Labyrinthulomycete diversity and abundance

迷路菌（迷路菌、thraustochytrids和aplanochytrids）是普遍存在的、多样化的、丰富的海洋原生生物。人们认为它们主要以物种的形式生活，从藻类、高等植物或动物来源的无生命颗粒物有机物质（POM）中获取营养。因此，虽然迷路菌在分类学意义上不是“真菌”，但在生态学意义上它们可能具有“真菌”的功能，在分解POM中发挥类似的作用。由于迷路菌所含的必需多不饱和脂肪酸（PUFAs）含量高，它还可能通过改善腐质食物质量（“营养升级”）对海洋后生动物的营养起作用。然而，它们分解海洋持久性有机污染物作用的证据多少是间接的，因此不能支持关于它们的功能或重要性的定量结论。该项目的长期目标是收集有关迷路菌丰度和多样性的证据，以便更好地了解它们在海洋生态系统中的作用。本项目旨在建立基于聚合酶链反应（PCR）的分子遗传学方法来研究迷路菌的多样性和丰度。现有的迷路菌18S核糖体DNA （rDNA）特异性PCR引物不能识别迷路菌多样性的一个潜在重要组成部分（部分迷路菌群）。研究人员将开发新的18S rDNA引物，以便更好地估计迷路菌的多样性，然后使用这些引物收集来自各种栖息地的18S rDNA序列数据。所得到的序列数据将使这些生物的多样性相对于目前在培养中的代表在野外被量化。这些引物（或在项目过程中设计的其他引物）将用于开发定量实时PCR分析，以确定环境样品中迷路菌（和迷路菌亚群）的丰度。在初步测序工作中，还将开发培养在当地沉积物中检测到的新型迷路菌的方法。更广泛的影响：正如对异养细菌重要性的认识彻底改变了我们对浮游食物网的理解一样，对迷路菌更全面的研究可能会改变我们对海洋中POM的命运及其与后生动物食物网的联系的理解。两名本科生将继续参与该项目，在分子遗传学方面（协助PCR，克隆和测序）和培养工作。让石溪大学（SBU）的不同学生群体参与研究，为增加科学领域代表性不足的群体的存在提供了机会。已经在从事这个项目的研究生也是一个代表性不足的群体的成员。每年夏天将有一到两名高中生在实验室从事这个项目；SBU和PI都有接待当地高中生参加赞助的学生与教师研究合作的良好记录。

The Labyrinthulomycetes (labyrinthulids, thraustochytrids, and aplanochytrids) are ubiquitous, diverse, and abundant marine protists. They are thought to live mainly as saprobes, obtaining their nutrition from non-living particulate organic matter (POM) of algal, higher plant, or animal origin. Thus, while Labyrinthulomycetes are not "fungi" in a taxonomic sense, they may function as "fungi" in an ecological sense, playing similar roles in the decomposition of POM. Because of their high content of essential polyunsaturated fatty acids (PUFAs), Labyrinthulomycetes may also play a role in the nutrition of marine metazoans by improving the food quality of detritus ("trophic upgrading"). However, evidence of their role decomposing marine POM is somewhat circumstantial, and thus does not support quantitative conclusions about their function or importance. The long-term goal of this project is to gather the evidence about Labyrinthulomycete abundance and diversity that will be needed to better understand their role in marine ecosystems.This project aims to develop molecular genetic methods based on the polymerase chain reaction (PCR) to investigate the diversity and abundance of Labyrinthulomycetes. The existing Labyrinthulomycete-specific PCR primers for 18S ribosomal DNA (rDNA) cannot recognize a potentially important component of Labyrinthulomycete diversity (some groups of thraustochytrids). The investigators will develop new 18S rDNA primers that will allow better estimation of the diversity of the Labyrinthulomycetes, and then use these primers to gather 18S rDNA sequence data from a variety of habitats. The resulting sequence data will diversity of these organisms to be quantified in the field relative to the representatives currently in culture. These primers (or others designed in the course of the project) will be used to develop quantitative real-time PCR assays to determine the abundance of Labyrinthulomycetes (and subgroups of Labyrinthulomycetes) in environmental samples. Methods will also be developed to cultivate novel Labyrinthulomycetes detected in local sediments during the preliminary sequencing efforts.BROADER IMPACTS: Just as the recognition of the importance of heterotrophic bacteria revolutionized our understanding of planktonic food webs, more complete investigation of the Labyrinthulomycetes could change our understanding of the fate of POM in the oceans and its linkage to metazoan food webs. Two undergraduates will be continuously involved in this project, working on both the molecular genetic aspects (assisting with PCR, cloning, and sequencing) and on the culturing efforts. Involving the diverse student body of Stony Brook University (SBU) in research provides an opportunity to increase the presence of underrepresented groups in the sciences. The graduate student already working on this project is also a member of an underrepresented group. One or two high school students will work in the lab each summer working on this project; both SBU and the PI have strong track records of hosting local high school students for sponsored student-faculty research collaborations.