The Evolution of Feeding Morphology in Rhabditida (Nematoda): Extension of the Caenorhabditis Paradigm

9318249 BALDWIN拟议的研究的目的是了解土壤线虫的摄食结构如何随着时间的推移而适应，包括从微生物食性（主要以有益细菌为食）到不同类型寄生的多样性。 这些不同的摄食适应性具有重要的生态（例如细菌饲养者），农业（例如植物和动物寄生虫）影响。 目前，不同的喂养策略被理解的粗糙的整体结构的颊囊（口部区域），但有很少或没有解释的各种喂养类型之间的系统发育关系。 了解不同的摄食结构的遗传需要解决有关其结构的冲突。 这些冲突可以通过建立在模型（食菌）线虫秀丽隐杆线虫（Caenorhabditis elegans）的详细形态和发育知识的基础上，并将该模型扩展到近缘食微生物近亲（小杆纲）以及更远的寄生近亲来解决。 比较详细的形态/发展将主要使用透射电子显微镜完成。 系统发育关系的形态/发育特征的颊囊线虫的范围将被解释在光从相同的线虫的DNA序列的一组平行的数据。 由于RNA聚合酶II亚基的序列似乎是特别有用的，它们将被用来开发一个独立的基于分子的系谱树。 这棵树将被用来推断最简单的解释的模式和方向的变化的颊囊喂养结构和相关的喂养适应。 土壤蠕虫是几乎所有生态系统中重要的、不可见的部分。 它们作为植物的寄生害虫和有益细菌的消耗者在经济上可能是重要的，或者，如果针对害虫生物体如杂草和昆虫害虫，这些相同的饲喂策略可能是有益的。 本项目将利用从详细研究口部和进食器官的超微结构以及从RNA聚合酶II基因部分的分子测序中获得的信息，调查各种线虫物种之间的关系。 ***

9318249 BALDWIN The objective of the proposed research is to understand how the feeding structures of soil nematodes have adapted with time to include diversity from microbivorism (primarily feeding on beneficial bacteria) to varying types of parasitism. These diverse feeding adaptations have important ecological (e.g. bacterial feeders), agricultural (e.g. plant and animal parasites) implications. Presently, different feeding strategies are understood in terms of crude overall structure of the buccal capsule (mouth region), but there is little or no explanation of phylogenetic relationships among the various feeding types. Understanding the phylogeny of diverse feeding structures requires the resolution of conflicts about their structure. These conflicts can be resolved by building upon the detailed morphological and developmental knowledge in the model (bacterial-feeding) nematode, Caenorhabditis elegans, and extending this model to close microbivorous relatives (Rhabditida) as well as more distant parasitic relatives. Comparative detailed morphology/development will be primarily accomplished using transmission electron microscopy. Phylogenetic relationships of morphological/developmental characters of buccal capsules in a range of nematodes will be interpreted in light of a parallel set of data from DNA sequences from the same nematodes. Since sequences from subunits of RNA polymerase II seem to be particularly informative, they will be used to develop an independent molecular-based genealogical tree. This tree will be used to infer the simplest explanation for the pattern and direction of change of buccal capsule feeding structures and associated feeding adaptations. %%% Soil dwelling nematode worms are an important, unseen part of virtually all ecosystems. They can be economically important as parasitic pests of plants and consumers of beneficial bacteria or, alternatively, these same feeding strategies can be beneficial if directed against pest organisms such as weeds and ins ect pests. This project will investigate relationships among a variety of nematode species by utilizing both information from detailed studies of the ultrastructure of the mouth parts and feeding apparatus and from molecular sequencing of portions of the RNA polymerase II gene. ***