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Studies on Polyoxins, Antifungal Antibiotics

1968; Phytopathological Society of Japan; Volume: 34; Issue: 4 Linguagem: Inglês

10.3186/jjphytopath.34.272

1882-0484

Shigeki Sasaki, Nobuya OTA, Jun Eguchi, Yasushi Furukawa, Takeo Akashiba, Tetsuo TSUCHIYAMA, Saburo Suzuki,

Plant Disease Resistance and Genetics

Polyoxins, antifungal antibiotics produced by Streptomyces cacaoi var. asoensis, are consisted of many active fractions such as A, B, D, E, F, G and etc., and have antifungal activities selectively against several plant pathogenic fungi. In this paper, fungicidal activities of Polyoxins against sheath blight of rice Pellicularia sasakii (Shirai) S. Ito, and behaviours in plant tissue were investigated.Among many active fractions, D fraction was the most effective for control of this disease. In vitro, Polyoxin complex was more active than organic arsenic compounds and other fungicides against the fungus. In the pot test in greenhouse, Polyoxin complex showed the same protective effect and the same inhibitory effect on development of lesion as methanearsonic acid-ferric, ammonium salt complex. Treating on rice plants, Polyoxin complex showed about the same stability for ultra violet as those of organic arsenic compounds.By bioassay method, it was recognized that Polyoxin complex penetrated into leaves of kidney bean from back side to surface and sheaths of rice plants from surface to tissue inside. Dipping the cut end of stem of kidney bean and no wounded root of rice plant into the solution of Polyoxin complex, a remarkable amount of Polyoxin complex was found to be absorbed and translocated. Being treated by Polyoxin complex on sheaths of rice plant, no rising of active fraction of Polyoxin was observed in the upper part of no wounded sheaths or diseased sheaths of rice plants, but a remarkable amount of active fraction of Polyoxin was observed in the upper of sheaths which were injured by needle prick method. We could not obtain any definite results of penetration of Polyoxin complex into mycelium of sheath blight of rice plant.