Warning: Lots of technical language in the link.
- ETI: Effector-triggered immunity - An immune response localized to inside the cell
- MPK3/MK6: Kinases which help mediate the response to an ETI.
- ROS: Reactive oxygen species, chemicals that are relatively reactive.
Essentially, when a plant cell detects a pathogen and the ETI chain is triggered, MPK3/MK6 inhibit photosynthesis, allowing greater concentrations of Hydrogen Peroxide (H2O2) and Superoxide (a negatively charged oxygen particle) to build up inside the cell, which may help defend the cell. Additionally, the cell will actively choose defense over growth in shutting down photosynthesis.