Induction of plant resistance to bean common mosaic virus (BCMV) via multiple applications of nanoparticle-conjugated dsRNA

Bean common mosaic virus (BCMV) is regarded as the most destructive to common beans, capable of causing yield losses of up to 100%. A non-transgenic approach involving the topical application of dsRNA to induce RNA interference is increasingly being utilized to develop efficient, eco-friendly, sustainable virus and vector management strategies. This approach does not require genetic modification and is particularly beneficial for crops that are challenging to modify through transgenesis or gene editing. This study aimed to evaluate the efficacy of multiple applications of nanoparticle-conjugated dsRNA in three different treatment assemblages, applied at varying time intervals, for the effective management of BCMV. Results from qRT-PCR assay showed significant downregulation of viral expression in all three assemblages with lower expression values upto 50 dpi, confirming the prolonged efficacy of topically applied dsRNA inducing RNAi. Following three topical applications of nanoparticle-conjugated dsRNA, viral expression in treated plants was significantly reduced to 1.218 and 1.493 for dsRNA targeting the HC-Pro and CP genes, respectively, as compared to a high viral expression value of 22.994 in positive control. This research represents a significant advancement in BCMV management, demonstrating that multiple applications of dsRNA can effectively suppress viral infection till the flowering stage of the crop and can be utilised as an environmental-benign and non-toxic alternative to manage viral infections in plants.