Figure 6.

Molecular mechanisms underlying the transgene-based (HIGS) or spray-mediated (SIGS) delivery strategy. (A), the molecular mechanism of HIGS is based on the plant’s silencing machinery. The integration of our findings supports the view that HIGS involves the processing of transgene-derived dsRNA in the plant (plant DCLs) and extracellular vesicle (EV)-mediated delivery into the interacting fungus. (B), the molecular mechanism of SIGS is controlled by the fungal silencing machinery. In summary, our findings support the model that SIGS involves the uptake of sprayed dsRNA by the plant (via stomata) and subsequent uptake of apoplastic dsRNA by the fungus resulting in fungal DCL-dependent production of siRNAs.