Specificity of ERECTA signaling in plant development - one-trick pony or jack-of-all-traits?

In recent decades, it has become apparent that plant development depends on the reuse of certain signaling networks to coordinate organogenesis, pattern formation, and tissue differentiation. It has been shown that Mitogen-Activated Protein (MAP) kinase cascades and leucine-rich repeat receptor-like kinases (LRR-RLKs), often serve as signaling hubs in orchestrating multiple developmental programs. However, little is known about how signaling specificity is achieved-how a single pathway can influence multiple, distinct developmental outputs. A prominent example is the ERECTA receptor kinase family (ERf), which represents a key signaling module playing a central role in diverse developmental contexts such as zygote polarization, female germline and epidermis development, inflorescence architecture, and radial growth. In this review, we summarize the current knowledge about the molecular mechanisms underlying ERf function across different developmental contexts. We compare conserved and context-specific features of ERECTA signaling by focusing on stomatal patterning, embryogenesis and radial growth, and discuss how specificity is generated within this multifaceted pathway.