To optimize energy homeostasis and ensure survival plants rapidly respond to abiotic and biotic stressors in their environment. Plant cells constantly monitor the environment via cell surface receptors and relay this information to the nucleus where signals from multiple sensory pathways are integrated. Signal relay from the cell surface largely relies on stimulus-induced post-translational modification of proteins and changes in protein-protein interactions. Within the nucleus, these signals are translated into appropriate transcriptional programs that ultimately allow plants to adapt to changes in their environment.
Signals indicative of microbial invasion perceived at the plant cell surface activate a transcriptional program that favors defense mechanisms over photosynthesis and plant growth. However, adverse environmental conditions can perturb activation of antimicrobial defense. While plant innate immunity is effective in warding off the majority of attempted attacks, adapted plant pathogens intercept activation of plant immunity by shuttling effector proteins into host cells. Several effector proteins specifically target the host cell nucleus where they interfere with transcription of defense genes. Therefore, the effectiveness of plant defense against microbial attack is dependent on environmental conditions and virulence strategies employed by the attacker. Several proteins appear to function as hubs of signal integration and pathogen effectors preferentially target these signaling nodes.
We aim to unravel molecular mechanisms of protein-mediated signaling events in and at the periphery of the plant cell nucleus. We substantiate this approach by obtaining structural information of key signaling proteins using x-ray crystallography. This work will provide insights into molecular interactions that plants use to integrate environmental information from various sensory pathways and reveal how plant pathogens manipulate this signaling network.