Chromosome-scale Reference Genome and RAD-based Genetic Map of Yellow Starthistle (Centaurea solstitialis) Reveal...

Area of Science:

• Genomics
• Evolutionary Biology
• Plant Science

Background:

• Invasive species provide insights into rapid adaptation and invasion mechanisms.
• Yellow starthistle (Centaurea solstitialis) is a highly invasive Eurasian plant in North and South American grasslands, known for enhanced growth and reproduction during invasion.

Purpose of the Study:

• To develop genomic resources for yellow starthistle.
• To map the genetic basis of traits contributing to its invasiveness.

Main Methods:

• Construction of a chromosome-scale reference genome for C. solstitialis using PacBio CLR and Dovetail Omni-C technologies.
• Functional gene annotation via RNAseq.
• Development of a restriction site-associated DNA (RAD)-based genetic map using an F2 population from a native x invasive cross.

Main Results:

• A high-quality reference genome was produced, revealing repeat structures and over 25% gene content from ancestral whole-genome duplications (paleologs).
• Thirteen quantitative trait loci (QTLs) associated with size traits evolved during invasion were identified.
• Evidence suggests structural variants, including an overdominant and pleiotropic variant, contribute significantly to key invader traits. Paleolog enrichment was observed under two QTLs.

Conclusions:

• New genomic resources facilitate the study of yellow starthistle invasion genetics.
• Structural variants play a crucial role in the rapid evolution of invasive traits.
• Understanding the genetic underpinnings of invasion can inform management strategies.