BASE COMPOSITION OF DNA FROM GLOMALEAN FUNGI - HIGH AMOUNTS OF METHYLATED CYTOSINE

Glomales (Zygomycetes) are obligate fungal symbionts of roots of land plants and form arbuscular mycorrhiza, Sporal DNA of 10 isolates belon ging to nine species was purified and the base composition was determi ned by RP-HPLC, Base composition fell in a narrow range between 30 and 35% G + C. A high amount of methylated cytosine (mC) accounting for 2 -4% of the total nucleotides was found in all taxa, The DNA melting pr ofile was defined for Scutellospora castanea, It corresponded to 32% G i + C, and the shape of the denaturation curve suggested a heterogenei ty in the GC content within the fungal genome, Knowledge of GC content s and variations between taxa are essential for evaluating nuclear DNA content using fluorimetric methods, and high proportions of mC/C + mC in the genomes of glomalean fungi could reflect the existence of repe ated DNA families, Results are discussed in relation to data for other fungi and eukaryotes. (C) 1997 Academic Press.