Analysis of four orchid protein-protein interactions networks to elucidate the mechanism of floral morphology diversity formation

Abstract The diversity of Orchidaceae plants and their complex adaptations to pollinators have made Orchidaceae a hot topic in the study of plant evolution and function. However, our current understanding of the molecular mechanisms behind the diverse floral morphologies of Orchidaceae plants remains limited.To address this gap in knowledge, our study presents an integration of protein network predictions and comparative analysis of four different orchid species (Apostasia odorata, Phalaenopsis equestris, Erycina pusilla, Dendrobium officinale) with widely varying floral organ structures. Our research findings suggest that the formation of the orchid labellum is linked to the presence or absence of AP3-3 and SEP4genes, and specific interaction patterns involving these genes in each of the four species may be key to regulating the mechanisms that drive differences in floral morphology.Our analysis indicates that the number and type of interacting proteins of the floral symmetry regulator DIVARICATA may play a role in the morphological formation of radial and bilateral symmetry in orchids. Furthermore, both MADS-box and MYB are involved in regulating pollen development. Additionally, we found that the MADS-box, MYB, and GRAS families of genes may regulate flower organ morphology by influencing hormone signaling pathways during flower organ development.To further explore these findings, we utilized the CRISPR/Cas9 technique to knock out the SYD gene, and agrobacterium-mediated genetic transformation of Arabidopsis thaliana was used to examine the effects. The results showed an increase in petal opening and mating degree, along with changes in the overlapping stamen distribution.