苯醌在赤拟谷盗成灾和竞争中的生态作用机理研究

The researches about the safe storage of processed grain, particularly wheat flour, have gradually been the focus of state grain and food safety in recent years. Why does Tribolium castaneum become an dominant insect population in stored wheat flour after processing from wheat stored in the whole grain storage ecosystem where multi-species insects frequently occur ? According to the scientific question, the project aims to detailedly investigate the following contents based on our previous researches: the relationship between T. castaneum population dynamics and the content of benzoquinone, the characteristic secretion by T. castaneum in stored wheat flour; the ecological mechanism of benzoquinone on manipulating the outbreak of Tribolium castaneum and its competition with other major stored grain insect Oryzaephilus surinamensis in stored wheat flour; the effect of benzoquinone on the physiological biochemistry of T. castaneum and O. surinamensis. Then, we analyze the gene expression profile difference of O. surinamensis and T. castaneum before and after treating with benzoquinone, by high-throughput sequencing technique RNA-seq and bioinformatics analysis. The key candidate genes associated with ecological adaptation of O. surinamensis and T. castaneum will be further screened by real-time fluorescent quantitative PCR technique. Subsequently, the potential functions of the key candidate genes will be validated with RNAi technique for elucidating the ecological mechanism of benzoquinone on the outbreak and competition of Tribolium castaneum infesting stored wheat flour from ecological, physiological biochemistry, and molecular aspects. These results can provide theoretical foundation and new ideas for scientifically monitoring the occurrence of insects by detecting the content of benzoquinone in stored wheat flour, effectively implementing insect ecological control.

近年来，成品粮安全储藏已成为国家食品安全重要研究内容。本项目针对多种害虫经常同时发生的粮食储藏生态系统中，为何赤拟谷盗T. castaneum能够成为小麦粉储藏过程中优势为害种群这一科学问题，在前期研究工作基础上，深入研究小麦粉中苯醌含量与赤拟谷盗种群动态的关系、苯醌在调控赤拟谷盗与小麦粉储藏期间其他主要害虫锯谷盗O. surinamensis竞争中的生态学功能、苯醌对赤拟谷盗与锯谷盗生理生化的影响，进而运用高通量测序技术RNA-seq和生物信息学方法比较分析苯醌处理前后赤拟谷盗和锯谷盗的基因表达差异；结合实时荧光定量PCR技术筛选苯醌处理影响赤拟谷盗和锯谷盗生态适应能力的关键基因，并用RNAi技术对关键基因进行功能验证，从生态、生理生化和分子层面阐明苯醌在赤拟谷盗成灾和竞争中的生态作用机理。本研究结果可为通过检测储粮中苯醌含量变化科学进行害虫预测预报、有效实施害虫生态防治提供新思路。

成品粮安全储藏日益成为国家食品安全重要组成部分。本项目针对多种害虫经常同时发生的储藏生态系统中，为何赤拟谷盗成为小麦粉中优势为害种群这一科学问题，深入研究苯醌在调控赤拟谷盗与小麦粉储藏期间其他主要害虫锯谷盗竞争中的生态学功能、苯醌对赤拟谷盗与锯谷盗生理生化的影响，进而运用高通量测序技术RNA-seq和生物信息学方法比较分析苯醌处理前后赤拟谷盗的基因表达差异，结合实时定量PCR技术筛选苯醌处理影响赤拟谷盗生态适应能力的关键基因，并用RNAi技术对其进行功能验证。研究结果表明，单独饲养情况下赤拟谷盗和锯谷盗种群数量均呈增长趋势；混合饲养情况下赤拟谷盗种群呈增长趋势，而锯谷盗呈下降趋势。赤拟谷盗为害后的小麦粉对锯谷盗卵、幼虫、成虫均有显著抑制作用，而锯谷盗为害后的小麦粉对赤拟谷盗影响不显著。赤拟谷盗与锯谷盗（1:1）混合饲养70 d时，锯谷盗种群数量仅4.33头，而赤拟谷盗438头；小麦粉中苯醌含量与赤拟谷盗为害程度密切相关，赤拟谷盗为害过的小麦粉对锯谷盗种群有抑制作用；含苯醌小麦粉对赤拟谷盗种群无显著影响，而对锯谷盗种群有显著抑制作用；在含有苯醌的小麦粉中，赤拟谷盗体内蛋白含量和细胞色素P450酶活性较高，过氧化氢酶活性、过氧化物酶活性、超氧物歧化酶活力及呼吸速率较低，而锯谷盗则相反；转录组分析结果表明，在T2vsT1、T3vsT1和T3vsT2处理中分别鉴定出总计5361、6923和683条差异表达基因。加权基因共表达网络分析（WGCNA）鉴定了6个由共表达差异基因组成的模块。利用RNAi技术对赤拟谷盗成虫在受到苯醌胁迫时显著上调表达的两个基因LOC655533、LOC100142088进行沉默后，赤拟谷盗再与正常饲养的锯谷盗共存时其竞争优势显著下降。本研究结果从昆虫生态、生理生化和分子层面阐明了苯醌在赤拟谷盗成灾和竞争中的生态作用机理，可为通过检测储粮中苯醌含量变化科学进行害虫预测预报、有效实施生态防治提供新思路，确保储粮品质和食品安全。