- 期刊
乙醯乳酸合成酵素抑制型除草劑抗性之生化及分子遺傳
Biochemistry and Molecular Genetics of Resistance to Acetolactate Synthase Inhibiting Herbicides
摘要
硫醯尿素類（sulfonylureas）除草劑為低劑量低毒性之除草劑，其所抑制的關鍵酵素是乙醯乳酸合成酵素（acetolactate synthase；ALS；E.C 4.1.3.18），此酵素是控制支鏈氨基酸leucine，isoleucine及valine合成之關鍵酵素。ALS酵素蛋白之合成乃受細胞核控制，而在葉綠體表現其活性。在植物體中抑制ALS活性之除草劑有四大類，即sulfonylurea，imidazolinone，triazolopyrimidine及pyrimidinyl oxybenzoate類除草劑。植物體對除草劑之抗性可從突變體選拔及基因轉殖方式獲得，引起抗性之原因包括植物體內ALS抗性基因之表現、啟動子（promoter）調節、葉綠體轉移胜肽等。從交感抗性類型之研究亦可了解，不同的點突變位置與特定之交感抗性類型有關，突變結果使ALS酵素蛋白之胺基酸發生取代置換，因而改變ALS對於除草劑之敏感度增加抗性。
並列摘要
Sulfonylureas are effectively applied in weed control with low-dosage and safety. The target site of this herbicide is acetolactate synthase (ALS; E.C 4.1.3.18), which protein synthesis is controlled by nucleic genome and which activity is expressed in chloroplast mainly. In plants, 4 kinds of ALS-inhibiting herbicides, i.e. sulfonylureas, imidazolinones, triazolopyrimidines and pyrimidinyl oxybenzoates, are described, and the related resistance could be obtained by mutant selection or gene transformation. The resistance of plants to sulfonylureas is resulted from expression of resistant ALS gene, regulation of promoter, etc. In general, different patterns of cross-resistance are closely related to point mutation, which causes substitution of specific amino acid in ALS protein and subsequently resulted in a lower sensitivity of ALS to ALS-inhibiting herbicides.