Isolation and phylogenetic analysis of related genes of cultivable cyanophages in Daqing Wetland

Abstract:

[Objective] To provide scientific data for studying the ecology of cyanophages isolated from Daqing wetland by analyzing their genetic diversity and phylogenetic positions. [Methods] Liquid enrichment culture and double-layer plate methods were used to isolate cultivable cyanophages by using host cyanobacteria Anabaena PCC7120, and the DNA of cultivable cyanophages was extracted. The biomarker genes of g20 encoding capsid assembly protein and pol encoding DNA polymerase in podoviruses were PCR amplified. The PCR products were cloned and sequenced. The sequences were constructed with references sequences into the phylogenetic trees to clarify the phylogenetic positions of cultivable cyanophage. [Results] One g20 sequence and four pol sequences were obtained. Phylogenetic analysis showed that the g20 sequence belongs to the cultivable cyanophage group (Cluster δ). Three pol sequences were closely related to cyanophage groups PG-Pol-I and PG-Pol-II that were observed in an alkaline paddy floodwater in Da'an, Jilin province, China; another pol sequence formed a unique clade. [Conclusion] The g20 gene from cultivable cyanophages infecting Anabaena PCC7120 belongs to the Cluster δ, and the pol genes are closely related to those of paddy floodwater in Da'an, China.