Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme III: PATHOGENS AND NUISANCES, FOOD AND MEDICINE Posters
and Narowal districts of Punjab. Assessment of prevalence
and disease intensity of leaf and root diseases was done.
Leaf and root fungi were isolated and identified. From leaf
and root samples Fusarium spp. were isolated.
Pathogenicity experiments were conducted on the two
commercial varieties of rice and wheat. Fusarium spp.
were pathogenic on wheat and rice varieties. Spore
suspension method was used for the evaluation of virulent
isolates of Fusarium spp. After 30 days the diseased roots
were platted and fungi were re-isolated and compared with
mother culture for the confirmation of Koch Postulates.
After pathogenicity the Random Amplified Polymorphic
DNA (RAPD) technique was used for identification and
differentiation of Fusarium isolates. For plant pathogenic
fungi, RAPD analysis has been used to analyze genetic
variations or distinguish races in Fusarium isolates. 100
strains were studied using a RAPD analysis with different
decamer primers. All the primers produced polymorphic
amplification patterns. The results were analyzed by Phylip
programme. From this survey it was concluded that
Fusarium was more prevalent fungi.
839 - Protection of Lepidium sativum against
phytopathogenic fungi Pythium ultimum by inoculation
of nonpathogenic Fusarium isolates
H. Ishimoto 1* , Y. Fukushi 2 & S. Tahara 2
1 INRA, 17 rue Sully, 21065 Dijon Cedex, France. -
2 Division of Applied Bioscience, Graduate School of
Agriculture, Hokkaido University, kita-9 Nishi-9,Kita-ku,
060-8589 Sapporo, Japan. - E-mail:
ishimotoh2001@yahoo.com
Two nonpathogenic Fusarium strains, Ls-F-in-4-1 and Rs-
F-in-11, induced the resistance in L. sativum against
pathogenic fungi, Pythium ultimum. These Fusarium
strains caused the increase of the content of antifungal
compounds and its precursor, isothiocyanate and
glucosinolate, in roots of the host plants. The resistance of
L. sativum against P. ultimum may be due to the increase of
isothiocyanate content induced by the inoculation of
Fusarium fungi. The increase of the content of
isothiocyanate occurred regardless of the abilities of
inoculated fungal strains whether they could hydrolyze
glucosinolate to isothiocyanate or not, so these changes
seemed to be the defense responses of host plant. Ls-F-in-
4-1, a Fusarium isolate which showed myrosinase activity,
inhibited the growth of P. ultimum on agar medium
containing glucosinolate. This isolate would hydrolyze
glucosinolate to generate isothiocyanate in tissue or
rhizosphere of host plant and inhibit the growth of
pathogenic fungi consequentially. This isolate may have
another protection mechanism in rhizosphere of L. sativum,
in addition to the ability to cause the increase of antifungal
compounds in the roots of host plant.
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Book of Abstracts
840 - Opportunistic mold development in controlled
environment agriculture
O.A. Jejelowo 1 , D.J. Barta 2 & K.P. Anthony 1*
1 Texas Southern University, 3100 Cleburne Avenue,
Houston, Texas, U.S.A. - 2 NASA, Johnson Space Center,
2101 NASA Road One, Mail Code EC3, Houston, Texas,
U.S.A. - E-mail: kanthony@mail.arc.nasa.gov
Hydroponically grown crop plants are being considered by
NASA for air revitalization and food production in space.
Hydroponic cultures can be infected by opportunistic
molds, which proliferate due to the humid environment and
warm temperature inside the growth chambers. This paper
reports mold development in different hydroponic cultures.
Fungal isolates include Pythium aphanidermatum, Pythium
dissotocum, Alternaria species, Cladosporium herbarium,
Penicillium species, Aspergillus species, Rhizoctonia
species and Fusarium species. The results are discussed in
terms of impact of pathogenic and opportunictic molds on
plant growth.
841 - Inhibition of sexual mating of Ustilago scitaminea
by bacterial extracts
Z.D. Jiang * , L. Ji, J.L. Xu & L.H. Zhang
Institute of Molecular Agrobiology, 1 Research Link,
National University of Singapore, Singapore 117604,
Singapore. - E-mail: zide@ima.org.sg
Ustilago scitaminea is an important pathogenic fungus of
sugarcane which causes culmicolous smut disease and
results in severe losses every year. Pathogenic infection of
the fungus is caused by dikaryotic mycelium which is
produced after mating of non-pathogenic, yeast-like
sporidia that derived from germination of teliospore on the
germinating nodes of sugarcane. Sexual mating is a short
period that separates the yeast-like sporidia and the
dikaryotic mycelium growth phases and is a potential target
for developing new approaches for disease control. To
explore the possibility, we isolated teliospores from the
infected sugarcane and confirmed that the sporidia of U.
scitaminae can be classified into two mating types. We
have screened more than 1400 bacterial isolates for matinginhibition
phenotype. Among them 16 were found to
secrete substances which inhibit mating or hyphae growth.
Preliminary taxonomic analysis suggests that they belong
to 10 genera, including Bacillus sp., Chryseobacterium sp.
and Filibacter sp. The inhibitors from the three species
have been extracted and showed to be heat-resistant and are
of low molecular weight, suggesting the non-enzymatic
nature of the inhibitors. Conventional and electron
microscopy indicate that the inhibitors have no effect on
morphology of both mating types of U. scitaminae
sporidia, except on hyphae development. Studies are in
progress to understand the chemical nature of these
inhibitors and their molecular targets.