Progress 01/10/03 to 06/11/07
Outputs
Progress Report Objectives (from AD-416) 1. Develop a phylogeny for Hypocrea, Trichoderma and related fungi with emphasis on two cryptic species-complexes, Trichoderma viride, the type species, and T. hamatum, the most commonly isolated group. 2. Develop a characterization and identification scheme for Hypocrea, Trichoderma and related groups used in the biological control of plant pathogenic fungi on specific commodities. Approach (from AD-416) Fresh specimens of Hypocrea and Trichoderma will be collected by the SY from around the world especially the sexual state from which ascospore isolates produce the Trichoderma state in culture. The morphology of both sexual and asexual states will be characterized using an image analysis system. All descriptive and potentially diagnostic structures are measured. Molecular sequences are obtained for each isolate. Phylogenetic analyses will use the ITS of rDNA as well as protein coding genes such as introns of the translation-elongation factor 1-alpha, RBP2, calmodulin and actin. Species concepts will be defined using both molecular and morphological data. A taxonomy will be developed and published as a taxonomic monograph. Isolates sent for identification will be studied using methods similar to those applied to isolates studied for the monographic accounts. New species not included in monographic studies will be described and illustrated in order to facilitate their use and development as biological control agents. An on- line, interactive identification system will be developed. For each species numerous graphics will be added to illustrate all morphological and cultural characteristics. Accomplishments Fungi used to control plant diseases: one group of Trichoderma described Fungi live in or on plants. Some fungi can be destructive causing diseases of plants while others are useful because they help plants fight the organisms that cause diseases. Fungi called Trichoderma are especially good at controlling plant diseases. In order to use fungi to control diseases, it is necessary to determine exactly which kinds or species of Trichoderma are most effective. Distinguishing between species of Trichoderma is complicated because these fungi are very small and do not have a lot of different shapes and colors. Information about their genome was used to precisely define species of Trichoderma. Within one group of Trichoderma, thirteen different species were defined. A description and illustrations of each species was presented along with a key to help scientists identify each species. Detailed analyses of how each fungus looks and grows as well as its geographic distribution are used to distinguish species. These species vary in biological characteristics such as whether they exist in the living leaves or trunks of plants and their ability to control diseases. Based on the genomic data, a unique molecular sequence or DNA barcode was determined for each species so that other scientists can easily identify them. This research will be used by plant pathologists who are working to control diseases without harmful chemicals. This research contributes to National Program 303: Research Component 4. Fungi used to control plant diseases: type species of Trichoderma defined Fungi in the genus Trichoderma are effective in the biological control of a number of plant diseases including those that attack cacao trees in South America and Africa. The use of these fungi to control diseases is hindered by lack of knowledge about how they look, how to find them, and how to tell them apart. The one species that serves as the standard point for defining all other closely related species in the genus Trichoderma was precisely defined. In addition three new species of Trichoderma were discovered, named, described and illustrated. Because these fungi are so small, they must be defined using characters such as the shape of their spores and how they grow as well as information about their genomes. These fungi have potential as biological control agents, thus this research will be used by plant pathologists who are working to control the diseases of cacao trees in South America and Africa. This research contributes to National Program 303: Research Component 4. Technology Transfer Number of Web Sites managed: 1 Number of Non-Peer Reviewed Presentations and Proceedings: 3 Number of Newspaper Articles,Presentations for NonScience Audiences: 2
Impacts
(N/A)
Publications
- Samuels, G.J., Dodd, S., Lu, B., Petrini, O., Schroers, H., Druzhinina, I. S., 2006. The Trichoderma Koningii Morphological Species. Studies in Mycology. 56:67-133.
- Jaklitsch, W.M., Samuels, G.J., Dodd, S.L., Lu, B., Druzhinina, I.S. 2006. Hypocrea Rufa/Trichoderma Viride: A reassessment, and description of three closely related species with and without Warted Conidia. Studies in Mycology. 56:135-177.
- Sanchez, V., Rebellodo, O., Piscaso, R.M., Cardenas, E., Cordova, J., Gonzalez, O., Samuels, G.J. 2007. In Vitro Antagonism of Tielaviopsis Paradoxa by Trichoderma Longibrachiatum. Mycopathologia. 163:49-58.
- Sharon, E., Chet, I., Viterbo, A., Bar-Eyal, M., Nagan, H., Samuels, G.J., Spiegel, Y. 2007. Parasitism of Trichoderma on Meloidogyne Javanica and role of the Gelatinous Matrix. European Journal of Plant Pathology. 118:247-258.
- Gams, W., Samuels, G.J., Schroers, H.J. 2007. Did Mussat make new combinations in Sylloge Fungorum XV, 1901? Mycotaxon. 100:221-225.
