Progress 07/10/07 to 04/22/12
Outputs
Progress Report Objectives (from AD-416): Develop effective biological disease control strategies leading to sustainable yield improvements of cacao. This includes: determining the molecular mechanisms of action critical to the development of diseases caused by Moniliophthora spp. in cacao and identify potential targets for intervention, determining the mechanisms of action in the interactions between cacao, pathogens of cacao (Moniliophthora spp.), and Trichoderma isolates which result in effective disease suppression and improved plant productivity, and developing and optimizing strategies for biological control of cacao diseases caused by Moniliophthora spp. Approach (from AD-416): The interactions between biocontrol agent, Trichoderma, isolates, cacao, and pathogens of cacao will be studied in detail. Diseases targeted for control include Witches� broom (Moniliophthora perniciosa), and frosty pod (Moniliophthora roreri). Isolates of Trichoderma that aggressively colonize aerial cacao tissue (leaves, stems, flowers, flower cushions, and pods) epiphytically and/or endophytically and that possess strong biocontrol ability against one or more of the targeted pathogens will be identified. Trichoderma isolates from cacao ecosystems will be characterized for their mechanisms of biocontrol action including mycoparasitism, antibiosis and induced resistance. The impact of environment on Trichoderma colonization of aerial cacao tissues will be determined using specially adapted weather stations at 3 sites, and formulation technologies will be developed to ameliorate any negative effects. Formulation development will include established materials, techniques, and technologies along with novel approaches targeted to specific cacao tissues. Molecular techniques such as quantitative polymerase-chain reaction using RNA and DNA will be employed to optimize isolate selection and determine the impact of environment and formulation on biocontrol performance. A study of the pathogens� genomes will be initiated to facilitate future research concerning their interactions with cacao and potential biocontrol agents. Ultimately, the best available isolates of Trichoderma based on mechanism of action, and epiphytic/ endophytic abilities, will be tested in combination with optimum formulations under field conditions and their efficacies at controlling cacao diseases determined. This is the final report for Project 1275-21220-225-00D, which was replaced by new Project 1275-21220-252-00D. For additional information concerning research associated with Project 1275-21220-225-00D, see the annual report for Project 1275-21220-252-00D. A limiting factor in using microbes to reduce yield losses due to stress is our inability to identify superior isolates. Isolates of the fungus Trichoderma (Trich) were screened for their ability to colonize cacao seedlings and activities against Moniliophthora roreri (Mr) and Moniliophthora perniciosa (Mp). Trich superior in cacao colonization were identified. The establishment of significant population of Trich in the above ground portions of plants is common in cacao but considered unusual in other crops. A possible explanation for the behavior of Trich on cacao was identified; Trich internally colonizes of cacao trichomes (surface hairs). Cacao suffers from drought stress. Isolate DIS 219b promoted seedling root growth, and delayed the onset of drought stress, a result verified in the field. Environment has a huge impact on disease management practices. Initial environmental measurements were carried out in Ecuador and Brazil. Under most conditions, available moisture for Trich spores germination and growth are limiting. The microenvironment strongly influenced the biocontrol activity of Trich against witches� broom. Field studies confirmed the activities of DIS 70a and DIS 219f against frosty pod rot (FPR) in Costa Rica. Trich isolate DIS 70a application equaled or exceeded the control provided by the fungicide check. A way of improving disease management using Trich treatments is the establishment of higher populations of Trich in the field. In order to establish higher Trich populations, two formulation strategies were considered: the inclusion of a humectant plus nutrient source, and the inclusion of an invert oil emulsion. Application of invert oil emulsions required the development of new technologies. With collaborators from CABI Bioscience, a formulation mixer was developed. Two years of field tests were carried out. DIS 70a strongly suppresses FPR when applied as an invert oil emulsion. These studies provide the best evidence that use of Trich may be a viable disease management practice for farmers growing cacao. We evaluated Trich from cacao for their potential in managing Phytophthora capsici on pepper. Three Trich delayed seedling death due to P. capsici. Two Trich induced plant defense responses in pepper. These studies demonstrated the value of the cacao associated Trich in managing diseases in other crops. A student at Penn State identified an endophytic Bacillus strains from Ecuador that inhibited