Citrus exosome-modified exogenous dsRNA delivery reduces plant pathogen resistance and mycotoxin production

Abstract

Plant-derived exosome-like nanoparticles (PENs) are crucial for intercellular communication. However, PEN-based transport of pathogenic fungal genes remains unclear. This study isolated and purified PENs from lane late navel orange citrus juice by following the sucrose gradient ultracentrifugation technique. Citrus PENs were round and oval-shaped with an average size of 154.5 ± 1.9 nm. Electroporation-based exogenous dsRNA to PENs loading efficiency remained at 6.0 %. Laser confocal microscopy was employed to investigate citrus PEN uptake by fungal spores. dsCrcB loaded PENs inhibited the CrcB gene expression in spores to alleviate Penicillium italicum resistance against prochloraz fungicide, which promoted resistant strains' mortality by 10-fold. Moreover, dsFUM21-loaded PENs suppressed the FUM21 gene expression in spores, which significantly reduced FB1 production in Fusarium proliferatum. These findings suggest that citrus PENs could potentially serve as nano-carriers to counter fungicide resistance and mycotoxin production in pathogenic plant fungi.