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Poster

Session: Session 2 Presenting Authors at Posters (Odds)

P-107 - Activity-based proteomics reveals suppressed hydrolase activities at the Pseudomonas syringae - Nicotiana benthamiana interface

Wednesday, July 16, 2025
13:30 - 15:15  
Location: Confex Hall 3
Effector Interference Mechanisms
Abstract Text:

The extracellular space of plant tissues harbours hundreds of hydrolases that can potentially disrupt microbial colonization. To establish infection, successful pathogens may suppress these hydrolase activities to facilitate disease progression. Here, we investigate the dynamics of extracellular hydrolases in Nicotiana benthamiana upon infection with three Pseudomonas syringae strains: pathovar tomato DC3000 (ΔhopQ1), pv. syringae B728a, and pv. tabaci 6605. Through comprehensive proteomic analysis, we identified 357 apoplastic hydrolases from N. benthamiana and 328, 454, and 470 apoplastic proteins from each pathogen respectively. Using activity-based proteomics with biotinylated probes, we simultaneously tracked the activity of 77 hydrolases, comprising 66 serine hydrolases and 11 cysteine proteases. The activity of 23 serine hydrolases and 4 cysteine proteases was consistently suppressed across all three pathogens. To further investigate potential pathogen-mediated suppression, we are using AlphaFold-Multimer to predict the complex structures of these suppressed hydrolases in interaction with pathogen-secreted proteins. This study demonstrates two powerful approaches for uncovering novel components of extracellular immunity, shedding light on host-pathogen interactions at the apoplastic interface.