Genome-Wide Characterization of PEBP, FD, and GRF Families in Amomum villosum Lour. and Their Potential Roles in Flowering

Amomum villosum Lour., a medicinal plant within the Zingiberaceae family, has not yet had its molecular mechanisms governing flowering time investigated. The florigen activation complex (FAC), which include PEBP, FD/bZIP, and GRF proteins, is crucial for controlling flowering time control in model plants. In this study, we identified 13 PEBP, 5 FD, and 19 GRF genes within the A. villosum genome. Our analyses included phylogenetic assessment, conserved motif characterization, gene structure examination, and promoter cis-regulatory element prediction. Protein-protein interactions among these three families were predicted through cross-species analysis and validated using yeast two-hybrid assays. Significantly, an AREB3-like FD protein (AvFD5) and a GRF protein (AvGRF13) were found to directly interact with specific PEBP members, whereas canonical FD-like proteins (AvFD1 and AvFD4) did not exhibit detectable interactions, differing from the classical rice FAC model (Hd3a-14-3-3-OsFD1). This study represents the first systematic characterization of FAC core gene families in A. villosum and, more broadly, within the Zingiberaceae family, thereby laying the groundwork for understanding flowering time regulation in this economically important plant family.