Engineering citrus for psyllid control: virus‐induced silencing of osmoregulatory genes reduces survival and development of Diaphorina citri

Abstract BACKGROUND The Asian citrus psyllid ( Diaphorina citri ) is the insect vector of ‘ Candidatus Liberibacter asiaticus’, the causal agent of huanglongbing (HLB), the most destructive citrus disease worldwide. Current management depends largely on repeated insecticide applications, underscoring the need for sustainable alternatives. Osmoregulation is indispensable for D . citri because the insect feeds exclusively on sucrose‐rich phloem sap and must continuously regulate carbohydrate metabolism and water balance to maintain physiological homeostasis. RNA interference (RNAi)‐mediated silencing of sucrose hydrolase ( DcSuh ) and aquaporin ( DcAQP ), two key components of the psyllid osmoregulatory network, significantly reduces psyllid survival. However, efficient and durable delivery systems capable of sustaining RNAi under natural plant‐feeding conditions remain limited. RESULTS We developed recombinant Citrus tristeza virus (CTV) vectors that express double‐stranded RNA (dsRNA) targeting DcSuh and DcAQP , enabling continuous citrus‐mediated RNAi. D . citri reared on citrus plants infected with these engineered CTV vectors were evaluated over two successive generations to determine the long‐term effects of gene silencing on insect performance. Silencing either target gene significantly reduced psyllid fitness by decreasing survival, longevity, and fecundity while increasing developmental abnormalities and mortality. These effects persisted in the second generation, demonstrating sustained RNAi activity. CONCLUSION This study demonstrates that CTV is an efficient and durable vehicle for plant‐mediated RNAi in citrus and identifies osmoregulation as a highly susceptible physiological target for management of D . citri . Integrating virus‐mediated dsRNA production with essential insect physiological targets offers a promising strategy for long‐term suppression of psyllid populations and a sustainable approach to reducing the spread of huanglongbing. © 2026 Society of Chemical Industry.