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.

禾本科 (Poaceae) 约有 10,000 种植物，其中 12 个亚科中最大的两个亚科之一是 Pooideae，约有 3300 种植物。该亚科包括温带和寒带地区的大部分禾本科植物。在许多其他物种中，它包括小麦、大麦、黑麦以及它们的小麦族的近亲，就其系统发育和基因组关系而言，小麦族一直是深入研究的焦点。杂交和多倍体的常见现象已在该群体中得到充分记录，部分原因是该物种在该组合中的经济重要性。该亚科的大多数物种（约 2200 个）属于另一个组，该组由以前分配给三个不同部落（燕麦亚科、早熟禾亚科和海纳亚科）的物种组成。这个群体，即 APH 复合体，包括许多具有经济重要性的物种，如燕麦、梯牧草、翦股颖、羊茅和早熟禾。康奈尔大学杰罗德·戴维斯教授获得的初步数据表明，先前在 APH 复合体中认识的三个主要部落在系统发育上是混合的。这表明传统上用于区分这些群体的特征已经多次平行出现，或者该群体内不同谱系的物种之间的杂交产生了新的（可能是多倍体）群体，这些群体结合了不同亲本的特征，正如经常发生的那样在相关的小麦科植物中。与小麦科相比，APH 群体要大得多，而且鲜为人知。这项工作的主要目标是为早熟禾亚科提出系统发育假说，特别关注 APH 复合体。为了实现这一目标，将分别或组合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) 以及包括小穗结构和叶子解剖结构等特征的结构字符集。将检查这些数据集之间不一致的实例，以确定字符平行和逆转以及谱系间杂交的证据。 ndhF 和 ndhH 的一个有趣的特性是它们位于质体基因组短单拷贝 (SSC) 区域的相对两端附近，靠近该区域与侧翼反向重复 (IR) 区域的边界。在一些草类中，ndhH 的 5' 末端延伸到 IR 区域，因此在基因组中复制，而在其他草类中，ndhF 的 3' 末端延伸到 IR 区域，因此在基因组中复制。除了工作的系统发育目标之外，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训本科生，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，并提供分类单元描述、数据矩阵、树木、图像和该类群的分类，并突出显示有问题的分类单元。 APH 群体包括许多具有经济重要性的物种，但如上所述，人们对该群体内部的系统关系知之甚少。该类群的物种以及整个早熟禾亚科的物种引起了各个领域的研究人员的极大兴趣，包括遗传学、生态学、农学、牧场管理等，并且有一个描述该类群草的网站，它描述了类群的特征以及它们之间的关系，将引起许多科学家和其他人的兴趣，并将刺激更多的研究。因此，在拟议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。