Phytopathological Chemistry of Black-rotten Sweet Potato

Part 15. Inhibitory Action of Ipomeamarone on Ceratostomella fimbriata (2)

Abstract

This report presents the investigation on the inhibitory effect of ipomeamarone, an abnormal metabolite of black-rotten sweet potato, on the phosphorous metabolism of Ceratostomella fimbriata.
In our experiments, using the spore cells suspension taken from the shaking culture. as well as the mycellium prepared from surface culture, we observed that ipomeamarone, even in a low concentration, prevented the inorganic phosphate absorption by Ceratostomella fimbriata from the medium and the conversion from inorganic-P to acid-soluble-organic-P and insoluble-P; while it promoted sopre respiration in the same dilution. The fact became more evident in the experiment using a medium containing P³²; e. g. ipomearone prevented the incorporation of inorganic P³² into acid-soluble-P and insoluble-P. Now we suppose that ipomeamarone takes part in the resistive action of sweet potato root against Ceratostomella fimbriata as an uncoupler.
Further investigation has been focused on the relation of ipomeamarone to the nucleic acid metablism of Ceratostomella fimbriata, the mutation and adaptation of the fungus.
We are grateful to Prof. Yusuke SUMIKI and Prof. Saburo FUNAHASHI for their guidances and advices, and Prof. Takashi KUBOTA for the gift of ipomeamarone.