入侵种红脂大小蠹原产地北美种群和入侵地中国种群化学通讯差异的比较研究

With increasing of international exchanges, biological invasion has become an international heated topic. Why has the invasive species always become a primary pest while it is a secondary pest in its native ranges? It is the key question of biological invasion, i.e., the role of the change of the invasion ability in the invasive mechanism. In recent, more research has been focused on co/symbiotic invasion among multiple species, such as native species and symbiotic/associated fungi, which were found to help invasive species to adapt new environment. However, the invasion ability of invasive species itself has been ignored. In this project, based on our finding on the differences in chemical communication between native population and invaded population of the invasive bark beetle Dendroctonus valens, we are going to confirm the difference and explore the molecular mechanism by comparatively studying the native population and the invaded population to understand why the bark beetle has become a primary pest in China while it is a secondary pest in its native ranges...Dendroctonus valens is one of the most destructive forest pests in China, which is native to North America. D. valens was introduced into Shanxi Province of China in the early 1980s when unprocessed logs were imported from the west coast of the United States and has spread rapidly to adjacent provinces, such as Shananxi, Henan, Hebei,and Beijing. Native population of D. valens occurs sympatrically with other Dendroctonus species in western North America, where it is considered to be a secondary pest and generally attacks only weakened or dying pines and freshly-cut stumps and logs. However, this introduced population of D. valens has become a primary pest and has caused the demise of over 10 million Chinese red pines, Pinus tabuliformis. ..Recently, the invasive beetles has been studied mainly on attack behavior, chemical communication and multiple level trophic relationship with related fungi/bacteria in China, which still could not understand well why the beetle could successfully adapt the new environment in China and has become a primary pest shifted from a secondary pest in its native ranges. Last year, I visited Prof Kenneth Raffa’s lab in University of Wisconsin-Madison and carried out comparative study focusing on this invasive bark beetle and found the beetles in USA responded differently to the aggregation pheromone frontalin and anti-aggregation pheromone exo-brevicomin identified in beetles from the invaded population in China. That’s amazing, which indicates some changes between the native and invaded populations of the invasive bark beetle may be responsible for why the secondary pest in North America has become a destructive pest in China. Here, based on our findings, we are going to do a comparative study with both the D. valens native and invaded populations to explore the differences and its underlying molecular mechanisms. We will make sure the differences between the native population and the invasive population in chemical communication and decipher why D. valens is a secondary pest in its native ranges and how it shift from a secondary pest in its native ranges to a primary pest in the invaded areas from the molecular level.

为什么入侵害虫通常在原产地为次期性害虫或不成灾而在新入侵地暴发成灾转变为主要害虫一直是入侵生物学的核心科学问题。本研究拟以我国重大林业入侵种红脂大小蠹为对象，以前期研究发现红脂大小蠹原产地北美种群和入侵地中国种群化学通讯差异为切入点，通过野外危害型调查、诱捕和室内模拟信息素产生比较研究红脂大小蠹北美种群和中国种群对化学信息反应及其产生的差异，阐明红脂大小蠹在入侵地中国聚集危害而在北美不聚集危害的化学生态学机制；进而通过转录组学方法分析确定调控两种群信息素产生和反应差异的信号通路，利用已测序的红脂大小蠹基因组信息，定位和克隆信息素产生和信息素感受差异基因，进而结合信息素体外表达和RNAi技术验证基因功能，明确两种群化学通讯差异的分子基础，阐明红脂大小蠹原产地种群和入侵地种群化学通讯差异的机制，揭示化学通讯变异介导的红脂大小蠹在原产地危害不严重而在入侵我国后爆发成灾的入侵机制。

为什么入侵害虫通常在原产地为次期性害虫或不成灾而在新入侵地暴发成灾转变为主要害虫一直是入侵生物学的核心科学问题。本研究拟以我国重大林业入侵种红脂大小蠹为对象，以前期研究发现红脂大小蠹原产地北美种群和入侵地中国种群化学通讯差异为切入点，通过野外危害型调查、诱捕和室内模拟信息素产生对比研究红脂大小蠹北美种群和中国种群对化学信息反应及其产生的差异，阐明红脂大小蠹在入侵地中国聚集危害而在北美不聚集危害的化学生态学机制；进而通过转录组学方法分析确定调控两种群信息素产生和反应差异的信号通路，利用已测序的红脂大小蠹基因组信息，定位和克隆信息素产生和信息素感受差异基因，进而结合信息素体外表达和RNAi技术验证基因功能，明确两种群化学通讯差异的分子基础，阐明红脂大小蠹原产地种群和入侵地种群化学通讯差异的机制，从化学生态角度阐明化学通讯变异介导的红脂大小蠹在原产地危害不严重而在入侵我国后爆发成灾的入侵机制。经过4年的研究，我们对比研究了中美种群危害型；对比研究了中美种群林间诱捕和信息素产生；进行了基因组和种群重测序，解析了红脂大小蠹在新入侵地适应的遗传基础；研究了可能的P450基因在聚集信息素frontalin合成路径中的作用，取得了预定的研究目标，为后续研究打下了坚实的基础。