- Bailey, B.A., Bae, H., Strem, M.D., Roberts, D.P., Thomas, S.E., Samuels, G.J., Choi, I., Holmes, K.A. 2006. Fungal and plant gene expression during the colonization of theobroma cacao seedlings by isolates of four trichoderma species. Planta. 224(6):1449-1464.
|
Progress 10/01/05 to 09/30/06
Outputs
Progress Report 1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? Economic loss to agricultural crops due to disease-causing fungi is estimated at $20 billion annually. Such crop loss can be reduced using environmentally friendly means known as biological controls. These biocontrol measures are urgently needed to decrease the use of chemical pesticides in farming. The fungi used most effectively in biological control are in the Hypocrea-Trichoderma group, however, their use in biological control is hindered by lack of knowledge about their classification and characterization. Beneficial fungi can be accurately defined using microscopic and molecular techniques to determine which strains are most useful as effective biological control agents. Accurate systematic knowledge of the characteristics of species of Hypocrea- Trichoderma is essential to plant
pathologists who are developing these biological control agents. Based on this research, effective non- chemical agents will be discovered, developed, and safely applied to control fungal diseases of crops. The project has two specific objectives: 1) to develop a phylogeny for Hypocrea, Trichoderma and related fungi with emphasis on two cryptic species-complexes, namely Trichoderma viride, the type species, and T. hamatum, the most commonly isolated group; and 2) to develop a characterization and identification scheme for Hypocrea, Trichoderma and related groups used in the biological control of plant pathogenic fungi on certain crops. The research to be undertaken falls under National Program 303 Plant Diseases and addresses goals in the component 2 Biocontrol. This research allows scientists to locate, accurately identify, and rapidly characterize fungi useful in controlling plant pathogens. The results provide the knowledge base to discover and develop fungi as effective
biological control agents for environmentally friendly disease control. 2. List by year the currently approved milestones (indicators of research progress) Year 1 (FY 2003) Obtain cultures/specimens of T. viride-H. rufa group. Begin morphological and molecular characterization. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Initiate on-line interactive identification system with previously described species. Year 2 (FY 2004) Circumscribe type and related species in T. viride-H. rufa group. Complete phylogenetic overview including analyses of molecular sequence data. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line identification system. Year 3 (FY 2005) Write descriptions; organize illustrations. Publish monograph of T. viride-H. rufa group. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents.
Add 10-20 additional species to on-line identification system. Year 4 (FY 2006) Obtain cultures/specimens of T. hamatum complex. Begin morphological and molecular characterization. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line identification system. Complete publication of species in the Trichoderma viride-Hypocrea rufa complex. Year 5 (FY 2007) Circumscribe species in T. hamatum group. Complete phylogenetic overview including analyses of molecular sequence data. Publish monograph of T. hamatum group. Describe new Trichoderma- Hypocrea connections. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line identification system. Complete addition of species in the Trichoderma hamatum complex. 4a List the single most significant research accomplishment during FY 2006. New species of Trichoderma useful in
biocontrol of cacao diseases Fungi in the genus Trichoderma are effective in the biological control of fungi that cause plant diseases. They have been especially useful in controlling the two most important diseases of the chocolate tree (cacao) in South America. In this research a survey was made of isolates of Trichoderma in Ecuador and Peru that occur in the living trunks of cacao trees. Two new species of Trichoderma was discovered and are named, described and illustrated. These fungi were tested for their effectiveness in controlling the diseases of the chocolate tree and were found to demonstrate an antibiotic effect against the fungus that causes one of the serious diseases of the chocolate tree. This research will be used by plant pathologists who are working to control the diseases of the chocolate tree in South America. National Program 303 Plant Diseases, Component 2 Biocontrol. 4b List other significant research accomplishment(s), if any. Identification manual for
bright-colored microfungi in the southeastern United States Fungi are a diverse group of organisms some of which cause diseases of plants. Within the fungi the Hypocreales are generally small, less than a pinhead in diameter, and thus not well-known, yet they attack many different kinds of crops and forest trees. This book is an identification manual for about 100 species of fungi in the Hypocreales that have been found in or near the Great Smoky Mts. National Park in the southeastern United States. It includes photographs of these fungi showing both the external and internal features that are needed to identify them. In addition there are short descriptions and information about the geographic distribution, host range, and references for each species. Although directed at those species that occur in the southeastern United States, many of these fungi have a much wider geographic distribution. This book will be used by agronomists, plant pathologists, foresters, ecologists, and
other scientists to identify these fungi when they are encountered in the southeastern United States and elsewhere. National Program 303 Plant Diseases, Component 2 Biocontrol. 5. Describe the major accomplishments to date and their predicted or actual impact. Monograph of green-spores Hypocrea and Trichoderma biocontrol fungi Fungi in the genus Hypocrea-Trichoderma are effective at controlling some diseases without chemicals, yet their identification is difficult. A monograph of 30 species of green-spored Hypocrea and their Trichoderma asexual states was completed and published. This group includes many species of Trichoderma that are used in biological control. Species descriptions are based on morphological characteristics with connections made between the Hypocrea sexual state and the Trichoderma asexual state. In addition, phylogenetic analyses of two genes for each species are included. Descriptions, illustrations and keys allow plant pathologists can identify the isolates
