Transcriptomics and Plant Hormone Analysis Reveal the Mechanism of Branching Angle Formation in Tea Plants (Camellia sinensis)

The branching angle of tea plants is a key factor in determining their branching structure, which significantly affects yield, suitability for mechanical harvesting, and overall plant architecture. However, the mechanisms underlying branching angle formation in tea plants remain unclear. In this study, we explored the mechanism of branching angle formation in tea plants by analysing the transcriptome and plant hormone levels of tea plant cultivars with different branching angles. The results indicated that gibberellin positively regulates the branching angle of tea plants, cytokinins, auxin, and abscisic acid involved in the formation of branching angles in tea plants. The transcriptome analysis revealed that candidate regulatory factors, including plant-hormone-related genes (the gibberellin synthesis gene GA3ox1 and metabolism gene GA2ox1; the cytokinin metabolism genes CKX and UGT; the auxin signal transduction-related gene LAX3; and the abscisic acid signal transduction gene PYL4), genes regulating cell division and growth (LAZY1, TAC1, and MAX1), and transcription factors (MYBs, WRKYs, TCPs, AP2/ERFs, and MADS-box), are involved in the formation of branching angles in tea plants. These results offer insights into the mechanism of branching angle formation in tea plants, providing important theoretical reference for the selection and breeding of tea cultivars suitable for mechanical harvesting, thereby improving agricultural efficiency and sustainability.