title: Mutation of alpha-tubulin genes in trifluralin-resistant water foxtail (Alopecurus aequalis).
abstract: BACKGROUND
  Trifluralin-resistant biotypes of water foxtail (Alopecurus aequalis) have been identified in wheat fields from northern Kyushu, Japan. Water foxtail is a winter-annual grassy weed, causing substantial crop losses. This study reports on mutation in α-tubulin (TUA) genes from water foxtail, the site of action of trifluralin.
  
  
  RESULTS
  Two trifluralin-sensitive (S) Chikugo and Ukiha biotypes and four trifluralin-resistant (R) Asakura-1, Asakura-2, Tamana and Tosu biotypes of water foxtail were used for herbicide resistance analysis. R biotypes showed 5.7-30.7-fold trifluralin resistance compared with the S biotypes. No differences in the uptake and translocation of (14)C-trifluralin were observed between Chikugo (S) biotype and Asakura-1 (R) biotype. Most of the (14)C detected in the plant material was in the root tissue, and no substantial increases were noted in shoot tissues. Comparative TUA sequence analysis revealed two independent single amino acid changes: change of Val into Phe at position 202 in TUA1 and change of Leu into Met at position 125 in TUA3 in Asakura-1 biotype. In the Tamana (R) biotype, two amino acid changes of Leu to Phe at position 136 and Val to Phe at position 202 were observed in the predicted amino acid sequence of TUA1, compared with Chikugo (S) biotype.
  
  
  CONCLUSIONS
  The results provide preliminary molecular explanation for the resistance of water foxtail to trifluralin, a phenomenon that has arisen as a result of repeated exposure to this class of herbicide. This is the first report of α-tubulin mutation in water foxtail and for any Alopecurus species reported in the literature.
authors.affiliation: Doctoral Program in Life Sciences and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Saima
authors.initials: S
authors.lastname: Hashim
authors.forename: Asad
authors.initials: A
authors.lastname: Jan
authors.forename: Yukari
authors.initials: Y
authors.lastname: Sunohara
authors.forename: Mayumi
authors.initials: M
authors.lastname: Hachinohe
authors.forename: Hideki
authors.initials: H
authors.lastname: Ohdan
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsumoto
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D053209:Herbicide Resistance; D006540:Herbicides / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics*; D006109:Poaceae / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D014274:Trifluralin / Q000494:pharmacology*; D014404:Tubulin / Q000235:genetics* / Q000378:metabolism
chemical_list: D006540:Herbicides; D010940:Plant Proteins; D014404:Tubulin; D014274:Trifluralin