Understanding evolutionary similarity and diversification of complex pathways of soil fungi to synthesize compounds with diverse ecological, biological and pharmaceutical functions

了解土壤真菌复杂途径的进化相似性和多样化，以合成具有多种生态、生物和药物功能的化合物

• 批准号: 1354944
• 负责人: Joseph Spatafora
• 金额: $ 47.66万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-15 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1354944&HistoricalAwards=false
• 关键词: Understanding; evolutionary; similarity; diversification; complex

Fungi produce biologically active molecules such as antibiotics and immune system suppressants through complex biosynthetic pathways. This research investigates the evolutionary processes that operate in the diversification of these pathways, and thus the metabolites they produce, using the soil dwelling fungus Tolypocladium. Species of Tolypocladium are known to be particularly rich in biologically active metabolites with the best-known example being Cyclosporin A, which is used medicinally to suppress the immune system in organ transplant patients. Recent advancements in genomics and computational biology show significantly greater diversity of metabolic pathways than previously detected by traditional chemical analyses. As such, science has only observed the "tip of the iceberg" of fungal biochemical diversity, while the majority await discovery as promising sources of pharmaceuticals, alternatives for the control of insect pests and bioremediation of contaminated soils, and essential in the development of biofuels. A more robust understanding of patterns and processes that have led to the diversification of fungal genomes, and subsequently their biologically active molecules, will enhance the ability to exploit fungi for the betterment of society. This research establishes a case study methodology by which other fungi can be studied and exploited for scientific advancements. In achieving these advancements, students and young researchers are trained in an interdisciplinary manner and equipped to study and develop biological solutions to the challenges of the modern World.Genomes of 20 fungal isolates will be sequenced, identifying and characterizing secondary metabolite gene clusters. These genomic analyses will be coupled with manipulative growth experiments and chemical analyses, linking the genetic factors, environment and ecology, with the metabolites produced, and resulting in a metabolite census of this group of fungi. Evolutionary processes and patterns of diversification (e.g., gene duplication-divergence, horizontal gene transfer, gene fusion, diversifying selection) will be tested using phylogenomic methodologies. The analyses will be coupled with liquid chromatography-tandem mass spectrometry metabolite profiling, selective growth experiments, and RNA sequencing to link secondary metabolite gene clusters with their metabolites. The specific aims and experimental plan are designed to compare two major hypotheses. The first is that diversification of secondary metabolites results from complex processes incongruent with phylogeny. The second is that homologous domains produce chemically distinct metabolites not previously suspected of having common evolutionary origins. The research determines if the complex patterns of evolution shown by genetically distinct non-ribosomal peptide synthetases and polyketide synthases represent homologous domains and genes, respectively, produced by evolutionary processes such as duplication-divergence, horizontal genet transfer, gene fusion, and diversifying selection. The integration of liquid chromatography-tandem mass spectrometry metabolite profiling, selective growth experiments, RNA sequencing and phylogenomic analyses will link secondary metabolite gene clusters and the metabolites they produce, showing the evolutionary connection between genotypes and chemical phenotypes.

真菌通过复杂的生物合成途径产生生物活性分子，如抗生素和免疫系统抑制剂。这项研究调查了在这些途径的多样化中运作的进化过程，以及它们产生的代谢产物，使用土壤真菌Tolypocladium。已知Tolypocladium的物种特别富含生物活性代谢物，最著名的例子是环孢菌素A，其在医学上用于抑制器官移植患者的免疫系统。基因组学和计算生物学的最新进展表明，代谢途径的多样性比以前通过传统化学分析检测到的要大得多。因此，科学只观察到真菌生物化学多样性的“冰山一角”，而大多数真菌仍在等待发现，它们是有希望的药物来源、控制虫害和污染土壤生物修复的替代品，以及开发生物燃料的关键。对导致真菌基因组多样化的模式和过程以及随后的生物活性分子的更深入了解，将提高利用真菌改善社会的能力。这项研究建立了一个案例研究方法，通过该方法可以研究和利用其他真菌促进科学进步。在实现这些进步的过程中，学生和年轻的研究人员以跨学科的方式接受培训，并配备研究和开发生物解决方案，以应对现代世界的挑战。20个真菌分离株的基因组将被测序，识别和表征次级代谢物基因簇。这些基因组分析将与操纵生长实验和化学分析相结合，将遗传因素，环境和生态与产生的代谢物联系起来，并导致这组真菌的代谢物普查。多样化的演变过程和模式（例如，基因复制-趋异、水平基因转移、基因融合、多样化选择）将使用基因组学方法进行测试。这些分析将与液相色谱-串联质谱代谢物分析、选择性生长实验和RNA测序相结合，以将次级代谢物基因簇与其代谢物联系起来。设计了具体的实验目的和实验方案，对两个主要假设进行了比较。第一种是次生代谢产物的多样化是由与次生代谢不一致的复杂过程引起的。第二个是同源结构域产生化学上不同的代谢物，以前没有怀疑有共同的进化起源。该研究确定了遗传上不同的非核糖体肽合成酶和聚酮酶所表现出的复杂的进化模式是否分别代表了由进化过程（如复制趋异、水平基因转移、基因融合和多样化选择）产生的同源结构域和基因。液相色谱-串联质谱代谢物谱分析、选择性生长实验、RNA测序和DNA基因组分析的整合将把次级代谢物基因簇和它们产生的代谢物联系起来，显示基因型和化学表型之间的进化联系。