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

植物原体是一组通过吸液昆虫（半翅目昆虫，包括叶蝉、飞虱和跳虱）在植物间传播的植物寄生细菌，以前人们知道它们主要是因为它们会引起栽培作物的严重疾病。最近从博物馆保存的半翅目昆虫标本中筛选的DNA样本表明，植物原体在自然界中广泛存在，世界各地的自然区域蕴藏着许多以前未记载的植物原体菌株。该项目旨在通过筛选保存在博物馆生物库中的大量昆虫和现代DNA测序技术，揭示世界范围内植物原体的真正多样性，重建它们的进化关系，并记录它们与昆虫和植物的联系。这些新数据将有助于确定全球植物原体多样性热点，阐明植物原体对寄主植物和昆虫媒介进化的影响程度，并有助于培养新一代植物原体生态学、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）驱动的，环境变化触发了来自邻近自然区域的以前未知的疾病病原体在受管理的栖息地（如农田）的定植。提高对自然地区植物原体总体多样性的认识将大大促进预测和管理新疾病暴发的努力。该项目的具体目标包括：1)利用下一代dna测序技术筛选存在植物原体的昆虫标本；2)获取新检测到的与昆虫相关的植物原体的部分基因组和寄主植物数据；3)重建所有已知植物原体之间的系统发育关系，对新发现的菌株进行分类，估计单个谱系的起源时间；4)更新现有的在线数据库，包括所有以前已知的和新发现的植物浆与宿主的关联；5)通过培训和指导学生采用前沿方法来研究多种多样且鲜为人知的农业重要微生物谱系，从而培养新的专业知识。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.