Screen of Non-annotated Small Secreted Proteins of Pseudomonas syringae Reveals a Virulence Factor That Inhibits Tomato Immune Proteases
| Autor: | Fan Yang, Mohammed Shabab, Rohini Chawla, Judit Kovács, Renier A. L. van der Hoorn, James R. Alfano, Selva Kumari, Tram Ngoc Hong, Tom Colby, Fang Tian, Anja C. Hörger, Takayuki Shindo, Farnusch Kaschani, Muhammad Ilyas, Jiorgos Kourelis |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0106 biological sciences
0301 basic medicine Leaves medicine.medical_treatment Pseudomonas syringae Plant Science Pathology and Laboratory Medicine 01 natural sciences Biochemistry Virulence factor Solanum lycopersicum Cysteine Proteases Medicine and Health Sciences Biology (General) Plant Proteins Virulence Effector Plant Bacterial Pathogens Plant Anatomy Pseudomonas food and beverages Agriculture Proteases Plants Enzymes Bacterial Pathogens Apoplastic space Medical Microbiology Plant bacterial pathogens Pathogens Biologie medicine.drug Research Article Virulence Factors QH301-705.5 Immunology Pseudomonas Syringae Plant Pathogens Crops Biology Microbiology Fruits 03 medical and health sciences Bacterial Proteins Tomatoes Virology Apoplastic Space Genetics medicine Protease Inhibitors Molecular Biology Microbial Pathogens Plant Diseases Protease Cysteine proteases Bacteria fungi Organisms Biology and Life Sciences Proteins Plant Pathology RC581-607 biology.organism_classification Protease inhibitor (biology) Plant Leaves 030104 developmental biology Enzymology Parasitology Immunologic diseases. Allergy 010606 plant biology & botany Peptide Hydrolases Crop Science |
| Zdroj: | PLoS Pathogens, Vol 12, Iss 9, p e1005874 (2016) PLoS Pathogens |
| Popis: | Pseudomonas syringae pv. tomato DC3000 (PtoDC3000) is an extracellular model plant pathogen, yet its potential to produce secreted effectors that manipulate the apoplast has been under investigated. Here we identified 131 candidate small, secreted, non-annotated proteins from the PtoDC3000 genome, most of which are common to Pseudomonas species and potentially expressed during apoplastic colonization. We produced 43 of these proteins through a custom-made gateway-compatible expression system for extracellular bacterial proteins, and screened them for their ability to inhibit the secreted immune protease C14 of tomato using competitive activity-based protein profiling. This screen revealed C14-inhibiting protein-1 (Cip1), which contains motifs of the chagasin-like protease inhibitors. Cip1 mutants are less virulent on tomato, demonstrating the importance of this effector in apoplastic immunity. Cip1 also inhibits immune protease Pip1, which is known to suppress PtoDC3000 infection, but has a lower affinity for its close homolog Rcr3, explaining why this protein is not recognized in tomato plants carrying the Cf-2 resistance gene, which uses Rcr3 as a co-receptor to detect pathogen-derived protease inhibitors. Thus, this approach uncovered a protease inhibitor of P. syringae, indicating that also P. syringae secretes effectors that selectively target apoplastic host proteases of tomato, similar to tomato pathogenic fungi, oomycetes and nematodes. Author Summary The extracellular space in the leaf (the apoplast) is colonized by a diversity of microbes that will have to deal with host-secreted hydrolytic enzymes, many of which accumulate during defence responses. We hypothesize that in addition to fungal and oomycete pathogens, the bacterial model plant pathogen Pseudomonas syringae also protects itself in the apoplast by secreting inhibitors targeting these apoplastic hydrolases. The genome of P. syringe harbours over 131 genes encoding putative small, non-annotated secreted proteins that have not been characterized previously. Here, we produced and purified 43 of these small proteins and tested them for their ability to inhibit the secreted immune protease C14 of tomato. We discovered a C14 protease inhibitor, coined Cip1, which carries chagasin-like motifs and contributes to virulence. Cip1 also effectively inhibits Pip1, another immune protease of tomato, known to suppress P. syringae infection. Interestingly, Cip1 has a lower affinity for the immune protease Rcr3, explaining why this protein, and PtoDC3000 producing Cip1, is not recognized in tomato plants carrying the Cf-2 resistance gene, which uses Rcr3 as a co-receptor to detect pathogen invasion. |
| Databáze: | OpenAIRE |
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