Molecular and Microscopic Methods
to Evaluate Activity of Beneficial Fungi (and Bacteria) in Soil Ecosystems

(this page under construction, but here are a few photos to get started!)

(above) Scanning electron micrographs of Trichoderma harzianum on seedcoat of pea, and Pseudomonas fluorescens on pea root surfaces.  Photos taken after pea seed treatment with these two potential biocontrol agents, respectively (L. M. Dandurand photos)

Some references:

Dandurand, L. M., D. J. Schotzko, and G. R. Knudsen. 1997. Spatial patterns of rhizoplane populations of Pseudomonas fluorescens. Appl. Environ. Microbiol. 63:3211-3217.

Dandurand, L. M., R. D. Mosher, and G. R. Knudsen. 2000. Combined effects of Brassica napus seed meal and Trichoderma harzianum on two soilborne plant pathogens. Can. J. Microbiol. 46:1051-1057.

(above)  Light micrographs of T. harzianum ThzID1-M3 transformed with GUS and GFP (green fluorescent protein) genes.  GUS expression shown at left, GFP at right    (Y. S. Bae photos)

(above)  Scanning confocal laser microscopy (SCLM) image of aquatic leaf litter inoculated with T. harzianum THZID1-M3.  At left, visible light illumination showing leaf fragments, miscellaneous fungal hyphae, bacteria, protozoa.  At right, epifluorescent lumination showing fluorescence of GFP-expressing T. harzianum.  This method allows us to monitor and quantify growth of a specific introduced fungus in a complex microbial habitat.  (G. R. Knudsen photos)

Some references:

Bae, Y. S., and G. R. Knudsen. 2001. Influence of a fungus-feeding nematode on growth and biocontrol efficacy of Trichoderma harzianum. Phytopathology 91:301-306.

Bae, Y. S., and G. R. Knudsen. 2000. Cotransformation of Trichoderma harzianum with b -Glucuronidase and green fluorescent protein genes provides a useful tool for monitoring fungal growth and activity in natural soils. Appl. Environ. Microbiol. 66:810-815.

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