A Role for Iron in Germination of Conidia of Colletotrichum musae

The time course of germination of conidia of Colletotrichum musae in the presence of different germination stimulants is consistent with the postulate that the stimulation of germination by anthranilic acid can be attributed to its previously established conversion to 2,3-dihydroxybenzoic acid in conidia. The activity of a number of synthetic chelating agents, such as EDTA and 1,10-phenanthroline, in promoting germination of the same order as 2,3-dihydroxybenzoic acid at about the same molarity provides support for the hypothesis that the chelating properties of the latter compound are important in its biological action.

Experiments with conidia produced on media of different iron concentrations indicate that in the absence of a germination stimulant there is a high inverse correlation between the percentage germination of conidia and conidial iron content. However, in the presence of anthranilic acid there is no significant correlation between these parameters, percentage germination remaining uniformly high regardless of the conidial iron concentration. It is concluded that conidial iron is involved in the inhibition of germination and that this inhibition can be relieved non-specifically by a variety of chelating agents.