A new amino acid substitution (Ala-205-Phe) in acetolactate synthase (ALS) confers broad spectrum resistance to ALS-inhibiting herbicides.
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.
Plant Sciences Department, The University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN, 37996, USA. jbrosnan@utk.edu.
James T
JT
Brosnan
Plant Sciences Department, The University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN, 37996, USA.
Jose J
JJ
Vargas
Plant Sciences Department, The University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN, 37996, USA.
Gregory K
GK
Breeden
BASF Corporation, 26 Davis Dr., Research Triangle Park, NC, 27709, USA.
Logan
L
Grier
BASF SE, Speyerer Str. 2, 67117, Limburgerhof, Germany.
Raphael A
RA
Aponte
BASF SE, Speyerer Str. 2, 67117, Limburgerhof, Germany.
Stefan
S
Tresch
Horticulture R&D Center, Agriculture and Agri-Food Canada, St-Jean-sur-Richelieu, QC, Canada.
Martin
M
Laforest
D000095:Acetolactate Synthase / Q000235:genetics / Q000378:metabolism*; D000409:Alanine / Q000378:metabolism; D019943:Amino Acid Substitution; D001483:Base Sequence; D053209:Herbicide Resistance; D006540:Herbicides / Q000494:pharmacology*; D006720:Homozygote; D008969:Molecular Sequence Data; D009154:Mutation; D010649:Phenylalanine / Q000378:metabolism; D031785:Poa / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D011994:Recombinant Proteins; D017422:Sequence Analysis, DNA
D006540:Herbicides; D011994:Recombinant Proteins; D010649:Phenylalanine; D000095:Acetolactate Synthase; D000409:Alanine
Acetolactate synthase; Annual bluegrass; Phenylalanine; Turf; Weed resistance