Studies on the Bioorganic Chemistry of Interaction's Substance between High Plant and Low Plant

While the interaction between higher and lower plants can take many forms，it is the attack of the micro-organism on the higher plant leading to plant disease。We studied bioorganic chemistry concerns the chemistry of interaction‘s substances between higher plant and pathogenic fungus.Outline of research work is summarized as follow.·Isolation and structural determination of new phytotoxin，three usnic acid derivatives from the pathogen causing circular leaf spot disease of Japanese persimmon，ampullicin and isoampullicin from fungus obtained from a dead pine tree and syringostatins A and B from the pathogenic bacterial blight of lilac。·To investigate the structure-activity relationships of host-specific PM-toxin A，a component of the host-specific corn pathotoxin，comparison of their biological activity demonstrated the general structural feature necessary for the potent activity。AM-toxin is know as host-specific toxin，host-specific toxin action mechanism is inverstigated the structure of a toxin-receptor peptide in apple leaves.·Biochemical defense mechanisms involving both pre-and post infectional changes in the host plant。Study of the protection mechanisms of rice plant against bacterial leaf blight.Oryzalides A and B，and oryzalic acid A，which were isolated from healthy flag leaves of rice plant.Antifungal stress compounds were isolated and identified from adzuki bean that had been treated with C.gregatum type B which is an avirulent strain fungus causing stem rot disease on the host plant.

While the interaction between higher and lower plants can take many forms, it is the attack of the micro-organism on the higher plant leading to plant disease. We studied bioorganic chemistry concerns the chemistry of interaction's substances between higher plant and pathogenic fungus.Outline of research work is summarized as follow.・ Isolation and structural determination of new phytotoxin, three usnic acid derivatives from the pathogen causing circular leaf spot disease of Japanese persimmon, ampullicin and isoampullicin from fungus obtained from a dead pine tree and syringostatins A and B from the pathogenic bacterial blight of lilac.・ To investigate the structure-activity relationships of host-specific PM-toxin A, a component of the host-specific corn pathotoxin, comparison of their biological activity demonstrated the general structural feature necessary for the potent activity. AM-toxin is know as host-specific toxin, host-specific toxin action mechanism is inverstigated the structure of a toxin-receptor peptide in apple leaves.・ Biochemical defense mechanisms involving both pre- and post infectional changes in the host plant. Study of the protection mechanisms of rice plant against bacterial leaf blight. Oryzalides A and B, and oryzalic acid A, which were isolated from healthy flag leaves of rice plant.Antifungal stress compounds were isolated and identified from adzuki bean that had been treated with C. gregatum type B which is an avirulent strain fungus causing stem rot disease on the host plant.