Transcriptome analysis reveals the role of GA in fruit development of 'Cuiguan' pear (Pyrus pyrifolia)

Fruit size is a crucial agronomic trait that significantly influences fruit quality and economic value. Gibberellin serves as an effective phytohormone that promotes fruit expansion and is widely utilized during the early stages of fruit development. However, the mechanisms underlying GA-mediated fruit enlargement in pear, along with the associated genes and regulatory mechanisms, remain poorly understood.

In this study, pear cultivar 'Cuiguan' was treated with various combinations of GAs, specifically GA3, GA4 + 7, and GA3 + 4 + 7 at 30 days after flowering. The combination of GA3 + 4 + 7 produced the most pronounced increase in pear fruit size, primarily through promoting elongation. Anatomical analysis revealed that this treatment enhanced both cell proliferation and expansion. RNA-seq was conducted and identified differentially expressed genes associated with GA3 + 4 + 7-mediated fruit enlargement. Functional annotation and enrichment analyses highlighted the involvement of genes related to plant hormone signaling, cell growth, cell division, cell cycle, and transcription factors. Nine DEGs associated with fruit size were validated by RT-qPCR analysis, confirming the RNA-seq results.

This study elucidates the molecular mechanisms by which gibberellins regulate pear fruit development and identify key genes involved in this process, providing a foundation for future research on GA3 + 4 + 7-mediated fruit size regulation.