Complexity and Innovation in Carnivorous Plant Genomes

Carnivorous plants are a paradigm of convergent evolution, but their genomes reveal even deeper layers of complexity. Recent work uncovers widespread polyploidy, including the decaploid East Asian pitcher plant (Nepenthes gracilis) genome and hybrid origins for the tetraploid Venus flytrap (Dionaea muscipula) and queen (hexaploid) and Cape (dodecaploid) sundews (Drosera regia and D. capensis, respectively). The bladderwort (Utricularia gibba) experienced extreme genome compaction while retaining otherwise typical gene number, challenging assumptions about genome size. Molecular convergence is conspicuous, from digestive enzyme recruitment to repeated amino acid substitutions under functional constraints. Drosera species further illustrate how centromere type (monocentric versus holocentric) shapes genome architecture. These discoveries position carnivorous plants as models for studying the plasticity and adaptive landscapes of plant genomes, including tradeoffs between local and global gene duplication and intergenic DNA deletion.