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

以木材为食的白蚁可能是极具破坏性的害虫。它们靠木头这样营养不良的食物生存的能力来自共生的肠道微生物。在某些白蚁中，这些微生物包括原生动物(原生动物)，它们可以吞噬木材颗粒，并使用特殊的酶提取糖。这个项目将决定原生生物如何进化他们的木材消化能力。他们是从细菌或真菌那里获得了木材降解酶的新基因，还是适应了也存在于非白蚁原生动物中的酶？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物化学品。由于大多数白蚁原生生物还没有被研究过，这个项目还将通过描述许多新的原生生物物种并确定它们之间以及它们与非白蚁原生生物之间的关系来阐明生命树的黑暗区域。作为生物多样性发现和文献工作的一部分，亚利桑那州立大学以课程为基础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种原生生物的转录组测序，31种来自与白蚁相关的谱系，12种来自相关的非白蚁谱系。这些转录本的研究将确定纤维素酶和半纤维素酶在原生动物超级门Metamonada的多样性、分布和系统发育。转录组数据还将用于系统基因组分析，以解决原生生物的系统发育问题，并提供一个框架来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少，将利用单细胞聚合酶链式反应对21种系统发育不同的白蚁物种中另外200种共生的原生生物进行形态特征和18S rRNA序列分析。这一数字估计包括50-70个目前未被发现的物种，这些物种将被正式描述。亚利桑那州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，作为基于课程的研究经验(CURE)的一部分。参与真实的研究已被证明能增加大学生对科学的欣赏和保留。拟议的解决方案将专门针对第一代大学生，包括当地社区大学的转学学生。研究成果将通过会议和两年一度的弗洛里达大学国际白蚁课程广泛传播给原生动物学、微生物生态学和白蚁专家群体。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。

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.