ATP6AP1 and cyst: Since distantly related subtilases can also activate Rcr3 in Nicotiana benthamiana, this suggests that there might be a network of proteolytic cascades in Solanaceous plants to provide robust apoplastic immunity (Kourelis et al., 2020; Paulus et al., 2020), which may also apply to cyst nematodes in Cf-2 resistant tomato plants.