PurSUiT: Revealing undiscovered diversity and distribution of phytoplasmas through screening of potential host insects in a museum biorepository

植原体是由吸液昆虫(半翅目，包括叶蝉、飞虱和跳虱)在植物之间传播的一组植物寄生细菌，以前主要是因为它们能引起栽培作物的严重病害而被人们所知。最近对保存下来的半翅目昆虫博物馆标本的DNA样本筛选表明，植原体在自然界中广泛存在，世界各地的自然地区都有许多以前没有记载的植原体菌株。该项目旨在通过筛选保存在博物馆生物仓库中的大量昆虫和现代DNA测序技术，揭示世界各地植原体的真实多样性，重建它们的进化关系，并记录它们与昆虫和植物的联系。新的数据将有助于确定世界各地植原体多样性的热点，阐明植原体对其宿主植物和昆虫媒介进化的影响程度，并有助于培训新一代植原体生态学、流行病学和进化方面的专家。新的植物疾病的出现可能是由环境变化(包括气候变化)推动的，环境变化触发了来自邻近自然地区的以前未知的病原体对受管理的栖息地(例如农田)的殖民。该项目的具体目标包括：1)利用下一代DNA测序技术筛选昆虫标本以发现植原体的存在；2)获得部分植原体基因组和新发现的与昆虫相关的植原体的寄主植物数据；3)重建所有已知植原体之间的系统发生关系，对新发现的菌株进行分类，并估计个别谱系的起源时间；4)更新现有的在线数据库，以包括所有已知和新发现的植原体-宿主关系；5)通过培训和指导学生学习各种不同的、鲜为人知的农业重要微生物谱系的前沿方法来培养新的专业知识。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Phytoplasmas, a group of plant-parasitic bacteria transmitted from plant to plant by sap sucking insects (Hemiptera, including leafhoppers, planthoppers and jumping plant lice), were previously known mainly because they cause severe diseases of cultivated crops. Recent screening of DNA samples from preserved museum specimens of hemipteran insects indicated that phytoplasmas are widespread in nature and that natural areas worldwide harbor many previously undocumented phytoplasma strains. This project aims to uncover the true diversity of phytoplasmas worldwide, reconstruct their evolutionary relationships, and document their associations with insects and plants by screening a large collection of insects preserved in a museum biorepository and modern DNA sequencing techniques. The new data will help identify hotspots of phytoplasma diversity worldwide, clarify the extent to which phytoplasmas have affected the evolution of their host plants and insect vectors, and contribute to training of a new generation of experts on phytoplasma ecology, epidemiology and evolution. Emergence of new plant diseases may be driven by environmental change (including climate change) that triggers the colonization of managed habitats (e.g., croplands) by previously unknown disease agents from adjacent natural areas. Improved knowledge on the overall phytoplasma diversity in natural areas will greatly facilitate efforts to predict and manage new disease outbreaks.Specific goals of the project include: 1) screen insect specimens for presence of phytoplasmas using next-generation DNA-sequencing technology; 2) obtain partial phytoplasma genomes and host plant data for newly detected insect-associated phytoplasmas; 3) reconstruct phylogenetic relationships among all known phytoplasmas, classify newly discovered strains and estimate the times of origin of individual lineages; 4) update an existing online database to include all previously known and newly discovered phytoplasma-host associations; 5) cultivate new expertise by training and mentoring students in leading-edge methods for studying a diverse and poorly known lineage of agriculturally important microbes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.