ubiquitin-proteasome
The ubiquitin-proteasome system is a cellular quality control pathway that tags damaged or unwanted proteins with ubiquitin molecules for degradation by the proteasome complex. In plants, this system plays a critical role in regulating responses to hormones, light, pathogens, and environmental stress by controlling the abundance of key signaling proteins. Understanding how plants deploy ubiquitin-mediated protein turnover has become essential for dissecting developmental processes and engineering stress-tolerant crops.
open_in_new WikipediaPubMed · 2026-04-22
Scientists discovered how a soil bacterium that causes devastating wilting disease in tomatoes and peppers disarms plant defenses: it injects a protein called RipG6 that hijacks the plant's own cellular recycling system to destroy a key immune signaling component.
RipG6 suppresses plant immune responses only when its F-box motif is intact, confirming it works by hijacking the plant's ubiquitin-proteasome protein-degradation machinery.
RipG6 directly interacts with and reduces the stability of a tomato immune kinase (RLCK-VIII-6), effectively dismantling a plant defense signaling component.
Closely related versions of the targeted kinase in wild tobacco and thale cress both function as positive regulators of plant immunity, suggesting this is a broadly conserved defense target across plant species.
