【作者】 周洁；

【导师】 罗朝喜；

【作者基本信息】 华中农业大学 ， 植物病理学， 2014， 硕士

【摘要】 桃褐腐病是由链核盘菌(Monilinia spp.)引起,在世界范围内可造成严重经济损失。目前对其防治仍以化学防治为主,但桃褐腐病菌对多种药剂均已产生抗药性。琥珀酸脱氢酶抑制剂(SDHI)作为一类新型杀菌剂,其作用位点独特,不易与其它药剂产生交互抗性,在病害防治上具有良好应用前景。本文就实验室的抗性菌株与敏感菌株进行研究,以探究褐腐病菌对啶酰菌胺的抗性机理。本试验首先克隆了桃褐腐病菌3个种中琥珀酸脱氢酶抑制剂的靶标琥珀酸脱氢酶基因,对比敏感菌株和抗性菌株该基因的异同,发现仅在SDHB亚基上存在不改变氨基酸的同义突变。通过农杆菌介导遗传转化体系将含有相应同义突变位点的SDHB基因导入敏感菌株中,发现转化子的抗性并没有明显变化,说明SDHB基因上的同义突变位点与病菌对啶酰菌胺的抗性无关。随后,本试验通过实时荧光定量PCR对桃褐腐病菌中的部分转运蛋白表达量进行了测定,发现已经被克隆的MfABC1基因的表达量在抗性菌株和敏感菌种中并无明显差别,而MfRTA1基因在抗性菌中表达量达到敏感菌株中的13倍,由此可得,在桃褐腐病菌中,MfRTA1基因的过量表达可能与病菌对啶酰菌胺抗性的产生相关。更多还原

【Abstract】 Peach brown rot caused by Monilinia spp. can cause serious economic losses in the world. Currently, chemical control is still the main method, but Monilinia spp. have developed resistance to a variety of fungicides. Succinate dehydrogenase inhibitor(SDHI) is a new class of fungicides, its unique site of action makes it hard to produce cross-resistance with other chemical classes, thus has a good prospect in disease control. In this paper, the resistant isolates and sensitive isolates have been studied to clarify the resistance mechanism of Monilinia fructicola to boscalid.The succinate dehydrogenase of Monilinia spp., the target of succinate dehydrogenase inhibitors, its genes have been cloned. Alignment of the succinate dehydrogenase genes of sensitive and resistant strains, revealed that only SDHB subunit had a few synonymous mutations that did not change the amino acid sequence. By Agrobacterium-mediated genetic transformation system, SDHB gene containing synonymous mutations in resistant strains Dmap3-08and BM09-4a were transformed into the sensitive strain HG12-3a for evaluating the correlation of such mutations and boscalid resistance. As a result, the transformants did not show resistance to boscalid, indicating that synonymous mutations on the SDHB gene are unrelated to the boscalid resistance.Subsequently, the expression of some transporter genes in M. fructicola were measured by real-time quantitative PCR. Results showed that the expression of MfABC1gene, which had been cloned in previous study, did not show significant difference between resistant and sensitive strains. Whereas expression level of MfRTAl gene in resistant strain Dmap3-08increased13times compared to that in sensitive strain. Therefore, the overexpression of MfRTAl gene most likely be associated with the resistance to boscalid in M. fructicola.更多还原