CAA: Molecular and Functional Signatures of Fungi from Temperate and Tropical Hypersaline Microbial Mats.

微生物能够适应温度、pH、干燥和盐度等极端环境条件。最有趣的微生物繁衍的极端栖息地之一是高盐度的垫子。以前对这些系统的研究侧重于细菌和藻类，而在很大程度上忽视了真菌可能发挥的作用。PI实验室最近的结果显示，真菌确实可以从高盐度垫子中分离出来，尽管目前尚不清楚它们只是污染物还是促成垫子活动的居民。微生物垫在从淡水到高盐的各种条件下都能找到。它们由复杂的层状微生物群落组成，这些微生物群落在功能上是集成的，并且是自我维持的。物理和化学条件(主要是光照条件)的每日和季节波动导致垫层和含有特定微生物种群的微环境的发展。原核生物，主要是蓝藻，在垫子中产生大量由复杂碳水化合物组成的胞外聚合物分泌物(EPS)。这些复杂的分泌物被垫子中的其他微生物消耗。真菌和异养细菌极有可能促进EPS的降解和随后的碳矿化。因此，该项目将研究真菌群落的多样性、结构和功能，这些真菌群落存在于温带和热带微生物垫系统中，跨越时间和空间。工作包括从温带微生物垫子中分离真菌，使用生理和分子技术对不同的分离物进行表征，包括核糖体RNA基因的测序和系统发育分析，以及直接从微生物垫子中提取DNA以构建基因组文库并使用分子指纹方法研究真菌群落的结构。这项研究将使用的技术将有助于阐明热带和温带微生物垫的多样性和相似性，以及它们在碳循环中的作用。该项目将支持国际和平研究所Sharon坎特雷尔博士在图拉博大学(波多黎各)的职业发展，并将为西班牙裔美国本科生和研究生研究人员提供培训机会。它将使拉美裔学生接触到真菌学、分子生物学和进化论领域的技术和仪器。作为教育和宣传活动的一部分，将制作一个电视节目，宣传真菌在环境中的重要性，重点是微生物垫，以及真菌在其中可能发挥的作用。该项目还将促进与当地、国家和国际大学的研究合作，并将加强国际和平研究所的基础设施。

Microorganisms can adapt to extreme environmental conditions with respect to temperature, pH, desiccation and salinity. One of the more interesting extreme habitats in which microbes thrive are hypersaline mats. Prior studies of these systems have emphasized bacteria and algae and largely ignored the possible role of fungi. Recent results from the PI's laboratory have revealed that fungi can, indeed, be isolated from hypersaline mats, although it is not yet clear whether they are merely contaminants or residents that contribute to mat activities. Microbial mats are found under conditions ranging from freshwater to hypersaline. They consist of complex, laminate microbial communities that are functionally integrated and self-sustaining. Daily and seasonal fluctuations in the physical and chemical conditions (predominantly the light regime) result in both mat stratification and development of microenvironments that harbor specific microbial populations. Prokaryotes, predominantly cyanobacteria, in mats produce large quantities of extracellular polymeric secretions (EPS) consisting of complex carbohydrates. These complex secretions are consumed by other microorganisms in the mats. It is highly likely that fungi in concert with heterotrophic bacteria contribute to the degradation of EPS and the subsequent mineralization of carbon. Accordingly, this project will study the diversity, structure and function of the fungal community, present in both temperate and tropical microbial mat systems through time and space. Work includes isolation of fungi from temperate microbial mats, characterization of different isolates using physiological and molecular techniques, including sequencing and phylogenetic analysis of ribosomal RNA genes, and extraction of DNA directly from the microbial mats to construct a genomic library and study the structure of the fungal community using molecular fingerprinting methods. The techniques that will be used in this study will help elucidate the diversity and similarities of tropical and temperate microbial mats, and their role in the carbon cycle. This project will support the career development of the PI, Dr. Sharon Cantrell, at the Univesidad del Turabo (Puerto Rico) and will provide training opportunities for Hispanic-American undergraduate and graduate researchers. It will expose Hispanic students to technology and instrumentation in the areas of mycology and molecular biology and evolution. As part of the educational and outreach activities, a TV program will be prepared to promote the importance of fungi in the environment, with emphasis in microbial mats, and the possible role of fungi therein. This project will also promote research collaborations with local, national and international universities and will enhance the infrastructure at the PI's institution.