Reproductive mode of central European <i>Fusarium graminearum</i> and <i>F. culmorum</i> populations
2008
Tóth, Beáta | Varga, János | Szabó-Hevér, Ágnes | Lehoczki-Krsjak, Szabolcs | Mesterházy, Ákos
Fusarium head blight caused mainly by <i>Fusarium graminearum</i> and <i>F. culmorum</i> is the most important disease of wheat in Central Europe. While <i>F. graminearum</i> is homothallic, no sexual cycle has been observed in <i>F. culmorum</i> . Knowledge regarding the species distribution and population structure of these pathogens is important to estimate their significance for breeding. There are two fundamental means by which fungi and other organisms transmit genes to the next generation: through clonal reproduction or by sexual recombination. To clarify the population structures of <i>F. culmorum</i> and <i>F. graminearum</i> in Central Europe, RAPD and IGS-RFLP data sets of the isolates were subjected to both the index of association tests and tree length tests. Our data indicate that the world-wide <i>F. graminearum</i> and <i>F. culmorum</i> populations have recombining structures, while both the Hungarian <i>F. culmorum</i> and <i>F. graminearum</i> populations reproduce clonally. The frequent occurrence of <i>F. graminearum</i> perithecia on corn residues indicates that this species undergoes a sexual cycle. Both mating type genes have been identified in each examined <i>F. graminearum</i> isolate, while the heterothallic distribution of mating type genes in <i>F. culmorum</i> indicates that this species lost its sexual cycle relatively recently.
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