Genetic Basis of Coleopteran Vectorial Capacity for Bean pod mottle virus Transmission

为什么一些有叶节肢动物传播植物病原体，而另一些不传播？此外，为什么通常只有一种媒介物种中的一小部分人擅长传播特定的病原体？相当数量的鞘翅目甲虫传播病毒，使经济上重要的蔬菜和农作物得病。然而，甲虫物种内部和物种之间携带和传播病原体的能力的差异程度是显著的(即它们的媒介能力)。毫无疑问，载体的基因构成对病原体感染和传播的易感性有很大贡献，然而影响载体能力的特定基因的特征被证明是难以捉摸的。这项拟议研究的长期目标是了解昆虫传播病原体的遗传相互作用和机制。识别干扰病原体媒介传播的基因将为疾病控制带来新的和有希望的途径。这项拟议的研究将利用大豆病理系统的独特属性，由三种甲虫组成，它们携带在北美流行的大豆病毒-菜豆豆荚斑驳病毒(BPMV)的能力在个体和物种水平上存在差异。我之前的研究有力地表明，BPMV传播能力的遗传关键在于甲虫自身的反流物，它在取食过程中沉积在叶片受伤的部位。鉴于昆虫效应基因在编码改变植物防御的蛋白质中所起的作用，我假设甲虫反流物中分泌的效应器的补体也影响寄主植物对昆虫传播的病原体入侵的敏感性。为了探索这一点，拟议的研究将结合甲虫返流转录本的比较以及媒介能力和基因组变异性的数据来识别，然后测试候选效应器对载体能力的影响。*目标1.表征效应器基因返流成分的种间和种内差异。*目标2.开发基于RNAi的工具来从功能上表征目标1中确定的候选效应器的作用。*目标3.确定自然种群中BPMV传播率和候选基因序列多态的差异程度。*我期望识别并在功能上暗示导致甲虫物种内和物种间BPMV载体能力差异的基因子集。此外，拟议的工作将使人们更好地了解驱动昆虫媒介疾病传播的遗传、进化和环境因素。

Why do some leaffeeding arthropods transmit plant pathogens while others do not? Moreover, why typically are only a small minority of individuals within a vector species proficient at transmitting a particular pathogen? A considerable number of coleopteran beetles transmit viruses that cause disease to economically important vegetables and crops. However, the degree of variation within and among beetle species in their ability to harbor and transmit pathogens is remarkable (i.e. their vector competence). The genetic makeup of the vector undoubtedly contributes significantly to its susceptibility to pathogen infection and transmission, yet characterization of specific genes that influence vector competence has proven elusive. The longterm goal of the proposed research is to understand the genetic interactions and mechanisms of pathogen transmission by insects. Identifying genes that disrupt vector-mediated pathogen transmission will lead to novel and promising avenues for disease control. The proposed research will harness the unique attributes of a soybean pathosystem, consisting of three beetle species that exhibit individual and species level variation in their ability to vector a soybean virus that is prevalent in North America, Bean pod mottle virus (BPMV). My previous research strongly suggested that the genetic key' to BPMV transmission capability lies in the beetle's own regurgitant, which is deposited at leaf wounding sites during feeding. Given the role of insect effector genes in encoding proteins that alter plant defenses, I hypothesized that the complement of effectors secreted in the beetle's regurgitant also impacts host plant susceptibility to insectborne pathogen invasion. To explore this, the proposed research will integrate comparisons of beetle regurgitant transcriptomes and data on vector competence and genomic variability to identify, and then test candidate effectors for their influence on vector competence.*** Objective 1. Characterize interspecific and intraspecific differences in the regurgitant composition of effector genes.*** Objective 2. Develop RNAibased tools to functionally characterize the role of candidate effectors identified in Objective 1.*** Objective 3. Determine the extent of variation in BPMV transmission rates and candidate gene sequence polymorphism in natural populations.******I expect to identify and functionally implicate a subset of genes that contribute to the differences in BPMV vectorial capacity within and among beetle species. Further, the proposed work will lead to a better understanding of the genetic, evolutionary and environmental factors that drive insect-vectored disease transmission.**