REVSYS: Phylogenetics and Taxonomic Revision of the Rhizophydium Clade (Chytridiomycota)

菊苣是一种具有鞭毛(活动)生活期的微型真菌(“游动孢子菌”)，在自然界中几乎无处不在，但鲜为人知，而且往往未被认识。一些最重要的chytrid真菌是根霉分支或谱系的成员，包括致命的两栖寄生虫Batrachochytrium endrobatidis，大量的藻类寄生虫，以及土壤中居住的难降解材料如花粉、纤维素、甲壳素和角蛋白的降解者。目前的分类学分类于1960年公布，已经过时，主要基于模糊的形态特征，这些特征显示出可塑性，使得识别属和种变得困难。基因测序和电子显微镜中的现代生物技术为利用形态和分子的系统发育信息特征重新评估这些生物提供了机会。最近对核糖体DNA序列的分析帮助确定了成员，并揭示了根霉分支中意想不到的遗传多样性，表明该类群的生物多样性被低估了。阿拉巴马大学的Martha Powell博士和Peter Letcher博士建议使用分子和游动孢子超微结构(细胞解剖学)特征来修订该类群的分类。他们将扩大采样的地理区域和栖息地，包括两个半球的温带雨林和热带雨林，分析的基因数量，以及游动孢子超微结构特征的细节。他们的目标是使菊苣的鉴定变得更容易，根据地理区域和栖息地记录它们在自然界中的存在，提供实验室培养来鉴定经典物种名称，培训一名未被充分代表的少数族裔学生，并与其他合作者合作，在栗子分类学和分类学方面进行合作。该项目的成果将是根霉分支的现代系统合成。这项工作将是第一次基于分子和超微结构特征对一大群菊苣进行专题合成。通过与澳大利亚、阿根廷和哥斯达黎加的科学家合作，研究人员将揭示热带和温带森林中龟类的多样性，这些栖息地正因森林砍伐和其他人为活动而迅速退化。使chytrid系统学更容易获得的工具将被添加到现有的网站上，其中包括数字图像、chytrid实验室培养数据库和交互式识别密钥。添加到GenBank中的分子序列将对探索脊椎动物在自然界中的功能作用的研究具有价值。与传播与教育技术中心合作，研究生实习生将学习视频制作、互动网络教育以及适合不同级别学生的适当内容。新制作的材料将通过印刷和数字格式向阿拉巴马州系统的许多中学生介绍真菌生物学和壶菌多样性。大多数学生、教师和门外汉一旦接触到龟裂，就会对这些生物产生兴趣。

Chytrids are microscopic fungi with flagellated (motile) life stages ("zoosporic fungi") that are nearly ubiquitous in nature, yet are poorly known and often unrecognized. Some of the most important chytrid fungi are members of the Rhizophydium clade or lineage, including the deadly amphibian parasite Batrachochytrium dendrobatidis, numerous algal parasites, and soil-inhabiting degraders of refractory materials such as pollen grains, cellulose, chitin, and keratin. The current taxonomic classification, published in 1960, is out of date and is based primarily on obscure morphological features that exhibit plasticity, making it difficult to identify genera and species. Modern biological techniques in gene sequencing and electron microscopy provide an opportunity to re-evaluate these organisms using phylogenetically informative characters, both morphological and molecular. Recent analyses of nuclear ribosomal DNA sequences have helped define membership and revealed unexpected genetic diversity within the Rhizophydium clade, indicating that the biodiversity of this group has been under-appreciated. Drs. Martha Powell and Peter Letcher at the University of Alabama propose to use molecular and zoospore ultrastructural (cell-anatomical) characters to revise the taxonomy of this group. They will expand the geographic areas and habitats sampled to include temperate and tropical rainforests in both hemispheres, the number of genes analyzed, and the details of ultrastructural characters of zoospores. Their goals are to make identification of chytrids easier, document their occurrence in nature by geographic region and habitat, provide laboratory cultures authenticating classical species names, and train a graduate student who is an underrepresented minority student, and work with other collaborators in chytrid systematics and taxonomy. The outcome of the project will be a modern systematic synthesis of the Rhizophydium clade. The work will be the first monographic synthesis of a large group of chytrids based on both molecular and ultrastructural characters. Through collaboration with scientists in Australia, Argentina, and Costa Rica, the investigators will reveal chytrid diversity in tropical and temperate forests, habitats that are rapidly being degraded by deforestation and other anthropogenic activities. Tools that make chytrid systematics more accessible will be added to an existing web site with digital images, a database of chytrid laboratory cultures, and interactive identification keys. Molecular sequences added to GenBank will be valuable for studies exploring the functional role of chytrids in nature. Working in concert with the Center for Communication and Educational Technology, the graduate student trainee will learn about video production, interactive web education, and appropriate content for students at different levels. Newly produced materials will introduce numerous middle-school students in the Alabama system to fungal biology and chytrid diversity through print and digital formats. Once introduced to chytrids, most students, teachers, and laypersons find these organisms fascinating.