Bacterial effector modulation of host E3 ligase activity suppresses PAMP-triggered immunity in rice.
Pathogen effector proteins are delivered to host cells to suppress plant immunity. However, the mechanisms by which effector proteins function are largely unknown. Here we show that expression of XopP(Xoo), an effector of rice pathogen Xanthomonas oryzae pv. oryzae, in rice strongly suppresses peptidoglycan (PGN)- and chitin-triggered immunity and resistance to X. oryzae. XopP(Xoo) targets OsPUB44, a rice ubiquitin E3 ligase with a unique U-box domain. We find that XopP(Xoo) directly interacts with the OsPUB44 U-box domain and inhibits ligase activity. Two amino-acid residues specific for the OsPUB44 U-box domain are identified, which are responsible for the interaction with XopP(Xoo). Silencing of OsPUB44 suppresses PGN- and chitin-triggered immunity and X. oryzae resistance, indicating that OsPUB44 positively regulates immune responses. Thus, it is likely that XopP(Xoo) suppresses immune responses by directly interacting with and inhibiting a positive regulator of plant immunity.
Department of Advanced Bioscience, Graduate School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
Kazuya
K
Ishikawa
Department of Advanced Bioscience, Graduate School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
Koji
K
Yamaguchi
Department of Advanced Bioscience, Graduate School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
Kazuaki
K
Sakamoto
Department of Advanced Bioscience, Graduate School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
Satomi
S
Yoshimura
Department of Advanced Bioscience, Graduate School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
Kento
K
Inoue
Graduate School of Life and Environmental Science, Kyoto Prefectural University, Kyoto 606-8522, Japan.
Seiji
S
Tsuge
Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Chojiro
C
Kojima
Department of Advanced Bioscience, Graduate School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
Tsutomu
T
Kawasaki
D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D020868:Gene Silencing / Q000502:physiology; D054884:Host-Pathogen Interactions / Q000276:immunology / Q000502:physiology*; D012275:Oryza / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D000069452:Pathogen-Associated Molecular Pattern Molecules / Q000378:metabolism*; D010457:Peptidoglycan / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D057865:Plant Immunity / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000502:physiology*; D014974:Xanthomonas / Q000472:pathogenicity* / Q000502:physiology
D001426:Bacterial Proteins; D000069452:Pathogen-Associated Molecular Pattern Molecules; D010457:Peptidoglycan; D010940:Plant Proteins; D044767:Ubiquitin-Protein Ligases