小麦赤霉病菌对多菌灵的抗药性与a2-微管蛋白序列无关析

Resistant mechanism of Fusarium graminearum against carben-dazim,unrelative to alpha2-tubulin gene

摘要:

【目的】研究小麦赤霉病菌对多菌灵的抗药性与a2-微管蛋白基因的相关性。【方法】比较对多菌灵不同敏感性水平菌株间在药剂作用下的形态学特征及其a2-微管蛋白基因异同。【结果】当敏感菌株和田间中抗菌株均在各自EC50 和EC90浓度作用下，两者分生孢子芽管和初生菌丝均表现畸形，肿胀，分支增多。根据小麦赤霉病菌核基因组测序菌株NRRL31 084（PH-1）的a2-微管蛋白基因核苷酸序列设计4对引物，采用PCR方法克隆并测定了小麦赤霉病菌（Fusarium graminearum）对多菌灵（MBC）不同敏感性表型的8个中国菌株的a2-微管蛋白基因全序列。DNA序列比对结果表明中国的4个敏感菌株和4个抗药性菌株的a2-微管蛋白基因核苷酸序列同源性没有差异，多菌灵抗药性与a2-微管蛋白无关。该基因全长1712 bp，含有4 个内元，编码453 aa；与NRRL31 084的a2-微管蛋白基因核苷酸序列同源性为99%，存在5个差异核苷酸，与其所编码的氨基酸序列同源性为100%；与其他9种真菌a2-微管蛋白基因所编码的氨基酸序列同源性为64%~89%。【结论】小麦赤霉病菌对多菌灵的抗药性与a2-微管蛋白序列无关。

Abstract:

[Objective] We studied the resistance of Fusarium graminearum against carbendazim, to confirm if the resistance was related to the whole nucleotide sequence of alpha2-tubulin. [Methods] The whole nucleotide sequence of alpha2-tubulin and morphological characteristic were analyzed from different sensitivie strains when treated with carbendazim. [Results] The results indicated that both sensitive strains and moderately resistant strains produced tube with swelled abnormality or germlings with more branches or cells of conidium swelled greatly, when treated with carbendazim at their EC50 or EC90. The full-length nucleotide sequence of α2-tubulin gene from each of 8 F. graminearum strains from China, which had different carbendazim (MBC) sensitivity phenotypes, were separated by using PCR with 4 primer sets designed in accordance with nucleotide sequence of the gene from the genomic sequencing strain, NRRL 31084 (PH-1). The DNA sequence comparison showed no difference in the nucleotide sequence of α2-tubulin gene among 4 sensitive and 4 resistant strains. This result demonstrates that there was no relationship between MBC-resistance and alpha2-tubulin gene. The full-length of the gene spanned 1712 bp, including 4 introns, encoding 453 amino acids. With 100% homology, there were 5 nucleotide differences in alpha2-tubulin gene between PH-1 isolate and the 6 strains from China. The homology of the deduced amino acid sequence of the gene was 100% among the 6 strains and PH-1 isolate, and 64%-89% among other 9 species of fungi. [Conclusion] The resistance of F. graminearum against carbendazim was irrelative to the nucleotide sequence of alpha2-tubulin.