From laboratory to field - Research on insecticide resistance using the example of a chimeric cytochrome P450 monooxygenase

从实验室到现场 - 以嵌合细胞色素 P450 单加氧酶为例进行杀虫剂抗性研究

• 批准号: 231612150
• 负责人: Dr. Nicole Joußen
• 金额: --
• 依托单位: Max-Planck-Institut für Chemische Ökologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/231612150?language=en
• 关键词: laboratory; field; Research; insecticide; resistance

Development of insecticide resistance in insect pest species is one of the main threats of agriculture nowadays. The cotton bollworm, Helicoverpa armigera, is the noctuid species possessing by far the most reported cases of insecticide resistance worldwide, correlated with one of the widest geographical distributions of any agricultural pest species. This turns H. armigera into an adequate model to study resistance mechanisms in detail. The main mechanisms underlying insecticide resistance are target side insensitivity and metabolism, mainly due to carboxylesterases and cytochrome P450 monooxygenases. Just recently, the resistance mechanism of an Australian H. armigera strain toward the pyrethroid fenvalerate was ascribed to a single P450, CYP337B3. CYP337B3 is a naturally-occurring chimera between CYP337B2 and CYP337B1 evolved by an unequal crossing-over event. This enzyme had acquired new and exclusive substrate specificities resulting in the detoxification of fenvalerate. This is the first known case of recombination as an additional genetic mechanism, besides over-expression and point mutation, leading to insecticide resistance. Therefore, CYP337B1, CYP337B2, and CYP337B3 are ideal candidates for studying structure-function relationships in P450s. The project aims to characterize amino acids that are crucial for the activity of CYP337B3 toward detoxification of fenvalerate. Additionally, cross-resistance conferred by CYP337B3 enables the determination of common structural moieties of pyrethroids favoring detoxification by CYP337B3 and those leading to resistance breaking. Pyrethroids with identified resistance breaking moieties could be used to control even pyrethroid-resistant populations of H. armigera. Another advantage of this system is the conferment of insecticide resistance by CYP337B3 that is not restricted to Australia but seems to be a more common mechanism as recently revealed by the finding of the chimeric P450 in a cypermethrin-resistant Pakistani strain. To shed light on the contribution of CYP337B3 to pyrethroid resistance of H. armigera and even closely related species worldwide, field populations from different countries will be screened by PCR for the presence of CYP337B3 and its parental genes. If applicable, the allele frequency of CYP337B3 will be determined being a convenient method to conclude the resistance level of the tested populations. Finally, the project will result in advising farmers on the control of populations of H. armigera and related species possessing CYP337B3. This will even become more important due to the climate change allowing H. armigera to spread northward including central Europe, where H. armigera is not yet able to survive wintertime.

害虫抗药性的发展是当今农业的主要威胁之一。棉铃虫（Helicoverpa armigera）是迄今为止全球报道最多的杀虫剂耐药性夜蛾物种，与农业害虫物种地理分布最广泛的物种之一相关。这就变成了H将棉铃虫转化为适当的模型，以详细研究抗性机制。抗药性的主要机制是靶标不敏感和代谢，主要是由于羧酸酯酶和细胞色素P450单加氧酶。就在最近，澳大利亚的H。棉铃虫品系对拟除虫菊酯氰戊菊酯的抗性归因于单一的P450，CYP 337 B3。CYP 337 B3是CYP 337 B2和CYP 337 B1之间的天然嵌合体，由不等交换事件进化而来。这种酶获得了新的和独特的底物特异性，导致氰戊菊酯的解毒。这是第一个已知的情况下，重组作为一个额外的遗传机制，除了过度表达和点突变，导致杀虫剂抗性。因此，CYP 337 B1、CYP 337 B2和CYP 337 B3是研究P450结构-功能关系的理想候选者。该项目旨在表征对CYP 337 B3对氰戊菊酯解毒活性至关重要的氨基酸。此外，CYP 337 B3赋予的交叉耐药性使得能够确定拟除虫菊酯的常见结构部分，这些结构部分有利于CYP 337 B3的解毒作用和导致耐药性破坏的结构部分。具有确定的抗性破坏部分的拟除虫菊酯可用于控制甚至对拟除虫菊酯具有抗性的H. armigera。该系统的另一个优点是通过CYP 337 B3赋予杀虫剂抗性，这并不限于澳大利亚，但似乎是一种更常见的机制，如最近在氯氰菊酯抗性巴基斯坦菌株中发现的嵌合P450所揭示的。为阐明CYP 337 B3对拟除虫菊酯抗性的作用。对于世界范围内的棉铃虫甚至是密切相关的物种，将通过PCR筛选来自不同国家的田间种群是否存在CYP 337 B3及其亲本基因。如适用，将测定CYP 337 B3的等位基因频率，这是一种方便的方法，可得出受试群体的耐药水平。最后，该项目将导致建议农民控制人口的H。棉铃虫和具有CYP 337 B3的相关种属。这将变得更加重要，因为气候变化允许H。armigera向北扩散，包括中欧，H. armigera还不能在冬天存活。