Figure 8.

Model of the signaling leading to insect resistance or sensitivity after pathogen infection. Infection with an avirulent pathogen increases SA levels, which has been shown to cause insect sensitivity. However, the simplest interpretation of the data presented in this paper is that an unknown signal from an avirulent infection apparently overrides the SA signaling, thereby increasing insect resistance. This signal may partly depend on HR and SA. Infection with a virulent pathogen appears to result in another unidentified signal that systemically increases insect sensitivity in an SA-independent manner.