Flowering plays a crucial role in blueberry production since fruits develop from flowers. In plants, FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1), which interact with the bZIP transcription factor FD, are central regulators of flowering. This study investigates the roles of their homologs in blueberries, VcTFL1 and VcFD, using RNA interference (RNAi) to silence these genes. Two RNAi constructs, VcFD-RNAi and VcTFL1-RNAi, were introduced into the northern highbush blueberry (Vaccinium corymbosum) cultivar ‘Aurora’ via Agrobacterium tumefaciens-mediated transformation. Phenotypic analysis of first-generation (T0) transgenic plants accessed flowering time, architecture, fruit and leaf bud development, plant height, and branching. Preliminary results revealed that VcFD-RNAi plants produced fewer shoots, while VcTFL1-RNAi plants exhibited reduced branching per shoot compared to nontransgenic ‘Aurora’ controls. Significant differences in leaf bud number were also observed between nontransgenic and transgenic lines. VcFD-RNAi plants were smaller than nontransgenic ‘Aurora’ plants, whereas no significant size difference was detected between VcTFL1-RNAi and wild-type plants. Transcriptomic comparisons between nontransgenic ‘Aurora’ and transgenic lines revealed differentially expressed genes (DEGs). The VcFD-RNAi vs. nontransgenic ‘Aurora’ identified 2,108 DEGs, including 49 flowering-related genes, 116 genes hormone pathway genes, and 57 sugar metabolism genes. Similarly, the VcTFL1-RNAi vs. nontransgenic ‘Aurora’ uncovered 2,030 DEGs, with 52 flowering-related, 111 hormone-related, and 55 sugar-metabolism-associated genes. Ongoing analyses of these DEGs aim to elucidate the molecular mechanism underlying VcFD- and VcTFL1-mediated flowering regulation of flowering and development in blueberry. This study will reveal the functional roles of VcFD and VcTFL1, offering potential targets for genetic improvement of blueberry architecture and yield.