that they are testing for use in the biological control of plant pathogens. National Program 303 Plant Diseases, Component 2 Biocontrol. On-line identification of biocontrol fungi Fungi in the genus Hypocrea-Trichoderma are effective at controlling some diseases without chemicals, yet their identification is difficult. An on-line identification system for 38 species of Hypocrea and Trichoderma is available at http://nt.ars-grin.gov. It is anticipated that this on-line monograph will be expanded to about 60-70, possibly up to 100 species of Trichoderma. This system includes numerous illustrations and descriptions of species both in culture as well as in nature. Providing an on-line relatively easy means for the identification and access to data about these biocontrol fungi is essential for users. This system allows plant pathologists who are not familiar with these difficult fungal species to make their own identifications and facilitates the development of new biological control
agents of plant pathogens. National Program 303 Plant Diseases, Component 2 Biocontrol. Monograph of stalked Hypocrea-Trichoderma Fungi in the genus Hypocrea-Trichoderma are effective at controlling some diseases without chemicals, yet many species have not been well- described and characterized. A monograph of 17 species of stalked Hypocrea and their Trichoderma states was completed and published. This group includes many species of temperate fungi that are associated with wood decomposition and soil microbiology. Considerable confusion existed about the two most common species that had been considered synonyms. Species descriptions based on morphological characteristics with illustrations and a key for identification were published with connections made between the Hypocrea sexual state and the Trichoderma asexual state, where known. This research will allow plant scientists to identify species of stalked Hypocrea when they are encountered as potential biocontrol agents and
biodiversity surveys. National Program 303 Plant Diseases, Component 2 Biocontrol. New species of Trichoderma discovered with biocontrol potential Fungi in the genus Hypocrea-Trichoderma are effective at controlling some diseases without chemicals, yet their identification is difficult. A new species of Hypocrea with a Trichoderma asexual state was discovered in Costa Rica. This species was provided with a scientific name along with a description and illustrations of both states and compared with similar species of Hypocrea and Trichoderma based on molecular sequences. A key was provided to all species of Trichoderma having yellow conidia. Based on this research it is possible to accurately identify species of Hypocrea that have Trichoderma with yellow conidia. This research will be used by plant pathologists who are working to develop effective biological ways to control of plant diseases. National Program 303 Plant Diseases, Component 2 Biocontrol. 6. What science and/or
technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? A workshop on the biocontrol fungus Trichoderma was conducted in Cameroon for plant pathologists working to use this fungus in biological control especially of diseases of the chocolate plant. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Dr. Samuels gave a workshop presentation on Trichoderma as a biological control agent for witches broom to plant pathologists in Cameroon in June, 2006. Dr. Samuels research on cacao biocontrol agents was discussed in a Wall Street Journal article entitled In fight to protect cocoa crops, good fungi battle bad fungi on June 26, 2006. Dr. Samuels
research and photographs reproduced in Garten praxis article entitled Wachstumsforderung durch antagonistische Pilze, Sept 2005.
Impacts
(N/A)
Publications
- Samuels, G.J. 2005. Changes in taxonomy, occurrence of the sexual stage and ecology of trichoderma spp. Phytopathology. 96:195-206
- Samuels, G.J., Rossman, A.Y., Chaverri, P., Overton, B., Poldmaa, K. 2006. Hypocreales of the South-eastern United States: An Identification Guide. Utrecht: Centraalbureau voor Schimmel cultures. 145 p.
- Samuels, G.J., Suarez, C., Solis, K., Holmes, K.A., Thomas, S.E., Ismaiel, A.A., Evans, H.C. 2006. Trichoderma theobromicola and t. paucisporum: two new species from south america. Mycological Research 110:381-392.
- Samuels, G.J., Thomas, S.E., Evans, H.C. 2006. Trichoderma endophytes of sapwood (Abstract). Inoculum 57(4):34.
- Holmes, K.A., Krauss, U., Samuels, G.J. 2006. Trichoderma ovalisporum, a novel biocontrol agent of frosty pod rot (moniliophthora roreri) of cocoa (theobroma cacao): from discovery to field. Proceedings of the 1st International Conference on Plant Microbe Interactions: Endophytes and Biocontrol Agents. Saariselka, Lapland, Finland 18-22nd April 2005. Eds Sorvari S and Toldi O. PP. 54-65.
|
Progress 10/01/04 to 09/30/05
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Economic loss to agricultural crops due to disease-causing fungi is estimated at $20 billion annually. Such crop loss can be reduced using environmentally friendly means known as biological controls. These biocontrol measures are urgently needed to decrease the use of chemical pesticides in farming. The fungi used most effectively in biological control are in the Hypocrea-Trichoderma group, however, their use in biological control is hindered by lack of knowledge about their classification and characterization. Beneficial fungi can be accurately defined using microscopic and molecular techniques to determine which strains are most useful as effective biological control agents. Accurate systematic knowledge of the characteristics of species of Hypocrea- Trichoderma is essential to plant pathologists who
are developing these biological control agents. Based on this research, effective non- chemical agents will be discovered, developed, and safely applied to control fungal diseases of crops. The project has two specific objectives: 1) to develop a phylogeny for Hypocrea, Trichoderma and related fungi with emphasis on two cryptic species-complexes, namely Trichoderma viride, the type species, and T. hamatum, the most commonly isolated group; and 2) to develop a characterization and identification scheme for Hypocrea, Trichoderma and related groups used in the biological control of plant pathogenic fungi on certain crops. The research to be undertaken falls under National Program 303 Plant Diseases and addresses goals in the Biocontrol component. This research allows scientists to locate, accurately identify, and rapidly characterize fungi useful in controlling plant pathogens. The results provide the knowledge base to discover and develop fungi as effective biological control agents
for environmentally friendly disease control. 2. List the milestones (indicators of progress) from your Project Plan. Year 1 (FY 2003) Obtain cultures/specimens of T. viride-H. rufa group. Begin morphological and molecular characterization. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Initiate on-line interactive identification system with previously described species. Year 2 (FY 2004) Circumscribe type and related species in T. viride-H. rufa group. Complete phylogenetic overview including analyses of molecular sequence data. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line identification system. Year 3 (FY 2005) Write descriptions; organize illustrations. Publish monograph of T. viride-H. rufa group. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line
