RNAi-based management for Fusarium wilt of banana

Banana is an important tropical crop and trading commodity in the world. However, Fusarium wilt is a severe risk for the world banana industry. Caused by the soil-borne fungal pathogen, Fusarium oxysporum f. sp. cubense (Foc), the disease is spreading insidiously and has been a source of enormous losses worldwide since the 1800s. Unfortunately, effective control methods are not available yet. The current study used an RNAi strategy, referred to as host-induced gene silencing (HIGS), to confer durable resistance against Fusarium by inhibiting in planta expression of Foc essential genes that are conserved in all Foc races and crucial for fungal virulence. In order to find efficient target genes, a wide search of literature has been conducted and four conserved target regions have been chosen after bioinformatics analysis. Preliminary findings from in vitro fungal inhibition assays showed significant reductions in fungal spore count, germination rate and mycelia growth after treating fungal cultures with double-stranded RNA (dsRNA) targeting four Foc genes, suggesting silencing of these genes was effective to reduce fungal growth. Intron hairpin constructs encoding dsRNA targeting selected Foc genes are in the process of being transformed into Arabidopsis thaliana for proof-of-concept of in planta fungal resistance.