Beetles and Their Yeast Associates from Basidiocarp Habitats

抽象的。真菌通常被认为是植物多样性的决定因素，植物多样性被认为是影响甲虫和其他昆虫群体多样性的主要因素。然而，真菌和昆虫进化之间的直接关系仍然没有得到重视。肠道真菌，包括酵母菌，已知对某些昆虫的营养至关重要。目前的研究是基于先前NSF支持的研究结果，其中PI从选定的巴拿马和美国地区的27个家族的甲虫消化道中分离出约200种新的酵母菌，增加了所有已知酵母菌的30%。统计分析估计，只有以前采样的限制栖息地的restriation可以产生额外的未描述的类群，以增加目前的酵母数量从世界各地的所有栖息地的50%。与甲虫相关的未描述酵母的巨大多样性的发现令人震惊，特别是当人们超越本研究高度限制的分类、时间、生态和地理范围进行推断时。系统发育分析将甲虫肠道酵母在至少45个独立的分支之间的所有已知的酵母与集群的主要昆虫相关的群体，这表明高酵母的多样性出现偶尔水平传播在共同的栖息地和随后的专业化与昆虫。除了发现新的酵母物种，目前的研究将攻击生理，生态和进化问题，关于酵母-昆虫协会的性质，协会的普遍性，以及酵母在栖息地扩张和昆虫物种形成中可能发挥的作用，PI将使用现场和文化方法以及分子技术，包括DNA测序来回答这些问题。这项研究将具有更广泛的科学意义，因为酵母在工业过程中具有巨大的潜力。在这项工作中，研究人员发现，与木甲虫有关的酵母菌具有将植物材料有效转化为燃料酒精的潜力。其他新发现的酵母合成了各种各样的其他酶和维生素，PI将合作确定这些在工业过程中是否有用。PI将继续保持高度互动，并将广泛传播本研究的结果。一个额外的好处将是继续培训本科生和研究生的现代进化和生态研究的方法，在以前的研究。除了培训研究生外，研究所还特别有效地利用前一个项目，重点培训了17名大学生，内容涉及昆虫-真菌关系;其中包括4名男子和13名妇女，其中两名是少数民族妇女。所有毕业的学生都去了研究生院或医学院;一个是乔治C。牛津大学马歇尔学者。发表了四篇由本科生撰写的论文，并在全国会议上发表了两篇有本科生参加的演讲。

Abstract. Fungi often have been suggested as determinants of plant diversity, and plant diversification has been implicated as a major factor affecting the diversity of beetles and other insect groups. Direct relationships between fungi and insect evolution, however, remain under appreciated. Gut-inhabiting fungi, including yeasts, are known to be essential to the nutrition of some insects. The current study is based on results of previous NSF supported research in which the PIs isolated about 200 new species of yeasts out of 650 isolates from digestive tracts of beetles in 27 families in selected Panamanian and USA localities, an increase of 30% of all known yeast species. Statistical analyses estimate that resampling of only the previously sampled restricted habitats could produce additional undescribed taxa to increase current yeast numbers from all habitats worldwide by 50%. The discovery of the great diversity of undescribed yeasts in association with beetles is stunning, especially when one extrapolates beyond the highly restricted taxonomic, temporal, ecological, and geographical scope of this study. Phylogenetic analyses placed the beetle gut yeasts in at least 45 independent clades among all known yeasts with clustering of major insect-associated groups, suggesting high yeast diversity arose by occasional horizontal transmission in common habitats and subsequent specialization with the insects. In addition to discovery of new yeast species the current study will attack physiological, ecological, and evolutionary questions, regarding the nature of the yeast-insect associations, the universality of associations worldwide, and the role that yeasts may play in habitat expansion and speciation of insects, and the PIs will use field and cultural methods as well as molecular techniques, including DNA sequencing to answer the questions. The study will have broader scientific significance because yeasts have great potential in industrial processes. In this work the PIs discovered that yeasts associated with wood-ingesting beetles have potential in efficient conversion of plant material to fuel alcohol. Other newly discovered yeasts synthesize a wide variety of other enzymes and vitamins, and the PIs will collaborate to determine if these might be useful in industrial processes. The PIs will continue to be highly interactive and will disperse the findings of this study widely. An added benefit will be the continued training of undergraduates and graduate students in methods of modern evolutionary and ecological studies as in the previous study. In addition to the training of graduate students, the PIs were especially effective in using the previous project as a focus for training 17 undergraduates on aspects of insect-fungus associations; these included 4 men and 13 women, two of whom were minority women. All graduated students have gone to graduate or medical school; one is a George C. Marshall Scholar at Oxford University. Four papers with undergraduate authors were published, and two presentations at national meetings involved undergraduates.