s - Mycological Society of America

E.A. MOMOL. J.W. KIMBROUGH, and H.C. KISTLER.
Department of Plant Pathology. Universtty of Florida,
Gainesville, FL 3261 1.
Electrophoretic karyotypes are dissimilar for two strains of
Fusarium owsDorum that differ in host range.
Protoplasts were obtained from strains of two formae
speciales of the wilt pathogen Fusarium owsporum. To
determine if genetic recombination could occur, protoplasts
of strain ATCC 9990 E. owsporum 1. sp. conalutinans (a
cabbage pathogen), and of strain ATCC 16601 E. owsporum
f. sp. raphani (a radish pathogen) were fused in the presence
of PEG. Chromosomes of fusants and parental strains were
separated using contour clamped homogenous electrical field
(CHEF) gel electrophoresis. . Karyotypes differed greatly
between strains and minimum number of 11 and 8
chromosomal bands were detected for ATCC 16601 and
ATCC 9990 respectively. Saccharomvces cerevisiae and
Schizosaccharomvces pombe chromosomes were used as
molecular size markers. Although strain ATCC 16601 and
strain ATCC 9990 had such different chromosome patterns,
chromosomal banding pattern of fusants were identical to
parental strains.
J.THOMAS MULLINS. Department of Botany,
University of Florida. Gainesville, FL
32611. Structure and function of soluble
cytoplasmic beta-glucans in Achlve.
Water-soluble beta-glucans are major
cytoplasmic constituents of Achlve. Two
forms of these glucans were found, a
neutral type (18%) and an acidic
phosphorylated type (82%). Both forms
release only glucose on hydrolysis, and
the polymer is formed by beta-glucosidic
linkages. These glucans function as
carbon, and probably phosphorus, reserves
in the mycelium, that support sexual and
asexual reproductive cycles during
staravation conditions. At least one
beta-glucanase can be demonstrated in the
mycelium, which is capable of hydrolyzing
these glucans.
MELANI K. OAKLEY. DAVID E. LEMKE and ROBEm D.
KOEHN. Department of Biology. Southwest Texas State Uni-
versity. San Marcos. TX 78666 -- Endomycorrhizal inoculum
potential of surface mined lands: A bioassay of different aged
sites.
Mycorrhfzal inoculum potential IMIP) of a site has been
recognized as an important factor in the reclamation of surface
mined lands. Successful revegetation efforts may well
hinge on the amount of V-A mycorrhizal inoculum present.
After d~sturbance. an unknown penod of time must elapse
before the MIP reacnes its pre-disturbance level. At a lignite
mine m central Texas. spoils varying in age from 0-35 years
were sampled, as was soil from an adjacent. undisturbed area
of the mine. These samples were anaiyzed for nurrient availa-
bility and pH. and bioassayed to determine the MIP for each
site. The bioassay was conducted uslng corn seedlings grown
in undiluted soil. as well as in soil dilutions of 1:4 and 1:40.
and undiluted sterilized soil. Roots were harvested after
periods of 30. 60. and 90 days and examined for the presence
of V-A mycorrhizal fungi. The MIP of the undisturbed soil
was greater than 50 percent, while that of the other sites de-
clined in proportion to their ages.
L. A. O'GORHAN, E. W. ROBINS. J. HAN, R. GUPTA and
H. E. BROCKMAN. Department of Biological Sciences,
Illinois State University, Normal, IL 61761.
Viability of ad-3 mutant conidia of Neurospora
crassa in pH 7 media.
We use plates of Westergaard's basal medium
supplemented with calcium pantothenate, casamino
acids, a mixture of vitamins, a trace (0.1 uglml) of
adenine sulfate, and 1% sucrose (reversion medium)
for assaying the reversion of ad-3 mutants of
Neurospora crassa carrying pan-2 and cot-l (causes
colonial growth) markers. Plates of the same medium
supplemented with 25 ug of adenine sulfate/ml
(survival medium) are used for measuring conidial
viability in the reversion experiments. We noted
low conidial viability (~5%) when the survival
medium was adjusted to pH 7, but not to pH 5 or 6.
This low viability at pH 7 was not observed with
another plating medium (Fries' basal medium
supplemented with calcium pantothenate, 100 ug of
adenine sulfate/ml, and 0.52 each of fructose and
glucose). Data will be presented showing that the low
viability in the survival medium at pH 7 is not due
to the difference in adenine sulfate concentration
or the presence of casamino acids or the mixture of
vitamins, but is due to the presence of sucrose
rather than fructose and glucose. When the standard
2 X lo7 conidialplate from each of 2 ad-3 mutants
were used on plates of the reversion medium, the
spontaneous reversion frequency was about the same
at pH 6, 7, and 8. We conclude that the decrease
in viability of conidia from ad-3 mutants of
-- N. crassa in pH 7 media is dependent on carbon
source and conidial concentration.
W. J. OTROSINA. T. E. CHASE. F. W. COBB, JR.. and K.
KORHONEN. USDA Forest Service. 1960 Addison Street,
Berkeley. CA. 94701; University of California.
Department of Plant Pathology. Berkeley. CA, 94704;
and Finnish Forest Research Insititute. Helsinki.
Finland.
Allozyme comparisons between intersterility groups of
North American and European Heterobasidion annosum.
Allozyme analyses were conducted for S, and P
intersterility (IS) groups of H. annosum from Europe
and western North America. Eleven enzyme systems and
13 loci were resolved. Very few alleles were shared
between IS groups from western North America.
indicating a large degree of genetic divergence and
lack of gene flow between them. Several loci such as
alcohol dehydrogenase, aconitase, and malate
dehydrogenase were virtually fixed for alternative
alleles between the two biological species and could