Inhibition of Mycelial Growth and Reproduction of Phytophthora Megasperma F. Sp. Glycinea by Trichothecin Produced by Trichothecium Roseum

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https://hdl.handle.net/2142/70611

Author(s)

Al-Heeti, Mohammad Badee

Issue Date

1987

Department of Study

Plant Pathology

Discipline

Plant Pathology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

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.

Graduation Semester

1987

Type of Resource

text

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http://hdl.handle.net/2142/70611

Graduate Theses and Dissertations at Illinois