1993 - Mycological Society of America

Wednesday, 845 am
Comparative utilization of protein by
ectomyco&izal and saprotrophic basidiomycetes
Steven L. Miller, Malavika Ghosh, and Terry McClean. Dept. of
Botany, Univ. of Wyoming, Lararnie, WY 82071.
To compare the ability of ectomycorrhizal fungi to utilize protein with
that of more widely recognized saprotrophic basidiomycetes, sapro-
trophic species of Agaricus and Copnus and edomycorrhizal species of
Hebeloma, Suillus, Amanifa and Rhizopgon were grown in liquid media
with bovine serum albumin as the sole nitrogen source. After two
weeks of growth, aliquots of nutrient solution were analyzed for free
amino acid composition on an WLC. Hebeloma showed the highest
concentration of amino acids, particularly alanine and leucine but
contained little asparagine or glutarnic a&d. Amrmita and Coprinus also
contained large amounts of amino acids and were high in glutamic
acid and leucine. Agaricus contained moderate amounts of amino acids
with phenylalanineand leucine being most abundant. Rhizopogon and
Suillus contained the least amount of free amino acids.
In a second experiment, the same species of Hebeloma used in the in
mtro study was inoculated onto the roots of lodgepole pine seedlings
growing in specially designed root miaocosms. Bovine serum albumin
was added into the rooting medium. At 3,7 and 12 days, a buffered
solution was leached through the miaocosms, collected and analyzed
for free amino acids. Most amino acids were found at day 7 and the
most abundant were glutamine, arginine and glutarnic acid. Only
alanine and leucine in very small quantities remained by day 12
suggesting that all of the BSA had been catabolized.
This demonstrates that ectomycorrhizal fungi are capable of cataboliz-
ing protein both in vitro and vivo and that some species may be able
to utilize protein to a greater extent than some saprotrophs. This sug-
gests thatthe saprotrophic capabilities of ectomycorrhizal fungi may
be greater than previously thought and should be studied more
thoroughly.
Wednesday, 830 am
Visualization and localization of enzyme activity
in ectomycorrhizal and saprotrophic basidiomycetes
Steven L. Milla and Terry McClean. Dept. of Botany, Univ. of
Wyoming, Lararnie, WY 82071.
Attempts at examining the saprotrophic capabilities of ectomycorrhizal
and saprotrophic basidiomycetes have necessitated deriving or adapt-
ing simple but sensitive colorometric assays for enzyme activity to a
variety of experimental growth situations. Enzymatic activity of ecto-
mycorrhizae and extramatrical hyphae growing in z&o can be visual-
ized by placing a piece of glass fiber filter paper containing one of
several reaction mixtures in direct contact with an intact edomycorrhi-
zal root system in specially designed microcosms. After exposure of
the assay paper to the mycelium, the paper is removed and developed,
if necessary, to complete colorimetric reactions. The assay paper is then
compared with the original fungal growth to determine locations of
enzyme activity. Conceptually, this is similar to a substrate gel for
visualizing enzyme activity on an electrophoretic preparation. Enzyme
activity of saprotrophic fungi can be similarly visualized by placing the
assay paper in contact with fungal mycelium growing through organic
substrate in the microcosm. Assays are currently being developed for
phenoloxidase enzymes including laccase, tyrosinase and peroxidase
and for cellulase, phosphatase and proteinase.
Tuesday, 11:OO am
Ultrastructure of Photinia leafspot disease
caused by Entomosporium mespili
C. W Mi= E. A. Richardson, and T. Sewall. Dept. of Plant
Pathology, Univ. of Georgia, Athens, GA 30605, and *Dept. of
Biology, Texas A&M Univ., College Station, TX 77801.
Entomosporium mespili can be a serious problem on Photinia sp., a popu-
lar ornamental grown in the Southeastern U.S. A recent outbreak of
this disease in Georgia prompted us to examine this disease using a
combination of light and electron microscopy. Examination of very
young lesions revealed that hyphae of the fungus grew both between
and through host cells. However, the fungus also produced distinctive
haustoria that terminated in host cells. Each haustorium possessed a
slender neck region and an enlarged haustorial body. Development of
aced began with the proliferation of hyphae between the cutide
and cells of either the upper or lower epidermis of the leaf. Developing
sporogenous cells displaced the cuticle and gave rise to distinctive con-
idia surrounded by a finely granular to fibrillar extracellular matrix.
Each conidium typically consisted of two larger cells, one apical and
one basal, and three smaller lateral cells. Except for the basal cell, each
cell was equipped with a slender, bristle-like appendage. The cuticle
over the acedus eventually split and a white column of conidia
emerged. Death of surrounding host cells led to the development of
circular lesions that expanded, often fusing with adjacent lesions to
form large neuotic areas. Defoliation was common in heavily infected
plants.
Poster E18; Sunday pm
Hypocrea ruga Pers.: Fr., H. schweintzii (Fr.: Fr.) Sacc.,
and H. sp.: formation of ascostroma in vitro
Susan B. Mitchelb Dept. of Biological Sciences, Univ. of South
Carolina, Columbia, SC 29208.
The perfect states of Trichoderma Pers.: Fr. have been infrequently
produced in mtro in the past Current studies of formation of asco-
stroma in mfro by 9 strains of Hypocrea rufn Pers.: Fr., 10 strains of H.
schweinifiii (Fr.: Fr.) Sacc., and 1 strain of an unidentified H. sp. have
been performed using standard media and culture methods. Asco-
stroma were consistently formed by strains of all three species.
Symposium; Sunday, 8.50 am
Methods for measuring fungal turgor pressure
Nicholas P. Money. Dept. of Biochemistry, Colorado State
Univ., Fort Collins, CO 80523.
Consider a hypha growing in liquid medium; the water potential of
this cell is likely to be dose to that of its surroundings. This assump-
tion allows us to measure turgor pressure indirectly. Using the incipi-
ent plasmolysis technique, or osmometry, we can estimate the osmotic
potential of the cell contents. The difference between the water poten-
tial of the medium and the osmotic potential of the cell drives water
uptake and is equal to the turgor. By contrast, no assumptions about
medium or cellular water potential are necessary for direct turgor
measurement. The micropipet-based pressure probe has been used to
measure turgor directly from a number of fungi. However, the instru-
ment can only be used to record from cells with diameters above
1Opm. In this presentation the author will describe and evaluate these
methods of turgor measurement.