A Sexual Hormone in Glomerella

Abstract

When certain self-fertile cultures of Glomerella cingulata are mated with cultures of this same fungus which are self-sterile, or nearly so, perithecia obtained from the line of contact between the paired cultures are of three types: (1) those that give rise to cultures of the self-fertile parent only, (2) those that give rise to both parental types, and (3) those that give rise to cultures of the self-sterile type only. Perithecia of the first type can be attributed to selfing of the self-fertile parent and those of the second type to cross-fertilization of the mated cultures, but the origin of perithecia of the third type has not been established. The fact that the latter occurred only in matings in which one member was a highly self-fertile culture suggested that a diffusible, fertility-inducing substance might be involved. Tests, in which filtrates from fertile cultures were applied to almost completely self-sterile cultures, resulted in a marked increase in the self-fertility of the latter. Studies of the production and nature of the active principle in such filtrates indicated that it was a specific sexual hormone rather than a non-specific or nutritional factor.