Trichoderma harzianum strain T22 parasitizes and controls many phytopatogenic fungi and is applied commercially as biological control agent. The production of hydrolitic enzymes appears to be a key factor in the paras...Trichoderma harzianum strain T22 parasitizes and controls many phytopatogenic fungi and is applied commercially as biological control agent. The production of hydrolitic enzymes appears to be a key factor in the parasitic process. We tested the endo-esochitinolitic and glucanolitic activities of culture filtrates of T22 grown under carbon and nitrogen starvation or in presence of biomass or cell walls of the phytopathogenic fungi Botrytis cinerea, Rhizoctonia solani and Pythium ultimum. The highest level of enzimatic activities was found in culture where the mycoparasite interacted with a phytopathogenic fungus. Therefore we used a proteomic approach to investigate changes in the complex mixture of extracellular proteins secreted by T. harzianum strain T22 in order to identify proteins of potential biotechnology value for commercial and industrial use.Proteome technology has greatly enhanced our ability to conduct functional genomics studies. Nevertheless only a few studies have been published so far on the fungal extracellular proteome. Sample preparation remains the most critical step in analyses based on two-dimensional gel electrophoresis (2-DE), and it requires to be optimized for each specific application. In this study, our first aim was to set up the extraction protocol of the extracellular proteins secreted by T . harzianum strain T22 when it was grown in vitro .The secreted proteins were analysed by two-dimensional electrophoresis (2-DE) and substantial changes in the extracellular proteome of the mycoparasite have been observed. Comparing the 2D maps of the fungus grown in minimal medium with glycerol as carbon source (used as control condition) with those obtained in inducing conditions, a lot of novel proteins appeared. The higher number of novel and up-regulated spots was obtained in the presence of Rhizoctonia solani biomass. Other spots were specifically up-regulated by the interaction with different plant pathogens. Differentially expressed proteins were subjected to matrix assisted laser desorption ionisation-time of flight (MALDI-TOF) mass spectrometry (MS) and N-terminal Edman sequencing. The in silico analyses of some of the novel and up-regulated spots showed interesting homology to hypothetical and putative proteins from other fungal species. These include novel enzymes, such as glycosylhydrolases and metalloprotease, proteins with conserved domains involved in pathogen-host interactions, such as Ras that regulates signal transduction pathways or LRRs that is involved in host recognition, etc. Work is in progress to demonstrate the role of some of these proteins in biocontrol and ability to induce systemic resistance.展开更多
The molecular factors involved in the three-way interaction between plant, pathogenic fungi and antagonistic/biocontrol fungi, such as Trichoderma, are still poorly understood, even if they represent a matter of inter...The molecular factors involved in the three-way interaction between plant, pathogenic fungi and antagonistic/biocontrol fungi, such as Trichoderma, are still poorly understood, even if they represent a matter of interest for improving crop management and developing new strategies for plant diseases control. The aim of this work is to investigate the components involved in this interaction and, for this purpose, a proteomic approach was used. 2-D maps of the protein extracts from the single components in various interactions between plants (potato, bean, tobacco or tomato), pathogens (Botrytis cinerea, Rhizoctonia solani or Pythium ultimum) and biocontrol fungi (Trichoderma atroviride strain P1 or Trichoderma harzianum strain T22) were obtained. The proteome of each partner was collected separately and extracted by acetone precipitation in presence of trichloroacetic acid and a reducing agent (DTT). The extracted proteins were separated by isoelectrofocusing (IEF), using IPG (Immobilized pH gradient) strips, followed by SDS-PAGE. In order to improve resolution the separations were performed both on wide than narrow pH range and on different gel lengths. Differential spots were noted in the proteome of the three-way interaction when compared to each single component. These were further characterized by mass spectrometry and in silico analysis with the aim of identifying and cloning the relative genes. During the in vitro interaction of T. harzianum strain T22 with tomato and the culture filtrate or cell walls of pathogens, the spot number was higher than in the presence of pathogen biomass. In terms of Trichoderma differential proteins displayed on 2D gels, the most important changes were obtained in the presence of P. ultimum . During the in vivo interaction with tomato, the antagonist proteome changed much more in presence of soilborne fungi R. solani and P. ultimum than with the foliar fungus B. cinerea, both in terms of total and increased or novel spots. In silico analysis of some of those spots revealed homology with intracellular enzymes (GTPases, hydrolases) and with stress-related proteins (heat shock proteins HSP70, bacteriocin cloacin). Specific proteins in the plant proteome, i.e. pathogenesis-related proteins, have been identified during the in vivo interaction of bean with R. solani and T. atroviride strain P1. This is in agreement with the demonstrated ability of these beneficial fungi to induce plant systemic disease resistance by activating expression of defence-related genes. Proteins extracted from T. atrovride strain P1 which were analysed by mass spectrometry, revealed some interesting homologies with a fungal hydrophobin of Pleurotus ostreatus and an ABC transporter of Ralstonia metallidurans. These could represent molecular factors involved in the antagonistic mechanisms of Trichoderma and play a role in the three-way interaction with the plant and other microbes.展开更多