lesion development in cacao inoculated with P. capsici. We participated in completing the Mp genome sequence and sequenced the Mr genome. Genes potentially involved in the development of pathogenicity in Moniliophthora spp. through horizontal gene transfer were identified. The Mp and Mr mitochondrial sequences were released. Knowing the genetic makeup of these pathogens, we may be able to target plant breeding or other disease management practices towards pathogen weaknesses. Significant Activities that Support Special Target Populations: Made plant biology presentations to the 6th grade science classes of the SEED School of Maryland, Baltimore, Maryland, a school serving disadvantaged children from throughout Maryland. Made plant biology presentations to 4th and 5th grade science classes at Cherokee Lane Elementary School, Maryland, a school with a majority Hispanic and African American population. A Specific Cooperative Agreement entitled �Characterizing the transcriptome of endophytic Tricoderma isolates� with New Mexico State University was created to develop improved biocontrol methods for plants important to the Southwestern region of the U.S. in particular peppers. Additional details can be found in the annual report for project 1275- 21220-252-22S. Accomplishments 01 Characterization of the molecular interaction between Moniliophthora perniciosa and cacao during parthenocarpic fruit formation. For the fir time, the molecular interaction between Moniliophthora perniciosa and cacao was characterized during parthenocarpic fruit formation giving insight concerning fungal processes critical to disease development and identifying plant defense responses potentially important in developing disease resistance. Infection of flower cushions by M. perniciosa result in parthenocarpy (formation of seedless fruit). Microscopic observations of parthenocarpic pods confirmed that fruits lack viable seed. Septate mycelia of M. perniciosa colonized parthenocarpic pods. Parthenocarpic pods had altered carbohydrate, organic acid, and amino acid levels. M. perniciosa expressed specific sets of transcripts targeting nutrient acquisition and survival while altering cacao pod physiology resulting i parthenocarpy. Specific cacao sequences related to plant defense were induced while others were repressed. Cacao sequences involved in maintaining plant hormone levels were induced in parthenocarpic pods, suggesting that regulation of plant hormone concentrations is critical t parthenocarpic fruit formation. The M. perniciosa and cacao molecular responses characterized suggest potential targets for intervention in th disease process either by development of chemicals targeting specific fungal processes or by genetic manipulation of cacao. 02 The mitochondrial genome of Moniliophthora roreri, the fungus that cause Frosty pod Rot of Cacao. Theobroma cacao is the tropical tree that is t source of cocoa beans and butter used to make chocolate. A fungal diseas call Frosty Pod Rot has greatly reduced yields throughout Central and South America and impacted the supply of cacao to U.S. chocolate makers. The fungus Moniliophthora roreri causes this disease. ARS scientists in collaboration have characterized and compared the mitochondrial genome o Moniliophthora roreri to the closely related fungus Moniliophthora perniciosa. M. perniciosa causes another disease of cacao called Witches broom disease. While these diseases have some similar aspects such as having a long phase where both fungi grow inside of the plant without causing the plant to die, each fungus causes very different diseases. Th circular genome of M. roreri is smaller than the M. perniciosa genome however the gene order and gene similarity for both are very high. The M roreri mitochondrial genome has three linear plasmids (smaller DNA molecules that are independent of the genome) but lacks the plasmid insertion found in the M. perniciosa mitochondria. There are also fewer repetitive regions in the M. roreri mitochondrial genome, which is the main reason for the size difference between the two genomes. The characterization and comparison of these mitochondrial genomes is key to our understanding of how these fungi grow and develop since mitochondria provide energy to the fungal cells. This information is important for th development of potential new control measures since many fungicides targ fungal mitochondrial genes.
Impacts
(N/A)
Publications
- Melnick, R.L., Poleatewich, A., Backman, P., Bailey, B.A. 2012. Detection and expression of enterotoxin genes in plant-associated strains of Bacillus cereus. Letters in Applied Microbiology. 54:468-474.
- Melnick, R.L., Marelli, J., Sicher, Jr., R.C., Strem, M.D., Bailey, B.A. 2012. The interaction of Theobroma cacao and Moniliophthora perniciosa, the causal agent of witches� broom disease, during parthenocarpy. Tree Genetics and Genomes. DOI: 10.1007/s11295-012-0513-8.
- Sicher Jr, R.C., Timlin, D.J., Bailey, B.A. 2012. Responses of growth and primary metabolism of water-stressed barley roots to rehydration. Journal of Plant Physiology. 169:686-695. DOI:10.1016/J.JPLPH.2012.01.002.
