This study demonstrates genetic transformation in the cyanobacterium Gloeocapsa alpicola and intergeneric transfer of antibiotic-resistance markers between G. alpicola and Anacystis nidulans. Researchers developed an effective DNA isolation method using lysozyme, sodium lauryl sulphate, and sodium aminosalicylate for cell lysis, yielding 1.5 mg DNA per gram of wet cells. While intraspecific transformation of streptomycin resistance within G. alpicola was unsuccessful using standard methods, calcium chloride treatment enabled successful transformation. Critically, intergeneric transformation succeeded: G. alpicola DNA transferred streptomycin resistance to A. nidulans at frequencies up to 2.6 × 10⁻⁶, far exceeding spontaneous mutation rates. Conversely, rifampicin resistance from A. nidulans transferred to G. alpicola at 7.5 × 10⁻⁷. Enzyme treatment experiments revealed that both DNA and RNA contribute to transformation efficiency, with DNAase reducing transformation by 84% and RNAase by 57.7%. This research expands understanding of genetic transformation in cyanobacteria beyond Anacystis species and suggests potential for transferring useful traits like nitrogen-fixation ability between blue-green algal species.

Key findings

• Genetic transformation successfully demonstrated in G. alpicola using calcium chloride treatment as a sensitization method
• First demonstration of intergeneric transformation of antibiotic-resistance markers between G. alpicola and A. nidulans in both directions
• Both DNA and RNA are required for transformation in G. alpicola, with DNA playing the major role (84% efficiency reduction with DNAase versus 57.7% with RNAase)
• Intergeneric transfer frequencies (up to 2.6 × 10⁻⁶) substantially exceeded spontaneous mutation rates (at least 75-fold higher for rifampicin resistance)