Transcriptomic profiling reveals bud dormancy stage dynamics in Japanese cedar (Cryptomeria japonica) throughout the nongrowing period.

This article focuses on characterizing the dormancy stages of Japanese cedar (Cryptomeria japonica) buds during the nongrowing period (October–March) through physiological twig experiments and transcriptome analysis. The study identifies four distinct stages: bud formation (October–November), bud hardening/endodormancy (December), ecodormancy with winter stress tolerance (January–February), and preparation for spring growth (March). Key regulatory genes, including CONSTANS-like (CjCOL), core clock genes, and phytohormone-related genes—particularly those involved in cytokinin signaling—were associated with dormancy transitions and variation in days to bud burst (DBB) among genotypes. The findings reveal unique molecular dormancy mechanisms in this gymnosperm species, differing from angiosperms and other conifers, and provide foundational insights for understanding conifer dormancy and potential impacts of climate change on bud phenology.