ERECTA-family receptor kinases: versatile regulators of plant developmental signaling

The ERECTA family of leucine-rich repeat receptor kinases has emerged as central coordinators of plant developmental signaling: three members of the ERECTA family-ERECTA and its paralogs ERECTA-LIKE1 (ERL1) and ERL2-uniquely as well as synergistically integrate diverse internal and environmental cues to regulate growth, morphogenesis, and stress responses. From the initial genetic characterization of the classic Arabidopsis Landsberg erecta (Ler) accession to the subsequent identification of EPIDERMAL PATTERNING FACTOR (EPF/EPFL) peptides as cognate ligands, studies on the ERECTA family have transformed our understanding of peptide-receptor signaling in plants. In this review, we first describe the developmental processes regulated by the EPF/EPFL-ERECTA family ligand-receptor module, including shoot apical meristem homeostasis, inflorescence stem growth, leaf serration, reproductive development, stomatal development, and vascular patterning. We then synthesize the signaling logic of the ERECTA family, with specific focus on the autocrine versus juxtacrine and paracrine modes of signaling as well as the mechanisms ensuring signal specificity. We further discuss the mechanisms of ERECTA-family receptor signaling, from ligand perception, receptor activation and attenuation, signal transduction, to subcellular trafficking. Lastly, we highlight emerging non-canonical functions of ERECTA-family receptors beyond the plasma membrane. Our review provides comprehensive and updated knowledge of ERECTA-family receptor kinases as versatile regulators of plant development, and highlights mechanistic insights to be leveraged for improving plant growth and resilience.