The Pseudomonas syringae Effector HopQ1 Promotes Bacterial Virulence and Interacts with Tomato 14-3-3 Proteins in a Phosphorylation-Dependent Manner
Open Access
- 15 February 2013
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 161 (4), 2062-2074
- https://doi.org/10.1104/pp.112.211748
Abstract
A key virulence strategy of bacterial pathogens is the delivery of multiple pathogen effector proteins into host cells during infection. The Hrp outer protein Q (HopQ1) effector from Pseudomonas syringae pv tomato (Pto) strain DC3000 is conserved across multiple bacterial plant pathogens. Here, we investigated the virulence function and host targets of HopQ1 in tomato (Solanum lycopersicum). Transgenic tomato lines expressing dexamethasone-inducible HopQ1 exhibited enhanced disease susceptibility to virulent Pto DC3000, the Pto ΔhrcC mutant, and decreased expression of a pathogen-associated molecular pattern-triggered marker gene after bacterial inoculation. HopQ1-interacting proteins were coimmunoprecipitated and identified by mass spectrometry. HopQ1 can associate with multiple tomato 14-3-3 proteins, including TFT1 and TFT5. HopQ1 is phosphorylated in tomato, and four phosphorylated peptides were identified by mass spectrometry. HopQ1 possesses a conserved mode I 14-3-3 binding motif whose serine-51 residue is phosphorylated in tomato and regulates its association with TFT1 and TFT5. Confocal microscopy and fractionation reveal that HopQ1 exhibits nucleocytoplasmic localization, while HopQ1 dephosphorylation mimics exhibit more pronounced nuclear localization. HopQ1 delivered from Pto DC3000 was found to promote bacterial virulence in the tomato genotype Rio Grande 76R. However, the HopQ1(S51A) mutant delivered from Pto DC3000 was unable to promote pathogen virulence. Taken together, our data demonstrate that HopQ1 enhances bacterial virulence and associates with tomato 14-3-3 proteins in a phosphorylation-dependent manner that influences HopQ1’s subcellular localization and virulence-promoting activities in planta.Keywords
This publication has 49 references indexed in Scilit:
- The tomato genome sequence provides insights into fleshy fruit evolutionNature, 2012
- The Role of the Plasma Membrane H+-ATPase in Plant–Microbe InteractionsMolecular Plant, 2011
- Tomato 14-3-3 Protein TFT7 Interacts with a MAP Kinase Kinase to Regulate Immunity-associated Programmed Cell Death Mediated by Diverse Disease Resistance ProteinsOnline Journal of Public Health Informatics, 2011
- A Receptor-like Cytoplasmic Kinase Phosphorylates the Host Target RIN4, Leading to the Activation of a Plant Innate Immune ReceptorCell Host & Microbe, 2011
- Genetic disassembly and combinatorial reassembly identify a minimal functional repertoire of type III effectors in Pseudomonas syringaeProceedings of the National Academy of Sciences of the United States of America, 2011
- Pseudomonas syringae hijacks plant stress chaperone machinery for virulenceProceedings of the National Academy of Sciences of the United States of America, 2010
- Pseudomonas syringae Effector Protein AvrB Perturbs Arabidopsis Hormone Signaling by Activating MAP Kinase 4Cell Host & Microbe, 2010
- Analyzing real-time PCR data by the comparative CT methodNature Protocols, 2008
- Identification of a host 14-3-3 protein that interacts with Xanthomonas effector AvrRxvPhysiological and Molecular Plant Pathology, 2008
- Expression Profiling of the 14-3-3 Gene Family in Response to Salt Stress and Potassium and Iron Deficiencies in Young Tomato (Solanum lycopersicum) Roots: Analysis by Real-time RT–PCRAnnals of Botany, 2006