Non-pathogenic Fusarium strains protect the seedlings of Lepidium sativum from Pythium ultimum

• Published in: Soil biology & biochemistry Vol. 36; no. 3; pp. 409 - 414
• Main Authors: Ishimoto, H., Fukushi, Y., Tahara, S.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.03.2004; New York, NY Elsevier Science
• Subjects: Agronomy. Soil science and plant productions; benzyl isothiocyanate; Biochemistry and biology; Biological and medical sciences; Brassicaceae; Chemical, physicochemical, biochemical and biological properties; Fundamental and applied biological sciences. Psychology; Fusarium; Glucosinolate; glucotropaeolin; Isothiocyanate; Lepidium sativum; Myrosinase; Non-pathogenic Fusarium; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Plant protection; Pythium ultimum; Soil science; Non-pathogenic Fusarium; Pythium ultimum; Glucosinolate; Myrosinase; Isothiocyanate; Plant protection; Brassicaceae; Lepidium sativum; Plant juvenile growth stage; Phycomycetes; Fungi; Cruciferae; Dicotyledones; Angiospermae; Fusarium; Soil science; Fungi Imperfecti; Isothiocyanates; Thallophyta; S-Glycosidases; Enzyme; Glycosidases; Apathogenic; Thioglucosidase; Hydrolases; Spermatophyta
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2003.10.016

Two root-colonizing Fusarium strains, Ls-F-in-4-1 and Rs-F-in-11, isolated from roots of Brassicaceae plants, induced the resistance in Lepidium sativum seedlings against Pythium ultimum. These strains caused an increase in the content of benzyl isothiocyanate, and of its precursor glucotropaeolin, in the roots of the host plants. The increased isothiocyanate content is one of the factors contributing to the resistance of L. sativum against P. ultimum. To be transformed into the fungitoxic compound benzyl isothiocyanate, glucotropaeolin has to be hydrolyzed by myrosinase, which can be produced either by plants or microorganisms. The Fusarium strain Ls-F-in-4-1 has a myrosinase activity but the strain Rs-F-in-11 has not. These results suggest that both strains are able to trigger the metabolic pathway leading to benzyl isothiocyanate production in the plant. In the case of the myrosinase-negative strain Rs-F-in-11, hydrolyzation into isothiocyanate is only due to the myrosinase activity of the plant, and in the other case, the myrosinase produced by the strain Ls-F-in-11 also would contribute to the production of isothiocyanate. This paper reports a new mode of action of non-pathogenic Fusarium strains in controlling P. ultimum.