Keon J P, White G A, Hargreaves J A
Department of Agricultural Sciences, University of Bristol, UK.
Curr Genet. 1991 Jun;19(6):475-81. doi: 10.1007/BF00312739.
A gene which confers resistance to the systemic fungicide carboxin (Cbx) has been isolated from the maize pathogen, Ustilago maydis, by transferring a plasmid gene library from a Cbx-resistant mutant strain into a sensitive strain and selecting for expression of the resistance gene. Five plasmids, rescued from transformants which exhibited enhanced resistance to Cbx, were shown to have DNA inserts with common restriction enzyme fragments. All the plasmids transformed a sensitive U. maydis strain to Cbx resistance. The gene (Cbxr), sub-cloned on a 3.2 kb EcoR1-HindIII fragment, transformed U. maydis to Cbx resistance at frequencies similar to those obtained with the bacterial Hygromycin B resistance (HygBr) gene. The sequence of the Cbxr gene showed a high degree of homology to succinate dehydrogenase (EC 1.3.99.1) iron-sulphur subunit genes from other organisms.
通过将来自抗羧菌灵（Cbx）突变菌株的质粒基因文库转移到敏感菌株中，并筛选抗性基因的表达，从玉米病原体玉米黑粉菌中分离出了一个赋予对系统性杀菌剂羧菌灵抗性的基因。从对Cbx表现出增强抗性的转化体中拯救出的五个质粒，显示其DNA插入片段具有共同的限制性酶切片段。所有这些质粒都能将敏感的玉米黑粉菌菌株转化为对Cbx具有抗性。该基因（Cbxr）亚克隆在一个3.2 kb的EcoR1 - HindIII片段上，能以与细菌潮霉素B抗性（HygBr）基因相似的频率将玉米黑粉菌转化为对Cbx的抗性。Cbxr基因的序列与其他生物体的琥珀酸脱氢酶（EC 1.3.99.1）铁硫亚基基因具有高度同源性。
