title: Phosphoproteomic analysis of induced resistance reveals activation of signal transduction processes by beneficial and pathogenic interaction in grapevine.
abstract: Protein phosphorylation regulates several key processes of the plant immune system. Protein kinases and phosphatases are pivotal regulators of defense mechanisms elicited by resistance inducers. However, the phosphorylation cascades that trigger the induced resistance mechanisms in plants have not yet been deeply investigated. The beneficial fungus Trichoderma harzianum T39 (T39) induces resistance against grapevine downy mildew (Plasmopara viticola), but its efficacy could be further improved by a better understanding of the cellular regulations involved. We investigated quantitative changes in the grapevine phosphoproteome during T39-induced resistance to get an overview of regulatory mechanisms of downy mildew resistance. Immunodetection experiments revealed activation of the 45 and 49kDa kinases by T39 treatment both before and after pathogen inoculation, and the phosphoproteomic analysis identified 103 phosphopeptides that were significantly affected by the phosphorylation cascades during T39-induced resistance. Peptides affected by T39 treatment showed comparable phosphorylation levels after P. viticola inoculation, indicating activation of the microbial recognition machinery before pathogen infection. Phosphorylation profiles of proteins related to photosynthetic processes and protein ubiquitination indicated a partial overlap of cellular responses in T39-treated and control plants. However, phosphorylation changes of proteins involved in response to stimuli, signal transduction, hormone signaling, gene expression regulation, and RNA metabolism were exclusively elicited by P. viticola inoculation in T39-treated plants. These results highlighted the relevance of phosphorylation changes during T39-induced resistance and identified key regulator candidates of the grapevine defense against downy mildew.
authors.affiliation: Department of Sustainable Agro-ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach (FEM), Via E. Mach 1, 38010 San Michele all'Adige, Italy. Electronic address: michele.perazzolli@fmach.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Perazzolli
authors.affiliation: Department of Sustainable Agro-ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach (FEM), Via E. Mach 1, 38010 San Michele all'Adige, Italy.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Palmieri
authors.affiliation: Biological Mass Spectrometry Unit DIBIT, San Raffaele Scientific Institute, Via Olgettina 58, 20132 Milano, Italy.
authors.forename: Vittoria
authors.initials: V
authors.lastname: Matafora
authors.affiliation: Biological Mass Spectrometry Unit DIBIT, San Raffaele Scientific Institute, Via Olgettina 58, 20132 Milano, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Bachi
authors.affiliation: Department of Sustainable Agro-ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach (FEM), Via E. Mach 1, 38010 San Michele all'Adige, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Pertot
mesh_terms: D060467:Disease Resistance; D054884:Host-Pathogen Interactions; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009868:Oomycetes / Q000502:physiology*; D010766:Phosphorylation; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D010940:Plant Proteins / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D040901:Proteomics; D015398:Signal Transduction; D014242:Trichoderma / Q000502:physiology*; D027843:Vitis / Q000276:immunology / Q000382:microbiology / Q000502:physiology*
chemical_list: D010940:Plant Proteins; D020928:Mitogen-Activated Protein Kinases
keywords: Gel-free proteomics; Induced resistance; Phosphoproteomics; Plant defense; Post-translational modifications; Vitis vinifera