Electrophoretic karyotype and gene assignment to resolved chromosomes of Trichoderma spp.

A molecular karyotype for three different Trichoderma species (T. harzianum, T. viride, and T. reesei) was determined by using two different systems: countour-clamped electric-field and rotating-electrode electrophoresis. Six chromosomal DNA bands were observed in T. harzianum and T. reesei and five in T. viride. The sizes of these molecules were estimated by their mobility relative to the Schizosaccharomyces pombe chromosomes and ranged between 2.2 and 7.4 megabase pairs (mbp). The estimated genome sizes range from 31 to 39 mbp. A number of genes were located in the different chromosomes by means of Southern analysis. The implications of these findings are discussed.