identification system. Year 4 (FY 2006) Obtain cultures/specimens of T. hamatum complex. Begin morphological and molecular characterization. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line identification system. Complete publication of species in the Trichoderma viride-Hypocrea rufa complex. Year 5 (FY 2007) Circumscribe species in T. hamatum group. Complete phylogenetic overview including analyses of molecular sequence data. Publish monograph of T. hamatum group. Describe new Trichoderma- Hypocrea connections. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line identification system. Complete addition of species in the Trichoderma hamatum complex. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If
not met, why. 1. Write descriptions; organize illustrations. Publish monograph of T. viride-H. rufa group. Milestone Substantially Met 2. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Milestone Fully Met 3. Add 10-20 additional species to on-line identification system. Milestone Fully Met 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? Year 4 (FY 2006) Complete and publish a monograph of species in the Trichoderma viride- Hypocrea rufa complex, most likely as a Studies in Mycology. This work will be used by plant pathologists and agronomists who are working to develop these fungi as agents to control the damage caused by plant pathogens. Cultures and specimens of the T. hamatum complex will be obtained. This will involve collecting the Hypocrea sexual state from under-collected regions of
the world. From fresh specimens, single ascospores will be grown to produce the Trichoderma state. Isolates will be examined for both morphological and molecular characteristics. Numerous isolates of Trichoderma are sent for identification throughout the year by plant pathologists working to develop biological control agents. These isolates are identified using both morphological and molecular characteristics. They are also included in the monographic accounts of species-complexes in Hypocrea-Trichoderma. Once a group of species of Trichoderma has been well defined and named, these taxa are added to the on-line identification system available at http://nt.ars-grin.gov. This allows users to accurately identify their isolates of Trichoderma. Year 5 (FY 2007) A monograph of all species in the Trichoderma hamatum complex will be published including both the Trichoderma and Hypocrea sexual states. It is anticipated that many new connections between species of Trichoderma and their
Hypocrea states will be discovered. Species in T. hamatum group will be defined using both morphological and molecular characteristics. A phylogenetic overview including analyses of molecular sequence data will be completed using two or more genes. Numerous isolates of Trichoderma are sent for identification each year by plant pathologists working to develop biological control agents. These are identified using both morphological and molecular characteristics. Year 6 (FY 2008) A monograph of all species in the Trichoderma koningii complex will be published including both the Trichoderma and Hypocrea sexual states. It is anticipated that many new connections between species of Trichoderma and their Hypocrea states will be discovered. Species in T. koningii complex will be defined using both morphological and molecular characteristics. A phylogenetic overview including analyses of molecular sequence data will be completed using two or more genes. Numerous isolates of Trichoderma are
sent for identification each year by plant pathologists working to develop biological control agents. These are identified using both morphological and molecular characteristics. 4a What was the single most significant accomplishment this past year? Monograph for identification of a group of Hypocrea-Trichoderma A monograph of 17 species of stalked Hypocrea and their Trichoderma states was completed and published. This group includes many species of temperate fungi that are associated with wood decomposition and soil microbiology. Considerable confusion existed about the two most common species that had been considered synonyms. Species descriptions based on morphological characteristics with illustrations and a key for identification were published with connections made between the Hypocrea sexual state and the Trichoderma asexual state, where known. This research will allow plant scientists to identify species of stipitate Hypocrea when they are encountered as potential
biocontrol agents and biodiversity surveys. 4b List other significant accomplishments, if any. A new species of Hypocrea with a Trichoderma asexual state was discovered in Costa Rica. This species was provided with a scientific name along with a description and illustrations of both states and compared with similar species of Hypocrea and Trichoderma based on molecular sequences. A key was provided to all species of Trichoderma having yellow conidia. Based on this research it is possible to accurately identify species of Hypocrea that have Trichoderma with yellow conidia. This research will be used by plant pathologists who are working to develop effective biological ways to control of plant diseases. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. A monograph of 30 species of green-spored Hypocrea and their Trichoderma asexual states was completed and published. This group includes many species of Trichoderma that are
used in biological control. Species descriptions are based on morphological characteristics with connections made between the Hypocrea sexual state and the Trichoderma asexual state. In addition, phylogenetic analyses of two genes for each species are included. Descriptions, illustrations and keys allow plant pathologists can identify the isolates that they are testing for use in the biological control of plant pathogens. An on-line identification system for 38 species of Hypocrea and Trichoderma is available at http://nt.ars-grin.gov. It is anticipated that this on-line monograph will be expanded to about 60-70, possibly up to 100 species of Trichoderma. This system includes numerous illustrations and descriptions of species both in culture as well as in nature. Providing an on-line relatively easy means for the identification and access to data about these biocontrol fungi is essential for users. This system allows plant pathologists who are not familiar with these difficult
fungal species to make their own identifications and facilitates the development of new biological control agents of plant pathogens. A monograph of the type species of Trichoderma viride and its sexual state, Hypocrea rufa, will be completed. These scientific names of T. viride have been misapplied. Accurate species descriptions will be based on morphological characteristics and newly discovered connections between the Hypocrea sexual state and the Trichoderma asexual state. In addition, phylogenetic analyses based on two or more genes will be included of all species. Descriptions, illustrations and keys are included so that plant pathologists can identify the isolates that they are testing for use in the biological control of plant pathogens. A monograph of species in the Trichoderma hamatum complex with its Hypocrea sexual states will be completed and published. Species descriptions will be based on morphological characteristics with connections made between the Hypocrea sexual
