Peptides in plant-microbe interactions: Functional diversity and pharmacological applications

As dynamic interfaces governing molecular recognition and signal transduction, interactions between plants and microbes fundamentally shape ecosystem dynamics and evolutionary trajectories. This review summarizes peptides involved in plant-microbe interactions, emphasizing their diversity, biological functions mediated at the cell surface, pharmacological applications, and recent methodological advances in their discovery. Plant-derived peptides, including cysteine-rich peptides (NCRs, RALFs, DEFs, nsLTPs) and post-translationally modified peptides (CLEs, CEPs, GLV/RGF, PSKs), regulate symbiotic relationships and plant defenses. Endophyte-derived peptides, notably Bacillus lipopeptides (surfactins, fengycins, iturins), exhibit pathogen inhibition and plant growth promotion. Additionally, plant polypeptides such as lipid transfer proteins, hevein-like peptides, thionins, defensins, and snakins significantly enhance plant immunity through direct antimicrobial action and systemic resistance. Technological advancements in isolation techniques, multi-omics approaches, bioinformatics, and artificial intelligence have accelerated peptide discovery. However, challenges remain regarding functional characterization, peptide stability, production costs, and ecological impacts. Addressing these through interdisciplinary research and collaboration will promote practical applications of peptides in agriculture and medicine.