Sulfated peptides and their receptors: Key regulators of plant development and stress adaptation

Four distinctive types of sulfated peptides have been identified in Arabidopsis thaliana. These peptides play crucial roles in regulating plant development and stress adaptation. Recent studies revealed that Xanthomonas and Meloidogyne can secrete plant-like sulfated peptides, exploiting the plant sulfated signaling pathway to suppress plant immunity. Over the past three decades, receptors of these four types of sulfated peptides have all been identified, all of which belong to the members of leucine-rich repeat receptor-like protein kinase (LRR-RLK) subfamily. A number of regulatory proteins were demonstrated to play important roles in their corresponding signal transduction pathways. In this review, we comprehensively summarize the discoveries of sulfated peptides and their receptors mainly in Arabidopsis thaliana. We also discuss their known biological functions in plant development and stress adaptation. Finally, we put forward a number of questions for the reference of future studies.