Figure 2.

Host-induced gene silencing (HIGS) and spray-induced gene silencing (SIGS) for controlling fungal pathogens. This schematic diagram illustrates the transmission of cross-kingdom RNAi signals in plant-fungal pathogen interactions, and how HIGS and SIGS can be used to protect plants against fungal infection. On the left panel, fungal pathogens deliver sRNA effectors into host plant cells and hijack the host innate immune system (blue arrows and blue block sign). To react, the host plant cells also export either endogenous sRNAs or artificial sRNAs into pathogen cells to silence virulence genes and other important genes for fungi growth (purple arrows and purple block sign). On the right panel, SIGS sRNAs or long dsRNAs, which target fungal pathogenicity-related genes, can be either taken up directly by pathogen cells, or indirectly move from hosts that uptake them to pathogen cells (red arrows).