Book of Abstracts (PDF) - International Mycological Association

IMC7 Thursday August 15th Lectures
species that attack free-living nematodes with adhesive
conidia and parasites of nematode eggs and cysts. The two
most important genera, Lecanicillium and Pochonia (syn.
Diheterospora) differ by formation of
dictyochlamydospores, stronger cyanophily of the mostly
short conidia, and absence of crystal formation in the latter.
In Lecanicillium (teleom. Torrubiella, Cordyceps), only
few taxa are mildly nematode-parasitic. P. chlamydosporia
(teleom. Cordyceps) and related species are efficient egg
parasites of Heterodera and Meloidogyne species,
promising in biological control. Species of Simplicillium
(teleom. Torrubiella), lacking verticillate phialides, fall
phylogenetically outside Lecanicillium; they also parasitize
nematode eggs. Species with adhesive conidia form a
discrete genus, Haptocillium. Its species were so far known
as V. balanoides, but at least 7 species are distinct, the most
frequent being H. sphaerosporum. Contrasting with
Drechmeria coniospora, Haptocillium species attack a
wider array of free-living nematodes and are promising
biocontrol candidates.
249 - Novel biologically active metabolites from
Pochonia chlamydosporia and preliminary studies on
their distribution in Verticillium-like anamorphs
M. Stadler 1* , V. Hellwig 1 & H.V. Tichy 2
1 Bayer AG, Pharma Research, P.O.Box 10 17 09, D-42096
Wuppertal, Germany, Germany. - 2 TÜV ISB, Engesserstr.
4b, D-79108 Freiburg, Germany. - E-mail:
marc.stadler@t-online.de
Extracts from the fungus Pochonia chlamydosporia var.
catenulata strain P0297 showed interesting antiviral and
antiparasitic activities. As active principles, we identified
the known fungal metabolites, Monorden and Pseurotin A,
besides several novel natural products, for which we
propose the trivial names Pochonins A-E. The isolation and
characterisation of these compounds is summarised in a
concurrent poster. The current paper deals with studies on
the distribution of secondary metabolites in strain P0297
and further Verticillium-like anamorphs from public
collections by HPLC-based secondary metabolite
fingerprinting, aided by morphological comparisons and
Minisatellite PCR, using the methodology recently
developed in our studies of Xylariaceae [Stadler et al,
Mycological Research 105, 1191-1205, 2001]. According
to preliminary results, the production of resorcylic acid
lactones is restricted to particular species of the genus
Pochonia sensu Gams & Zare [Nova Hedwigia 72 (3-4),
329-337, 2001], while these compounds were not detected
in several species now accomodated in Lecanicillium and
Haptocillium. Therefore, the recent segregation of the
genus Pochonia from other Verticillium-like anamorphs
based on morphological and molecular methods by Gams,
Zare and co-workers also appears justified from a
chemotaxonomical point of view.
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Book of Abstracts
250 - Rhizosphere biology of nematophagous fungi
H.-B. Jansson * , J.J. Bordallo, L.V. Lopez-Llorca & J.
Salinas
Depto. de Ciencias Ambientales y Recursos Naturales,
Universidad de Alicante, Apdo 99, E-03080 Alicante,
Spain. - E-mail: hb.jansson@ua.es
Nematophagous fungi can infect, kill and digest living
nematodes. Most of these fungi can also live
saprophytically and some even have mycoparasitic
abilities. Since most plant-parasitic nematodes attack plant
roots, the rhizosphere biology of nematophagous fungi is
important from a biological control point of view. We
previously knew that nematophagous fungi were more
abundant in the rhizosphere than in bulk soil. In this study,
barley and tomato axenic plants were inoculated with the
nematode-trapping Arthrobotrys oligospora or the eggparasitic
fungus Pochonia chlamydosporia (=Verticillium
chlamydosporium). Roots were sequentially sampled, cryosectioned,
and observed under light- or cryo-scanning
electron microscopes. Both fungi grew inter- and
intracellularly, formed appressoria when penetrating plant
cell walls of epidermis and cortex cells, but never entered
vascular tissues. Using histochemical stains we could show
plant defence reactions, e.g. papillae, lignitubers and other
cell wall appositions, but these never prevented root
colonization. Nematophagous fungi grew extensively
especially in monocotyledon plants producing abundant
mycelia, conidia and chlamydospores (P. chlamydosporia).
Whether this endophytic growth induces systemic
resistance in plants is yet unknown, but worth further
investigations. The ability to colonize plant roots may also
be a survival strategy of these fungi and could explain soil
suppressiveness to plant-parasitic nematodes in nature.
251 - Holocarpic biflagellate parasites of nematodes
including Chlamydomyzium and Myzocytiopsis
S.L. Glockling
Northern Illinois University, NIU, DeKalb, Illinois, IL
60115-2861, U.S.A. - E-mail: sally@glockling.com
In comparison to related straminipilous fungi that are easily
cultured, the obligate nematode parasites are a little known
group that have been considerably understudied. Because
of their host-dependent nature and the paucity in
phylogenetically significant data, their position within the
peronosporomycetes, and their relationship to one another,
has yet to be established. The nematode parasites produce a
holocarpic thallus inside the bodies of their bactiverous
nematode hosts. The infective agents are either motile
biflagellate zoospores or adhesive aplanospores, which
attach to the nematode cuticle and penetrate with a germ
tube to initiate infection. This presentation looks at the
main diagnostic characteristics of Chlamydomyzium and
Myzocytiopsis and at the diversity within the genera.
Development of the thallus into sporangia or into resting