- Thomazella, D.P., Teixeira, P., De Oliveira, H., Saviani, E., Rincones, J., Toni, I., Osvaldo, R., Garcia, O., Meinhardt, L.W., Salgado, I., Pereira, G.A. 2012. The hemibiotrophic cacao pathogen Moniliophthora perniciosa depends on a mitochondrial alternative oxidase for biotrophic development. New Phytologist. 194(4):1025-1034.
- Costa, G.G., Cabrera, O., Tiburico, R.A., Medrano, F., Carazzolle, M., Thomazella, D., Schuster, S., Carlson, J.E., Guiltinan, M.J., Bailey, B.A., Mieckowski, P., Pereira, G.A., Meinhardt, L.W. 2012. The Mitochondrial Genome of Moniliophthora roreri, the frosty pod rot pathogen of cacao. Fungal Biology. 116(5):551-562.
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) Develop effective biological disease control strategies leading to sustainable yield improvements of cacao. This includes: determining the molecular mechanisms of action critical to the development of diseases caused by Moniliophthora spp. in cacao and identify potential targets for intervention, determining the mechanisms of action in the interactions between cacao, pathogens of cacao (Moniliophthora spp.), and Trichoderma isolates which result in effective disease suppression and improved plant productivity, and developing and optimizing strategies for biological control of cacao diseases caused by Moniliophthora spp. Approach (from AD-416) The interactions between isolates of the biocontrol agent Trichoderma, cacao, and pathogens of cacao will be studied in detail. Diseases targeted for control include Witches� broom (Moniliophthora perniciosa), and frosty pod (Moniliophthora roreri). Isolates of Trichoderma that aggressively colonize aerial cacao tissue (leaves, stems, flowers, flower cushions, and pods) epiphytically and/or endophytically and that possess strong biocontrol ability against one or more of the targeted pathogens will be identified. Trichoderma isolates from cacao ecosystems will be characterized for their mechanisms of biocontrol action including mycoparasitism, antibiosis and induced resistance. The impact of environment on Trichoderma colonization of aerial cacao tissues will be determined using specially adapted weather stations at 3 sites, and formulation technologies will be developed to ameliorate any negative effects. Formulation development will include established materials, techniques, and technologies along with novel approaches targeted to specific cacao tissues. Molecular techniques such as quantitative polymerase-chain reaction using RNA and DNA will be employed to optimize isolate selection and determine the impact of environment and formulation on biocontrol performance. A study of the pathogens� genomes will be initiated to facilitate future research concerning their interactions with cacao and potential biocontrol agents. Ultimately, the best available isolates of Trichoderma based on mechanism of action, and epiphytic/ endophytic abilities, will be tested in combination with optimum formulations under field conditions and their efficacies at controlling cacao diseases determined. Seventy-seven Trichoderma isolates from Ecuador were systematically screened for their abilities to colonize cacao tissues as endophytes and inhibit growth of cacao pathogens. An endophyte is an organism capable of living inside plant tissues without causing any damage to the plant. Large scale field tests included 2 Trichoderma isolates evaluated in combination with new formulations for their abilities to reduce frosty pod rot of cacao in Costa Rica. In the first year, yield of healthy cacao pods was approximately tripled in response to treatment with Trichoderma ovalisporum isolate DIS 70a combined with an invert corn oil formulation. A second year of testing gave similar results. The use of new technologies offers promise for enhancing disease suppression in response to Trichoderma applications. The unique nature of the Trichoderma endophytic relationship with cacao was detailed with the characterization of the plant growth promoting capabilities of Trichoderma isolate DIS 219b. In growth chamber studies, treating cacao seedlings with DIS 219b enhanced root growth and delayed plant stress caused by drought. The ability of Trichoderma species to enhance cacao root growth was verified in the field in Ecuador. Trichoderma has potential to enhance cacao root growth and reduce damage to cacao seedling due to drought stress following transplanting into the field. A unique association was discovered between endophytic Trichoderma isolates and the glandular trichomes of cacao seedling. When Trichoderma colonizes cacao seedlings, the mycelium grows along the trichome surface to the tip of the trichome where it penetrates the trichome and lives within the trichome. This observation partially explains why so many Trichoderma species colonize above ground parts of cacao. Knowing this, formulations for applying Trichoderma to cacao can be developed that accentuate this process possibly enhancing disease suppression. In collaborations with Penn State University and The Instituto Nacional de Investigaciones Agropecuarios (INIAP) in Ecuador, Bacillus species were evaluated for their abilities to suppress cacao diseases. Some Bacillus isolates suppressed disease caused by Phytophthora capsici on cacao leaves in growth chamber studies and reduced disease caused by M. perniciosa in the field in Ecuador. The possibility exists to combine Bacillus isolates with Trichoderma isolates resulting in enhanced disease control and increased yields. We provided genome sequence data supporting the final publication and release of the Moniliophthora perniciosa genome, causal agent of witches� broom on cacao. We sequenced the genome of Moniliophthora roreri, the cause of frosty pod rot on cacao. We are using the genome sequences to characterize the interactions between the two pathogens, Moniliophthora roreri and M. perniciosa, and cacao. By understanding the genomes of M. roreri and M. perniciosa we will be able to identify events critical to the disease process and hopefully develop new disease control approaches for the diseases they cause in cacao.
