Carnivory in Lamiales
Understanding character evolution, substitution rate plasticity, and genome miniaturization
Utricularia quelchii. Photo: W. Barthlott.
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 smallest 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 ccompanying 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 analyses 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.
- Deutsche Forschungsgemeinschaft (DFG) (grant MU2875/2 to K. Müller)