Host inhibition of a bacterial virulence effector triggers immunity to infection.
Plant pathogenic bacteria secrete effector proteins that attack the host signaling machinery to suppress immunity. Effectors can be recognized by hosts leading to immunity. One such effector is AvrPtoB of Pseudomonas syringae, which degrades host protein kinases, such as tomato Fen, through an E3 ligase domain. Pto kinase, which is highly related to Fen, recognizes AvrPtoB in conjunction with the resistance protein Prf. Here we show that Pto is resistant to AvrPtoB-mediated degradation because it inactivates the E3 ligase domain. AvrPtoB ubiquitinated Fen within the catalytic cleft, leading to its breakdown and loss of the associated Prf protein. Pto avoids this by phosphorylating and inactivating the AvrPtoB E3 domain. Thus, inactivation of a pathogen virulence molecule is one mechanism by which plants resist disease.
Sainsbury Laboratory, Colney, Norwich NR4 7UH, UK.
Vardis
V
Ntoukakis
Tatiana S
TS
Mucyn
Selena
S
Gimenez-Ibanez
Helen C
HC
Chapman
Jose R
JR
Gutierrez
Alexi L
AL
Balmuth
Alexandra M E
AM
Jones
John P
JP
Rathjen
D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007113:Immunity, Innate; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology*; D050505:Mutant Proteins / Q000378:metabolism; D010766:Phosphorylation; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology*; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D044224:Pseudomonas syringae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity*; D015398:Signal Transduction; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D054875:Ubiquitination; D037521:Virulence Factors / Q000037:antagonists & inhibitors / Q000378:metabolism
D001426:Bacterial Proteins; D050505:Mutant Proteins; D010940:Plant Proteins; C120613:Prf protein, Lycopersicon esculentum; D037521:Virulence Factors; C081695:avrPto protein, Pseudomonas syringae; D044767:Ubiquitin-Protein Ligases; C091599:Fen protein, Lycopersicon esculentum; C084354:Pto protein, Lycopersicon; D017346:Protein Serine-Threonine Kinases