ENDOPHYTIC MICROBIOME-MEDIATED STRATEGIES FOR SUSTAINABLE MANAGEMENT OF PLANT VIRAL DISEASES

Abstract

Plant viruses pose a serious threat to global crop production and food security; however, effective and durable management strategies to mitigating viral diseases remain limited. Rapid viral evolution, reservoir hosts, mixed infections, and climate change further complicate their management. Conventional strategies such as vector management and the development of resistant cultivars often provide incomplete and short-term protection. Endophytes, including bacteria, fungi, actinomycetes, and arbuscular mycorrhizal fungi that reside asymptomatically within plant tissues are increasingly recognized as sustainable biocontrol agents against plant viral diseases. These microorganisms enhance host defence by inducing systematic resistance through priming salicylic acid, jasmonic acid, and ethylene signalling pathways, thereby promoting the accumulation of pathogenesis-related proteins and modulating antioxidant systems. In addition, several endophytes produce antiviral metabolites, including ribonucleases and other bioactive compounds, that directly interfere with viral replication, limit insect vector feeding and transmission, and reduce symptom development. Recent advances in symbiont-mediated RNA interference (SMR) using engineered endophytes to deliver double-stranded RNA (dsRNA) further expand the potential of endophytes for durable and systemic viral suppression. This review expands our current understanding of the direct and indirect mechanisms of endophyte mediated viral inhibition and highlights future prospects for endophyte-based bioformulations and their integration into effective viral disease management strategies.