CAREER: Wood-eating protists: An evolutionary transition enabled by gene transfer?

食木白蚁是极具破坏性的害虫。它们在像木头这样营养不良的食物上生存的能力来自于共生的肠道微生物。在某些白蚁体内，这些微生物包括原生生物（原生动物），它们可以吞噬木头颗粒，并利用特殊的酶提取糖。这个项目将确定原生生物如何进化他们的木材消化能力。它们是从细菌或真菌那里获得木材降解酶的新基因，还是它们适应了非白蚁原生生物中也存在的酶？更好地了解原生生物对木材的消化可能有助于制定白蚁控制策略或学习如何将木质生物质转化为生物燃料或其他生化物质。由于大多数白蚁原生生物尚未被研究，该项目还将通过描述许多新的原生生物物种，并确定它们彼此之间以及与非白蚁原生生物之间的关系，照亮生命之树的黑暗区域。作为生物多样性发现和文献工作的一部分，亚利桑那州立大学的一个基于课程的本科生研究经验将培训大约200名学生进行系统学和生物多样性研究。研究活动将包括43个原生物种的转录组测序，其中31个来自白蚁相关谱系，12个来自相关的非白蚁谱系。这些转录组将被研究以确定纤维素酶和半纤维素酶的多样性、分布和系统发育。转录组学数据也将用于系统基因组分析，以解决原生系统发育问题，并提供一个框架，以解释木材消化的进化。由于对白蚁肠道原生生物的研究还很不充分，我们将利用单细胞PCR对21种系统发育多样的白蚁物种中共生的约200种原生生物进行形态学和18S rRNA序列的表征。这个数字包括估计50-70个目前未被发现的物种，这些物种将被正式描述。亚利桑那白蚁原生物种的特征将由接受分类学和系统学培训的本科生团队进行，作为课程研究经验（CURE）的一部分。参与真实的研究已被证明可以增加本科生对科学的欣赏和保留。拟议中的CURE将专门针对第一代大学生，包括从当地社区大学转来的学生。研究成果将通过会议和两年一次的佛罗里达大学国际白蚁课程广泛传播给原生生物学、微生物生态学和白蚁专家社区。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。

Wood-feeding termites can be highly destructive pests. Their ability to survive on such a nutritionally poor diet as wood comes from symbiotic gut microbes. In certain termites, these microbes include protists (protozoa) that can engulf wood particles and extract sugars using specialized enzymes. This project will determine how the protists evolved their wood-digesting ability. Did they acquire new genes for wood-degrading enzymes from bacteria or fungi, or did they adapt enzymes that are also present in non-termite protists? A better understanding of wood digestion in protists could be useful for developing termite control strategies or learning how to convert woody biomass into biofuels or other biochemicals. Because most termite protists have not been studied, this project will also illuminate a dark area of the tree of life by describing many new protist species and determining how they are related to one another and to non-termite protists. As part of the biodiversity discovery and documentation effort, a course-based undergraduate research experience at Arizona State University will train approximately 200 students in systematics and biodiversity research. The research activities will include transcriptome sequencing of 43 protist species, 31 from termite-associated lineages and 12 from related, non-termite lineages. These transcriptomes will be studied to determine the diversity, distribution, and phylogeny of cellulases and hemicellulases in the protist superphylum Metamonada. Transcriptomic data will also be used for phylogenomic analyses to resolve the protist phylogeny and provide a framework against which to interpret the evolution of wood digestion. Because termite gut protists are so understudied, an additional ~200 protist species symbiotic in 21 phylogenetically diverse termite species will be characterized by morphology and 18S rRNA sequence by single cell PCR. This number includes an estimated 50-70 currently undiscovered species that will be formally described. The characterization of Arizona termite protist species will be carried out by teams of undergraduate students receiving training in taxonomy and systematics as part of a course-based research experience (CURE). Involvement in authentic research has been shown to increase undergraduates’ appreciation of and retention in science. The proposed CURE will specifically target first-generation college students, including transfer students from a local community college. Research results will be disseminated broadly to protistology, microbial ecology, and termite specialist communities through conferences and the biennial International Termite Course at the University of Florida.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.