Mitochondrial DNA variability in Fusarium proliferatum (Gibberella intermedia)

Abstract

Restriction fragment length polymorphisms (RFLP) were used to assess genetic diversity of mitochondrial DNA (mtDNA) among 184 isolates of Fusarium proliferatum recovered from maize, asparagus, palms and reed. All strains were cross-fertile with standard mating type tester strains of Gibberella intermedia. Sixteen mitochondrial haplotypes were identified following digestion of DNAs with HaeIII, with seven, seven, five and six different haplotypes from maize, asparagus, palms and reed, respectively. Four haplotypes (I, III, IV and VII) were found on more than one host. Of these four, haplotype I was dominant on maize, representing 71% of the isolates. The banding patterns for haplotypes III and IV were >90% similar to the banding pattern of haplotype I. Haplotypes I, III and IV accounted for 87% of the isolates from maize, but were less common on the other hosts, accounting for 70%, 52% and 33% of the isolates from asparagus, palms and reed, respectively. Thirteen of the 16 haplotypes were recovered from only a single host plant species. When comparing the banding patterns and frequencies of these haplotypes, at least five were recovered at a higher frequency from one host relative to the others. Our results suggest that mtDNA RFLP analysis is a useful indicator of genetic divergence in Fusarium proliferatum.