Photoinduced perithecial formation by Nectria haematococca on media containing either L-tyrosine; L-phenylalanine; or D-glucose + NaNO3 as sole carbon and nitrogen sources

Abstract

A homothallic isolate of Fusarium solani produced red perithecia when illuminated and grown on a simple basal medium containing L-tyrosine; L-phenylalanine; or D-glucose + NaNO3 as a sole carbon and nitrogen source. Few or no perithecia formed in darkness on these media. Quantitative comparisons of perithecial formation in illuminated treatments indicated that L-tyrosine was a significantly better sole source of carbon and nitrogen than either L-phenylalanine or D-glucose + NaNO3. There was no significant difference between the responses on media containing L-phenylalanine and D-glucose + NaNO3. If dark-grown treatments were subsequently illuminated, perithecia formed on media containing L-tyrosine and D-glucose + NaNO3 but not on L-phenylalanine. The initial pH of the medium containing L-tyrosine did not seem to affect the fruiting response in illuminated cultures. A reduction in the amount of L-tyrosine in the basal medium resulted in a corresponding decrease in perithecial formation.The results are discussed in connection with a possible relationship of sexual reproduction, the light requirement, and tyrosine metabolism.