state and the Trichoderma asexual state. In addition, phylogenetic analyses of at least two genes for each species will be included. Descriptions, illustrations and keys will be included so that plant pathologists can identify the isolates that they are testing for use in the biological control of plant pathogens. Endophytic isolates of Trichoderma from woody tissue of cacao trees will be identified and new species described as they are encountered. Exploring this new niche for biological control organisms reveals the life history of these fungi that will contribute to their use in biological control. It is suggested that their presence induces resistance to disease-causing fungi. This research will result in effective biological control of diseases of the chocolate plant. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the
constraints, if known, to the adoption and durability of the technology products? A workshop on the biocontrol fungus Trichoderma was conducted in Cameroon for plant pathologists working to use this fungus in biological control especially of diseases of the chocolate plant. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Dr. Aime gave a presentation in Costa Rica on the systematics of the fungi that cause the two most serious diseases of the chocolate plant, namely frosty pod and witches' broom in February, 2005. Dr. Samuels gave a presentation on Trichoderma as a biological control agent for witches' broom to plant pathologists in Cameroon in June, 2005.
Impacts
(N/A)
Publications
- Chaverri, P., Samuels, G.J., Hodge, K.T. 2005. The genus Podocrella and its nematode-killing anamorph Harposporium. Mycologia. 97(2):433-443.
- Samuels, G.J. 2004. Changes in taxonomy, occurrence of the sexual stage and ecology of Trichoderma spp. Phytopathology 94 (6-Suppl.): S 138
- Bailey, B.A., Bae, H., Strem, M.D., Samuels, G.J., Evans, H.C., Thomas, S. E., Holmes, K.A. 2005. Molecular responses resulting from the endophytic association between Trichoderma species and cocoa (Theobroma cacao). American Phytopathological Society Annual Meeting. Phytopathology 95:S5
- De Souza, J.T., Bowers, J.H., Samuels, G.J., Hebbsr, P.K., Pomella, A. 2003 Genetic diversity and activity of Trichoderma stromaticum, a myco- parasite of the cocoa witches' broom pathogen. Phytopathology. 93:S20
- Chamberlain, H.L., Rossman, A.Y., Stewart, E.L., Ulvinen, T., and Samuels, G.J. 2004. The stipitate species of Hypocrea (Hypocreales, Hypocreaceae) including Podostroma. Karstenia. 44:1-24.
- Druzhinina, I, P. Chaverri, P. Fallah, C. Kubicek, G.J. Samuels. 2004. Hypocrea flavoconidia, a new species from Costa Rica with yellow conidia. Studies in Mycology 50: 401-407.
- Holmes, K.A., H.-J. Schroers, S.E. Thomas, H.C. Evans & Samuels, G.J. 2004. Taxonomy and biocontrol potential of a new species of Trichoderma from the Amazon. Mycological Progress 3: 199-210
|
Progress 10/01/03 to 09/30/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Crop loss due to disease-causing fungi can be reduced using environmentally friendly means known as biological controls. Such control measures are urgently needed to decrease the use of chemical pesticides in farming. Microfungi in the Hypocrea-Trichoderma group, are effective for biological control of crop pathogens. However, their use in biological control is hindered by lack of knowledge about their classification and characterization. These fungi are a confused complex of species that are difficult to identify. Beneficial fungi can be accurately defined using microscopic, biochemical, and molecular techniques to determine which strains are most useful as effective biological control agents. Populations of related species are differentiated based on their microscopic and genetic characters. Based
on this research, effective non-chemical agents will be discovered, developed, and safely applied to control fungal diseases of crops. The project has two specific goals: 1) to develop a phylogeny for Hypocrea, Trichoderma and related fungi with emphasis on two cryptic species-complexes, namely Trichoderma viride, the type species, and T. hamatum, the most commonly isolated group; and 2) to develop a characterization and identification scheme for Hypocrea, Trichoderma and related groups used in the biological control of plant pathogenic fungi on certain crops. The research to be undertaken falls under National Program 303 Plant Diseases and addresses goals in the Biocontrol component. This research allows scientists to locate, accurately identify, and rapidly characterize fungi useful in controlling plant pathogens. The results provide the knowledge base to discover and develop fungi as effective biological control agents for environmentally friendly disease control. Economic loss
to agricultural crops due to disease-causing fungi is estimated at $20 billion annually. Excess input of chemicals in agricultural systems and the use of methyl bromide to control plant diseases threaten environmental quality in the U.S. Many of these chemicals will not be available in the coming years. It is crucial to farmers that alternative means for controlling fungal diseases be developed. Organisms that parasitize and/or control plant pathogens are called biological control agents. The most commonly used fungi used in biological control are microfungi such as Hypocrea-Trichoderma. Accurate systematic knowledge of the characteristics of species of Hypocrea- Trichoderma is essential to plant pathologists who are developing these biological control agents. 2. List the milestones (indicators of progress) from your Project Plan. Year 1 (FY 2003) Obtain cultures/specimens of T. viride-H. rufa group. Begin morphological and molecular characterization. Provide identifications for
plant pathologists working to develop Trichoderma as biocontrol agents. Initiate on-line interactive identification system with previously described species. Year 2 (FY 2004) Circumscribe type and related species in T. viride-H. rufa group. Complete phylogenetic overview including analyses of molecular sequence data. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line identification system. Year 3 (FY 2005) Write descriptions; organize illustrations. Publish monograph of T. viride-H. rufa group. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line identification system. Year 4 (FY 2006) Obtain cultures/specimens of T. hamatum complex. Begin morphological and molecular characterization. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species
to on-line identification system. Complete publication of species in the Trichoderma viride-Hypocrea rufa complex. Year 5 (FY 2007) Circumscribe species in T. hamatum group. Complete phylogenetic overview including analyses of molecular sequence data. Publish monograph of T. hamatum group. Describe new Trichoderma- Hypocrea connections. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line identification system. Complete addition of species in the Trichoderma hamatum complex. 3. Milestones: A. The three milestones listed below were scheduled to be completed in Year 2. All milestones were completed. Circumscribe type and related species in T. viride-H. rufa group. Complete phylogenetic overview including analyses of molecular sequence data. Provide identifications for plant pathologists working to develop Trichoderma as biocontrol agents. Add 10-20 additional species to on-line identification
