Figure 3.

Hypothetical model for the role of Arabidopsis ROPGAPs in ROP mediated signaling. During pathogen attack, ROPs are activated via ROPGEFs, which catalyze the exchange of ROP bound GDP for GTP. RLKs were identified as possible upstream activators of ROPGEFs, but other modes of activation should not be excluded. Active ROPs might support via downstream effectors susceptibility to powdery mildews, while ROPGAP mediated inactivation of ROPs act antagonistic to these processes. There is also a possible influence of known ROP-regulated processes such as ROS production, gene expression, cytoskeleton organization or hormone responses on susceptibility to powdery mildew (shown as dotted line).