Trichoderma is a fungal genus of great and demonstrable biotechnological value, but its genome is poorly surveyed compared with other model microorganisms. Due to their ubiquity and rapid substrate colonization, Trich...Trichoderma is a fungal genus of great and demonstrable biotechnological value, but its genome is poorly surveyed compared with other model microorganisms. Due to their ubiquity and rapid substrate colonization, Trichoderma species have been widely used as biocontrol organisms for agriculture, and their enzyme systems are widely used in industry. Therefore, there is a clear interest to explore beyond the phenotype to exploit the underlying genetic systems using functional genomics tools. The great diversity of species within the Trichoderma genus, the absence of optimized systems for its exploration, and the great variety of genes expressed under a wide range of ambient conditions are the main challenges to consider when starting a comprehensive functional genomics study. An initial project started by three Spanish groups has been extended into the project TRICHOEST, funded by the EU (FP5, QLRT-2001-02032) to target the transcriptome analysis of selected Trichoderma strains with biocontrol potential, in conditions related to antagonism, nutrient stress and plant interactions. Once specific conditions were defined, cDNA libraries were produced and used for EST sequencing. Nine strains from seven Trichoderma species have been considered in this study and an important amount of gene sequence data has been generated, analyzed and used to compare the gene expression in different strains. In parallel to sequencing, genomic expression studies were carried out by means of macro-arrays to identify genes expressed in specific conditions. In silico analysis of DNA sequencing data together with macro-array expression results have lead to a selection based on the potential use of the gene sequences. The selected clone sequences were completed and cloned in appropriate vectors to initiate functional analysis by means of expression studies in homologous and heterologous systems.展开更多
The choice of active Trichoderma strains is important in designing effective and safe biocontrol applications. Many species of Trichoderma have multiple strategies for fungal antagonism and indirect effects on plant h...The choice of active Trichoderma strains is important in designing effective and safe biocontrol applications. Many species of Trichoderma have multiple strategies for fungal antagonism and indirect effects on plant health, such as growth promotion, systemic resistance induction and fertility improvements. Some strains are powerful antibiotic producers, and their suitability for use in biocontrol systems must be carefully assessed. However, many other active strains have no antibiotic capacity, and these are likely to be more useful in food production systems since they have not adverse effects on important groups of beneficial soil organisms. We have assessed the performance of selected naturally occurring Trichoderma strains (singly and in combination) and developed TUSAL, a mixture of Trichoderma harzianum and T. viride that has demonstrated to be effective against major pathogens in sugar beet and horticulture. TUSAL, has been bulked up and tested under field conditions, showing positive effects on precocity and root development, and increasing the crop production in field trials carried out in different pathosystems. The environmental impact of TUSAL strains on beneficial organisms in the environment were assessed before release, and molecular detection methods were developed to monitor the presence and performance of strains in the field. In addition, Trichoderma protein extracts with high glucanase and chitinase activities, have also been obtained from wild type strains and their effectiveness as biofungicides was tested in laboratory and field conditions, defining the concentration of protein necessary to produce fungicide effects. The genes coding for protein production were introduced into suitable organisms for large-scale production in the laboratory, never released to the environment. The effect of these novel biofungicide proteins was studied separately and synergistically with Trichoderma conidia, and with minimal doses of chemical fungicides. Suitable active Trichoderma strains are being registered in the EU by the company NBT. Both Trichoderma strains and proteins are included in formulations patented as biocontrol agents.展开更多
Species of the fungus Trichoderma, a genus of Hyphomycetes, are ubiquitous in the environment, but especially in soil. They have been used in a wide range of commercial applications including the production of hydrola...Species of the fungus Trichoderma, a genus of Hyphomycetes, are ubiquitous in the environment, but especially in soil. They have been used in a wide range of commercial applications including the production of hydrolases and in the biological control of plant diseases. A fundamental part of the Trichoderma antifungal system consists of a series of genes coding for a surprising variety of extracellular cell wall degrading enzymes (CWDE). Characterisation and identification of strains at the species level is the first step in utilizing the full potential of fungi in specific applications. One aim when isolating Trichoderma strains is to identify those which can be used in new agricultural and industrial applications. In the past it was not uncommon that biocontrol strains were defined as T. harzianum Rifai, due to the limited classification system of the genus Trichoderma. In recent years, several PCR-based molecular techniques have been used to detect and discriminate among microorganisms. Sequence analysis of the ITS regions of the ribosomal DNA and gene fragments as those corresponding to tef1 gene have been helpful in the neotypification, description and characterization of species in the genus Trichoderma. Another useful method for the identification of Trichoderma strains is the randomly amplified polymorphic DNA (RAPD) technique. Isozyme polymorphisms evaluation of five putative extracellular lytic enzymes loci (β-1,3-glucanase, β-1,6-glucanase, cellulase, chitinase and protease antivities) were carried out using representative strains of defined molecular groups. CWDE groupings obtained from biocontrol strains are discussed in relation to their phylogenetic location and antifungal activities. Compiling morphological, biochemical and sequence information data into a common database would provide a useful resource that could be used to accurately name new haplotypes identified in the future and correctly place them within the genus Trichoderma.展开更多