Impacts
(N/A)
Publications
- Bae, H., Roberts, D.P., Lim, H.S., Strem, M.D., Park, S., Ryu, C., Melnick, R., Bailey, B.A. 2011. Endophytic Trichoderma isolates from tropical environments delay disease onset and induce resistance against Phytophthora capsici in hot pepper using multiple mechanisms. Molecular Plant-Microbe Interactions. 24:336-351.
- Melnick, R.L., Bailey, B.A., Backman, P.A. 2011. Isolation of endophytic endospore-forming bacteria from Theobroma cacao as potential biological control agents of cacao dieseases. Biological Control. 57:236-245.
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) Develop effective biological disease control strategies leading to sustainable yield improvements of cacao. This includes: determining the molecular mechanisms of action critical to the development of diseases caused by Moniliophthora spp. in cacao and identify potential targets for intervention, determining the mechanisms of action in the interactions between cacao, pathogens of cacao (Moniliophthora spp.), and Trichoderma isolates which result in effective disease suppression and improved plant productivity, and developing and optimizing strategies for biological control of cacao diseases caused by Moniliophthora spp. Approach (from AD-416) The interactions between biocontrol agent, Trichoderma, isolates, cacao, and pathogens of cacao will be studied in detail. Diseases targeted for control include Witches� broom (Moniliophthora perniciosa), and frosty pod (Moniliophthora roreri). Isolates of Trichoderma that aggressively colonize aerial cacao tissue (leaves, stems, flowers, flower cushions, and pods) epiphytically and/or endophytically and that possess strong biocontrol ability against one or more of the targeted pathogens will be identified. Trichoderma isolates from cacao ecosystems will be characterized for their mechanisms of biocontrol action including mycoparasitism, antibiosis and induced resistance. The impact of environment on Trichoderma colonization of aerial cacao tissues will be determined using specially adapted weather stations at 3 sites, and formulation technologies will be developed to ameliorate any negative effects. Formulation development will include established materials, techniques, and technologies along with novel approaches targeted to specific cacao tissues. Molecular techniques such as quantitative polymerase-chain reaction using RNA and DNA will be employed to optimize isolate selection and determine the impact of environment and formulation on biocontrol performance. A study of the pathogens� genomes will be initiated to facilitate future research concerning their interactions with cacao and potential biocontrol agents. Ultimately, the best available isolates of Trichoderma based on mechanism of action, and epiphytic/endophytic abilities, will be tested in combination with optimum formulations under field conditions and their efficacies at controlling cacao diseases determined. After completing a systematic screening of 77 Trichoderma isolates from Ecuador, screening of 200 Trichoderma isolates from the upper Amazon in Peru was initiated with collaborators from ICT-Peru. Building on successes from 2 years of large scale field tests of 2 Trichoderma isolates in Ecuador, new Trichoderma formulations containing corn oil were evaluated. Yields of healthy cacao pods were approximately tripled by the inclusion of corn oil in the formulations. A second year of formulation field testing has been initiated. The unique nature of the Trichoderma endophytic relationship with cacao was further detailed with the characterization of the plant growth promoting capabilities of the Trichoderma isolate DIS 219b which had a positive impact on drought tolerance. In addition, the characterization of the endophytic association between Trichoderma species and trichomes on the surface of cacao stems was conducted. In collaborations with Penn State University