Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme IV: POPULATION DYNAMICS AND ECOLOGY Posters
technique can also be used to isolate microsatellite loci in
any organism.
959 - Componets and techniques of spore sampling
from determining presence to molecular biology
M.G. Eversmeyer 1* , C.L. Kramer 2 & R.L. Bowden 1
1 USDA-ARS, Throckmorton Hall, Manhattan, Kansas
66506, U.S.A. - 2 Division of Biology, Ackert Hall,
Manhattan, Kansas 66506, U.S.A. - E-mail:
epidem@ksu.edu
Spore samplers, from a simple petri dish or glass slide to
complex volumetric samplers, have been used to determine
the presence, concentration, and identification of airborne
fungal spores since the beginning of mycological studies.
The simplest of spore traps that collect spores by gravity
deposition, have been used primarily for identification of
spores present in the air. Volumetric samplers provide the
added advantage of measuring the concentrations of fungal
spores under existing wind conditions within a given air
mass. Flow meters that provide variable adjustments in the
rate of air intake of the sampler may be used to obtain isokinetic
volumetric samplers. Small personal samplers have
been developed for use by individuals with specific
allergies to obtain levels of allergens that individuals may
encounter on a daily basis. Techniques for identification of
fungal spores collected by volumetric samplers using
molecular markers are being developed. This presentation
identifies various types of samplers that have been used in
studies of identification, production, release, local dispersal
and long distance transport, survival, and deposition of
mycological material important in disease epidemics.
Photos or sketches of many of the samplers used in
research in our laboratory are shown including photos of
the initial samplers used in private aircraft or on board
ships. Major advantages and disadvantages of each type
sampler are discussed.
960 - Monitoring a non-pathogenic strain of Fusarium
oxysporum on tomato plant using Green Fluorescence
Protein gene marker
J. Fatehi * , A. Lindberg & B. Gerhardson
Plant Pathology & Biocontrol Unit, SLU, P.O. Box 7035,
Uppsala 750 07, Sweden. - E-mail:
jamshid.fatehi@vpat.slu.se
Non-pathogenic strains of Fusarium are known organisms
to effectively reduce the incidence of wilt diseases caused
by the pathogenic isolates of this genus. Competition for
nutrition in soil and rhizosphere, induced systemic
resistance and competition for root colonization have been
suggested as modes of action involved in such antagonistic
effects. Here a non-pathogenic strain of Fusarium
oxysporum, previously demonstrated to be an effective
inhibitor of the tomato wilt pathogen caused by Fusarium
oxysporum f.sp. lycopersici, was genetically transformed
with both hygromycin B resistance and a gene for green
fluorescence protein (GFP). Stable transformants with
bright green fluorescence and resistant to hygromycin B
were obtained. Several transformants with similar growth
rate and colony morphology to the wild-type isolate were
further used for the inoculation of tomato seedlings, in
order to study their behavior on the host and the pattern of
colonization of the roots. The growth of fungal mycelia on
the root surface, penetration into the root cortex and
colonization of this tissue were observed using a
fluorescence microscopy. Re-isolation of the transfromants
from surface sterilized root and stem tissues of inoculated
tomato plants, 4 weeks after inoculation, indicated that the
fungus was able to extensively colonize its host tissues.
961 - Dynamics of microbial communities associated
with submerged Typha angustifolia litter: effects of
litter manipulations on microbial decay processes
A.J. Foley * , M.D. Collins, R.K. Neely & K.A. Kuehn
Department of Biology, Eastern Michigan University, 316
Mark Jefferson, Ypsilanti, Michigan 48197, U.S.A. - Email:
afoley@online.emich.edu
In wetlands, most of the plant biomass enters the detrital
pool to be decomposed by microorganisms. Prior studies of
wetland plant decay have often used litter that has been
prematurely harvested and/or manipulated (e.g, oven-dried)
prior to submergence. We examined the effects of litter
manipulations, such as oven drying and litter age
(senescent vs. standing-dead), on microbial assemblages
associated with decaying litter of Typha angustifolia. Plant
litter of T. angustifolia was harvested after senescence and
after a period of standing-dead decay. Litter of both age
groups were air-dried and oven-dried (80 °C), placed into
litter bags (1 mm mesh), and submerged in the wetland.
Litter bags were retrieved periodically and analyzed for
mass loss, microbial biomass, fungal production rates, and
rates of microbial respiration. Several microbial parameters
differed markedly between the litter treatments. Fungal
biomass (ergosterol) associated with oven-dried litter was
62% lower than air-dried litter during the first 114 days of
decay (i.e., 83 ±53 and 220 ±43 µg ergosterol g -1 AFDM,
respectively). Rates of fungal production and microbial
respiration exhibited similar trends. Initial rates of
microbial respiration showed a 5-fold difference between
oven-dried and air-dried treatments (ca. 10 vs. 70 µg CO2-
C g -1 AFDM h -1 , respectively). These results point to
contrasting patterns in microbial dynamics during emergent
macrophyte decay as a result of litter manipulations.
Book of Abstracts 289