Dr. Priscila Chaverri

Assistant Professor

Email: pchaverr@umd.edu
Office: 2112 Plant Sciences Building
Phone: 301.405.7041
Fax: 301.314.9308
Web Site: mycology.umd.edu
Dr. Priscila Chaverri

Education:

  • 1993. B.Sc. Forestry, Instituto Tecnologico de Costa Rica
  • 2003. Ph.D. Plant Pathology, The Pennsylvania State University

Research Interests:

Biodiversity, systematics, and molecular phylogenetics / evolution of fungi important in agroecosystems and tropical forests.

My primary research interests are in the systematics (taxonomy) and biodiversity of ascomycetous fungi.  Until now, I have focused my work on the order Hypocreales (Ascomycota), more specifically, with fungi that have biocontrol properties against plant pests and diseases (e.g. Trichoderma and Aschersonia). Currently, I also have research projects that deal with the taxonomy of endophytes in the tropics and the systematics of fungal pathogens associated with hardwood trees in temperate and tropical regions. In my research, I use a synergy of traditional taxonomic techniques, such as field collecting, microscopy and culture in artificial media, as well as modern tools, such as molecular phylogenetic analyses using DNA sequences from multiple genes.


Research Projects

    • Biodiversity of fungal endophytes in rubber trees: Towards understanding their role as plant protection agents.

      This project will characterize fungal endophytic species in rubber trees (Hevea brasiliensis) to evaluate their potential role as plant protection agents. Some suggest that symbiotic fungal endophytes have coevolved with host plants to protect them from natural enemies. Rubber trees grown in plantations suffer from a variety of plant diseases, and endophytes may play a role in their protection. Because most fungal endophytes are horizontally transmitted, seeds from H. brasiliensis that are used in plantations may lack coevolved endophytes. Based on this premise, it is hypothesized that rubber trees in the wild host greater species richness and abundance of fungal endophytes than trees in plantations. If this hypothesis is supported, plantation trees may lack beneficial endophytes that could prevent some diseases and pests found on plantations. The diversity and species composition of fungal endophytes in rubber trees in their native (i.e. Upper Amazon) and managed settings (i.e. plantations) will be studied through fieldwork; isolation and cultivation of endophytes from different parts of the tree; and identification of fungal species using morphological and molecular approaches. Preliminary assays and experiments on the antifungal properties of these endophytes will also be conducted.

    • Monographic studies of the plant- and insect-associated genera: Nectria, Neonectria, and Cosmospora (Nectriaceae, Hypocreales).

      This study will define the taxonomy of three major genera of the Nectriaceae:  Nectria, Cosmospora, and Neonectria.  These genera are significant because they include several species that are widespread plant pathogens and potential biological control agents of insects.  None of these genera have received modern monographic treatment. The proposed monographic projects include: (1) Nectria with Tubercularia asexual states, a group of about 30–40 taxa.Most species of Nectria occur on recently dead hardwood trees in temperate and tropical regions. (2) Cosmospora with asexual states in acremonium-like, Chaetopsina, Fusarium sect. Eupionnotes, Stilbella, verticillium-like, and Volutella.  Cosmospora occur primarily on stromatic fungi and insects. (3) Neonectria with Cylindrocarpon asexual states. This genus includes species that cause cankers on hardwood and conifer trees in temperate and tropical regions, a subgroup common on recently dead woody plants in the tropics, and another group isolated from soil. The taxonomy of these genera will be studied using morphology, microscopy, cultural characteristics, and DNA-sequence analyses.

    • Systematics of plant pathogenic and endophytic fungi based on multigene phylogenies.

      This project will characterize plant pathogenic and endophytic fungi, with special emphasis in the Colletotrichum gloeosporioides complex. Colletotrichum gloeosporioides causes important diseases in many kinds of crops. In addition, C. gloeosporioides is one of the most common endophytes in leaves of dicotyledoneous plants.

    • Fungal diversity in Saharan Dust Storms

      This project deals with the identification of fungi that travel in Saharan dust storms and its potential threats to agriculture in the United States and other countries in the Americas. In collaboration with Dr. Vernon Morris (Atmospheric Sciences Department, Howard University), samples are being collected, fungi are being identified using morphology and DNA sequences, and the most likely geographical source of these dust samples is being tracked.
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Courses

PLSC489O: Special Topics in Plant Science: Biology of Fungi. 3 credits. (Fall 2009) Introduction to the diversity of fungi, their biology, taxonomy, evolution, and impact on other organisms, such as plants and animals. The course is an integration of lectures and laboratory exercises, as well as a few field trips. Prereq: PLSC100 or 101 or BSCI105.

Graduate Students:

  • Romina Gazis. Project: Biocontrol potential of fungi associated to Hevea spp.
  • Serenella Linares. Project: Fungi in Saharan dust storms
  • Dr. Yuuri Hirooka (post-doctoral associate), Project: Taxonomy of Nectria-like fungi
  • Catalina Salgado. Project: Systematics of Nectria-like fungi

 

Representative Publications:

    Books and Monographs:

  • Chaverri, P., Liu, M., Hodge, K.T. 2008. A monograph of the entomopathogenic genera Hypocrella, Moelleriella, and Samuelsia gen. nov. (Ascomycota, Hypocreales, Clavicipitaceae), and their Aschersonia-like anamorphs in the Neotropics. Studies in Mycology 60. Centraalbureau voor Schimmelcultures (CBS): Baarn. 68 p. (Free via Open Access: http://www.studiesinmycology.org/cgi/content/full/60/1/1)
  • Samuels, G. J., Rossman, A. Y., Chaverri, P., Overton, B. E., Põldmaa, K. 2006. Hypocreales of the Southeastern United States: An Identification Guide. CBS Biodiversity Series No. 4. Centraalbureau voor Schimmelcultures: Baarn. 145 p. (For a web-based interactive key of this book, go to http://nt.ars-grin.gov/taxadescriptions/keys/HypocrealesSouthEastIndex.cfm)
  • Chaverri, P., Samuels, G.J. 2003. Hypocrea/Trichoderma (Ascomycota, Hypocreales, Hypocreaceae): Species with Green Ascospores. Studies in Mycology 48. Centraalbureau voor Schimmelcultures (CBS): Baarn. 116 p.
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    In peer-reviewed journals:

