【作者】 国伟；

【导师】 沈佐锐；

【作者基本信息】 中国农业大学 ， 农业昆虫与害虫防治， 2005， 博士

【摘要】 麦长管蚜Macrosiphum miscanti Takahashi是我国重要的农业害虫,它分布广、食性杂、繁殖力强,不仅直接吸食小麦的汁液,而且还是麦类黄矮病毒病的重要传播媒介。由于麦蚜种群有较强的异质性,遗传变异度大,长期以来,有关该害虫的暴发机理及在我国具体的迁飞路线、迁飞距离及往返规律等还不甚清楚。本研究应用分子遗传学标记技术和GIS分析技术,对麦长管蚜不同地理种群的遗传多样性、地理种群间的遗传分化与基因流等问题进行了研究,分析了麦长管蚜地理种群时空动态的分子特征。深入研究麦长管蚜的种群遗传结构和种群间基因交流这些问题,有利于从根本上了解麦蚜的适应机理和成灾机理,从而为准确把握其发生规律并进行有效防治提供依据。 本研究采用微卫星标记技术对不同地理种群麦长管蚜的遗传多样性进行研究,针对麦长管蚜建立了一套特异性的微卫星DNA标记系统,筛选出5个多态性高、重复性好、可用于麦蚜种群遗传分析的微卫星位点,然后利用这套微卫星标记对北京上庄、河北衡水、河北石家庄、河南郑州、山西太原、山西太谷、山东济南、陕西宝鸡、陕西杨陵、青海大通、宁夏固原、江苏南京、湖南长沙、贵州贵阳、湖北武汉等15个地理种群的麦长管蚜样品进行种群遗传分化和基因流的分析。得到以下结论:麦长管蚜不同地理种群间的基因交流与地理距离间呈现一定的相关关系。东部麦蚜种群基因交流比较频繁,西部麦蚜种群间基因交流非常少,有相对的基因隔离,我们认为,地理差异是影响麦长管蚜种群遗传结构的重要因素,麦长管蚜经过长距离的迁飞增加了种群间的基因交流,降低了种群间的遗传分化。麦长管蚜15个地理种群有着各不相同的环境因素,经度、纬度以及海拔高度等都有可能影响麦长管蚜的种群遗传结构。 此外,我们把Wolbachia这一麦蚜体内的细胞内共生细菌作为特殊标记,研究了不同地理种群麦长管蚜体内Wolbachia的感染率,结果发现不同地理种群麦蚜Wolbachia的感染率差别很大。随着经度的增加,Wolbachia的感染率也有递增的趋势,东部地区感染率高而内陆地区感染率低,我们推测可能是由于地理隔离造成了一定程度上的生殖隔离。这个结论也与采用微卫星标记得出的麦蚜遗传结构的结论相吻合。 最后,本研究利用GIS技术结合生物地理统计学(geo-statistics)对麦长管蚜的空间分布、空间相关分析、麦蚜发生动态的时空模拟等进行研究,以VC++为开发平台,以MapX控件作为图形平台,开发研制出了具有空间数据与属性数据编辑、查询、分析等基本功能的麦蚜基因流地理信息系统。其主要目的在于将抽象的麦蚜发生为害信息、麦蚜基因流信息以及相关的气象信息等以地图的形式快速、直观地显示,利用地理信息系统的空间分析、地统计分析等功能进行麦蚜迁飞的气象地理生物学分析,研究麦蚜种群空间格局的特征,并结合麦蚜历年的迁飞记录、气流资料以及气象数据等,推测麦长管蚜在我国可能的迁飞路线。 本研究将微观的分子生态学与宏观的空间生态学有机的联系为一体,这对于从理论上进一步揭示麦蚜的暴发机理和迁飞规律,从实践中有效地开展综合治理都具有重要的参考价值。更多还原

【Abstract】 Macrosiphum miscanthi (Takahashi) (Homoptera: Aphididae), widespread throughout the country, is one of the most common and destructive pests attacking the wheat. Colonies of the aphid not only feed upon the wheat leaves, but also transmit the barley yellow dwarf virus (BYDV) to some small crops. In addition, the long-distance migration of the aphids would cause the crop’s damage extension and virus disease spreading. Here we used microsatellite markers and geographic information system (GIS) to discuss migration and population genetics of the grain aphid in relation to the geographic distance and gene flow.Samples of the grain aphid collected from 15 locations in China have been examined at 5 polymorphic microsatellite loci. Overall, genetic diversity displays a relation between the migration and gene flow in the grain aphid: a free and frequent gene flow is found in the eastern populations, and gene isolation occurs in the two western populations, especially Datong population and Guiyang population. The natural barriers may present an insurmountable obstacle preventing gene flow and aphid migration. However, a spatial genetic differentiation between populations is correlated with their geographical separation, indicating the geographic differentiation may play an important role in shaping the genetic structure of M. miscanthi populations. In addition, it seems that the long distance migration of the grain aphid may enhance gene flow and decrease genetic differentiation among different populations.Wolbachia, found in reproductive tissues of arthropods, are transmitted through the cytoplasm of eggs and have evolved various mechanisms for manipulating reproduction of their hosts. Based on the amplification of part of wsp gene encoding the outer membrane protein of Wolbachia, the presence of Wolbachia has been successfully detected in the grain aphid M. miscanthi. Moreover, it is shown that Wolbachia infection rates in different populations of the grain aphid have been obvious dissimilarity. After molecular identification of wsp gene, some factors contributing to this uncongnience are discussed here.Based on VC++ developing platform, we developed Aphid GIS system with many functions such as editing, querying, analysis of space data and attribute data, etc. and using the MapX control as the graphical platform. Anyway geographic differentiation and environment factors (e.g. altitudes, longitude and relative humidity) seem the most adequate explanation for spatial genetic structure of the aphid. Further studies are necessary to clarify the genetic background of M. miscanthi to find genetics correlated with abiotic (e.g. climate and topography) and biotic (e.g. life-cycle) factors by analyzing more populations at more loci for more information. We hope these results could be useful in modeling and forecasting outbreaks of grain aphid and in designing rational control strategies.更多还原