Effector dsRNA delivery via MgFe-layered double hydroxide nanocarriers confers prolonged protection against powdery mildew in pea

Layered double hydroxides (LDHs) have emerged as promising nanocarriers for RNA interference (RNAi)-based crop protection due to their ability to stabilize and effectively deliver pathogen-specific double-stranded RNA (dsRNA). However, their potential against obligate biotrophic pathogens like powdery mildews remains unexplored. In this study, we investigated Magnesium Iron-LDH (MgFe-LDH) nanomaterials as carriers of fungal effector dsRNA (Ef-dsRNA) and evaluated the efficacy of the resulting complex in suppressing Erysiphe pisi (powdery mildew) infection in pea (Pisum sativum) via foliar spray application. The synthesized LDH nanomaterial exhibits strong leaf adherence, biocompatibility, and high dsRNA loading capacity, protects the dsRNA against RNase-mediated degradation, and facilitates its sustained release over time. Foliar spray application of the Ef-dsRNA-LDH complex on intact pea plants results in enhanced gene silencing of the target fungal effector and confers greater and prolonged local and systemic powdery mildew disease protection compared to treatments with dsRNA or LDH alone. Following spray application, the LDH nanomaterial is rapidly taken up by intact pea leaf cells and from the plant into E. pisi hyphae via haustoria, enabling efficient dsRNA delivery and silencing of the target gene up to 15 days post-application. Overall, our Ef-dsRNA-LDH formulation offers a robust, sustainable, and targeted approach for RNAi-mediated control of powdery mildews.