A century-old fight against Huanglongbing with antimicrobial peptides opening the door to citrus health

Huanglongbing (HLB) is a devastating citrus disease threatening global citrus production. The disease, associated with Candidatus Liberibacter asiaticus (CLas), is primarily spread by the Asian citrus psyllid (Diaphorina citri). Traditional management strategies, including chemical control and antibiotics, have limitations such as environmental impacts and resistance development. This review explores the transformative potential of antimicrobial peptides (AMPs) in managing HLB. AMPs offer a dual role by directly targeting CLas bacteria and by enhancing plant immune responses. Resistance sources such as Australian finger lime (Citrus australasica) could be a promising model for developing AMP-based HLB resistance due to its inherent resistance traits. The review highlights the efficacy of AMPs in reducing CLas titers, enhancing plant immunity, and their synergistic potential with existing management practices. Despite challenges in AMPs application, such as cytotoxicity and proteolytic degradation, continued research and integration of AMPs with genetic engineering and soil health management hold promise for sustainable HLB management and citrus industry revival. Future research directions may involve optimizing AMP delivery systems and long-term field studies.