Characterization of Tissue-specific Transcriptomic Responses to Seedlessness Induction by Gibberellin in Table Grape

Abstract

Gibberellins are widely used to induce seedlessness in table grape production, but are not effective for every cultivar or developmental stage. In order to characterize the potential physiological mechanism behind gibberellin-induced seedlessness, we conducted tissue-specific transcriptome analysis of ovules and ovaries from cultivars with different levels of receptiveness to seedlessness induction. GA₃ treatment at full bloom highly induced gibberellin signaling and various phytohormone signaling pathway genes in ovules at two days after treatment, but had less effect in ovaries, which suggests that GA₃ directly affects seed development. During the development to six days after GA₃ application, cell cycle-related genes in the ovules were markedly downregulated, indicating that this may be related to ovule abortion induction. The marked transcriptomic responses were largely absent in a cultivar with low receptiveness to gibberellin-induced seedlessness, suggesting a crucial role for the observed tissue-specific responses in the successful induction of seedlessness by GA₃ application. Collectively, our transcriptome analysis highlights distinct tissue-specific reactions to GA₃ during early berry development, providing important insights for the successful production of seedless berries by gibberellin application.