# A chromosome-level genome assembly of the varied leaved jewelflower, Streptanthus diversifolius, reveals a recent whole genome duplication

## TL;DR

A new chromosome-level genome assembly of Streptanthus diversifolius reveals a recent whole genome duplication that may have helped the species adapt to diverse environments in California.

## Contribution

The paper provides a chromosome-level genome assembly of Streptanthus diversifolius and confirms a recent whole genome duplication in the Thelypodieae clade.

## Key findings

- A chromosome-level genome assembly of Streptanthus diversifolius was constructed using Illumina, Hi-C, and HiFi sequencing.
- The assembly provides evidence for a recent whole genome duplication unique to the Thelypodieae clade.
- This genome duplication may have enabled the Streptanthoid Complex to rapidly adapt to and occupy diverse and often inhospitable environments.

## Abstract

The Streptanthoid complex, a clade of primarily Streptanthus and Caulanthus species in the Thelypodieae (Brassicaceae) is an emerging model system for ecological and evolutionary studies. This complex spans the full range of the California Floristic Province including desert, foothill, and mountain environments. The ability of these related species to radiate into dramatically different environments makes them a desirable study subject for exploring how plant species expand their ranges and adapt to new environments over time. Ecological and evolutionary studies for this complex have revealed fascinating variation in serpentine soil adaptation, defense compounds, germination, flowering, and life history strategies. Until now a lack of publicly available genome assemblies has hindered the ability to relate these phenotypic observations to their underlying genetic and molecular mechanisms. To help remedy this situation, we present here a chromosome-level genome assembly and annotation of Streptanthus diversifolius, a member of the Streptanthoid Complex, developed using Illumina, Hi-C, and HiFi sequencing technologies. Construction of this assembly also provides further evidence to support the previously reported recent whole genome duplication unique to the Thelypodieae. This whole genome duplication may have provided individuals in the Streptanthoid Complex the genetic arsenal to rapidly radiate throughout the California Floristic Province and to occupy commonly inhospitable environments including serpentine soils.