Comparative Genomic and Expression Analysis of the PEBP Gene Family in Three Allium Species with Emphasis on Garlic (Allium sativum)

Across plants, the PEBP gene family is reported to regulate storage organ formation, developmental plasticity, and floral transitioning. However, its evolutionary dynamics and functional diversification within Allium species remain poorly understood. In this study, we performed genomic and transcriptomic analyses of the PEBP gene family across three economically important Allium species, including Allium fistulosum (bunching onion), Allium sativum (garlic), and Allium cepa (onion), identifying 19, 17, and 21 PEBP genes, respectively. The genes were assigned into five subfamilies (FT-like, TFL1-like, MFT-like, BFT-like, and PEBP-like), with MFT-like members being the most abundant. Structural analysis revealed strong conservation of key motifs (e.g., GxHR and DPDxP) across species, while substantial variation in intron–exon organization suggested subfunctionalization. Collinearity analysis indicated that segmental duplication primarily drove PEBP gene expansion in garlic and onion, whereas tandem duplication was absent in bunching onion. Promoter analysis showed enrichment of light- and hormone-related cis-regulatory elements, implicating their involvement in environmental and hormonal regulation. Expression profiling demonstrated clear tissue specificity, with AsPEBP11/13/14/16/19 exhibiting significantly higher expression in normal flowers than in abnormal ones, suggesting key roles in floral morphogenesis. Together, these findings will prove useful for future breeding programs aimed at improving reproductive development and fertility in Allium species.