Diversity and sexuality in Gibberella zeae
1997
Bowden, R.L. | Leslie, J.F. (Kansas State Univ. Kansas (USA). Dept. of Plant Pathology)
Analyses of genetic diversity in pathogen populations are useful for evaluating risks associated with various control strategies. Diverse sexual populations can reassort genes through recombination to produce novel gene combinations more quickly than can asexual populations, which must rely primarily on mutation. The genotypic diversity of Gibberella zeae (anamorph: Fusarium graminearum Group 2) was analyzed on both macro- and micro- geographic scales using vegetative compatibility groups and DNA fingerprinting with an oligonucleotide probe. Genotypic diversity was high at both scales. Gibberella zeae is homothallic and has not been reported to participate in sexual outcrossing. In laboratory studies using marked strains, it was found that isolates of G. zeae from South Africa, Asia, and Kansas were sexually interfertile, but that none of these isolates was cross-fertile with a set of four isolates of F. graminearum Group 1. Sexual outcrossing could account for the high diversity observed in populations of G. zeae.
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