Molecular characterization of benzimidazole-resistant isolates of Cladosporium fulvum.
Molecular characterization of benzimidazole-resistant isolates of Cladosporium fulvum.
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DOI：
10.1111/j.1574-6968.2007.00999.x
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发表时间：
2008
影响因子：
2.1
通讯作者：
Leiyan Yan;Jie Chen;Chuanqing Zhang;Zhonghua Ma
中科院分区：
文献类型：
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作者：
Leiyan Yan;Jie Chen;Chuanqing Zhang;Zhonghua Ma
苯并咪唑类杀菌剂甲基托布津是我国防治番茄叶霉病的常用药剂。本研究对32株C.结果表明，黄曲霉对甲基托布津的敏感性较高，并鉴定出两种苯并咪唑抗性（BenR）表型BenR 1和BenR 2。BenR 1菌株对甲基硫菌灵具有抗性，但对苯基氨基甲酸酯杀菌剂乙霉威比野生型菌株更敏感。对甲基硫菌灵有抗性的BenR 2菌株对乙霉威不敏感。所有供试菌株均对二甲酰亚胺类杀菌剂异菌脲敏感。从该真菌中分离出完整的β-微管蛋白基因，以研究其在苯并咪唑抗性中的潜在作用。β-微管蛋白基因的DNA序列分析表明，BenR 1分离株在密码子198处有一个点突变，导致谷氨酸被丙氨酸取代。在BenR 2分离物中，检测到密码子200处的点突变，导致苯丙氨酸取代为酪氨酸。基于这些点突变，多重等位基因特异性PCR方法首次成功地开发，在单一PCR扩增中同时检测β-微管蛋白基因的两个点突变。
The benzimidazole fungicide thiophanate-methyl is commonly applied to control leaf mould of tomato caused by Cladosporium fulvum in China. In this study, 32 isolates of C. fulvum were examined for their sensitivities to thiophanate-methyl, and two benzimidazole-resistant (BenR) phenotypes BenR1 and BenR2 were identified. The BenR1 isolates were resistant to thiophanate-methyl, but were more sensitive to the phenylcarbamate fungicide diethofencarb than the wild-type isolates. The BenR2 isolates resistant to thiophanate-methyl were insensitive to diethofencarb. All tested isolates were sensitive to the dicarboximide fungicide iprodione. The complete beta-tubulin gene was isolated from this fungus to study its potential role in benzimidazole resistance. Analysis of the DNA sequence of the beta-tubulin gene showed that the BenR1 isolates had a point mutation at codon 198, causing a substitution of glutamic acid to alanine. In the BenR2 isolates, a point mutation at codon 200 causing a substitution of phenylalanine to tyrosine was detected. Based on these point mutations, a multiplex allele-specific PCR method was developed successfully for the first time to detect two point mutations at the beta-tubulin gene simultaneously in single PCR amplifications.