First, second, and fifth authors: Agricultural & Veterinary Research Labs, Meiji Seika Kaisha Ltd., 760, Morooka, Kohoku-ku, Yokohama 222-8567, Japan; third and fourth authors: Health & Bioscience Labs, Meiji Seika Kaisha Ltd., 5-3-1, Chiyoda Sakado-shi, Saitama 350-0289, Japan; and sixth and seventh authors: Laboratory of Plant Pathology, Faculty of Horticulture, Chiba University, 648, Matsudo, Matsudo-shi, Chiba 271-8510, Japan
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Accepted for publication 23 March 2004.
In the rice blast fungus pathosystem, cerebroside, a compound categorized as a sphingolipid, was found in our previous study to be a non-racespecific elicitor, which elicits defense responses in rice. Here we describe that cerebroside C is produced in diverse strains of Fusarium oxysporum, a common soilborne agent of wilt disease affecting a wide range of plant species. In addition, some type of cerebroside elicitor involving cerebroside A, B, or C was detected in other soilborne phytopathogens, such as Pythium and Botrytis. Treatment of lettuce (Lactuca sativa), tomato (Lycopersicon esculentum), melon (Cucumis melo), and sweet potato (Ipomoea batatas) with cerebroside B resulted in resistance to infection by each pathogenic strain of F. oxysporum. Induction of pathogenesis-related genes and H2O2 production by treatment with cerebroside B were observed in tomato root tissues. The cerebroside elicitor showed no antifungal activity against F. oxysporum in vitro, indicating that the cerebroside elicitor activates defense mechanisms to confer resistance to Fusarium disease. These results suggest that cerebroside functions as a non-race-specific elicitor in a wide range of plant-phytopathogenic fungus interactions. Additionally, cerebroside elicitor serves as a potential biologically derived control agent.
plant defense activator,
© 2004 The American Phytopathological Society