title: Molecular and phenotypic characterization of Als1 and Als2 mutations conferring tolerance to acetolactate synthase herbicides in soybean.
abstract: BACKGROUND
  Sulfonylurea (SU) herbicides are effective because they inhibit acetolactate synthase (ALS), a key enzyme in branched-chain amino acid synthesis required for plant growth. A soybean line known as W4-4 was developed through rounds of seed mutagenesis and was demonstrated to have a high degree of ALS-based resistance to both post-emergence and pre-emergence applications of a variety of SU herbicides. This report describes the molecular and phenotypic characterization of the Als1 and Als2 mutations that confer herbicide resistance to SUs and other ALS inhibitors.
  
  
  RESULTS
  The mutations are shown to occur in two different ALS genes that reside on different chromosomes: Als1 (P178S) on chromosome 4 and Als2 (W560L) on chromosome 6 (P197S and W574L in Arabidopsis thaliana).
  
  
  CONCLUSIONS
  Although the Als1 and Als2 genes are unlinked, the combination of these two mutations is synergistic for improved tolerance of soybeans to ALS-inhibiting herbicides.
authors.affiliation: DuPont Pioneer, Hayward, CA, USA.
authors.forename: Kay L
authors.initials: KL
authors.lastname: Walter
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Strachan
authors.forename: Nancy M
authors.initials: NM
authors.lastname: Ferry
authors.forename: Henrik H
authors.initials: HH
authors.lastname: Albert
authors.forename: Linda A
authors.initials: LA
authors.lastname: Castle
authors.forename: Scott A
authors.initials: SA
authors.lastname: Sebastian
mesh_terms: D000095:Acetolactate Synthase / Q000235:genetics*; D001483:Base Sequence; D053209:Herbicide Resistance / Q000235:genetics*; D006540:Herbicides / Q000633:toxicity*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D016133:Polymerase Chain Reaction; D013025:Glycine max / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D013453:Sulfonylurea Compounds / Q000633:toxicity
chemical_list: D006540:Herbicides; D013453:Sulfonylurea Compounds; D000095:Acetolactate Synthase
keywords: acetohydroxyacid synthase; acetolactate synthase; herbicide resistance; herbicide tolerance; mutation; soybean; sulfonylurea