热激蛋白介导的高温胁迫对禾谷缢管蚜抗药性的影响

The bird cherry-oat aphid, Rhopalosiphum padi (Linnaeus) is a devastating pest of wheat, which has become the dominant species in many wheat growing regions in China. The elevating temperature caused by climate warming and intensive application of chemical pesticides are the important reason for aggravation of its damages. The metabolic activity of insects depends on the environmental temperature. The enhancement of detoxification enzyme metabolism is one of the important mechanisms for resistance generation and development. Heat shock proteins are the important stress protein of organism in response to environmental stresses, whereas its role in resistance variation under heat stress is not illuminated. Preliminary research of applicant found that Hsp genes of R. padi play an essential role in response to heat stress and insecticide. On this basis, this project will study the influence of heat stress to resistance of R. padi mediated by heat shock protein. Bioassay will be used to analyze the influence of heat stress to resistance level of R. padi. The detoxification enzyme activities under heat stress will be analyzed by enzyme activity assay. qRT-PCR will be applied to analyze the expression level of Hsp genes and detoxification enzyme genes under heat stress. RNAi technology will be used to reveal function of Hsp genes in resistance of R. padi. The results will clarify the mechanism of resistance variety of R. padi under heat stress. This research will have important significance for resistance management and sustainable control under the background of climate warming.

禾谷缢管蚜是重要的小麦害虫，已成为我国许多小麦种植区的优势种。气候变暖引起温度升高和杀虫剂广泛使用导致抗药性上升，是导致其危害加重的重要原因。昆虫的代谢活动依赖于环境温度，而解毒酶代谢增强是昆虫抗性产生和发展的重要机制之一。热激蛋白是生物体响应环境胁迫的重要应激蛋白，但其在高温胁迫下害虫抗性变化中的作用未被阐明。申请人前期研究发现，Hsp基因在禾谷缢管蚜响应高温和杀虫剂胁迫中具有重要作用。在此基础上，本项目将研究热激蛋白介导高温胁迫对禾谷缢管蚜抗药性的影响：通过生物测定分析高温胁迫对禾谷缢管蚜抗性水平的影响；利用酶活性测定研究高温胁迫下解毒酶活力的变化；利用实时荧光定量PCR分析高温胁迫下Hsp和解毒酶基因的表达量；利用RNAi技术研究Hsp基因在禾谷缢管蚜抗药性中的功能；研究结果将阐明高温胁迫压力下禾谷缢管蚜抗性水平变化的机理，对于气候变暖背景下的抗性治理与可持续控制具有重要意义。

禾谷缢管蚜是重要的小麦害虫，由于气候变暖引起的温度升高和杀虫剂广泛使用导致抗药性上升，近年来在我国的危害逐年加重。本研究发现27℃热驯化后禾谷缢管蚜体内4种解毒酶（CarE、AChE、GST和P450s）的酶活力均呈现升高趋势。通过对热驯化后的转录组分析，表明热驯化后有240个基因上调和290个基因下调，差异表达的基因中包括1条Hsp、6条细胞色素P450、1条GST和5条UGT的差异基因，其中7条为上调的基因，6条为下调基因。通过qRT-PCR验证，结果显示热驯化后12条解毒酶基因表达量均显著变化，与转录组结果相一致。. 通过生物测定，结果显示热驯化后禾谷缢管蚜对吡虫啉、高效氯氰菊酯和啶虫脒的LC50值均变大，热驯化降低了其对3种杀虫剂的敏感性；相反热驯化后禾谷缢管蚜对阿维菌素的LC50值变小，热驯化提高了禾谷缢管蚜对阿维菌素的敏感性，说明热驯化对不同种类的杀虫剂敏感性影响不同。. 短时高温处理后，禾谷缢管蚜体内解毒酶活力受到不同程度的影响，30℃和36℃短时处理后解毒酶活力具有不同的变化模式，但整体上对解毒酶活力的影响差异不显著；常温种群和热驯化种群在不同短时高温处理后解毒酶活力变化规律亦不同。qRT-PCR结果表明，禾谷缢管蚜体内8种解毒酶基因显著受到短时高温胁迫的诱导表达，且这种高表达可以维持至处理后24h，尤其30℃短时处理后解毒酶基因的表达量更高。. 根据生物测定结果，对啶虫脒LC30处理后进行转录组分析，分析表明热驯化种群在啶虫脒胁迫后诱导表达更多的差异基因，且多个解毒酶基因参与啶虫脒胁迫的响应。. 研究结果对于气候变暖背景下禾谷缢管蚜的抗性治理与可持续控制具有重要意义。