Rosa lucieae (syn. Rosa wichurana or R. wichuraiana; Rosaceae) is a major wild progenitor of modern rose cultivars. In breeding roses, R. lucieae has contributed both ornamental traits and hardiness including success under harsh conditions and high resistance to diseases and pests. Wild R. lucieae occurs in exposed littoral sandy banks or rocky habitats, where drought stress and high salinity inhibit plant growth. In this study, we generated a chromosome-level genome assembly of a wild R. lucieae accession from a saline coastal environment to elucidate the genomic basis and evolutionary mechanisms underlying salt tolerance shaped by natural habitats. Comparative and evolutionary genomic analyses highlighted pronounced gene family expansion driven by recent and rapid gene duplication. Notably, rapidly evolving gene families were significantly enriched for functions related to salt tolerance, such as stress signaling, homeostasis, detoxification, protein repair, and secondary metabolism. Multiple modes of gene duplication, including tandem, segmental, and transposition-duplication, contributed to the diversification of salt tolerance-related genes. Together, this study contributes substantially to our understanding stress adaptation in wild roses, which promises the enhancement of our efforts of developing stress-tolerant rose cultivars in breeding programs.
Jeon et al. (Wed,) studied this question.