system. B. The Year 3, 4 and 5 milestones are listed below with a description of the anticipated outcomes. Year 3 (FY 2005) Molecular work to define species on the Trichoderma viride-Hypocrea rufa complex will be completed. Numerous isolates will be examined to determined if there are phenotypic characteristics that correlate with groups based on sequence data. In addition, cultural characters including growth optima will be determined. These definitions of species will be communicated to the user community through the on-line identification system and workbooks to be used at workshops. In that way plant pathologists will learn to identify of isolates of Trichoderma used in biological control of plant pathogens. List the milestone Numerous isolates of Trichoderma are sent for identification throughout the year by plant pathologists working to develop biological control agents. These isolates are identified using both morphological and molecular characteristics. They are also
included in the monographic accounts of species-complexes in Hypocrea-Trichoderma. Once a group of species of Trichoderma has been well defined and named, these taxa are added to the on-line identification system available at http://nt.ars-grin.gov. This allows users to accurately identify their isolates of Trichoderma. Year 4 (FY 2006) Publication of a monograph of species in the Trichoderma viride-Hypocrea rufa complex will be completed, most likely as a Studies in Mycology. This work will be used by plant pathologists and agronomists who are working to develop these fungi as agents to control the damage caused by plant pathogens. Cultures and specimens of the T. hamatum complex will be obtained. This will involve collecting the Hypocrea sexual state from under-collected regions of the world. From fresh specimens, single ascospores will be grown to produce the Trichoderma state. Isolates will be examined for both morphological and molecular characteristics. Numerous isolates of
Trichoderma are sent for identification throughout the year by plant pathologists working to develop biological control agents. These isolates are identified using both morphological and molecular characteristics. They are also included in the monographic accounts of species-complexes in Hypocrea-Trichoderma. Once a group of species of Trichoderma has been well defined and named, these taxa are added to the on-line identification system available at http://nt.ars-grin.gov. This allows users to accurately identify their isolates of Trichoderma. Year 5 (FY 2007) A monograph of all species in the Trichoderma hamatum complex will be published including both the Trichoderma and Hypocrea sexual states. It is anticipated that many new connections between species of Trichoderma and their Hypocrea states will be discovered. Species in T. hamatum group will be defined using both morphological and molecular characteristics. A phylogenetic overview including analyses of molecular sequence
data will be completed using two or more genes. Numerous isolates of Trichoderma are sent for identification each year by plant pathologists working to develop biological control agents. These are identified using both morphological and molecular characteristics. 4. What were the most significant accomplishments this past year? A monograph of 30 species of green-spored Hypocrea and their Trichoderma asexual states was completed and published. This group includes many species of Trichoderma that are used in biological control. Species descriptions are based on morphological characteristics with connections made between the Hypocrea sexual state and the Trichoderma asexual state. In addition, phylogenetic analyses of two genes for each species are included. Descriptions, illustrations and keys allow plant pathologists can identify the isolates that they are testing for use in the biological control of plant pathogens. B. Other Significant Accomplishments: An isolate of Trichoderma
asperellum from Russia was identified that is being used in field trials against head blight of wheat. Based of this accurate identification, scientists have been able to locate additional isolates of T. asperellum that may have potential for controlling this important disease. Trichoderma asperellum is being evaluated to control black pod disease (Phytophthora megakarya) of the chocolate plant in Cameroon. Isolates of Trichoderma were provided to scientists working in biological control who are seeking to understand the mechanism of biological control. These Trichoderma isolates produce high quantities of laminarinase, an enzyme that breaks down beta glucans, a component of the cell wall of Phytophthora. This may explain the effectiveness of specific isolates of Trichoderma in controlling Phytophthora and provide the basis for seeking more effective biocontrol agents. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. A
monograph of 30 species of green-spored Hypocrea and their Trichoderma asexual states was completed and published. This group includes many species of Trichoderma that are used in biological control. Species descriptions are based on morphological characteristics with connections made between the Hypocrea sexual state and the Trichoderma asexual state. In addition, phylogenetic analyses of two genes for each species are included. Descriptions, illustrations and keys allow plant pathologists can identify the isolates that they are testing for use in the biological control of plant pathogens. An on-line identification system for 38 species of Hypocrea and Trichoderma is available at http://nt.ars-grin.gov. It is anticipated that this on-line monograph will be expanded to about 60-70, possibly up to 100 species of Trichoderma. This system includes numerous illustrations and descriptions of species both in culture as well as in nature. Providing an on-line relatively easy means for
the identification and access to data about these biocontrol fungi is essential for users. This system allows plant pathologists who are not familiar with these difficult fungal species to make their own identifications and facilitates the development of new biological control agents of plant pathogens. Numerous isolates of Trichoderma were identified for scientists working on the biological control of plant pathogens. An isolate of Trichoderma asperellum from Russia was identified that is being used in field trials against head blight of wheat. Isolates of T. asperellum were identified that are being evaluated to control black pod rot (Phytophthora megakarya) of the chocolate plant in Cameroon. Based of this accurate identification, the scientists has been able to locate additional isolates of T. asperellum that may have potential for controlling these important diseases. A monograph of the type species of Trichoderma viride and its sexual state, Hypocrea rufa, will be completed.
