DISSERTATION RESEARCH: CHEMICAL ECOLOGY OF INTERACTIONS AMONG PLANTS, PATHOGENS, AND DISEASE VECTORS

寄生虫经常以有利于将寄生虫传播给其他宿主的方式操纵它们的宿主。对于通过昆虫媒介传播的病原体，寄主的气味可能是这种操纵的目标，因为植物和动物喂养的昆虫在觅食时都使用气味线索。但是，关于病原体对宿主气味和其他宿主化学方面的影响如何影响昆虫传播疾病的生态学，人们知之甚少。该项目将探索一种广泛存在的植物病原体黄瓜花叶病毒对其寄主植物特征的影响，这些特征影响了与蚜虫的关键相互作用，蚜虫是该病毒的常见昆虫载体。初步结果表明，蚜虫对黄瓜花叶病毒感染的植株表现不佳，一旦有机会向健康植株转移，蚜虫就会迅速离开感染的植株。令人惊讶的是，蚜虫仍然会被感染植物的气味所吸引，这种气味会释放出一种高浓度的空气中混合的化学物质，而这种化学物质与健康植物的气味相似。这些发现表明，病原体夸大昆虫媒介用来寻找宿主的线索可能是一种很好的策略。本研究项目将通过结合生态学、化学和植物生理学的技术和概念来检验这一假设，以检查病原体、植物和昆虫媒介之间未被充分研究的相互作用，以及这些变化对害虫昆虫与其天敌之间相互作用的影响。从这项研究中获得的知识将有助于制定控制农业病毒的管理策略。更一般地说，该项目的结果与了解疾病生态学和进化，包括由昆虫媒介传播的人类疾病，如疟疾，具有更广泛的相关性。拟议的研究将与旨在培养高中和本科理科学生的教育活动相结合。这个项目非常适合K-12教育，因为它很容易分解成不同的假设单元，可以为没有实验室经验的学生提供研究机会。该项目还将支持一名研究生的论文研究。

Parasites often manipulate their hosts in ways that favor the transmission of the parasite to other hosts. For pathogens that are transmitted by insect vectors, host odors are a likely target for such manipulation, because both plant- and animal-feeding insects use odor cues when foraging for food. But, little is known about how pathogen effects on host odors and other aspects of host chemistry influence the ecology of disease transmission by insects. This project will explore the effects of a widespread plant pathogen, cucumber mosaic virus on features of its host plant that influence key interactions with aphids, a common insect vector for the virus. Preliminary results indicate that aphids perform poorly on plants infected by cucumber mosaic virus, and rapidly leave infected plants when given an opportunity to move to healthy plants. Surprisingly, aphids are nevertheless attracted to the odors of infected plants, which release elevated levels of a blend of airborne chemicals that is otherwise similar to the odor of healthy plants. These findings suggest that it may be a good strategy for pathogens to exaggerate the cues used by insect vectors to find hosts. This research project will test that hypothesis by combining techniques and concepts from ecology, chemistry, and plant physiology to examine the understudied interactions among pathogens, plants, and insect vectors, and the consequences of these changes to interactions between pest insects and their natural enemies.The knowledge gained from this study will be useful in developing management strategies for controlling viruses in agriculture. More generally, results from this project have broader relevance to understanding disease ecology and evolution, including human diseases that are spread by insect vectors, such as malaria. The proposed research will be integrated with educational activities aimed at training high-school and undergraduate science students. This project is well suited for K-12 education because it is easily broken down into units addressing distinct hypotheses that can provide research opportunities for students with little previous laboratory experience. This project will also support the dissertation research of a graduate student.