Contrasting centromere structures in carnivorous sundews uncover a dynamic evolutionary trajectory shaped by polyploidy and chromosomal remodeling

Sundews (Drosera) are carnivorous plants that capture prey using mucilage-producing glands with both secretory and absorptive functions. Within a remarkably diverse clade that includes the Venus flytrap (Dionaea), East Asian pitcher plants (Nepenthes), the African carnivore Triphyophyllum (which bears three leaf types, one sundew-like) and the non-carnivorous vine Ancistrocladus, sundews show striking chromosomal variation. We present chromosome-scale genome assemblies for Drosera regia and D. capensis, comparing them with genomes of relatives. Complex allopolyploidies are revealed that prohibit depiction as bifurcating phylogenies. Characterization of centromere sequences demonstrated holocentric and monocentric chromosomes in D. regia and D. capensis, respectively, with corresponding structural divergence. Chromosomal fusions in D. regia likely trace to a shared allohexaploid ancestor shared with the dodecaploid and highly rearranged D. capensis genome. This comparative framework highlights genomic plasticity in a carnivorous plant lineage that offers a valuable model for studying morphological and ecophysiological diversity, polyploidy and centromere variation in angiosperms.