Tea plant is a globally important cash crop, yet reproductive growth severely compromises yield and quality. Elucidating the molecular mechanisms of flowering is essential for ecological cultivation in tea plant. We conducted a transcriptome analysis of floral buds from two tea cultivars (‘Y9’, ‘Y1’) across developmental stages and identified 3,244 DEGs in ‘Y9’. GO analysis indicated strong enrichment of the photoperiod and age pathways among both upregulated and downregulated DEGs. Ectopic overexpression of three photoperiod pathway genes CsATH1 / CsCIP1 / CsCSU2 in Arabidopsis produced delayed-flowering or early-flowering phenotypes. Expression of the flowering repressor FLC was induced in CsATH1 and CsCIP1 transgenic plants but reduced in CsCSU2 lines. Furthermore, strong CsCIP1 expression in young buds, the floral meristem, and at lateral-branch bases supported its role in flowering regulation. DAP-seq revealed that motif sequence as AAAAAKAAAAAAAAA was the most enriched cis -element among CsCSU2 ’s binding sites. Beyond flowering-related pathways, CSU2 also regulates phenylpropanoid metabolism and ubiquitin–protein transferase activity.
Man et al. (Fri,) studied this question.