Figure 8.

Simplified model on the effect of JA and flg22 on AtPep-triggered responses. A, In untreated wild-type plants, AtPeps elicit a moderate defense response compared with MAMP-triggered responses (Krol et al., 2010; Ranf et al., 2011). A so-far-unknown PEPR-specific pathway leading to RbohD/RbohF activation is only weakly expressed; therefore, AtPeps trigger only low amounts of apoplastic ROS. B, JA positively regulates PEPR abundance. Increased levels of PEPRs trigger stronger responses upon AtPep perception. C, Previous perception of flg22 specifically triggers expression of the PEPR-specific ROS pathway. Thus, subsequent treatments with AtPeps lead to highly induced ROS production, but other AtPep-triggered responses remain unchanged.