessing the Ser-264-Gly mutation conferring resistance to simazine also had a homozygous Ala-205-Phe substitution on ALSb, caused by two nucleic acid substitutions in one codon. In vitro ALS activity assays with recombinant protein and whole plant testing confirmed that this Ala-205-Phe substitution conferred resistance to imidazolinone, sulfonylurea, triazolopyrimidines, sulfonylamino-carbonyl- triazolinones, and pyrimidinyl (thio) benzoate herbicides. This is the first report of Ala-205-Phe mutation conferring wide spectrum resistance to ALS inhibiting herbicides.