Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme IV: POPULATION DYNAMICS AND ECOLOGY Posters
parvisclerotigenus (small sclerotial morphotype or S strain)
was primarily confined to eastern Texas and Louisiana
where cotton is intensively grown. A. parasiticus was most
common along the southern Atlantic coast, particularly in
areas where peanuts are cultivated. A. tamarii and A.
caelatus occurred at low incidences along most of the
transect, and A. nomius was detected only in the
Mississippi River Delta region (Louisiana and Mississippi).
Individual vegetative compatibility groups of A. flavus and
A. parasiticus were widely distributed along the transect. In
a single peanut field from southwestern Georgia included
in the transect, soil populations of A. flavus and A.
parasiticus were genetically diverse, as indicated by the
large number of vegetative compatibility groups.
975 - Isolated Pinus contorta seedlings in coastal dunes
are supported primarily by fungi with high host
specificity whose spores are carried in deer feces
T.R. Horton * , S. Ashkannejhad & C. Hazard
SUNY-ESF, Syracuse, NY 13210, U.S.A. - E-mail:
trhorton@esf.edu
Pinus contorta seedlings are establishing in sand dunes on
the coast of Oregon, U.S.A. in a primary succession
pattern. The seedlings establish at least 100 m away from
the continuous forest and thus establish without the benefit
of an existing ectomycorrhizal network. Over 120 species
of fungi in 37 genera have been recorded fruiting along the
edges of the continuous forests and spores from these fungi
may disperse to the isolated seedlings via wind, water or
mammals. We identified EM fungi associated with the
roots of the isolated seedlings and found that they are
colonized almost exclusively by `suilloid' fungi: Suillus
brevipes, S. umbonatus, S. tomentosus, Rhizopogon
fuscorubens, R. occidentalis, and R. vulgaris. Deer
commonly traverse the dune system from the surrounding
forest past the isolated seedling areas and their fecal pellets
contain large amounts of spores. Spore slurries made by
bringing up individual fecal piles with variable pellet
numbers in 100 ml of water and were found to contain
between 1 x 10 6 and 1 x 10 8 spores/ml. In a bioassay,
seedlings inoculated with 20 ml of slurries made from fresh
fecal piles became colonized by the same fungi observed
on the field-collected seedlings. These results suggest that
1) deer can vector suilloid spores to areas where
mycorrhizal networks are non-existent, 2) suilloid spores
may lie dormant in soils until pine seedlings germinate, and
3) in contrast to other early succession work, pine seedlings
establish and are supported by fungi with high host
specificity.
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Book of Abstracts
976 - Effect of root endophytes on the germination of
seed of the Australian terrestrial orchid Caladenia
formosa G. W. Carr
T.T. Huynh 1 , C.B. McLean 1* & A.C. Lawrie 2
1
University of Melbourne, Institute of Land and Food
Resources, School of Resource Management, Burnley
College 500 Yarra Boulevard, Ricmond, Victoria, 3121,
Australia. -
2 RMIT University, Department of
Biotechnology & Environmental Biology, GPO Box 71,
Bundoora, Vic, 3083, Australia. - E-mail:
cmclean@unimelb.edu.au
This study investigated two seed germination methods to
determine which would maximise the production of plants
of the endangered Australian orchid Caladenia formosa for
use in re-establishment in situ. Root endophytes were
isolated from adult plants in the wild at various stages in
the orchid life cycle (budding, leafing, flowering, capsule
production and senescence). Seed was germinated on
minimal (Oatmeal Agar) and complex (PA5 containing
coconut water) media with and without root endophytes
under axenic conditions. Germination and subsequent
growth was recorded at monthly intervals for a period of
twelve months. Mycorrhizal status of the seedlings was
determined by SEM. Seed grown on minimal media
inoculated with mycorrhizal fungi from the leafing,
budding and flowering stages gave fastest (within one
month) and maximum (>50%) germination rates. Seed
grown on the complex media did not germinate in the first
month. Symbiotic seedlings grown on the minimal medium
were defasked and survived to produce tubers under
glasshouse conditions.
977 - Effects of in vivo sub-culturing on changes in
morphology and virulence of the entomogenous fungus
Metarhizium anisopliae
L. Ibrahim 1* , T.M. Butt 2 & P. Jenkinson 1
1 Harper Adams University College, Newport, Shropshire,
U.K. - 2 University of Wales Swansea, Singleton Park,
Swansea, U.K. - E-mail: librahim@harper-adams.ac.uk
One of the major drawbacks with fungal biocontrol agents
is that they can lose virulence if maintained on artificial
culture media. This attenuation of virulence has been
reported by several workers and is a major concern in the
development of insect-pathogenic fungi for pest control.
Understanding the factors responsible for this phenomenon
will contribute important information for development of
media to stabilise or increase virulence. The effects on
pathogenicity of Metarhizium anisopliae (Metsch.) Sor.
isolate V208 following one passage through the
heterologous insect-host Myzus persicae and 11 in vitro
successive subcultures were investigated. Attenuation of
virulence as measured by LT 50 (median lethal time) was
manifested in rapid decline with recovery and slight
decline after recovery. Similarly, sporulation of attenuated