These scientific name of T. viride has been misapplied. Accurate species descriptions will be based on morphological characteristics and newly discovered connections between the Hypocrea sexual state and the Trichoderma asexual state. In addition, phylogenetic analyses based on two or more genes will be included of all species. Descriptions, illustrations and keys are included so that plant pathologists can identify the isolates that they are testing for use in the biological control of plant pathogens. A monograph of species in the Trichoderma hamatum complex with its Hypocrea sexual states will be completed and published. Species descriptions will be based on morphological characteristics with connections made between the Hypocrea sexual state and the Trichoderma asexual state. In addition, phylogenetic analyses of at least two genes for each species will be included. Descriptions, illustrations and keys will be included so that plant pathologists can identify the isolates that
they are testing for use in the biological control of plant pathogens. Endophytic isolates of Trichoderma from woody tissue of cacao trees will be identified and new species described as they are encountered. Exploring this new niche for biological control organisms reveals the life history of these fungi that will contribute to their use in biological control. It is suggested that their presence induces resistance to disease-causing fungi. This research will result in effective biological control of diseases of the chocolate plant. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? A workshop on the biocontrol fungus Trichoderma was conducted in Viet Nam for plant pathologists working to use this fungus in biological control especially of diseases of
the chocolate plant. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. Samuels. G.J. 2003. Trichoderma: a taxonomist reports. Gro-Cocoa 4: 6-8. Samuels, G.J. 2004. Trichoderma in biological control: a taxonomist reports. CABI-Biocontrol News & Information 25(1): 1-7. Dr. Samuels gave a presentation in Ecuador on the endophytic fungi discovered in the chocolate plant that may be useful in biological control of witches' broom and other diseases. Dr. Samuels gave a presentation on Trichoderma discovered as endophytes in living woody tissue and living leaves of chocolate trees in Panama and their role in protecting the plants against disease. Dr. Samuels presented an invited paper at a Symposium on Trichoderma at the American Phytopathological Society Meeting in August, 2004. This paper provides the community of plant pathologists working on Trichoderma as a biological control agents with the latest
research on the systematics of the genus Trichoderma.
Impacts
(N/A)
Publications
- Samuels, G.J., Chaverri, P. 2003 Hypocrea/trichoderma (ascomycota, hypocreales, hypocreaceae): species with green ascospores. Studies in Mycology. 48: 1-116
- Chaverri, P., Castlebury, L.A., Overton, B., Samuels, G.J. Hypocrea/trichoderma: species with conidiophore elongations and green conidia. Mycologia. Vol. 95(6)pp.1100-1140,2003.
- Lu, B., Samuels, G.J. 2003. Hypocrea stilbohypoxyli and its trichoderma koningii-like anamorph: a new species from puerto rico on stilbohypoxylon muelleri. Sydowia. Vol. 55(2) pp.255-266.
- Chaverrri, P., Samuels, G.J. Hypocrea lixii, the teleomorph of trichoderma harzianum. Mycological Progress.Vol.2(4)pp.283-286,2002.
- Chaverri, P., Candoussau, F., Samuels, G.J. Hypocrea phyllostachydis and its trichoderma anamorph, a new bambusicolous species from france. Mycological Progress, Vol. 3(1)pp.29-36, 2004.
- Lu, B., Druzhinina, I., Fallah, P., Chaverri, P., Gradinger, C., Kubicek, C., Samuels, G.J. Hypocrea/trichoderma species with pachybasium-like conidiophores: teleomorphs for t. minutisporum and t. polysporum and their newly discovered relatives. Mycologia. Vol. 96(2)pp.310-342, 2004
- Samuels, G.J. 2004. FUNGICOLOUS HYPOCREACEAE (ASCOMYCETES: HYPOCREALES) FROM KHAO YAI NATIONAL PARK, THAILAND. Sydowia. 56(1):79-130.
