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were mixed-infected with both CyMV and ORSV; 27.2% were not
infected. The indirect ELISA method was used for virus detection.
118
nase was not associated with immunization in Xanthi-nc
tobacco. Total soluble carbohydrate increased in Kyl4 and
Xanthi-nc immunized with P. tabacina but not in regenerants of
immunized Kyl4 or Kyi4 immunized by TMV.
PHENOL OXIDASES OF FIVE ARMILLARIA BIOSPECIES.
P.M. Wargo, U.S.D.A. Forest Service, Hamden, CT
S.F. Marsh and
06514
122
ASSOCIATION OF PATHOGENESIS-RELATED PROTEINS(PRs), PEROXIDASE
Three isolates each
and
of Armillaria
VII were
biospecies
assayed
groups I,III,V,VI
for constitutive phenol oxidases after 11,
(PER), 0-1,3-GLUCANASE(GL) AND CHITINASE(CH) WITH INDUCED
RESISTANCE OF TOBACCO TO PERONOSPORA TABACINA BUT NOT TO
18,25,32 and 39 days growth in liquid culture. Laccase was
measured in the mycelium, rhizomorphs and extracellular culture
medium. Tyrosinase was only found intracellularly. Averaged
across isolates, intracellular laccase activity was highest at
11 days while tyrosinase and extracellular laccase were highest
at 18 days. Activities of laccase and tyrosinase were not
different among biospecies groups because there were large
differences between isolates within a biospecies group. Among
rhizomo~ph-producing isolates (12), isolates that produced more
rhizomorphs had higher laccase activity. Laccase activity was
also present in isolates that produced no rhizomorphs. Preliminary
results indicate that peroxidase activity may be present
in some isolates. No relation between the enzyme activities
and reported pathogenicity, pH of culture medium, phenol production
or mycelial pigmentation has been found,
SYSTEMIC TOBACCO MOSAIC VIRUS. X. S. Ye S. Q. Pan and J.
Kuc. Dept. of Plant Pathology, University of Kentucky,
Lexington, KY 40546-0091.
Tobacco Ky 14 inoculated with TMV and held at 23C for 3-12
days had localized necrosis on the inoculated leaves and was
systemically protected against blue mold and TMV. Above 28C,
systemic mosaic was apparent. Accumulation of PRs and activi-
ties of PER, GL and CH increased in induced plants. When TMV-
inoculated leaves were removed 12 days after inoculation and
plants were challenged with TMV or P. tabacina and transfered
from 23C to 28C one day after challenge, induced resistance to
P. tabacina but not TMV was apparent. Accumulation of PRs and
activities of PER, GL and CH were further increased after
challenge in induced plants at 23C and 28C. Transfer of plants
from 23C to 28C for 7 days after induction and removal of
inducer leaves did not affect induced resistance to P.
119
tabacina and TMV when challenged and held at 23C for 7 days.
ASSOCIATION OF PEROXIDASE WITH SYSTEMIC RESISTANCE TO
CLADOSPORIUM CUCUMERINUM INDUCED BY COLLETOTRICHUM LAGENARIUM
IN CUCUMBER CULTIVARS RESISTANT OR SUSCEPTIBLE TO C.
CUCUNERINUM. R. Reuveni and J. Ku6. Department of Plant
Pathology, University of Kentucky, Lexington, KY 40546-0091.
123
ENHANCED PEROXIDASE AND ITS PERSISTENCE IN CUCUMBER PLANTS
IMMUNIZED AGAINST ANTHRACNOSE BY FOLIAR INOCULATION WITH
COLLETOTRICHUM LAGENARIUM. R. F. Dalisay and J. Kuc, Dept
Cucumber cultivars susceptible or resistant to C. cucumerinum
were systemically protected by infection of leaf 1 with C.
lagenarium. The protection of leaf 2 was positively correlated
with the concentration of C. lagenarium inoculum, negatively
correlated with the concentration of challenge inoculum
and was not overcome by 106 conidia/ml of C. cucumerinum.
Peroxidase activity increased in protected-leaf 2. After
challenge, peroxidase increased further in protected plants
and was detected as early as 24 hr after challenge in resistant
protected plants. The increase in peroxidase activity
and tandte the apprteaned appearance pants.d and intensification int e icreastion operoxidase of peroxidase ativty isozymes
occurred in the absence of visible damage. Peroxidase after
of Plant Pathology, University of Kentucky, Lexington, KY
40546-0091.
Inoculation of the first true leaf of cucumber plants with
conidia of C. lahenarium induces systemic resistance against
theisa f fr-wkWen temiculate (inde
the same fungus for 4-6 weeks. When the inoculated (inducer
leaf was detached one week after inoculation, resistance was
reduced but persisted for the same time period. Peroxidase
activity was 3-10 x greater in induced plants than in plants
treated with water on leaf 1 and was consistently higher in
plants after leaf with 1 the was inducer induced leaf followed attached. the same Leaves pattern 4-12 for in the protec- bud
to n eoiaeatvt sla .Rslssgetta
challenge may be a useful marker for both induced and non- signal produc e dur ith fs 7aaf te iulation o
induced resistance.