and Instituto Nacional de Investigaciones de Agropecuarias, Pichilingue, Quevedo, Ecuador (INIAP) Bacillus species were evaluated in Ecuador for their biocontrol activity against Moniliophthora species pathogenic to cacao with positive results. The M. roreri (the causal agent of frosty pod rot disease of cacao) genome sequencing has been completed and efforts are being made to publish and release the mitochondrial genome of Moniliophthora roreri, which will be followed by the publication and release of the nuclear genome. We are using the genome sequence to characterize the interactions between the two pathogens, Moniliophthora roreri and M. perniciosa, and cacao (the source of chocolate). This research is being carried out by collaborations with Penn State University and a consortium of scientists from Brazil. Accomplishments 01 The endophytic association between Trichoderma species and cacao trichom was discovered and characterized. Cacao is a unique plant species capabl of supporting endophytic associations with many fungi including species Trichoderma. In contrast with the typically observed nature of Trichoder species as soil inhabitants, Trichoderma species are often isolated from above ground cacao tissues raising the possibility that these isolates o Trichoderma can be used to control cacao disease, which attack above ground cacao tissues (stems, flower cushions, pods). Trichoderma species were observed to form associations with cacao trichomes, microscope plan hairs, heretofore unseen in Trichoderma plant interactions. Trichoderma species actively entered into trichomes on cacao stems. This observation provides a possible explanation of how Trichoderma species are capable o colonizing and persisting in above ground tissues of cacao. These studie were carried out by SPCL scientists using permanent funds. These finding could lead to the identification of new biocontrol agents that reduce th use for fungicides that prevent plant diseases thus leading to safer foo supplies. 02 Mitochondrial Genome Sequence of Moniliophthora roreri completed and comparison to that of M. perniciosa made. Frosty Pod Rot disease (FPR) o cacao affects all cacao growing regions in Central America and most Ande countries of South America. This disease caused by Moniliophthora roreri has significantly reduced cacao yields in all of these growing regions, which impacts U.S industry and consumers. A comparison of the complete mitochondrial genomes of Moniliophthora roreri and M. perniciosa showed high degree of relatedness, with both genomes showing a high degree of similarity in gene number, orientation and sequence composition. The mai differences are associated with plasmid numbers, their locations and in the number of repetitive sequences within each genome. These studies wer carried out by SPCL scientists using permanent funds through collaborations with Penn State University and scientists from Brazil. These results are helping researchers model the disease interaction and potentially could impact disease resistance breeding programs.
Impacts
(N/A)
Publications
- Tiburcio, R.A., Costa, G.G., Carazzolle, M.F., Schuster, S.C., Carlson, J. E., Guiltinan, M.J., Bailey, B.A., Argueso, J.L., Mieckowski, P., Meinhardt, L.W., Pereira, G.A. 2009. Genes acquired by horizontal transfer are potentially involved in the evolution of phytopathogenicity in Moniliophthora perniciosa and Moniliophthora roreri, two of the major pathogens of cacao. Journal of Molecular Evolution. 70:85-97.
- Loguercio, L.L., Santos, L.S., Pomella, A.W., Miranda, R.A., Souza, J.T., Collins, R.T. 2009. Canopy-microclimate effects on the antagonism between Trichoderma stromaticum and Moniliophthora perniciosa in shaded cacao. Plant Pathology. 58(6):1104-1115.
- Bailey, B.A., Strem, M.D., Wood, D.F. 2009. Trichoderma species form endophytic associations within Theobroma cacao trichomes. Mycological Research. 113:1365-1376.
