FINGERPRINTING OF CYANOBACTERIA BASED ON PCR WITH PRIMERS DERIVED FROM SHORT AND LONG TANDEMLY REPEATED REPETITIVE SEQUENCES

The presence of repeated DNA (short tandemly repeated repetitive [STRR ] and long tandemly repeated repetitive [LTRR]) sequences in the genom e of cyanobacteria was used to generate a fingerprint method for symbi otic and free-living isolates. Primers corresponding to the STRR and L TRR sequences were used in the PCR, resulting in a method which genera te specific fingerprints for individual isolates. The method was usefu l both with purified DNA and with intact cyanobacterial filaments or c ells as templates for the PCR. Twenty-three Nostoc isolates from a tot al of 35 were symbiotic isolates from the angiosperm Gunnera species, including isolates from the same Gunnera species as well as from diffe rent species. The results show a genetic similarity among isolates fro m different Gunnera species as well as a genetic heterogeneity among i solates from the same Gunnera species. Isolates which have been postul ated to be closely related or identical revealed similar results by th e PCR method, indicating that the technique is useful for clustering o f even closely related strains. The method was applied to nonheterocys tus cyanobacteria from which a fingerprint pattern was obtained.