Exploring\nthe Tomato Root Protein Network Exploited\nby Core Type 3 Effectors from the Ralstonia solanacearum Species Complex

Proteomics\nhas become a powerful approach for the identification\nand characterization of type III effectors (T3Es). Members of the Ralstonia solanacearum species complex (RSSC) deploy\nT3Es to manipulate host cells and to promote root infection of, among\nothers, a wide range of solanaceous plants such as tomato, potato,\nand tobacco. Here, we used TurboID-mediated proximity labeling (PL)\nin tomato hairy root cultures to explore the proxeomes of the core\nRSSC T3Es RipU, RipD, and RipB. The RipU proxeome was enriched for\nmultiple protein kinases, suggesting a potential impact on the two\nbranches of the plant immune surveillance system, being the membrane-localized\nPAMP-triggered immunity (PTI) and the RIN4-dependent effector-triggered\nimmunity (ETI) complexes. In agreement, a transcriptomics analysis\nin tomato revealed the potential involvement of RipU in modulating\nreactive oxygen species (ROS) signaling. The proxeome of RipB was\nputatively enriched for mitochondrial and chloroplast proteins and\nthat of RipD for proteins potentially involved in the endomembrane\nsystem. Together, our results demonstrate that TurboID-PL in tomato\nhairy roots represents a promising tool to study <i>Ralstonia</i> T3E targets and functioning and that it can unravel potential host\nprocesses that can be hijacked by the bacterial pathogen.