Exogenous dsRNA-Induced Silencing of the Phytophthora infestans Elicitin Genes inf1 and inf4 Suppresses Its Pathogenicity on Potato Plants

Phytophthora infestans, an Oomycete pathogen, has a devastating impact on potato agriculture, leading to the extensive use of chemical fungicides to prevent its outbreaks. Spraying double-stranded RNAs to suppress specific genes of the pathogen via the RNA interference (RNAi) pathway may provide an environmentally friendly alternative to chemicals. However, this novel approach will require various target genes and application strategies to be tested. Using the L4440 backbone, we have designed two plasmids to express dsRNA targeting inf1 and inf4 genes of P. infestans that are known to contribute to the disease development at different stages. The dsRNA produced by the bacteria was tested on potato explants and demonstrated a statistically significant reduction in lesions five days after inoculation compared to water treatment. The study results allow us to consider our approach to be promising for potato late blight control.