Identification and Characterization of Carbendazim-Resistant Isolates of Gibberella zeae
Identification and Characterization of Carbendazim-Resistant Isolates of Gibberella zeae
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玉米赤霉多菌灵抗性分离株的鉴定和表征
DOI：
10.1094/pdis-94-9-1137
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发表时间：
2010-09-01
期刊：
影响因子：
4.5
通讯作者：
Ma, Zhonghua
中科院分区：
文献类型：
--
作者：
Liu, Xin;Yin, Yanni;Ma, Zhonghua
通过测定菌丝在添加杀菌剂的培养基上的生长情况，测定了玉米赤霉菌对多菌灵的敏感性。在测试的1,529个菌株中，31个菌株对多菌灵(杀菌剂浓度，导致菌丝生长抑制50%，10.35-30.26 mg a.i.)表现出高水平的抗性(HR)。L(-1))和10株中抗(MR)菌株(EC50为4.50~7.28 mg a.i.升(-1))。其余1,488个菌株对多菌灵敏感，不能在添加多菌灵的马铃薯葡萄糖琼脂上生长。升(-1)。对β2-微管蛋白(Tub2)基因的DNA序列分析表明，所有10株MR分离株均在第198位密码子发生点突变，导致谷氨酸被谷氨酰胺取代。在31株HR分离株中，有28株在167位密码子上的苯丙氨酸被酪氨酸取代。其余3株HR分离株在第200位密码子有点突变，该密码子将苯丙氨酸转化为酪氨酸。根据Tub2基因的这些点突变，开发了等位基因特异性聚合酶链式反应引物来快速检测这些点突变。该快速分子检测方法将成为监测玉米多菌灵抗性的有效工具。此外，HR分离株GJ33中β1-微管蛋白基因(Tub1)的缺失导致对多菌灵的耐药性增加。这些结果表明，Tub1基因在玉米赤霉菌对多菌灵的敏感性中起着重要作用。
Sensitivity of Gibberella zeae to carbendazim was determined by measuring mycelial growth in fungicide-amended media. Among 1,529 isolates tested, 31 isolates showed a high level of resistance (HR) to carbendazim (fungicide concentration that results in 50% inhibition of mycelial growth [EC50] of 10.35 to 30.26 mg a.i. liter(-1)) and 10 isolates were moderately resistant (MR) (EC50 of 4.50 to 7.28 mg a.i. liter(-1)). The remaining 1,488 isolates were sensitive to carbendazim and were unable to grow on potato dextrose agar amended with carbendazim at 2 mg a.i. liter(-1). Analysis of DNA sequences of the beta 2-tubulin (Tub2) gene showed that all 10 MR isolates had a point mutation at codon 198 causing a replacement of glutamic acid by glutamine. At the codon position 167, the amino acid phenylalanine was replaced by tyrosine in 28 of 31 HR isolates. The remaining three HR isolates had a point mutation at codon 200 which converted phenylalanine to tyrosine. Based on these point mutations in the Tub2 gene, allele-specific polymerase chain reaction primers were developed for rapid detection of the point mutations. The rapid molecular method will be a valuable tool for the monitoring of carbendazim resistance in G. zeae. Additionally, deletion of the beta 1-tubulin gene (Tub1) in the HR isolate GJ33 resulted in increased resistance to carbendazim. These results indicate that Tub1 plays a role in the sensitivity of G. zeae to carbendazim.