Multiple activities of the plant pathogen type III effector proteins WtsE and AvrE require WxxxE motifs.
The broadly conserved AvrE-family of type III effectors from gram-negative plant-pathogenic bacteria includes important virulence factors, yet little is known about the mechanisms by which these effectors function inside plant cells to promote disease. We have identified two conserved motifs in AvrE-family effectors: a WxxxE motif and a putative C-terminal endoplasmic reticulum membrane retention/retrieval signal (ERMRS). The WxxxE and ERMRS motifs are both required for the virulence activities of WtsE and AvrE, which are major virulence factors of the corn pathogen Pantoea stewartii subsp. stewartii and the tomato or Arabidopsis pathogen Pseudomonas syringae pv. tomato, respectively. The WxxxE and the predicted ERMRS motifs are also required for other biological activities of WtsE, including elicitation of the hypersensitive response in nonhost plants and suppression of defense responses in Arabidopsis. A family of type III effectors from mammalian bacterial pathogens requires WxxxE and subcellular targeting motifs for virulence functions that involve their ability to mimic activated G-proteins. The conservation of related motifs and their necessity for the function of type III effectors from plant pathogens indicates that disturbing host pathways by mimicking activated host G-proteins may be a virulence mechanism employed by plant pathogens as well.
Ham
Jong Hyun
JH
Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio 43210, USA.
Majerczak
Doris R
DR
Nomura
Kinya
K
Mecey
Christy
C
Uribe
Francisco
F
He
Sheng-Yang
SY
Mackey
David
D
Coplin
David L
DL
D020816:Amino Acid Motifs / Q000502:physiology; D017360:Arabidopsis / Q000378:metabolism / Q000382:microbiology; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D016923:Cell Death; D004721:Endoplasmic Reticulum / Q000378:metabolism; D007425:Intracellular Membranes; D009154:Mutation; D020636:Pantoea / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D010802:Phylogeny; D021382:Protein Sorting Signals; D044224:Pseudomonas syringae / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D014774:Virulence; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D003313:Zea mays / Q000166:cytology / Q000378:metabolism / Q000382:microbiology
D001426:Bacterial Proteins; D021382:Protein Sorting Signals; D037521:Virulence Factors