Carnivory in Lamiales: understanding character evolution, substitution rate plasticity, and genome miniaturization

在被子植物目层叠目中，食肉植物的多样性最大，其中一些代表表现出最极端的食肉综合征。在这里发现了最小的被子植物核基因组，并且一些基因组区域显示出最高的DNA替代率之一。这些特性使该群体成为研究控制替代率和基因组大小变化的因素的完美模型系统。该项目希望为了解食肉动物在Lamiales的进化成功，以及随之而来的形态适应，生理变化和非正统的基因组进化提供基础。这需要(1)精确地识别lentibullariaceae和可能密切相关的Byblis在Lamiales中的亲缘关系，以及基于密集的分类群采样，获得Genlisea， Utricularia和Pinguicula主要亚系之间和内部关系的更具代表性的图像。由此得出的结果将允许(2)历史生物地理分析和对多样化年龄、绝对多样化和替代率的精确估计，有助于将分子进化的转变与形态或生理的关键创新联系起来。(3)基因组大小和倍性水平将通过密集采样确定，从而实现基于系统发育的相关性分析，这可能为驱动极端基因组小型化的机制提供见解。(4)对4个叶绿体全基因组进行成本效益高的pyrosequencing，并与已知的非肉食性和寄生近缘植物基因组进行比较，将阐明肉食性对替代率、基因含量、正选择和负选择DNA位点的影响，并有助于查明与寄生植物的相似性。

In the angiosperm order Lamiales, the greatest diversity of carnivorous plants evolved, with some representatives exhibiting the most extreme embodiment of the carnivorous syndrome. The smal-lest angiosperm nuclear genomes have been found here, and some genomic regions exhibit one of the highest DNA substitutional rates reported. These attributes make the group a perfect model system for studying factors governing substitutional rate and genome size shifts. The project hopes to provide the basis for understanding the evolutionary success of carnivory in Lamiales, along with the accompanying morphological adaptations, physiological shifts, and unorthodox genome evolution. This requires (1) identifying precisely the affinities of Lentibulariaceae and the potentially closely related Byblis in Lamiales, as well as obtaining a more representative picture of relationships among and within major sublineages of Genlisea, Utricularia and Pinguicula, based on a dense taxon sampling. Results from this will allow (2) historical biogeographic analys-es and a precise estimation of diversification ages, absolute diversification- and substitution rates, serving to relate shifts in molecular evolution to morphological or physiological key innovations. (3) Genome sizes and ploidy levels will be determined for a dense sampling, enabling phylogeny-based correlation analyses that may provide insights in mechanisms driving the extreme genome miniaturization. (4) Cost-efficient pyrosequencing of four complete chloroplast genomes and comparisons with known genomes from non-carnivorous and parasitic relatives will illuminate the impact of carnivory on substitutional rates, gene content, and positively and negatively selected DNA sites, and allow to pinpoint similarities to parasitic plants.