P-159 - The effector protein RipBJ of Ralstonia solanacearum interacts with plant ROS homeostasis enzymes to modulate host responses

Wednesday, July 16, 2025

13:30 - 15:15

Location: Confex Hall 3

Effector Interference Mechanisms

Presenting Author(s)

CC

Chiu-Ping Cheng

Director/Professor
Institute of Plant Biology, National Taiwan University
Taipei, Taipei, Taiwan (Republic of China)

Author(s)

GS

Guan-Ming Su

National Taiwan University
Taipei, Taipei, Taiwan (Republic of China)
LC

Li-Wen Chu

National Taiwan University
Taipei, Taipei, Taiwan (Republic of China)
PL

Pei-Shan Liao

National Taiwan University
Taipei, Taipei, Taiwan (Republic of China)
CC

Chih-Cheng Chien

National Taiwan University
Taipei, Taipei, Taiwan (Republic of China)

Reactive oxygen species (ROS) are crucial in regulating many plant functions, and NADPH oxidases and catalases (CATs) are key enzymes of ROS homeostasis. Our studies aim to understand the role of the effector protein RipBJ, originated from the hemi-biotrophic phytopathogenic bacterium Ralstonia solanacearum, in pathogen-plant interactions. Functional genetic analyses revealed that the expression of ripBJ reduced bacterial infection by triggering plant cell death, the accumulation of H₂O₂, and multiple defense signaling pathways. Protein analyses further demonstrated that RipBJ directly interacted with the tomato NADPH oxidase SlWfi1, positively impacting RipBJ’s effects on plants. Notably, SlWfi1 expression was induced during the early stages following R. solanacearum infection and played a key role in defense against this bacterium. These results uncover the plant NADPH oxidase as an interacting target of a pathogen’s effector, providing valuable insights into plant defense mechanisms. Furthermore, RipBJ also directly interacted with tomato CAT2 (SlCAT2), reducing RipBJ-induced plant cell death. These studies point to the key role of ROS in the arms race between the pathogen and its host plants.