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Molecular characterization of a recombinant replication protein (Rep) from the Antarctic bacterium Psychrobacter sp. TA144.
No full textMolecular characterization of a recombinant replication protein (Rep) from the Antarctic bacterium Psychrobacter sp. TA144.
No full textPhosphoproteomic analysis of induced resistance reveals activation of signal transduction processes by beneficial and pathogenic interaction in grapevine
No full textProtein 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 49 kDa 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
Trichoderma harzianum T39 biocontrol activity against Plasmopara viticola: rola of protein phosphorylation in initiating grapevine resistance
No full textProteomic characterization of grapevine resistance against downy mildew activated by Trichoderma harzianum T39
No full textThe host-specific oomycete Plasmopara viticola is the causal agent of downy mildew, one of the most important grapevine diseases. In recent years, several molecules able to induce a plant-mediated resistance against P. viticola have been described. Some inducers, i.e. benzothiaziadole (BTH), activate a direct resistance involving constitutive barriers and local and systemic defences, with a high metabolic cost for the plant. On the other hand Trichoderma harzianum T39, a beneficial microorganism, primes for defence against grapevine downy mildew. This mechanism presents advantages in terms of energy costs for the plant, because defence responses are expressed upon pathogen attack and, therefore, only when they are really needed.
The present study aims to understand cellular processes involved in reaction to P. viticola inoculation in plants pre-treated with the biocontrol agent T. harzianum T39 in comparison to the water-treated and BTH-treated ones. By monitoring the kinetic of intercellular colonization of P. viticola, callose and lignin deposition in grapevine cell wall and the production of reactive oxygen species, we demonstrated a priming mechanism for the post-invasion reactions in T39- and BTH-treated plants with difference in timing and magnitude of responses.
Moreover, to explore the processes involved in grapevine self-defence induced by T. harzianum T39 before and after pathogen inoculation, a proteomic approach was used following an 8-plex differential mass tags iTRAQ protocol. Among proteins identified and quantified by LC-MS-MS (more than 900), 89 were significantly modulated 1 day post P. viticola inoculation in water-treated plants. Eighty-three proteins were directly modulated by T39 prior pathogen infection and 104 in T39-treated plants at 1 day post P. viticola inoculation. A general re-direction of primary and secondary metabolism, together with a reaction involving early steps of recognition (receptors and downstream signalling molecules) were induced by P. viticola within the first day of infection in water-treated plants. On the contrary a general number of proteins including hormones signalling, pathogenesis related proteins and oxidative stress-related proteins, were induced or primed for induction upon pathogen inoculation in T39-treated plants.
All these results offer a greater understand of the mechanisms underlying the grapevine T39-induced resistance and illustrate the priming effect of T39 on both defence-related proteins abundance and constitutive barriers formation. Further research will be focused on a detailed functional characterization of potential elicitors of grapevine defence mechanism
Dissecting the tripartite interaction between Vitis vinifera, Plasmopara viticola and the biocontrol agent Trichoderma harzianum T39
No full textThe biocontrol agent Trichoderma harzianum T39 reduce downy mildew severity on susceptible grapevines by inducing plant resistance. By cytological and molecular approaches, we aimed to identify mechanisms responsible of the grapevine self-defence. T39 resulted to induce a direct modulation of the receptor and recognition plant-machinery and activates a priming state for enhanced expression of stress-related proteins after pathogen inoculation
Proteomic analysis of grapevine resistance induced by Trichoderma harzianum T39 reveals specific defence pathways activated against downy mildew
Full text linkDowny mildew, caused by the oomycete Plasmopara viticola, is one of the most serious of grapevine diseases. The beneficial microorganism Trichoderma harzianum T39 (T39) has previously been shown to induce plant-mediated resistance and to reduce the severity of downy mildew in susceptible grapevines. In order to better characterise the cellular processes associated with T39-induced resistance, proteomic and histochemical changes activated by T39 were analysed in grapevine before and one day after P. viticola inoculation. A comprehensive proteomic analysis of T39-induced resistance in grapevine was performed using an eight-plex iTRAQ protocol, resulting in the identification and quantification of a total of 800 proteins. Statistical analysis revealed 58 and 60 proteins to be significantly modulated by T39 treatment before and after P. viticola inoculation, respectively. In addition, 128 proteins were modulated by P. viticola inoculation in control plants. Most of the proteins directly modulated by T39 were involved in signal transduction, indicating activation of a complete microbial recognition machinery. T39-induced resistance was associated with rapid accumulation of reactive oxygen species and callose at infection sites, as well as modulation of the proteins involved in response to stress and redox balance, indicating an active defence response to downy mildew. On the other hand, proteins affected by P. viticola in control plants were mainly negatively modulated, which suggests that a compatible interaction may be taking place. As well as yielding data on the molecular processes responsible for T39-induced resistance, the high-throughput iTRAQ protocol allowed the improvement of protein sequences of the V. vinifera cv. Pinot Noir proteome
Molecular characterisation of a recombinant replication protein (Rep) from the Antartic bacterium Psychrobacter sp. TA144
No full textSynapsin phosphorylation by src tyrosine kinase enhances src activity in synaptic vesicles
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