Genomic insights into karyotype evolution and adaptive mechanisms in Polygonaceae species

Polygonaceae, with ecological versatility and global distribution, is an ideal system for investigating plant adaptation. However, the genomic mechanisms underlying its karyotype evolution and environmental resilience remain unclear. We herein present chromosome-level genomes of 11 species from 10 Polygonaceae genera. Our analyses reveal that Gypsy retrotransposons are key drivers of genome size variations in Polygonaceae. We reconstructed a Polygonaceae ancestral karyotype comprising 28 proto-chromosomes and elucidated evolutionary trajectories via extensive chromosomal rearrangements. Furthermore, we constructed a cross-genus super pan-genome for Polygonaceae, identifying 80,055 gene families, of which 9,845 (12.30%) are core gene families. Private genes are found to contribute significantly to interspecific differences in adaptability. Notably, gene copy number variations are identified as a critical factor influencing adaptations to diverse niches involving species-specific increases in metabolic pathways. This study provides a genomic framework for Polygonaceae karyotype plasticity and adaptive innovation, offering insights into plant evolution under environmental challenges.