Variability in the anatoxin a gene clusters of Cuspidothrix issatschenkoi from Germany, New Zealand, China and Japan. ana

Anatoxin-a production has been detected worldwide in the cyanobacterial genera Dolichospermum, Cuspidothrix, Phormidium, Oscillatoria, Tychonema and Cylindrospermum. The ana gene clusters (anaA-anaG) (circa 22 kb) of two ANTX producing C. issatschenkoi strains: NIVA-CYA 711 (Germany); and CYN 16 (New Zealand) were sequenced and compared with the known ana gene clusters of three C. issatschenkoi strains from Japan (RM-6 and LBRI48) and China (CHABD3). All five ana gene clusters are characterized by the same gene order for anaA-anaG and their similarities are with 99.5% highest between NIVA-CYA 711, CYN 16 and CHABD3. The Japanese strains RM-6 and LBRI48 are distinguished by a much lower similarities of around 91.7%. This is also reflected in the number and presence of single nucleotide polymorphisms (SNP’s) and insertions/deletions (In/Dels) in the ana gene clusters. Altogether 1990 variable sites (285 SNPs and 5 In/Dels, comprising 1705 nucleotides) were found in the ana gene clusters of the German, New Zealand and Japanese strains compared to the strain CHABD3. The ana gene clusters of NIVA-CYA 711, CYN16 RM-6 and LBRI48, were characterized by 84, 81, 253 and 228 SNPs to CHABD3, respectively. The anaE and anaF genes showed the highest variability in all five strains and is recommended as the best genetic markers for further phylogenetic studies of the ana gene cluster of C. issatschenkoi.