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Progress 10/01/08 to 09/30/09
Outputs
Progress Report Objectives (from AD-416) Develop effective biological disease control strategies leading to sustainable yield improvements of cacao. This includes: determining the molecular mechanisms of action critical to the development of diseases caused by Moniliophthora spp. in cacao and identify potential targets for intervention, determining the mechanisms of action in the interactions between cacao, pathogens of cacao (Moniliophthora spp.), and Trichoderma isolates which result in effective disease suppression and improved plant productivity, and developing and optimizing strategies for biological control of cacao diseases caused by Moniliophthora spp. Approach (from AD-416) The interactions between biocontrol agent, Trichoderma, isolates, cacao, and pathogens of cacao will be studied in detail. Diseases targeted for control include Witches� broom (Moniliophthora perniciosa), and frosty pod (Moniliophthora roreri). Isolates of Trichoderma that aggressively colonize aerial cacao tissue (leaves, stems, flowers, flower cushions, and pods) epiphytically and/or endophytically and that possess strong biocontrol ability against one or more of the targeted pathogens will be identified. Trichoderma isolates from cacao ecosystems will be characterized for their mechanisms of biocontrol action including mycoparasitism, antibiosis and induced resistance. The impact of environment on Trichoderma colonization of aerial cacao tissues will be determined using specially adapted weather stations at 3 sites, and formulation technologies will be developed to ameliorate any negative effects. Formulation development will include established materials, techniques, and technologies along with novel approaches targeted to specific cacao tissues. Molecular techniques such as quantitative polymerase-chain reaction using RNA and DNA will be employed to optimize isolate selection and determine the impact of environment and formulation on biocontrol performance. A study of the pathogens� genomes will be initiated to facilitate future research concerning their interactions with cacao and potential biocontrol agents. Ultimately, the best available isolates of Trichoderma based on mechanism of action, and epiphytic/endophytic abilities, will be tested in combination with optimum formulations under field conditions and their efficacies at controlling cacao diseases determined. Significant Activities that Support Special Target Populations A systematic screening process for selected Trichoderma isolates from Ecuador and Peru was put in place involving collaborators from CABI- Bioscience-United Kingdom, INIAP-Ecuador, and ICT-Peru. Having screened 77 Trichoderma isolates from Ecuador in the lab, 14 selected Trichoderma isolates were further screened in small scale field tests for control of frosty pod in Costa Rica and witches� broom in Ecuador. A large scale field test of 2 Trichoderma isolates was completed and both isolates reduced disease and enhanced yield for the second year in a row. A field study was initiated in Costa Rica with these same 2 isolates to evaluate the influence of formulations incorporating oils, humectants, and nutrients on control of disease. In addition, in collaborations with Penn State University and INIAP, Bacillus species were evaluated in Ecuador for their biocontrol activity against Moniliophthora species pathogenic to cacao with positive results. The M. roreri genome sequence was greatly improved with the addition of additional sequence using Solexa and paired end analysis sequencing technologies. Over 33X coverage of the M. roreri genome sequence has been obtained. This research was carried out by collaborations with Penn State University and a consortium of scientists from Brazil. Technology Transfer Number of New/Active MTAs(providing only): 1
Impacts
(N/A)
Publications
- Mondego, J.M., Carazolle, M.F., Costa, G., Formighieri, L.P., Parizzi, L.P. , Rincones, J., Cotomacci, C., Vidal, R.O., Estrela, R.C., Garcia, O., Castro, L.A., Gramacho, K.P., Goncalves, M.S., Neto-Goes, A., Barbosa, L.V. , Guiltinan, M.J., Bailey, B.A., Meinhardt, L.W., Cascardo, J.C., Pereira, G.A. 2008. A genome survey of Moniliophthora perniciosa gives new insights into Witches� Broom Disease of cacao. Biomed Central (BMC) Genomics. 9:548.
- Bae, H., Kim, S., Sicher, Jr., R.C., Kim, M.S., Strem, M.D., Bailey, B.A., Melnick, R. 2009. The beneficial endophyte, Trichoderma hamatum, isolate DIS 219B promotes growth and delays the onset of the drought response in Theobroma cacao. Journal of Experimental Botany. 60:3279-3295.
- Meinhardt, L.W., Rincones, J., Bailey, B.A., Aime, M.C., Griffith, C., Zhang, D., Pereira, G. 2008. Moniliophthora perniciosa, the causal agent of witches� broom disease of cacao: What�s new from this old foe. Molecular Plant Pathology. 9(5):577-588.
