To identify stable reference genes for qRT-PCR analysis across different developmental stages and color variations of tender leaves in Litsea coreana, seven candidate reference genes were selected based on existing transcriptome data. qRT-PCR was performed on tender leaves of L. coreana at various stages and under different color conditions. The stability of these genes was evaluated using GeNorm (version 2003), NormFinder (version 0953), BestKeeper (version 2003), and ReFinder software (version 2004). The most stable genes were selected, and the stability of the chosen reference genes was validated. RPL and ACT were the most stable genes across different leaf developmental stages, while ACT and EF1-α showed the highest stability across different leaf colors. Overall, ACT and EF1-α were the most stable reference genes for both developmental stages and color variations. ACT and EF1-α can be used as reliable reference genes for gene expression studies in the color change process of L. coreana tender leaves. This will provide a foundation for further research into the molecular mechanisms of leaf color changes and the development of color regulation genes in L. coreana.

TCP transcription factors represent a crucial family of plant regulators that contribute significantly to growth and developmental processes. Although the TCP gene family has been extensively studied in various plant species, research on Chimonanthus praecox (wintersweet) remains limited. Here, we performed genome-wide identification and analysis of the TCP gene family in C. praecox and identified 22 CpTCP genes. We further systematically examined the associated physicochemical properties, evolutionary relationships, gene structures, and regulatory features. Analysis revealed that all CpTCP proteins possess a conserved TCP domain, and subcellular localization prediction indicated their localization in the nucleus. Promoter analysis revealed that multiple cis-elements are associated with abiotic stress responses and plant growth regulation. Further analysis revealed high CpTCP2 expression in the leaves and stamen, with significantly increased levels during flower senescence. CpTCP2 expression was upregulated in response to methyl jasmonate (MeJA), salicylic acid, abscisic acid, and shade. CpTCP2 overexpression in Arabidopsis thaliana resulted in a reduced leaf area, delayed flowering, and increased rosette leaf numbers. Moreover, MeJA treatment accelerated leaf senescence in CpTCP2 transgenic Arabidopsis. These findings provide insights into the evolutionary characteristics of the TCP family in C. praecox, highlighting the functional role of CpTCP2 in regulating leaf development and flowering time in Arabidopsis, thereby offering valuable genetic resources for wintersweet molecular breeding.