文摘Trichoderma is a fungal genus of great and demonstrable biotechnological value, but its genome is poorly surveyed compared with other model microorganisms. Due to their ubiquity and rapid substrate colonization, Trichoderma species have been widely used as biocontrol organisms for agriculture, and their enzyme systems are widely used in industry. Therefore, there is a clear interest to explore beyond the phenotype to exploit the underlying genetic systems using functional genomics tools. The great diversity of species within the Trichoderma genus, the absence of optimized systems for its exploration, and the great variety of genes expressed under a wide range of ambient conditions are the main challenges to consider when starting a comprehensive functional genomics study. An initial project started by three Spanish groups has been extended into the project TRICHOEST, funded by the EU (FP5, QLRT-2001-02032) to target the transcriptome analysis of selected Trichoderma strains with biocontrol potential, in conditions related to antagonism, nutrient stress and plant interactions. Once specific conditions were defined, cDNA libraries were produced and used for EST sequencing. Nine strains from seven Trichoderma species have been considered in this study and an important amount of gene sequence data has been generated, analyzed and used to compare the gene expression in different strains. In parallel to sequencing, genomic expression studies were carried out by means of macro-arrays to identify genes expressed in specific conditions. In silico analysis of DNA sequencing data together with macro-array expression results have lead to a selection based on the potential use of the gene sequences. The selected clone sequences were completed and cloned in appropriate vectors to initiate functional analysis by means of expression studies in homologous and heterologous systems.
文摘The choice of active Trichoderma strains is important in designing effective and safe biocontrol applications. Many species of Trichoderma have multiple strategies for fungal antagonism and indirect effects on plant health, such as growth promotion, systemic resistance induction and fertility improvements. Some strains are powerful antibiotic producers, and their suitability for use in biocontrol systems must be carefully assessed. However, many other active strains have no antibiotic capacity, and these are likely to be more useful in food production systems since they have not adverse effects on important groups of beneficial soil organisms. We have assessed the performance of selected naturally occurring Trichoderma strains (singly and in combination) and developed TUSAL, a mixture of Trichoderma harzianum and T. viride that has demonstrated to be effective against major pathogens in sugar beet and horticulture. TUSAL, has been bulked up and tested under field conditions, showing positive effects on precocity and root development, and increasing the crop production in field trials carried out in different pathosystems. The environmental impact of TUSAL strains on beneficial organisms in the environment were assessed before release, and molecular detection methods were developed to monitor the presence and performance of strains in the field. In addition, Trichoderma protein extracts with high glucanase and chitinase activities, have also been obtained from wild type strains and their effectiveness as biofungicides was tested in laboratory and field conditions, defining the concentration of protein necessary to produce fungicide effects. The genes coding for protein production were introduced into suitable organisms for large-scale production in the laboratory, never released to the environment. The effect of these novel biofungicide proteins was studied separately and synergistically with Trichoderma conidia, and with minimal doses of chemical fungicides. Suitable active Trichoderma strains are being registered in the EU by the company NBT. Both Trichoderma strains and proteins are included in formulations patented as biocontrol agents.
文摘Species of the fungus Trichoderma, a genus of Hyphomycetes, are ubiquitous in the environment, but especially in soil. They have been used in a wide range of commercial applications including the production of hydrolases and in the biological control of plant diseases. A fundamental part of the Trichoderma antifungal system consists of a series of genes coding for a surprising variety of extracellular cell wall degrading enzymes (CWDE). Characterisation and identification of strains at the species level is the first step in utilizing the full potential of fungi in specific applications. One aim when isolating Trichoderma strains is to identify those which can be used in new agricultural and industrial applications. In the past it was not uncommon that biocontrol strains were defined as T. harzianum Rifai, due to the limited classification system of the genus Trichoderma. In recent years, several PCR-based molecular techniques have been used to detect and discriminate among microorganisms. Sequence analysis of the ITS regions of the ribosomal DNA and gene fragments as those corresponding to tef1 gene have been helpful in the neotypification, description and characterization of species in the genus Trichoderma. Another useful method for the identification of Trichoderma strains is the randomly amplified polymorphic DNA (RAPD) technique. Isozyme polymorphisms evaluation of five putative extracellular lytic enzymes loci (β-1,3-glucanase, β-1,6-glucanase, cellulase, chitinase and protease antivities) were carried out using representative strains of defined molecular groups. CWDE groupings obtained from biocontrol strains are discussed in relation to their phylogenetic location and antifungal activities. Compiling morphological, biochemical and sequence information data into a common database would provide a useful resource that could be used to accurately name new haplotypes identified in the future and correctly place them within the genus Trichoderma.
