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Science 8 May 2009:
Vol. 324. no. 5928, pp. 784 - 787
DOI: 10.1126/science.1169430
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Reports

Host Inhibition of a Bacterial Virulence Effector Triggers Immunity to Infection

Vardis Ntoukakis, Tatiana S. Mucyn, Selena Gimenez-Ibanez, Helen C. Chapman, Jose R. Gutierrez, Alexi L. Balmuth, Alexandra M. E. Jones, John P. Rathjen*

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.

The Sainsbury Laboratory, Colney, Norwich NR4 7UH, UK.

* To whom correspondence should be addressed. E-mail: john.rathjen{at}tsl.ac.uk

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Proteolysis of a Negative Regulator of Innate Immunity Is Dependent on Resistance Genes in Tomato and Nicotiana benthamiana and Induced by Multiple Bacterial Effectors.
Y. Luo, K. S. Caldwell, T. Wroblewski, M. E. Wright, and R. W. Michelmore (2009)
PLANT CELL 21, 2458-2472
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Recent Advances in PAMP-Triggered Immunity against Bacteria: Pattern Recognition Receptors Watch over and Raise the Alarm.
V. Nicaise, M. Roux, and C. Zipfel (2009)
Plant Physiology 150, 1638-1647
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Crystal Structure of the Complex between Pseudomonas Effector AvrPtoB and the Tomato Pto Kinase Reveals Both a Shared and a Unique Interface Compared with AvrPto-Pto.
J. Dong, F. Xiao, F. Fan, L. Gu, H. Cang, G. B. Martin, and J. Chai (2009)
PLANT CELL 21, 1846-1859
   Abstract »    Full Text »    PDF »


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