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|Title:||Inhibition of Mycelial Growth and Reproduction of Phytophthora Megasperma F. Sp. Glycinea by Trichothecin Produced by Trichothecium Roseum|
|Author(s):||Al-Heeti, Mohammad Badee|
|Department / Program:||Plant Pathology|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Agriculture, Plant Pathology|
|Abstract:||The antagonism between Gliocladium roseum, Trichoderma harzianum, or Trichothecium roseum and Phytophthora megasperma f. sp. glycinea (Pmg) was studied. Culture filtrates of T. roseum inhibited mycelial growth as well as zoosporangenesis of Pmg in culture and soil, but not those of G. roseum and T. harzianum. The antagonism by culture filtrates of T. roseum was found to be due to the production of trichothecin, an antifungal compound.
Trichothecin was identified by using thin-layer chromatography, gas-chromatography (GC), and mass spectrometry. A trichothecin standard completely inhibited mycelial growth, zoosporangenesis, and oospore germination of Pmg in vitro at 6, 1, and 20 $\mu$g/ml, respectively. Seventeen isolates of T. roseum were compared. Filtrates in which each isolate was grown inhibited both mycelial growth and zoosporangenesis of Pmg in vitro. The GC was used to quantify the amount of trichothecin in the culture filtrate of each isolate. A range of 18-61 mg/L was found among them. Trichothecin production was not related to spore size, colony growth and color, or mycelial dry weight.
T. roseum reduced Pmg inoculum in steam sterilized soil, but only slightly reduced disease on soybean seedlings in the greenhouse. Extraction of soil in which T. roseum was introduced indicated the presence of trichothecin. In the field, T. roseum also reduced the incidence of Pmg in fumigated and nonfumigated soil.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987.
|Date Available in IDEALS:||2014-12-15|