Honeybee pollination enhances pollen germination, pollen tube growth, phytohormone responses and gene expression in pear pistils

BACKGROUND: Honeybee pollination significantly enhances the yield of pear (Pyrus spp.), yet the early physiological mechanisms of pollination and fertilization remain underexplored. In this study, pollen germination, pollen tube growth, and ovule development were analyzed, along with the phytohormones in pistil and the gene expression associated with phytohormone biosynthetic and signal transduction pathways to the differential mechanisms after honeybee and artificial pollination. RESULTS: The results demonstrated that, compared to artificial pollination, honeybee pollination induced more efficient pollen germination within 2 h, pollen tubes reached ovary within 24 h, and ovule fertilization completed after 48 h, significantly accelerating the fertilization process. Moreover, between 48 and 72 h after honeybee pollination, the expression of biosynthesis and signal transduction genes associated the indole acetic acid (IAA), cytokinin (CK), gibberellic acid, abscisic acid (ABA), and jasmonic acid (JA) were induced, resulting in higher phytohormone levels than those after artificial pollination. Conversely, the 1-aminocyclopropanecarboxylic acid (ACC) levels were significantly reduced, and gene expression was suppressed. The WRKY24, WRKY75, MYB108-like, ERF106-like, ERF113-like, TCP4-like, NF-YC-3-like, NF-YA-7-like and the indole, TRP, tZRMP, JA-Ile were identified to establish regulatory network associated with honeybee pollination. CONCLUSION: This study elucidates the influence of different pollination methods on early fertilization from the perspective of phytohormone and offers practical insights for optimizing pollination strategies and promoting honeybee pollination in pear. © 2026 Society of Chemical Industry.