Enhanced Resistance to Pokkah Boeng Disease in Sugarcane Through Host-Induced Gene Silencing Targeting FsCYP51 in Fusarium sacchari.

Pokkah boeng disease (PBD), a common and highly destructive disease of sugarcane, is mainly caused by Fusarium sacchari. Breeding sugarcane resistant to PBD is challenging due to the limited availability of immune or highly resistant germplasm resources. Host-induced gene silencing (HIGS) based on RNA interference (RNAi) is a promising disease-control method that offers strong disease-targeting ability with low environmental impact. This study found that silencing either three FsCYP51 genes (FsCYP51A, FsCYP51B and FsCYP51C) simultaneous or two of them (FsCYP51A and FsCYP51C) could inhibit the growth, development, and virulence of F. sacchari. Subsequently, we developed CYP51-HIGS transgenic sugarcane lines using gene-gun genetic transformation and obtained seven lines expressing dsFsCYP51. Both the results of laboratory inoculation assays and field trials indicated that all the seven transgenic lines had significant resistance to PBD. Moreover, in the field trials, the yield losses of transgenic sugarcane due to PBD were reduced compared with those of the control. This is the first report using the HIGS strategy to inhibit PBD infection in sugarcane. This breakthrough provides clear guidelines and practical approaches for the future breeding of sugarcane varieties with strong antifungal resistance.