March 2008 - Mycological Society of America

(1.7%), plus other eukaryotes (Alveolata, Stramenopila, and Mycetozoa).
The fungi were distributed among known fungal phyla with
37.2% ascomycetes, 15.7% basidiomycetes, 8.6% glomeromycetes
and few zygo- (0.9%) or chytridiomycetes (0.2%). Nearly 40% of the
fungal OTUs could not be assigned to a phylum because of unclear
affinities or affinities exclusively to environmental reads. When the
treatment effects were analyzed, neither the richness nor diversity responded
to manipulations (P>0.05). However, 21 (~10%) of the 200
most abundant OTUs responded to altered precipitation. We conclude
that MPS is an efficient high throughput tool to assess diversity, species
richness and community composition. Contributed Presentation
Kariuki, George M. 1 * , Mibey, Richard K. 2 and Mutitu, Eunice W. 3
1 NARL, Kenya Agricultural Research Institute, P.O. Box 14733 Nairobi,
Kenya, 2 Department of Botany, University of Nairobi, P.O. Box
30197 Nairobi, Kenya, 3 Department of Crop Protection, University of
Nairobi, P.O. Box 30197 Nairobi, Kenya. gmmkariuki@yahoo.com.
Some potential mycoherbicides candidates for the biocontrol of
water hyacinth in Kenya. A survey of plant pathogenic fungi associated
with naturally infected water hyacinth Eichhornia crassipes was conducted
at different sites in Kenya. Twenty fungal isolates belonging to
different genera were isolated. Two Alternaria spp. isolates designated
WH3b1 and WH3b2 were found to be pathogenic to the water hyacinth
both under green house and field conditions. On the basis of conidial
measurements, growth characteristics and pigmentation in cultures, the
two Alternaria spp. were identified as A. alternata and A. eichhorniae
respectively. A. eichhorniae caused severe leaf blight. Symptoms started
to appear between fifth and the seventh day after inoculation and
were manifested in the form of leaf spots and leaf blotches usually on
the older leaves. For A. alternata, symptoms appeared 3 days after inoculation
as small yellowish, chlorotic lesions with necrotic brown centers.
Later these lesions enlarged gradually and centers turned dark
brown with pale yellow margins. Contributed Presentation
Kasuga, Takao 1 *, Greenwald, Charles 2 , Wilkinson, Heather 2 , Ebbole,
Dan 2 , Shaw, Brian 2 and Glass, Louise. 11 Department of Plant & Microbial
Biology, Univ. California, Berkeley, CA 94501, USA, 2 Department
of Plant Pathology & Microbiology, Texas A&M University,
College Station, TX 77843, USA. kasugat@berkeley.edu. mRNA profiling
revealed enrichment of orphan gene transcripts during asexual
development of a filamentous ascomycete Neurospora crassa.
We asked if there is any correlation between the pattern of expression
and phylogenetic age for Neurospora crassa genes. N. crassa genes
were classified into six mutually exclusive groups (Cai et al., J. Mol.
Evol 2006): (1) Eukaryote/Prokaryote-core, a group of genes whose orthologs
were identified in non-fungal Eukaryotes and/or Prokaryotes,
(2) Basidiomycota-core, genes shared with basidiomycetes, (3) Hemiascomycete-core,
(4) Euascomycete-specific, (5) N. crassa orphans,
which lack sequence similarity to any of the genes in SIMPS database
and (6) Remainder. We then examined the mRNA profiles obtained
during vegetative growth and conidiation using N. crassa microarray
representing all the predicted ORFs (c.a. 11,000). We found an overrepresentation
of Euascomycete-specific genes in very young hyphae
(0 to 3 hours old) and in mature hyphae engaged in conidiation (18 to
27 hours old; enrichment test, p