A chromosome-scale genome of Sarracenia purpurea reveals a significant expansion of plant defense and stress response gene families following paleopolyploidization.

Plant carnivory evolved through gene co-option and whole genome duplications (WGDs) over millions of years in at least 13 independent flowering plant lineages, but its genetic mechanisms remain largely unknown. To elucidate these mechanisms in Sarraceniaceae, we sequenced and assembled the Sarracenia purpurea genome and conducted a comparative analysis with both carnivorous and non-carnivorous species within a phylogenetic framework. Our chromosome-scale assembly is the first carnivorous genome from the order Ericales and the largest carnivorous genome sequenced (3.41 Gbp). This assembly has an N50 > 220 Mbp, L50 = 7, and Nmax > 281.4 Mbp and contains 52,067 gene models, 96% of which are supported by direct mRNA evidence. The genome shows evidence of an ancient paleopolyploidization event about 81-84 Mya, which may have facilitated the evolution of different carnivory flavors within Sarraceniaceae. The WGD event resulted in the expansion of ∼33 gene families enriched in seven metabolic and regulatory pathways. The network of these seven pathways regulates plant defense and stress responses and appears to underpin carnivory in this species. Our comparative genomic analysis revealed that gene gain, rather than loss, was the primary driver of functional innovation and adaptation in Sarracenia and identified key orthogroups that may have contributed to the evolution of plant carnivory across different lineages. This genome is key to uncovering the genetic basis of plant carnivory, with broad relevance to evolution, ecology, and functional genomics.