Full-length transcriptome and RNA-Seq analyses reveal the molecular mechanism of light protection in Hosta ventricosa

Hosta ventricosa is a popular shade-tolerant ornamental perennial vulnerable to high light, whose molecular mechanisms of high-light stress response remain unclear. To clarify this, we measured leaf morphology, photosynthetic physiology, and performed integrated analyses using PacBio full-length and Illumina transcriptome sequencing on plants under full sunlight (FS), moderate shade (MS), and deep shade (DS) treatments. The results indicated that MS showed optimal growth, whereas FS and DS inhibited growth, each associated with distinct gene expression profiles. High light induced VDE by 5.68-fold to activate the xanthophyll cycle and repress light-harvesting complex II and ribulose-1,5-bisphosphate carboxylase/oxygenase genes, whereas deep shade inhibited the photosynthetic apparatus and triggered stress genes. In contrast, deep shade conditions suppressed the photosynthetic machinery and induced the expression of stress-related genes. This study elucidates the molecular mechanisms underlying light stress responses in H. ventricosa, providing valuable insights for future molecular breeding efforts.