文摘Trichoderma harzianum strain T22 parasitizes and controls many phytopatogenic fungi and is applied commercially as biological control agent. The production of hydrolitic enzymes appears to be a key factor in the parasitic process. We tested the endo-esochitinolitic and glucanolitic activities of culture filtrates of T22 grown under carbon and nitrogen starvation or in presence of biomass or cell walls of the phytopathogenic fungi Botrytis cinerea, Rhizoctonia solani and Pythium ultimum. The highest level of enzimatic activities was found in culture where the mycoparasite interacted with a phytopathogenic fungus. Therefore we used a proteomic approach to investigate changes in the complex mixture of extracellular proteins secreted by T. harzianum strain T22 in order to identify proteins of potential biotechnology value for commercial and industrial use.Proteome technology has greatly enhanced our ability to conduct functional genomics studies. Nevertheless only a few studies have been published so far on the fungal extracellular proteome. Sample preparation remains the most critical step in analyses based on two-dimensional gel electrophoresis (2-DE), and it requires to be optimized for each specific application. In this study, our first aim was to set up the extraction protocol of the extracellular proteins secreted by T . harzianum strain T22 when it was grown in vitro .The secreted proteins were analysed by two-dimensional electrophoresis (2-DE) and substantial changes in the extracellular proteome of the mycoparasite have been observed. Comparing the 2D maps of the fungus grown in minimal medium with glycerol as carbon source (used as control condition) with those obtained in inducing conditions, a lot of novel proteins appeared. The higher number of novel and up-regulated spots was obtained in the presence of Rhizoctonia solani biomass. Other spots were specifically up-regulated by the interaction with different plant pathogens. Differentially expressed proteins were subjected to matrix assisted laser desorption ionisation-time of flight (MALDI-TOF) mass spectrometry (MS) and N-terminal Edman sequencing. The in silico analyses of some of the novel and up-regulated spots showed interesting homology to hypothetical and putative proteins from other fungal species. These include novel enzymes, such as glycosylhydrolases and metalloprotease, proteins with conserved domains involved in pathogen-host interactions, such as Ras that regulates signal transduction pathways or LRRs that is involved in host recognition, etc. Work is in progress to demonstrate the role of some of these proteins in biocontrol and ability to induce systemic resistance.
文摘The molecular factors involved in the three-way interaction between plant, pathogenic fungi and antagonistic/biocontrol fungi, such as Trichoderma, are still poorly understood, even if they represent a matter of interest for improving crop management and developing new strategies for plant diseases control. The aim of this work is to investigate the components involved in this interaction and, for this purpose, a proteomic approach was used. 2-D maps of the protein extracts from the single components in various interactions between plants (potato, bean, tobacco or tomato), pathogens (Botrytis cinerea, Rhizoctonia solani or Pythium ultimum) and biocontrol fungi (Trichoderma atroviride strain P1 or Trichoderma harzianum strain T22) were obtained. The proteome of each partner was collected separately and extracted by acetone precipitation in presence of trichloroacetic acid and a reducing agent (DTT). The extracted proteins were separated by isoelectrofocusing (IEF), using IPG (Immobilized pH gradient) strips, followed by SDS-PAGE. In order to improve resolution the separations were performed both on wide than narrow pH range and on different gel lengths. Differential spots were noted in the proteome of the three-way interaction when compared to each single component. These were further characterized by mass spectrometry and in silico analysis with the aim of identifying and cloning the relative genes. During the in vitro interaction of T. harzianum strain T22 with tomato and the culture filtrate or cell walls of pathogens, the spot number was higher than in the presence of pathogen biomass. In terms of Trichoderma differential proteins displayed on 2D gels, the most important changes were obtained in the presence of P. ultimum . During the in vivo interaction with tomato, the antagonist proteome changed much more in presence of soilborne fungi R. solani and P. ultimum than with the foliar fungus B. cinerea, both in terms of total and increased or novel spots. In silico analysis of some of those spots revealed homology with intracellular enzymes (GTPases, hydrolases) and with stress-related proteins (heat shock proteins HSP70, bacteriocin cloacin). Specific proteins in the plant proteome, i.e. pathogenesis-related proteins, have been identified during the in vivo interaction of bean with R. solani and T. atroviride strain P1. This is in agreement with the demonstrated ability of these beneficial fungi to induce plant systemic disease resistance by activating expression of defence-related genes. Proteins extracted from T. atrovride strain P1 which were analysed by mass spectrometry, revealed some interesting homologies with a fungal hydrophobin of Pleurotus ostreatus and an ABC transporter of Ralstonia metallidurans. These could represent molecular factors involved in the antagonistic mechanisms of Trichoderma and play a role in the three-way interaction with the plant and other microbes.
