Deciphering the molecular roles of antimicrobial peptides in plant innate immunity and their potential applications in crop protection

Plants rely heavily on a complex innate immune system to repel microbial attacks, and antimicrobial peptides (AMPs) play a crucial role as central immune modulators of their immune response. These small, structurally diverse molecules exhibit broad-spectrum activities against bacteria, fungi, viruses, and nematodes through direct membrane disruption, interference with intracellular targets, and modulation of host signaling networks. Recent progress in multi-omics technologies, including genomics, transcriptomics, proteomics, and metabolomics, combined with synthetic biology, has led to a significant increase in our understanding of classification, biosynthetic pathways, structure-function relationships, and the regulatory integration of AMPs within pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Some of these latter tools accelerate rational peptide design and enable applications in agriculture: among others, transgenic crops possessing constitutive or pathogen-inducible AMP expression, as well as peptide-based agrochemicals, represent eco-friendly alternatives to classical pesticides. Despite such breakthroughs, major challenges persist that currently limit large-scale deployment: rapid pathogen evolution of resistance, insufficient target specificity, peptide instability under field conditions, potential phytotoxicity, and complex regulatory approval pathways. Such barriers will require integrated systems-biology approaches, improved delivery platforms, for example, nanotechnology or bioencapsulation, and precise engineering of AMP-host interactions. This review consolidates current information on plant AMPs, highlighting transformative multi-omics insights and critically assessing the remaining hurdles to be overcome for the full utilization of AMPs in next-generation sustainable crop protection and global food security.