Electrophoretic karyotype analysis in some species of Bolbitius and Conocybe (Bolbitiaceae, Agaricales)

Contour-clamped homogeneous electric field electrophoresis (CHEF) is a mode rn method to separate small eukaryotic chromosomes. In the present study th is method was applied to protoplasted mycelium cultures of Bolbitius vitell inus, B. titubans, Conocybe affinis and C. rickeniana Four chromosomal band s were resolved in B. vitellinus and B. titubans, six in C. affinis and C. rickeniana, suggesting haploid chromosome numbers of n = 4 and n = 6, respe ctively. The chromosome number in the Conocybe species agrees with earlier light microscopical literature data. For Bolbitius chromosome numbers were not known previously. Using Schizosaccharomyces pombe as size standard, gen ome sizes were estimated (8.8 Mb in B. titubans, 8.0 Mb in B. vitellinus, 1 4.4 Mb in C. affinis, and 16.2 Mb in C, rickeniana). In Conocybe rickeniana , one of the chromosomes could be identified as nucleolus-organizing, apply ing Southern-hybridization with probes derived from the internal transcribe d spacers 1 and 2 of the rDNA of Trichoderma harzianum.