s - Mycological Society of America

K.K. Klein and T.J. Leonard, Department of Biological
Sciences, Mankato State University. Mankato MN 56002
and Department of Botany, University of Wisconsin,
Madison WI 53706
Genetic control of dikaryotic sectoring in
Schizophvllun commune.
KLICH. M. A.. A. R. LAX and J. M. BLAND. USDA.
ARS. Southern Regional Research Center, P.O. Box
19687. New Orleans. LA 70179.
Inhibition of some mycotoxigenic fungi by Iturin A.
a peptidolipid produced by Bacillus subtilis.
The current concern about potential environmental
Sectoring, a phenotype in which there are distinct
damage by commercial fungicides has led to an
outgrowths from dikaryotic colonies, is under the
increasing demand for new control methods.
control of at least three different genetic loci
Bacillus subtilis produces peptidolipid compounds
in the basidiomvcete Schizophvllum commune. \de
of the iturin group which have been shown to have
have isolated one homokarvotic strain, dm71, which
antifungal properties, but not all fungal species
produces the sectoring plle~~olypt. when mated with
are sensitive co these compounde. In this study.
wild type strains W80 and Pil. A cross of Pi1 and
the activity of Iturin A, produced by B. subtilis
H13 also produces a sectoring dikaryon, as does
strain B-3, was tested. Paper disks impregnated
a cross of W80 and H13. W80 does not produce a
with various concentrations of Iturin A were placed
sectoring dikaryon when mated to Pil. Progency
on agar plates seeded with conidia of toxigenic
@f a cross of dm71 with W80, display segregation
species of Fusarium, Penicillium or Aspergillus.
for the sectoring phenotype when mated individually
All isolates vere inhibited at Iturin A
with wild-type strains H13 and Pil. 48 of 101 pro-
concentrations as low as 4 ugldisk. Penicillium
duced the sectoring phenotype when mated with H13
italicum, P. viridicatum and A. ochraceus were most
(approx. 1:l) and 73 of 101 produced sectoring when
strongly inhibited by the iturin whereas P.
mated with Pi1 (approx. 3:l). We conclude that
citrinum, A. flavus, A. parasiticus, and F.
there are two loci which determine sectoring in
moniliforme were least sensitive to Iturin A.
matings with Pi1 and one locus which determines
sectoring in matings with H13. Statistical tests
show that the sectoring determinant in the H13derived
dikaryons is independent (not linked) to
either of the two determinants in the Pil-derived
ROBERT KOEHN and MELANI OAKLEY. Southwest Texas
dikaryons. Progeny of a cross of Pi1 and H13 were
State University, Department of Biology, San Marcos,
tested for their ability to form sectoring dikaryons
Texas. 78666
with dm71 and W80. Results of this cross suggest
that genes in both partners in a dikaryon are impor-
A stinkhorn-grass symbiosis.
tant for the sectoring phenotype.
The lavender-hued "eggs" of Phallus hadriani (Vent.)
were collected from a St. Augustine grass environment
in November 1989. It was noted that the mycelial
cord was attached to the grass roots. More careful
observations indicated that the mycelial-grass root
-
association was ectomycorrhizal . We be1 ieve that
I(-D- m I G 1 E.B. SlNUX and K.F. RAFFA.
this association is of interest because grasses have
w=-ml= of Plant Pathology ard EnmDlogy,
not previously been known to form ectomycorrhizal
-1 Labs, 1630 Lirden Drive, Madison, WI 53706. structures. Futhermore, stinkhorns have previously
mistatic activity of extracts from red pine
not been reported to form symbiotic relationships of
lmJtarauhium texebrantis.
the mycorrhizal type.
Fungi in the genus Le-urn exhibit vary-
&-, of virulence on thelr coniferaus hmts. We
wished to &tenhe if fungistatic mapands are L.M. KOHN and J.B. ANDERSDN. Dept. of Botany,
involved in the defense of red p h to
University of Toronto, Erindale College, Mississauga, Ontario,
-rantis. Pentane &methanol SRracts werexmde Canada L5L 1C6.
from the phloan of mature red pines subjected to the A dispersed, repetitive DNA element fingerprints mycelial
foil* trea-: inoculation with viable L.
compatibility groups in field samples of Sclerotinia
terebmntis, inaxlation with autoclaved &.
sclerotiorum.
erebrant'
Sixty-four sclerotial strains of Sclerotinia sclerotiorum were
obtained from transects in two fields of Canola (oilseed rape)
in Harriston. Ontario. Mycelial pairings of the strains in all
chloroform, solubilized in amtone and water, and
combinations on agar medium produced either a compatible
reaction in which two strains merged to form one unitorm
incorporated into potato dextrnse agar. Linear
colony, or an incompatible reaction in which a reaction line
graJth was significantly higher car uMmended media developed in the interaction zone and the two strains, though
thanonmediaamm3edwithredpinee&actsan3.
growing together, remained distinct. Among the 34 strains of
slightly, hut significantly, inhibited by extracts
the first field. 6 mycelial compatibility groups (MCGs) were
from ummuxled tissw. Extracts frm mchanically recognized, the largest group containing 17 strains. Among
Klnrledaswellasinaxlatedtissue~
the 30 strains of the second field, many more compatibility
pronamced, significant inhibition of fungal grmth groups were defined. Three molecular criteria indicated
w f i e n ~ t o e x t r a c t s f n r a ~ ~ luniformity s ~ within MCGs; by one of these criteria, each MCG
uMmended media. These results indicate that the
was uniquely fingerprinted. This fingerprint was produced by
response of red pine to fungal invasion, as well as a random fragment of nuclear DNA (ca. 4.5 kb) from S.
kcudiq, involves the prduction of some cmpmxI(s)
capable of fungistatic activity.