Metabolite-mediated plant immunity: From traditional defenders to artificial elicitors

The accelerating global population growth and increasing environmental pressures driven by climate change have made food security an urgent scientific objective. In addition to genetic modifications aimed at yield improvement, minimizing yield reduction and postharvest decay caused by pathogenic infections is essential for reinforcing global food supply systems. Metabolites, as fundamental biochemical constituents of life, form the basis of many plant defense strategies that have evolved over millions of years to counter pathogen invasion-functioning both as direct antimicrobial and anti-herbivory agents as well as inducers of internal immune signaling networks. Despite the extensive diversity and intricate biosynthetic pathways of plant metabolites, advances in high-performance mass spectrometry and nucleotide sequencing have clarified the immune-related roles of several metabolites through conventional genetic and transcriptomic analyses. The emergence of artificial intelligence (AI) has provided a transformative means by which to integrate and interpret complex, large-scale data sets, offering insights unattainable through traditional approaches and expediting the mapping of metabolite-immunity interactions. This review summarizes recent progress in elucidating the functions of various plant metabolites, including primary metabolites and secondary metabolites, in plant immune responses. This study also details their reprogramming by pathogens. Finally, it examines the prospective applications of nanoscience, de novo domestication, and artificial intelligence in the rational design of next-generation artificial elicitors.