RNA interference-based gene silencing of dicer-like 2 in Fusarium oxysporum f. sp. cubense tropical race 4 mitigates fusarium wilt disease in banana

Abstract

Banana Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) is a severe threat to global banana production which drastically reduces yields. Currently, no effective control measures exist for this destructive pathogen. RNA interference (RNAi)-based exogenous application of double-stranded RNAs (dsRNAs) has emerged as an environmental-friendly plant protection strategy in recent years. This innovative approach combats plant pathogens by silencing their essential genes. The dicer-like 2 (DCL2) gene which is an important component in the RNAi pathway, was silenced using in vitro synthesized long dsRNAs. The efficacy of Foc TR4-DCL2 dsRNAs was evaluated in vitro to determine optimal concentration and duration against Foc TR4, and their potential to suppress disease progression in planta. Relative transcript abundance analysis revealed that DCL2 gene was partially silenced at a threshold concentration of 1000 ng/mL after 72 h of dsRNA treatment, compared to the control (water) in vitro. In planta studies demonstrated that disease progression in roots and rhizomes was significantly inhibited in plants treated with Foc TR4-DCL dsRNAs, indicating that RNAi-mediated gene silencing mechanism could be a promising method for controlling banana Fusarium wilt in the future.