SURVEY OF FUSARIUM-SAMBUCINUM (GIBBERELLA-PULICARIS) FOR MATING TYPE, TRICHOTHECENE PRODUCTION, AND OTHER SELECTED TRAITS

The bisexual heterothallic ascomycete Gibberella pulicaris (anamorph = Fusarium sambucinum) is an important trichothecene-producing plant pathogen that has been used to study the genetics of trichothecene synthesis and pathogenicity by analysis of naturally occurring variants. To obtain additional useful natural variants, 53 strains, identified as F. sambucinum, were tested for their ability to make trichothecenes and to form fertile crosses. Eight new fertile strains were identified. These eight strains, plus 40 of the nonfertile strains, made detectable trichothecenes in liquid shake culture. In all cases, 4,15-diacetoxyscirpenol (DAS) was the primary trichothecene produced. However, variations in the level of trichothecenes produced by the eight new fertile strains indicated that they may provide unique alleles for trichothecene production genes. Comparison of the data from this study to that previously published for 20 other G. pulicaris strains revealed a high correlation between trichothecene production, sexual fertility, and the original isolation of the strain from a diseased plant. These correlations suggest that trichothecene production may be involved in both the pathogenicity and fertility of G. pulicaris.