Genome-wide identification of growth−regulating factor and GRF−interacting factor gene families across three Solanaceae species with functional analysis in pepper regeneration

The growth-regulating factor (<i>GRF</i>) and <i>GRF</i>-interacting factor (<i>GIF</i>) gene families play crucial roles in enhancing plant genetic transformation efficiency. However, the functional contributions of pepper <i>GRF</i> and <i>GIF</i> genes in improving transformation efficiency remain unexplored. In this study, we identified 31 <i>GRF</i> genes and 9 <i>GIF</i> genes across pepper, tomato, and tobacco. A systematic analysis was conducted to characterize their phylogenetic relationships, gene structures, collinearity, and expression patterns. Collinearity analysis revealed large-scale duplication events among these three Solanaceae species. Furthermore, qRT-PCR analysis demonstrated significantly elevated ex-pression levels of pepper GRF and GIF genes in regenerative tissues, indicating their critical functional roles during pepper regeneration processes. Our findings provide novel insights into the evolution of <i>GRF</i> and <i>GIF</i> gene families in Solanaceous plants and identify several key candidate genes for future functional studies aimed at enhancing pepper regeneration efficiency and genetic transformation.