120
signal produced during the first 7 days after inoculation of
leaf 1 affects protection and peroxidase activity of expanded
leaves and leaves in the bud. Once triggered, the response
persists in the absence of the signal.
BIOSYNTHESIS OF SESQUITERPENOID PHYTOALEXINS IN
BACTERIALLY INOCULATED COTTON LEAVES AND COTYLEDONS.
M. Essenberg, H. Hamada, and G. D. Davis. Dept. of Biochemistry,
Oklahoma State University, Oklahoma Agricultural Experiment Siation,
Stillwater, OK 74078-0454.
124
PMG WALL GLUCAN IS AN EFFICIENT ELICITOR OF ISOFLAVONES BUT IS
NOT AN EFFICIENT ELICITOR OF GLYCEOLLIN IN SOYBEANS. T. L.
Graham and M. Y. Graham, Dept. of Plant Pathology, The Ohio
Chemical degradation of 2,7-dihydroxycadalene (DHC) and 2-hydroxy-7methoxycadalene
(HMC) produced in cotton cotyledons from [2-14C,5-
3
H]mevalonolactone following inoculation with an incompatible race of
Xanthomonas campestris pv. malvacearum revealed that biosynthesis of DHC
and
probably
HMC
occurs
involves
as
a
hydrogen
1,3-hydride
transfer to the
shift
isopropyl
during
side chain,
cyclization
which
of the farnesyl
precursor. Gas chromatographic/mass spectrometric analysis of cotyledonary
extracts showed the presence of inoculation-induced substances of molecular
weights 204, 206, 216, 218, and 232, whose mass spectra suggest that they
are intermediates on the pathway to DHC and HMC. High-resolution mass
spectrometry and tH-nmr of the MW 218 compound indicate that it is
C15H22O, 7-hydroxycalamenene.
State University, Columbus, OH 43210.
The cell wall glucans of Phytophthora megasperma f. sp. glycinea
(PMG) elicit glyceollin at nearly hormonal (ng/ml) levels.
However, they are non-race specific elicitors of glyceollin.
Because we have demonstrated that preformed
of
pools
the glyceollin
of conjugates
precursor, daidzein, are used in race
specific accumulation of glyceollin in PMG infected tissues, we
were interested to re-examine the specific role of the glucan
elicitors in relation to these events. We discovered that PMG
glucan is a highly efficient elicitor of daidze in, but is a
very inefficient elicitor of glyceollin. Only 3-20% of the
daidzein in PMG glucan treated tissues is converted to glyceollin,
depending on factors such as light intensity, wounding and
121
tissue age. The results complement earlier studies in
suggesting that effective glyceollin elicitation may require
RELATIONSHIP OF f3-1,3-GLUCANASE AND TOTAL SOLUBLE
either a second elicitor or a specific physiological state of
the tissue perceiving the PMG wall glucan.
CARBOHYDRATE TO THE IMMUNIZATION OF TOBACCO AGAINST BLUE MOLD
CAUSED BY PERONOSPORA TABACINA. S. Q. Pan, x. s. Ye and J. 125
Kuc, Department of Plant Pathology,
Lexington, Ky 40546-0091.
University of Kentucky,
BACTERIAL AND PLANT GENE EXPRESSION IN POTATO SOFT ROT. Z.
Stem injection of Kyl4 tobacco with sporangiospores of P.
acina or leaf inoculation with tobacco mosaic virus (TMV)
tab-
Yfang, C.L. Cramer, and G.M.
Biology of Plant Stress, VPI&SU,
Lacy, Laboratory for Molecular
Blacksburg, VA 24061-0330.
systemically immunized plants against disease caused by both
pathogens and systemically increased -1,3-glucanase activity.
After challenge with P. tabacina, lI-1,3-glucanase also increased
earlier and more rapidly in immunized plants and their
tissue culture regenerants than in controls. One dominant
intercellular isozyme of P-l,3-glucanase was associated with
immunization before and after challenge and another with symptom
expression after challenge only in controls. P-1,3-gluca-
A membrane-separated system involving potato tuber slices and
Erwinia carotovora subsp, carotovora (Ecc) was used to study
simultaneous in planta regulation of bacterial pathogenicity-
related and defense-related genes in soft-rot interaction.
Northern hybridization showed increases in pathogenicity-
related genes including endo- and exo-pectate lyases (PLs) and
endo-polygalacturonase (PG) within 3 hr reaching maxima beteen
6 and 12 hr. Most defense responses were monitored by phenylal-
1150 PHYTOPATHOLOGY