Phylogenetics and Morphological Diversity of the Grass Subfamily Pooideae (Poaceae)

禾本科禾本科（Poaceae）的系统发育和形态多样性

• 批准号: 0318686
• 负责人: Jerrold Davis
• 金额: --
• 依托单位: Cornell Univ - State: AWDS MADE PRIOR MAY 2010
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0318686&HistoricalAwards=false
• 关键词: Phylogenetics; Morphological; Diversity; Grass; Subfamily

Within the grass family (Poaceae), which includes about 10,000 species, one of the two largest of the twelve subfamilies is the Pooideae, with about 3300 species. This subfamily includes most of the grasses of temperate and boreal regions. Among many other species, it includes wheat, barley, rye, and their relatives of the tribe Triticeae, which has been the focus of intensive study, in terms of its phylogenetic and genomic relationships. The common occurrence of hybridization and polyploidy have been thoroughly documented in this group, in part because of the economic importance of the species in this assemblage. Most species of the subfamily (about 2200) fall within another group, which consists of species formerly assigned to three different tribes (Aveneae, Poeae, and Hainardieae). This group, the APH complex, includes many species of economic importance such as oats, timothy, bentgrass, the fescues, and the bluegrasses. Preliminary data acquired by Prof. Jerrold Davis at Cornell University indicate that the three major tribes previously recognized within the APH complex are intermixed phylogenetically. This suggests that the characters traditionally used to distinguish these groups have arisen in parallel several times or that hybridization among species from different lineages within the group has generated new (possibly polyploid) groups that combine the features of the various parents, as has occurred so frequently in the related Triticeae. In comparison to the Triticeae, the APH group is much larger, and much more poorly known. The main goal of the proposed work is to generate a phylogenetic hypothesis for subfamily Pooideae, with specific attention to the APH complex. To accomplish this, three data sets will be generated and analyzed separately and in combination. The three character sets are a set of linked genes in the plastid genome (ndhF, ndhH, and rbcL), a nuclear-encoded gene (GBSSI), and a structural character set that includes features such as spikelet structure and leaf anatomy. Instances of incongruence among these data sets will be examined to identify evidence of character parallelisms and reversals, and inter-lineage hybridization. One interesting quality of ndhF and ndhH is that they lie near opposite ends of the short single-copy (SSC) region of the plastid genome, near the boundaries of this region with the flanking inverted repeat (IR) regions. In some grasses the 5' end of ndhH extends into the IR region, and thus is duplicated in the genome, while in others the 3' end of ndhF extends into the IR region, and thus is duplicated. In addition to the phylogenetic goals of the work, the distribution of these attributes, the sizes of the duplicated portions, and the dynamics of gene exchange between these regions are topics of research.One of the broader impacts of the proposed work will be the training of undergraduate students, who will be engaged in study of molecular and structural characters of the target group. Also, a website will be developed that will depict the critical structural and anatomical features of the subfamily, and will provide taxon descriptions, data matrices, trees, images, and a classification of the group, with problematic taxa highlighted. The APH group includes numerous species of economic importance, yet, as indicated above, systematic relationships within the group are poorly understood. The species of this group, and of subfamily Pooideae as a whole, are of great interest to investigators in a variety of areas, including genetics, ecology, agronomy, range management, etc., and a website that describes the grasses of this group, and that depicts characteristics of the taxa and relationships among them, will be of interest to many scientists and other persons, and will stimulate additional investigation. Thus, the information generated during the course of the proposed work will be disseminated rapidly to students, professionals, and other persons.

在禾本科（Poaceae）中，约有10，000种，其中12个亚科中最大的两个之一是Pooideae，约有3300种。这个亚科包括温带和北方地区的大多数草。在许多其他物种中，它包括小麦，大麦，黑麦，以及它们在小麦族的亲属，这一直是深入研究的焦点，就其系统发育和基因组关系而言。杂交和多倍性的普遍发生在这个组中已经被彻底地记录，部分原因是这个组合中的物种的经济重要性。亚科的大多数物种（约2200种）属于另一个组，该组由以前分配到三个不同部落（Aveneae，Poeae和Hainardieae）的物种组成。这一组，APH复合体，包括许多经济上重要的物种，如燕麦，梯牧草，茅草，羊茅草和早熟禾。康奈尔大学的杰罗德·戴维斯教授获得的初步数据表明，先前在APH复合体中确认的三个主要部落是混合遗传的。这表明，传统上用于区分这些群体的性状已经平行出现了几次，或者来自群体内不同谱系的物种之间的杂交已经产生了新的（可能是多倍体）群体，这些群体联合收割机了不同亲本的特征，就像在相关的小麦族中经常发生的那样。与小麦族相比，APH组要大得多，而且知之甚少。拟议的工作的主要目标是产生一个系统发育假说的亚科Pooideae，特别注意APH复杂。为了实现这一目标，将分别和合并生成和分析三个数据集。这三个字符集是质体基因组中的一组连锁基因（ndhF，ndhH和rbcL），核编码基因（GBSSI）和结构字符集，包括小穗结构和叶解剖学等特征。将检查这些数据集之间的不一致性，以确定特征平行和反转以及谱系间杂交的证据。ndhF和ndhH的一个有趣的性质是它们位于质体基因组的短单拷贝（SSC）区域的相对末端附近，靠近该区域与侧翼反向重复（IR）区域的边界。在一些禾本科植物中，ndhH的5'端延伸到IR区域，因此在基因组中复制，而在其他禾本科植物中，ndhF的3'端延伸到IR区域，因此复制。除了系统发育的目标之外，这些属性的分布、重复部分的大小以及这些区域之间的基因交换的动态也是研究的主题。拟议工作的更广泛影响之一将是培养本科生，他们将从事目标群体的分子和结构特征的研究。此外，还将开发一个网站，描述该亚科的关键结构和解剖特征，并提供分类描述、数据矩阵、树木、图像和该组的分类，突出显示有问题的分类。APH组包括许多具有经济重要性的物种，然而，如上所述，组内的系统关系知之甚少。这一组的物种，以及作为一个整体的亚科Pooideae，是非常感兴趣的研究人员在各种领域，包括遗传学，生态学，农学，范围管理等，一个描述这一组的草的网站，描述分类群的特征和它们之间的关系，将引起许多科学家和其他人的兴趣，并将激发更多的研究。因此，在拟议的工作过程中产生的信息将迅速传播给学生，专业人士和其他人。