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Progress 10/01/07 to 09/30/08
Outputs
Progress Report Objectives (from AD-416) Develop effective biological disease control strategies leading to sustainable yield improvements of cacao. This includes: determining the molecular mechanisms of action critical to the development of diseases caused by Moniliophthora spp. in cacao and identify potential targets for intervention, determining the mechanisms of action in the interactions between cacao, pathogens of cacao (Moniliophthora spp.), and Trichoderma isolates which result in effective disease suppression and improved plant productivity, and developing and optimizing strategies for biological control of cacao diseases caused by Moniliophthora spp. Approach (from AD-416) The interactions between biocontrol agent, Trichoderma, isolates, cacao, and pathogens of cacao will be studied in detail. Diseases targeted for control include Witches� broom (Moniliophthora perniciosa), and frosty pod (Moniliophthora roreri). Isolates of Trichoderma that aggressively colonize aerial cacao tissue (leaves, stems, flowers, flower cushions, and pods) epiphytically and/or endophytically and that possess strong biocontrol ability against one or more of the targeted pathogens will be identified. Trichoderma isolates from cacao ecosystems will be characterized for their mechanisms of biocontrol action including mycoparasitism, antibiosis, and induced resistance. The impact of environment on Trichoderma colonization of aerial cacao tissues will be determined using specially adapted weather stations at 3 sites, and formulation technologies will be developed to ameliorate any negative effects. Formulation development will include established materials, techniques, and technologies along with novel approaches targeted to specific cacao tissues. Molecular techniques such as quantitative polymerase-chain reaction using RNA and DNA will be employed to optimize isolate selection and determine the impact of environment and formulation on biocontrol performance. A study of the pathogens� genomes will be initiated to facilitate future research concerning their interactions with cacao and potential biocontrol agents. Ultimately, the best available isolates of Trichoderma based on mechanism of action, and epiphytic/endophytic abilities, will be tested in combination with optimum formulations under field conditions and their efficacies at controlling cacao diseases determined. Significant Activities that Support Special Target Populations A systematic screening process for Trichoderma isolates from Ecuador and Peru was put in place involving collaborators from CABI-Bioscience-United Kingdom, INIAP-Ecuador, and ICT-Peru. 77 Trichoderma isolates from Ecuador were evaluated for their endophytic abilities on cacao and for their mycoparasitic and antibiosis activity against the two Moniliophthora species pathogenic on cacao. Having completed these screens, small scale field tests are being initiated in Ecuador and Costa Rica in order to identify the best isolates under field conditions in preparation for large scale field tests in the coming years. Sequencing projects for the M. perniciosa and M. roreri genomes were completed. Approx. 7 X coverage of the M. perniciosa genome was obtained by pyrosequencing and combined with the 1X Sanger sequence coverage obtained by the Brazilian consortium to more fully cover the genome. Over 20X coverage of the M. roreri genome sequence was obtained by pyrosequencing. Analysis of both sequences is continuing and should be completed over the next year. All this research was carried out by collaborations with Penn State University and a consortium of scientist from Brazil. These accomplishments contribute to National program 303 Plant Disease under Problem Statement 4A: Biological and Cultural Control Technologies and Problem Statement 4B: Pathogen, Plant, and Antagonist Interactions. Technology Transfer Number of Active CRADAS: 1
Impacts
(N/A)
Publications
- Desouza, J.T., Pomella, A.W., Bailey, B.A., Bae, H., Erbe, E.F., Murphy, C. A. 2008. Colonization of cacao seedlings by Trichoderma stromaticum, a mycoparasite of the witches� broom pathogen, and its influence on plant growth and resistance. Biological Control 46:36-45.
- Melnick, R.L., Zidack, N.K., Bailey, B.A., Maximova, S.N., Guitinan, M., Backman, P.A. 2008. Bacterial endophytes: Bacillus spp. from vegetable crops as potential biological control agents of black pod rot of cacao. Biological Control. 46:46-56.
- Bae, H., Kim, S., Kim, M.S., Sicher, Jr., R.C., Strem, M.D., Natarajan, S. S., Bailey, B.A. 2008. Coordinated regulation of polyamine biosynthesis in Theobroma cacao (cacao) tissues responding to stress. Plant Physiology and Biochemistry. 46:174-188.
- Bailey, B.A., Bae, H., Strem, M.D., Crozier, J., Thomas, S.E., Samuels, G. J., Holmes, K.A. 2008. Antibiosis, mycoparasitism, and colonization sucess for endophytic Trichoderma isolates with biological control potential in Theobroma cacao. Biological Control. 46:24-35.
- Aruna Kilaru, A., Bailey, B.A., Hasenstein, K.H. 2007. Moniliophthora perniciosa produces hormones and alters endogenous auxin and salicylic acid in infected cocoa leaves. Federation of European Microbiological Societies Microbiology Letters. 274:238-244.
- Garcia, O., Macedo, J., Tiburcio, R., Zaparoli, G., Bittencourt, L.M., Ceita, G., Rincones, J., Micheli, F., Gesteira, A., Mariano, A., Schiavinato, M.A., Medrano, F., Meinhardt, L.W., Pereira, G.A., Cascardo, J.C. 2007. Characterization of Necrosis and Ethylene inducing Proteins (NEP) in the Basidiomycete Moniliophthora perniciosa, the Causal Agent of Witches� Broom in Theobroma cacao. Mycological Research. 111:443-455.
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