BIOCHEMICAL STUDIES ON RICE BLAST DISEASE. PART 10. THE BIOCHEMICAL CLASSIFICATION OF PIRICULARIA ORYZAE CAVARA (6)
ARMY BIOLOGICAL LABS FREDERICK MD
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Forty-seven strains of piricularia oryzae were cultivated in a thiamine-free synthetic culture medium, and in a synthetic medium to which nicotinic acid was added. Nine strains reproduced rather well in a thiamine-free synthetic medium, and these strains produce 0.17-2.91 gramsml of nicotinic acid in the culture filtrates. The other strains require thiamine. It was shown that there is excellent growth of piricularia oryzae in general in a complete synthetic medium to which thiamine has been added. Also, eight strains developed relatively well in a medium to which nicotinic acid was added in place of thiamine, and it was established that nicotinic acid can be employed here as a substitute for thiamine. Strains were cultivated which require thiamine in a complete culture medium to which thiamine was added, and found that from 0.11 to 2.64 gramsml of nicotinic acid was produced. On the basis of the results the system of biochemical classification of piricularia oryzae was revised into 13 types.