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United States Department of Agriculture

Agricultural Research Service

Research Project: SYSTEMATICS OF MICROFUNGI USED IN BIOLOGICAL CONTROL OF PLANT DISEASES AND INSECT PESTS Project Number: 1275-22000-269-00
Project Type: Appropriated

Start Date: Feb 03, 2009
End Date: Mar 22, 2012

Objective:
1. Provide a phylogenetic framework for potential biological control fungi in Trichoderma and Hypocrea in order to predict biocontrol ability from among unknown strains or species. Emphasis will be on the Trichoderma harzianum group and Trichoderma endophytes of Theobroma and other tropical woody crops. 2. Develop a taxonomy and compare endophytic and non-endophytic strains of species of microfungi, especially those in the taxonomically difficult genera Colletotrichum and Phomopsis that are found as leaf endophytes in Theobroma species and other woody and vegetable crops. 3. Conduct molecular systematic and population genetic studies of insect-pathogenic fungi to clarify species concepts and provide monographic studies of Beauveria and Metahizium. Identify cryptic species lineages of Beauveria bassiana and their role in natural epizootics of insects.

Approach:
The diversity of endophytic fungi in native cacao in its native range will be isolated during two collecting trips to Peru. Trichoderma cultures will be identified by sequencing the protein-coding gene translation elongation factor 1 alpha (tef1). For interesting or problematic isolates two more genes will be sequenced. Cultures of Trichoderma that are deemed to be undescribed or rare will be characterized morphologically. In vitro, cultures will be evaluated for mycoparasitism and production of antibiotics. Mycoparasitism of Phytophthora megakarya will be assayed using the ‘inoculated leaf disk method. For the project on leaf endophytes isolates will be obtained in a similar manner and analyzed using both molecular and morphological characteristics. Isolates will be tested for host specificity and pathogenicity. For the project on insect pathogens, isolates will be obtained by field collection by the SY and collaborators, from culture collections. Phylogenetic markers will be used to resolve relationships among and within genera of clavicipitalean fungi. The following nuclear genes will be sequenced: translation elongation factor-1 alpha (EF-1'), the largest and second largest subunits of ribosomal polymerase B (RPB1, RPB2) '-tubulin ('tub), heat-shock protein 90 (hsp90) and DNA lyase (dlya). Additionally, more rapidly evolving markers, including nuclear intergenic regions and the nuclear ribosomal intergenic spacer (Pantou et al. 2003) will be developed for analysis of species complexes in Beauveria and Metarhizium, respectively. Web-accessible resources for identification of entomopathogenic fungi will be developed. Population genetic marker data (microsatellites and SNPs) will be analyzed to generate intra-population genetic statistics and to estimate genetic distances and structuring among populations.

Last Modified: 9/2/2014
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