  • Liu, M., Milgroom, M.G., Chaverri, P., Hodge, K.T. 2009. Speciation of a tropical fungal species pair following transoceanic dispersal. Molecular Phylogenetics and Evolution (accepted March 2009).
  • Samuels, G.J., Lu, B.-S., Chaverri, P., Candoussau, F., Fournier, J., Rossman, A.Y. 2009. Cyanonectria, a new genus for Nectria cyanostoma and its Fusarium anamorph. Mycological Progress 8: 1-81.
  • Tadych, M., Chaverri, P., Bergen, M., White, J.F. 2009. Moelleriella zhongdongii: stromal development and identification of Hirsutella-like and Aschersonia synanamorphs. Mycological Research (In Press)
  • Rojas, E.I., Herre, E.A., Mejía, L.C., Arnold, A.E., Chaverri, P., Samuels, G.J. 2008. Endomelanconiopsis endophyticum, a new Botryosphaeria leaf endophyte from Panama. Mycologia 100: 760-775.
  • Degenkolb, T., Ralf, D., Nielsen, K.F., Grafenhan, T., Theis, C., Zafari, D., Chaverri, P., Ismaiel, A., Bruckner, H., Von Dohren, H., Thrane, U., Petrini, O., Samuels, G.J. 2008. The Trichoderma brevicompactum clade: a new lineage with new species, new peptaibiotics, and mycotoxins. Mycological Progress 7: 177-209.
  • Chaverri, P., Vílchez, B. 2006. Hypocrealean (Hypocreales, Ascomycota) fungal diversity in different stages of succession in a tropical forest in Costa Rica. Biotropica 38: 531-543.
  • Liu, M., Chaverri, P., Hodge, K.T. 2006. A taxonomic revision of the insect biocontrol fungus Aschersonia aleyrodis, its allies with white stromata and their Hypocrella sexual states. Mycological Research 110: 537-554.
  • Chaverri, P., Bischoff, J.F., Evans, H.C., Hodge, K.T. 2005. Regiocrella, a new entomopathogenic genus with a pycnidial anamorph and its phylogenetic placement in the Clavicipitaceae. Mycologia 97: 1225-1237.
  • Chaverri, P., Bischoff, J.F., Hodge, K.T. 2005. A new species of Hypocrella, H. macrostroma, and its relationship to other species with large stromata. Mycological Research 109: 1268-1275.
  • Bischoff, J.F., Chaverri, P., White, J.F. 2005. Clarification of the host substrate of Ascopolyporus (Clavicipitaceae, Hypocreales) and description of Ascopolyporus philodendrus sp. nov. Mycologia 97: 710-717.
  • Chaverri, P., Samuels, G. J., Hodge, K. T. 2005. The genus Podocrella and its nematode-killing anamorph Harposporium. Mycologia 97: 433-443.
  • Druzhinina, I. S., Chaverri, P., Fallah, P., Kubicek, C. P., Samuels, G. J. 2004. Hypocrea flaviconidia, a new species from Costa Rica with yellow conidia. Studies in Mycology 50: 401-407.
  • Chaverri, P., Candoussau, F., Samuels, G.J. 2004. Hypocrea phyllostachydis and its Trichoderma anamorph, a new bambusicolous species from France. Mycological Progress 3: 29-36.
  • Arguedas, M., Chaverri, P., Verjans, J-M. 2004. Problemas fitosanitarios de la teca en Costa Rica [Phytosanitary problems on teak trees, Tectona grandis, in Costa Rica]. Rev. Recursos Naturales y Ambiente 41: 130-135.
  • Lu, B.S., Druzhinina, I.S., Fallah, P., Chaverri, P., Gradinger, C., Kubicek, C.P., Samuels, G.J. 2004. Hypocrea/Trichoderma species with pachybasium-like conidiophores: teleomorphs for T. minutisporum and T. polysporum, and their newly discovered relatives. Mycologia 96: 310-342.
  • Chaverri, P., Castlebury, L.A., Overton, B.E., Samuels, G.J. 2003. Hypocrea/Trichoderma: species with conidiophore elongations and green conidia. Mycologia 95: 1100-1140.
  • Chaverri, P., Castlebury, L.A., Samuels, G.J., Geiser, D.M. 2003. Multilocus phylogenetic structure of Trichoderma harzianum/Hypocrea lixii complex. Molecular Phylogenetics and Evolution 27: 302-313.
  • Dodd, S.L., Lieckfeldt, E., Chaverri, P., Overton, B.E., Samuels, G.J. 2002. Taxonomy and phylogenetic relationships of two species of Hypocrea with Trichoderma anamorphs. Mycological Progress 1: 409-428.
  • Chaverri, P., Samuels, G.J. 2002. Hypocrea lixii, the teleomorph of Trichoderma harzianum. Mycological Progress 1: 283-286.
  • Chaverri, P., Samuels, G.J., Stewart, E.L. 2001. Hypocrea virens sp. nov., the teleomorph of Trichoderma virens. Mycologia 93: 1113-1124.
  • Chaverri, P., Samuels, G.J., Stewart, E.L., Umaña, L. 2001. Hypocrea nigrovirens sp. nov., a new species with a gliocladium-like anamorph. Mycologia 93:758-763.

 

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