Induction of oospore formation of Aphanomyces euteiches drechsler by calcium ion
1995
Yokosawa, R. (Health Sciences Univ. of Hokkaido, Tobetsu (Japan)) | Kuninaga, S. | Sakushima, A.
Abundant oospores of Aphanomyces euteiches Drechsler were formed in corn meal broth culture, however, none in nutrient broth culture. The extract of mycelial mat in corn meal broth culture induced mycelial mat in nutrient broth culture to form oospores. This indicated the possibility of an inducer in the extract to form oospores. This was further supported by the fact that inorganic factions from the extract induced oospore formation. Among the inorganic compounds that are possibly included in inorganic fractions, CaO, CaCO3 and CaCl2 have induced oospore formation. From these results, it was thought that Ca(2+) might play a role in inducing oospore formation. Ca(2+) concentrations of corn meal broth and nutrient broth were 1.3 x 10(-4) and 8.4 x 10(-6) M, respectively. The eight inorganic compounds, containing Ca(2+), were able to induce oospore formation and of these, CaCl1.2H2O was the most effective at 10(-4) M. Oospore formation did not occur in corn meal broth with a Ca(2+) content lower than 7 x 10(-5) M by the addition of chelating reagents. We conclude from these facts that Ca(2+) is indispensable for the oospore formation in A. euteiches
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