- Samuels, G.J., Mantiri, F.R., Brayford, D., Honda, B. 2004 Neonectia and cylindrocarpon, the 'nectria mammoidea' group and species lacking microconidia. Mycologia. 96(3:572-597.
- De Souza, J.T., Rehner, S.A., Samuels, G.J., Pomella, A.W., Hebbar, P.K. Phylogenetic analysis of trichoderma stromaticum, a mycoparasite of crinipellis perniciosa, the cause of witches' broom disease of cacao. Phytopathology.Vol.94(6)p.S25,2004.
- Samuels, G.J. Trichoderma in biological control: a taxonomist reports. Biocontrol News and Information. Vol.25(1)pp.1-7,2004.
- Samuels, G.J. Clark thomas rogerson, 1918 - 2001. Mycologia. Vol. 95(4)pp. 773-779,2003.
|
Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? Crop loss due to disease-causing fungi can be reduced using environmentally friendly means known as biological control. Such control measures are urgently needed to decrease the use of chemical pesticides in farming. Although microfungi in the Hypocrea-Trichoderma group are effective for biological control of crop pathogens, their use in biological control is hindered by lack of knowledge about their classification and characterization. Trichoderma and its sexual state Hypocrea are a confused complex of species that are difficult to identify. Moreover, the probability of finding new Trichoderma species and biotypes for use as biological control agents is high in unusual habitats and unexplored geographic areas. These beneficial fungi can be accurately defined using microscopic, biochemical, and molecular techniques to determine which strains are most useful as biological control agents.
Complexes of related species are differentiated based on microscopic and genetic characters. Using this research, potential non-chemical agents will be discovered allowing plant pathologists and other researchers to develop, characterize and safely apply them to control fungal diseases of crops. 2. How serious is the problem? Why does it matter? Economic loss to agricultural crops due to disease-causing fungi is estimated at $20 billion annually. Environmental quality in the U.S. is threatened by the excess input of chemicals in agricultural systems and the use of methyl bromide to control plant diseases. Many of these chemicals will not be available in the coming years. It is crucial to farmers that alternative means for controlling fungal diseases be developed. Organisms that control plant diseases are called biological control agents, of which the most commonly used fungi are in the Hypocrea- Trichoderma group. Accurate systematic knowledge including the discovery and
characterization of new species of Hypocrea-Trichoderma is essential to plant pathologists who are developing these biological control agents. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? As part of ARS National Program 303, Plant Diseases (100%) in the Biocontrol component, this research allows scientists to locate, accurately identify, and rapidly characterize biocontrol fungi useful in controlling plant pathogens. The results provide the knowledge base to discover and develop fungi as effective biological control agents for environmentally friendly disease control. 4. What were the most significant accomplishments this past year? Single Most Significant Accomplishment during FY 2003 year: A new species of Hypocrea was discovered that is the sexual state of Trichoderma atroviridis, a commonly used biocontrol fungus. The sexual state, Hypocrea atroviridis, was described and illustrated as a species new to science.
The connection of this new species to the asexual T. atroviridis was proven using both morphological and molecular characteristics. This work will be used by plant pathologists who are working to develop more effective biological controls agents that can be used in the control of plant diseases. B. Other Significant Accomplishments: None. C. Significant Accomplishments/Activities that Support Special Target Populations: None. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. This project was initiated on January 10, 2003. It is anticipated that this research will result in a new understanding of the systematics of the biocontrol fungus Trichoderma that will facilitate the development of new biocontrol products to manage a diverse range of plant diseases with emphasis on diseases of cacao and coffee. This project will build on the accomplishments of the previous CRIS project in isolating and identifying new species of
Trichoderma useful for biocontrol of plant diseaease from previously unsampled habitats, determining their genetic variability, and continuing to make sexual-asexual state connections for these fungi. 6. What do you expect to accomplish, year by year, over the next 3 years? FY 2004: A monograph of the Hypocrea rufa complex will be completed. This group includes species related to the type species, Trichoderma viride, and many species that are of economic importance. FY 2005: An interactive identification system for Trichoderma that reflects the current state of knowledge will be completed. Fungi discovered as endophytes of cacao will be identified and described. FY 2006: The mating system of sexually reproducing strains of Hypocrea-Trichoderma will be characterized using DNA to fingerprint the parents and their offspring. These results will demonstrate if this mating system is similar to related fungi for which mating genes have been found. 8. List your most important publications
in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). Spillman, A. Fungal detectives uncover the truth about green mold. ARS News Service. 2003. January 2.
Impacts
(N/A)
Publications
- Chaverri, P., Castlebury, L.A., Samuels, G.J., Geiser, D.M. Multilocus phylogenetic structure within the Trichoderma harzianum/Hypocrea lixii complex. Molecular Phylogenetics and Evolution. 2003. v. 27. p. 302-313.
- Dodd, S.L., Lieckfeldt, E., Samuels, G.J. Hypocrea atroviridis sp. nov., the teleomorph of Trichoderma atroviride. Mycologia. 2003. v. 95. p. 27-40.
- Nalim, F.A., Samuels, G.H., Wijesundera, R.L., Geiser, D.M. Biogeography of the Fusarium solani species complex: sampling in the southern hemisphere. Inoculum. 2003. v. 54. Abstract p. 37.
|
|