Smart Scaffolds: How WD40 Proteins Integrate Plant Development, Metabolism, and Stress Adaptation

WD40 repeat proteins are evolutionarily conserved molecular scaffolding that function as key regulators of plant growth, development, and stress resilience. These proteins, highlighted by tandem WD (Trp-Asp) motifs forming a stable β-propeller structure, serve as versatile platforms for protein-protein and protein-DNA interactions, facilitating the assembly of multiprotein complexes and the integration of environmental and hormonal signals into specific physiological responses. In plants, WD40 proteins orchestrate essential functions such as anthocyanin biosynthesis, blooming timing, embryogenesis, gametogenesis, and fruit development, often through regulatory modules like the MYB-bHLH-WD40 (MBW) complex. In addition to development, they serve as crucial centers for adaptation to abiotic and biotic stress by regulating phytohormonal interactions, maintaining reactive oxygen species balance, and facilitating ubiquitin-mediated protein degradation, especially via SCF E3 ligase complexes. These roles relate significant hormone pathways, such as abscisic acid, auxin, gibberellin, ethylene, and brassinosteroids, to environmental interactions. Recent progress in CRISPR-based functional genomics, interactome mapping, and high-resolution structural modeling is revealing the plasticity and evolutionary conservation of WD40 scaffolds. This review strengthens current findings relating their structural properties, molecular mechanisms, and functional diversity, underscoring their potential as targets for developing stress-resilient, high-yield crops in a changing climate.