Female fertility and single nucleotide polymorphism comparisons in Cylindrocladium pauciramosum

Cylindrocladium pauciramosum is well established in South America, and has recently been collected from nurseries in South Africa, Italy, and the Unit ed States. Isolates were compared with respect to the percentages of hermap hrodites and the respective mating types in the different samples. Based on these data, the effective population size could be determined for the diff erent areas studied. All nurseries had mating type ratios significantly dif ferent from an idealized 1:1 ratio. In the South African nursery, the MAT-1 mating type was dominant, while the MAT-2 mating type dominated in other s amplings. This is consistent with an introduction of a small starter popula tion. High percentages of hermaphrodites also agreed with recent introducti ons into nurseries in Italy and the United States. Variability of DNA seque nces of the 5' end of the beta -tubulin gene from a set of C. pauciramosum isolates from different geographic regions was low to high. Isolates from S outh Africa, the United States, and Australia had identical beta -tubulin D NA sequences; this sequence was also found in the Italian sample, along wit h another unique group. Finally, a group of isolates obtained from South an d Central America had the highest variation of all isolates investigated, a nd also included isolates that shared single nucleotide variations with ano ther species, C. candelabrum. These findings suggest that C. pauciramosum m ost likely has a Central or South American center of origin.