【作者】 杨霞； 俞欣妍； 李顺鹏； 何健； 李永丰； 李贵；

【Author】 Yang Xia;Yu Xin-Yan;Li Shun-Peng;He Jian;Li Yong-Feng;Li Gui;Institute of Plant Protection,Jiangsu Academy of Agricultural Sciences;College of Life Sciences,Nanjing Agriculture University;

【机构】 江苏省农业科学院植物保护研究所； 南京农业大学生命科学学院；

【摘要】 乙酰羟酸合酶（AHAS）是植物、真菌和细菌细胞内必需的支链氨基酸生物合成第一阶段的关键酶,是AHAS抑制剂类除草剂的作用靶标。本文筛选得到了抗磺酰脲类、咪唑啉酮类、三唑嘧啶磺酰胺类与嘧啶水杨酸类这四大类AHAS抑制剂类除草剂的日本看麦娘抗性生物型,利用PCR技术分别从日本看麦娘抗感品系中分离得到dHAS大亚基基因,经比对分析发现:其抗性生物型AHAS大亚基有2个氨基酸位点发生突变(Ser₂₂₂→Asn₂₂₂,Gly₂₃₀→Asp₂₃₀。将日本看麦娘抗感品系的AHAS大亚基基因分别转入酵母中进行表达,测得抗性转化子的表达产物对各类AHAS抑制剂类除草剂具有较强的抗性,并且抗性表达产物的纯化酶活性为7.3 U/mg,高于敏感1.9 U/mg,表明日本看麦娘AHAS大亚基氨基酸位点突变是杂草对乙酰羟酸合酶抑制剂类除草剂产生抗性的原因,同时也是新发现的AHAS突变位点。更多还原

【Abstract】 Acetohydroxyacid synthase（AHAS） is the first key enzyme in branched-chain amino acid biosynthesis pathway in plants,fungi and bacteria,which is the target site of AHAS-inhibiting herbicides.This research has screened the resistant biotypes from Alopecurus japonicus Steud.endowing herbicidal resistance of sulfonylurea,imidazolinone,triazolopyrimidine and pyrimidinyl-thiobenzoate.AHAS large subunit genes were isolated from the resistant and sensitive biotypes of Alopecurus japonicus Steud.using PCR assay.Two putative amino acid mutations(Ser₂₂₂→Asn₂₂₂、Gly₂₃₀→Asp₂₃₀) were found in the resistant AHAS compared with the sensitive AHAS.The AHAS genes from resistant and sensitive biotypes were ligated into yeast expression vector and successfully expressed in Pichia Pastoris respectively.The results showed that AHAS large subunit from resistant biotype had stronger resistance to AHAS-inhibiting herbicides.The specific activity of resistant AHAS was 7.3 U/mg,which was 1.9 U/mg more than the sensitive AHAS specific activity.Therefore,amino acid site mutations of AHAS are the reasons of resistance to AHAS-inhibiting herbicides,which are also the new-found AHAS mutating sites.更多还原