Mutations in a β-Tubulin Confer Resistance of Gibberella zeae to Benzimidazole Fungicides
Mutations in a β-Tubulin Confer Resistance of Gibberella zeae to Benzimidazole Fungicides
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DOI：
10.1094/phyto-99-12-1403
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发表时间：
2009-12-01
期刊：
影响因子：
3.2
通讯作者：
Zhou, Ming-Guo
中科院分区：
文献类型：
--
作者：
Chen, Chang-Jun;Yu, Jun-Jie;Zhou, Ming-Guo
小麦赤霉病（Gibberella zeae，无性型：Fusarium graminearum）是一种严重威胁我国粮食安全的病害，其主要原因是小麦赤霉病菌（Gibberella zeae，无性型：Fusarium graminearum）对小麦收获后的籽粒产生了霉菌毒素污染，病害频繁发生，部分地区由于病原菌对苯并咪唑产生抗药性，导致化学防治失败。而G.对苯并咪唑杀真菌剂（尤其是多菌灵;活性成分：苯并咪唑-2-基氨基甲酸甲酯[MBC]）的抗性了解甚少。对G.分析了玉米的遗传组成。在中度耐药菌株（MBCMR）中，β（2）tub中的突变包括密码子167处的TTT（Phe）->达特（Tyr）或密码子200处的TTC（Phe）-> TAC（Tyr）。高耐药株（MBR 10）有两个点突变，一个在第73位密码子CAG（Gln）→ CGG（Arg），另一个在第198位密码子GAG（Glu）→ CTG（Leu）。为了证实β（2）tub中的突变赋予对苯并咪唑杀真菌剂的抗性，从G.玉米。生成的.来自MBCMR和MBS 2菌株的Δ β（2）tub突变体在无MBC的马铃薯葡萄糖琼脂培养基上生长正常，并且对MBC超敏感。的补充。通过用来自其亲本菌株的完整β（2）Tub基因座的拷贝转化的β（2）Tub突变体表现出比原始菌株更低的抗性，并且β（2）Tub基因座的互补性。通过用来自敏感菌株的完整β（2）Tub基因座的拷贝转化的β（2）Tub突变体恢复了MBC敏感性。结果表明，β（2）tub基因的突变导致了G.该基因可作为G.玉米。
Wheat head blight caused by Gibberella zeae (anamorph: Fusarium graminearum) is a threat to food safety in China because of mycotoxin contamination of the harvested grain, the frequent occurrence of the disease, and the failure of chemical control in some areas due to benzimidazole resistance in the pathogen population. The molecular resistance mechanism, however, of G. zeae to benzimidazole fungicides (especially carbendazim; active ingredient: methyl benzimidazol-2-yl carbamate [MBC]) is poorly understood. DNA sequences of a beta-tubulin gene (beta(2)tub) (GenBank access number FG06611.1) in G. zeae were analyzed. Mutations in beta(2)tub in moderately resistant strains (MBCMR) included TTT (Phe) -> TAT (Tyr) at codon 167 or TTC (Phe) -> TAC (Tyr) at codon 200. A highly resistant strain (MBCHR) had two point mutations, one at codon 73, CAG (Gln) -> CGG (Arg), and the other at codon 198, GAG (Glu) -> CTG (Leu). To confirm that mutations in the beta(2)tub confer resistance to benzimidazole fungicides, the entire beta(2)Tub locus was deleted from MBCMR and MBCHR strains of G. zeae. The resulting. Delta beta(2)tub mutants from both MBCMR and MBCHR strains grew normally on MBC-free potato dextrose agar medium and were supersensitive to MBC. Complementation of the. beta(2)tub mutants by transformation with a copy of the intact beta(2)Tub locus from their parent strains exhibited less resistance than the original strains, and complementation of the. beta(2)tub mutants by transformation with a copy of the intact beta(2)Tub locus from sensitive strains restored MBC sensitivity. The results indicated that the mutations in the beta(2)tub gene conferred resistance of G. zeae to benzimidazole fungicides and this gene can be used as a genetic marker in G. zeae.