The role of fungal chitinases in the tripartite interactions among insects, plants and entomopathogenic fungi

Background Chitinases are ubiquitous hydrolytic enzymes in fungi that specifically degrade chitin, a major structural component of insect exoskeletons and fungal cell walls. Increasing evidence indicates that chitinases play multifaceted roles not only in entomopathogenic fungal infection, but also in plant immune modulation and cross‐kingdom interactions. However, their integrative functions within the insect‐fungus‐plant tripartite system remain insufficiently characterized. This review aims to systematically elucidate the molecular mechanisms and ecological functions of fungal chitinases across multitrophic interactions. Results Accumulated studies demonstrate that: Chitinases act as critical virulence factors by facilitating fungal adhesion, cuticle degradation, and host penetration during insect infection; In plant–microbe interactions, chitinases contribute to microbial colonization while simultaneously generating chitin‐derived oligomers that function as elicitors to activate plant innate immunity; Within the insect–fungus–plant tripartite system, chitinases mediate resource turnover and signal exchange, thereby shaping complex ecological networks and influencing multilevel biological interactions. Conclusion Chitinases serve as pivotal molecular hubs linking pathogenicity, symbiosis and ecological regulation across kingdoms. A comprehensive understanding of their multifunctional roles provides critical insights into cross‐kingdom interaction mechanisms, and offers promising avenues for advancing biological control strategies, crop resistance improvement and microbial resource exploitation.