Plant Pathology Laboratory, Faculty of Agriculture, Aristotelian University, Thessaloniki, Greece.
Pest Manag Sci. 2011 Aug;67(8):1029-36. doi: 10.1002/ps.2226. Epub 2011 Jun 23.
Previous studies have shown that resistance of Botrytis cinerea to QoI fungicides has been attributed to the G143A mutation in the cytochrome b (cytb) gene, while, in a part of the fungal population, an intron has been detected at codon 143 of the gene, preventing QoI resistance. During 2005-2009, 304 grey mould isolates were collected from strawberry, tomato, grape, kiwifruit, cucumber and apple in Greece and screened for resistance to pyraclostrobin and for the presence of the cytb intron, using a novel real-time TaqMan PCR assay developed in the present study.
QoI-resistant phenotypes existed only within the population collected from strawberries. All resistant isolates possessed the G143A mutation. Differences were observed in the genotypic structure of cytb. Individuals possessing the intron were found at high incidence in apple fruit and greenhouse-grown tomato and cucumber populations, whereas in the strawberry population the intron frequency was lower. Cultivation of QoI-resistant and QoI-sensitive isolates for ten culture cycles on artificial nutrient medium in the presence or absence of fungicide selection showed that QoI resistance was stable.
The results of the study suggest that a high risk for selection of QoI-resistant strains exists in crops heavily treated with QoIs, in spite of the widespread occurrence of the cytb intron in B. cinerea populations. The developed real-time TaqMan PCR constitutes a powerful tool to streamline detection of the mutation by reducing pre- and post-amplification manipulations, and can be used for rapid screening and quantification of QoI resistance.
先前的研究表明,灰葡萄孢对 QoI 类杀菌剂的抗性归因于细胞色素 b(cytb)基因第 143 位密码子的 G143A 突变,而在部分真菌种群中,基因第 143 位密码子处检测到一个内含子,从而阻止了 QoI 类杀菌剂抗性的产生。2005-2009 年,从希腊的草莓、番茄、葡萄、猕猴桃、黄瓜和苹果中采集了 304 株灰霉病菌株,用于对吡唑醚菌酯的抗性和 cytb 内含子的存在进行筛选,使用了本研究中开发的一种新型实时 TaqMan PCR 检测方法。
只有在草莓种群中存在 QoI 类杀菌剂抗性表型。所有抗性分离株均携带 G143A 突变。在 cytb 的基因型结构上观察到差异。在苹果果实和温室番茄和黄瓜种群中,高频率存在携带内含子的个体,而在草莓种群中,内含子的频率较低。在含有或不含有杀菌剂选择的人工营养培养基上对 QoI 抗性和 QoI 敏感分离株进行 10 个培养周期的培养表明,QoI 抗性是稳定的。
研究结果表明,尽管在灰葡萄孢种群中广泛存在 cytb 内含子,但在大量使用 QoI 类杀菌剂的作物中,存在选择 QoI 类杀菌剂抗性菌株的高风险。所开发的实时 TaqMan PCR 构成了一种强大的工具,通过减少扩增前和扩增后的操作,简化了突变的检测,可用于快速筛选和定量 QoI 类杀菌剂抗性。