title: A resistance mechanism dependent upon the inhibition of ethylene biosynthesis.
abstract: BACKGROUND
  The highly selective auxin-type herbicide quinclorac is widely used to control important dicotyledon and monocotyledon weeds in rice fields. Echinochloa crusgalli var. zelayensis is one of the most troublesome weeds in China, and is very difficult to control in east China due to misuse of herbicides.
  
  
  RESULTS
  The JZD -R, JTJ -R, JCW -R and SSX -R biotypes of E. crusgalli var. zelayensis had resistance to quinclorac with resistance levels ranked as JZD -R < JTJ -R < JCW -R < SSX -R. Growth reduction in different biotypes was positively correlated with ethylene production. Stimulated levels of ethylene and 1-aminocyclopropane-1-carboxylic acid (ACC) and activities of ACC synthase and ACC oxidase in resistant biotypes were less than the susceptible biotype, and were negatively correlated with quinclorac resistance levels, suggesting that inhibition of ethylene biosynthesis was positively correlated with resistance levels.
  
  
  CONCLUSIONS
  Considering the resistance-dependent inhibition in the ethylene biosynthetic pathway, the mechanisms of resistance to quinclorac in E. crusgalli var. zelayensis involved alteration(s) in the ethylene response pathway, consisting of at least alteration in induction of the enzymes activity of ACC synthase and ACC oxidase.
authors: College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China; Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, Nanjing 210095, China.
authors: Jiangyan
authors: J
authors: Xu
authors: Bo
authors: B
authors: Lv
authors: Qiong
authors: Q
authors: Wang
authors: Jun
authors: J
authors: Li
authors: Liyao
authors: L
authors: Dong
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000187:drug effects; D031747:Echinochloa / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D005030:Ethylenes / Q000096:biosynthesis*; D053209:Herbicide Resistance; D006540:Herbicides / Q000494:pharmacology*; D008190:Lyases / Q000037:antagonists & inhibitors / Q000378:metabolism; D012275:Oryza / Q000254:growth & development; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D057685:Plant Weeds / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D011804:Quinolines / Q000494:pharmacology*
chemical_list: D005030:Ethylenes; D006540:Herbicides; D010940:Plant Proteins; D011804:Quinolines; C489048:quinclorac; C036216:ethylene; D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase
keywords: ACC oxidase; ACC synthase; E. crusgalli var. zelayensis; ethylene; herbicide resistance