Collaborative Research: A Multi-Gene Approach to Chlorophytan Phylogeny and Diversity

合作研究：叶绿素系统发育和多样性的多基因方法

• 批准号: 0128952
• 负责人: Marc Anderson
• 金额: --
• 依托单位: North Dakota State University Fargo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-02-15 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0128952&HistoricalAwards=false
• 关键词: Collaborative; Research; Multi; Gene; Approach

0128952FawleyThree research teams (Buchheim at University of Tulsa, Fawley at North Dakota State University, and Zechman at California State University at Fresno) have begun a collaboration that will address questions about the hierarchical (i.e., phylogenetic) relationships among green algal groups that are collectively known as the Chlorophyta. The Chlorophyta, which has phylum status in the Linnean nomenclatural system, represents one of two branches of the green plant lineage-the other branch being the land plant alliance. The Chlorophyta comprise organisms that range from the microscopic to the macroscopic, exhibit a variety of reproductive strategies (e.g., sexual vs. asexual), and live in a broad spectrum of habitats (e.g., freshwater, saltwater and terrestrial). Some aspects of the current classification scheme for the Chlorophyta, based largely on comparative morphology, have been challenged by new evidence from comparative molecular data. A comprehensive interpretation of the new evidence, however, has not been forthcoming because (1) these new molecular data have not been applied to all groups within the Chlorophyta and (2) in most cases only a single gene has been used to evaluate diversity among select groups of Chlorophyta (unlike the land plants where diversity in some groups has been studied using three or more different genes). The goal of this project is to develop a comprehensive assessment of diversity in the Chlorophyta using a comparative study of DNA sequence data in three different genes, the nuclear 18S ribosomal RNA and 26S ribosomal RNA genes, and the chloroplast rbcL gene. The two rRNA genes code for portions of all ribosomes found in living cells. The rbcL gene is part of the chloroplast genome and codes for a portion of the enzyme responsible for carbon fixation in plants. The Zechman lab at CSU-Fresno will be responsible for gathering data from the chlorophyte group known as the Ulvophyceae. The Fawley lab group at North Dakota State University will be responsible for gathering data from the chlorophyte group known as the Prasinophyceae. The Buchheim lab group at the University of Tulsa will gather data from the two chlorophyte groups, Trebouxiophyceae and Chlorophyceae. The project will culminate in (1) a phylogenetic synthesis of all molecular data for the Chlorophyta, (2) a fundamental re-assessment of chlorophyte classification, integrating morphological and photosynthetic pigment data, and (3) an integration of the chlorophyte molecular phylogenetic data with (published) parallel data from the land plant lineage. Studies using chlorophyte green algae as model organisms (for example, the genus Chlamydomonas, easily cultured in the laboratory) have significantly advanced our understanding of fundamental processes such as photosynthesis and flagellar function. As biologists continue to dissect the molecular and biochemical basis for biological phenomena, new chlorophyte models will be explored in order to understand the spectrum of variation associated with these phenomena. A more comprehensive understanding of the relationships among all chlorophyte groups will be vital to interpreting the results (for example, assessing the broader applicability) from studies of chlorophytes used as model organisms. Moreover, the results from a comprehensive assessment of chlorophyte diversity will inform future studies of biological processes that rely on green algae to model the mechanisms. Lastly, studies of diversity within the Chlorophyta are critical to advancing our understanding of the origins and evolution of the green plant lineage.

0128952Fawley 三个研究小组（塔尔萨大学的 Buchheim、北达科他州立大学的 Fawley 和加州州立大学弗雷斯诺分校的 Zechman）已开始合作，解决统称为绿藻门的绿藻类群之间的层次（即系统发育）关系问题。 绿藻门在林奈命名系统中具有门地位，代表绿色植物谱系的两个分支之一，另一个分支是陆地植物联盟。 绿藻门包括从微观到宏观的生物体，表现出多种繁殖策略（例如有性与无性），并且生活在广泛的栖息地（例如淡水、咸水和陆地）。当前绿藻门分类方案的某些方面主要基于比较形态学，但受到来自比较分子数据的新证据的挑战。 然而，对新证据的全面解释尚未出现，因为（1）这些新的分子数据尚未应用于绿藻内的所有类群，（2）在大多数情况下，仅使用单个基因来评估选定的绿藻类群之间的多样性（与陆地植物不同，其中某些类群的多样性是使用三个或更多不同基因来研究的）。 该项目的目标是通过对三种不同基因（核 18S 核糖体 RNA 和 26S 核糖体 RNA 基因以及叶绿体 rbcL 基因）DNA 序列数据的比较研究，对绿藻的多样性进行全面评估。 这两个 rRNA 基因编码活细胞中所有核糖体的一部分。 rbcL 基因是叶绿体基因组的一部分，编码负责植物碳固定的酶的一部分。 科罗拉多州立大学弗雷斯诺分校的 Zechman 实验室将负责收集绿藻纲叶绿素的数据。 北达科他州立大学的福利实验室小组将负责收集叶绿藻类（Prasinophyceae）的数据。 塔尔萨大学的布赫海姆实验室小组将收集来自两个叶绿藻类（Trebouxiophyceae 和 Chlorophyceae）的数据。 该项目的最终目标是（1）对绿藻门所有分子数据进行系统发育综合，（2）对叶绿植物分类进行根本性重新评估，整合形态和光合色素数据，以及（3）将叶绿植物分子系统发育数据与（已发表的）陆地植物谱系的平行数据进行整合。使用叶绿藻作为模式生物（例如，易于在实验室培养的衣藻属）的研究极大地增进了我们对光合作用和鞭毛功能等基本过程的理解。 随着生物学家继续剖析生物现象的分子和生化基础，将探索新的叶绿素模型，以了解与这些现象相关的变异范围。 更全面地了解所有叶绿素类群之间的关系对于解释用作模式生物的叶绿素研究结果（例如，评估更广泛的适用性）至关重要。 此外，对叶绿素多样性的综合评估结果将为未来依赖绿藻来模拟机制的生物过程研究提供信息。 最后，对绿藻内多样性的研究对于增进我们对绿色植物谱系的起源和进化的理解至关重要。