s - Mycological Society of America

S. C. REDLIN and A. Y. ROSSMAN. Systematic
Botany and Mycology Laboratory, USDA-ARS;
Beltsville, MD 20705. Cry~todiaporthe
corni (Diaporthales) and its distinctively-
pigmented anamorph.
CrvDtodiaDorthe corni (Wehmeyer) Petrak is
a pyrenomycetous teleomorph reported on
Cornus spp. This fungus is associated with
a twig blight and was collected on pagoda
dogwood (cornus alternifolia L.) in the
northern United States during investigations
on dogwood anthracnose. h distinctive
bright orange pigment produced in pure
culture on several media was similar to the
color observed on dogwood twigs containing
ascocarps and conidion~ata. The anamorph
was produced abundantly in cultures derived
from single ascospores. MYXOSDO~~U~ nitidum
Berkeley and Curtis is the earliest name for
this anamorph, also known as Zvthia
aurantiaca (Peck) Sacc. This study includes
the first description of the fungus in pure
culture and a redescription of the
teleomorph and anamorph . Results indicate
that Crv~todia~orthe corni is restricted to
Cornus alternifolia. Characteristics of the
growth in culture, the conidiomata, and the
conidia differ significantly from the
dogwood anthracnose fungus.
STEF HEN REHNER and RYTAS VILGALYS. Dept. of
Botany, Duke University, Durham, N.C. 27706.
Sequence evolution of the 25s nuclear
ribosomal RNA subunit and phylogenetic
analysis of the Agaricales
Due to their universal occurrence and conserved
structure, the nuclear ribosomal genes (rDNA) are a
potential source of informative characters for
inferring patterns of evolutionary relationships
among the extant lineages of fungi. We describe a
series of oligonucleotide primers developed for the
polymerase chain reaction (PCR) to amplify
ribosomal genes from fungi. The amplified rDNA
can be used for restriction analysis, cloning, or
nucleotide sequencing. Sequence analysis of the 5'
half of the 25s genes of Microm~hale, Mvcena,
Amanita, and &tharellus has revealed two modes
of sequence evolution of rDNA in fungi, either
through direct nucleotide substitution or length
mutation. The picture that emerges is that the 25s
ribosomal genes are comprised of conserved
regions interspersed with more divergent domains,
the latter often differing significantly in primary
sequence and length. A data set of sequences from
representatives of Agaric families will be
presented and its use for evolutionary analysis will
be discussed.
-- Don R. Rrvnolds, Natural History Museum of
Los Angeles County. 900 Expositio~l
Boulevard, Los Angeles, California 90007
and John W. Taylor, Plant Biology
Department, University of California.
~erkele~, California 94720.
Preliminary Observations Concerning a
Phylogenetic
Ascomycetes.
Hypothesis for Ascostromatic
The fungi of interest historically are known
as the loculoascomycetes or bitunicate
ascomycetes. A major problem' in the
classification of these fungi, and its sister
groups, is a lack of understanding of robust
monophyletic groups. A phylogenetic
hypothesis for loculoascomycetes sensu lato,
as ascostromatic ascomycetes with a
fissjtunicate, rostrate or extend-itunicate
ascus, is being tested with molecular
techniques and methods. Preliminary results
from the study are reported.
DNA sequencing is being carried out on DNA
from pure culture isolates as well as from
material obtained directly from nature and
from herbarium collections. Sequencing data
from the relatively large, evolutionary
conservative, tandem, nuclear ribosomal.
repeat DNA are being analyzed for
confirmation of the monophyletic units
discovered with macrocharacter analysis.
P.L. RICHTER and J.M. BRUHN. School Of Forestry ard Uocd Products,
Michigan Tuhnological University, noughton, Michigan 19931.
Shifts in mycorrhizal fvlpus colonization of Pinus resinoss seedlings
follwing outplanting.
An ordered shift in mycorrhizal fmra colonization occurred on
--
Pinus resinosa Ait. seedlings wtplanted on three recently cleared
northern hardwwd sites in the Uppr Peninsula of Michigan. The shift,
related to seedling mge fran ourplmting, was demonstrated by
quantification of nycorrhizml mrphology types, lsboratory isolation of
fmgi fran mycorrhizee, phy$iological categorization of fmgi recovered
frun ycorrhizae, and surveys of fruiting bodies associated with
seedlings. Uith increasing plantation age, 1) the -r of
nomncorrhizal root tips encantered declined to zero. 2) the cannon
nursery ysorrhizae decreased in abnd.nce, 3) m wcorrhizal types
(especially Cmococcrn md u) k c m more abundant, 4)
cellulolytic f w i (in part representing ectmjomycorrhizal fungi)
uere isolated fran nycorrhizae less frequently, while 5)
utomycorrhizal f w i uere isolated from mycorrhizae more fr-tty.
The nvrber of apparently different mycorrhizal f w species isolated
fran mycorrhizae increased fran 5 in the first year after outplanting
to 22 in the fwrth year.
The squcnce of ycorrhizal funpi Colonizing red pine seedlings from
nursery to four years follwing outplanting was as follows. Ectcndo-
wcorrhizal fmgi. Thelechora terrestris, md Laccaris laccata uere
present on nursery seedlings. Ectendaycorrhizal fungi nave wy to
further colonization by utnycorrhizal f w i soon after outplanting.
1. terrestris and 1. Iaccata persisted on outplated seedlings, but
allowed colonization by g. geophilun and L. bicolor during the first
year. The Latter tw cpecies increased (n abundance on seedlings,
while gt&& spp. appeared bring the sued year. Lactarius spp.
appared during the third year, and llekluna sw. appeared during the
fwrth year. ALmg uith the major ptners Listm above, additiarsl
unidentified ectcmycorrhizal fmgi (possibly species of m,
Boletus, Rhizooogon, etc.) formed mycorrhizse with seedlings,
especislty during the third end fourth year after outplanting.