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

## TL;DR

Scientists sequenced the genome of Sarracenia purpurea and found that ancient genome duplication expanded gene families related to plant defense and stress, which may have helped carnivorous traits evolve.

## Contribution

The study provides the first chromosome-scale carnivorous plant genome in Ericales and identifies gene family expansions linked to carnivory evolution.

## Key findings

- The Sarracenia purpurea genome shows evidence of an ancient whole-genome duplication event around 81–84 Mya.
- Approximately 33 gene families involved in defense and stress responses expanded following the duplication, potentially underpinning carnivory.
- Gene gain, rather than loss, was the main driver of functional innovation in Sarracenia.

## Abstract

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 N
50 > 220 Mbp, L
50 = 7, and N
max > 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.

Carnivorous plants like Sarracenia purpurea evolved their carnivorous traits millions of years ago, but the genetic basis of carnivory is still not well understood. Scientists sequenced and analyzed the S. purpurea genome to uncover the genetic mechanisms behind plant carnivory and to compare it with other carnivorous and non‐carnivorous plants. The genome is the largest carnivorous plant genome sequenced so far (3.41 Gbp). Evidence of a whole‐genome duplication ∼80 million years ago was found. This duplication expanded ∼33 gene families involved in stress and defense responses, later adapted for carnivory. Gene gains, rather than gene losses, were the main drivers of carnivorous traits. The S. purpurea genome provides the first large‐scale genetic resource for understanding carnivory in its plant family. These findings highlight the role of genome duplications and gene expansions shaped the evolution of carnivorous plants.