DISSERTATION RESEARCH: Virus Roles in Wild Cucurbita pepo and the Risks of Genetically Engineered Virus Resistance

虽然植物病原体对野生植物种群有显著影响，但对野生植物种群中病毒生态学的研究却很少。基因工程（GE）抗病毒作物（已插入抗病毒基因）的两大生态风险促使人们有必要了解植物内部病毒的相互作用以及病毒对野生植物种群的影响。(1)如果转基因抗病毒作物与附近亲缘关系密切的野生植物群体杂交，那么转基因抗病毒基因就可以进入野生植物群体。如果目标病毒通常会抑制野生植物的繁殖或生存，那么病毒抗性可能会增加野生植物的适应性，并可能增加野生植物对自然和农业栖息地的入侵性。(2)如果几种病毒相互竞争以成功感染一种植物（作物或野生），那么该植物对一种病毒的抗性可能会导致以前竞争较弱的病毒的感染增加。该项目将研究一种转基因抗病毒南瓜（Cucurbita pepo）和一种野生南瓜，以研究病毒感染对野生植物种群的影响，并评估转基因抗病毒的相关风险。在迄今为止的研究中，pi已经通过对照实验证实，当病毒感染普遍存在时，转基因病毒抗性增加了野生南瓜的适应性。2004年，pi将确定野生南瓜种群中病毒感染的流行程度，以预测转基因病毒抗性对非实验性野生南瓜适应性的影响。先前的研究已经发现了南瓜病毒之间的竞争。在2004年和2005年，pi将进行一系列温室实验，以更严格地研究这种相互作用。该研究将提供有价值的病毒生态学信息，并评估转基因作物抗病毒的潜在生态影响。

Although plant pathogens can significantly affect wild plants populations, the ecology of viruses in wild plant populations is rarely studied. Two ecological risks of genetically engineered (GE), virus-resistant crops (into which genes for virus-resistance have been inserted) prompt a need to understand the interactions of viruses within plants and the impact of viruses on wild plant populations. (1) If GE, virus-resistant crops interbreed with nearby, closely related wild plant populations, then GE virus resistance genes could enter wild populations of plants. If the targeted virus typically suppresses wild plant reproduction or survival, then virus- resistance may increase wild plant fitness and potentially increase the wild plant's invasiveness in natural and agricultural habitats.(2) If several viruses compete with each other to successfully infect a plant (crop or wild), then the plant's resistance to one virus could result in increased infection by formerly less competitive viruses. This project will examine a GE, virus-resistant squash (Cucurbita pepo) and a wild squash to examine the affect of viral infection in wild plant populations and to assess the associated risks of GE virus-resistance. In research to date, the PIs have confirmed with controlled experiments that GE virus-resistance increases wild squash fitness when virus infection is prevalent. In 2004, the PIs will determine the prevalence of virus infection in wild squash populations to predict the affect of GE virus-resistance on non-experimental, wild squash fitness. Prior research has detected competition between squash viruses. In 2004 and 2005, the PIs will conduct a series of greenhouse experiments to study this interaction more rigorously. This research will provide valuable information about virus ecology and assess potential ecological impacts of GE virus-resistance in crops.