The divergence of cpcBA-IGS sequences between Dolichospermum and Aphanizomenon (Cyanobacteria) and the molecular detection of Dolichospermum flos-aquae in Taihu Lake, China

Abstract

Wang Z., Liu Y., Xu Y., Xiao P. and Li R. 2013. The divergence of cpcBA-IGS sequences between Dolichospermum and Aphanizomenon (Cyanobacteria) and the molecular detection of Dolichospermum flos-aquae in Taihu Lake, China. Phycologia 52: 447–454. DOI: 10.2216/12–125.1

The occurrence of bloom-forming heterocystous cyanobacteria such as Dolichospermum flos-aquae has become increasingly serious. This study was conducted to provide a detailed understanding of diversity, distribution and seasonal dynamics of Dolichospermum flos-aquae populations in Taihu Lake, China. Morphological identifications showed Dolichospermum flos-aquae and Aphanizomnon flos-aquae were the two main heterocystous cyanobacteria in Taihu Lake. Phylogenetic analysis based on cpcBA-IGS sequences, the highly variable intergenic spacer (IGS) region between two phycobilisome subunits (cpcB and cpcA), distinguished Dolichospermum from other filametous cyanobacterial genera. Therefore, the real-time PCR detection of Dolichospermum flos-aquae based on cpcBA-IGS sequences was developed to study the distribution and abundance of Dolichospermum flos-aquae. The investigation began in August 2008 and extended through September 2010. Dolichospermum flos-aquae occurred throughout the entire lake. There was an average abundance of 2.0 × 10⁶ gene copies L⁻¹, and the peak abundance was in the western part of Taihu Lake during late spring when it reached 4.0 × 10⁷ copies L⁻¹. Dolichospermum flos-aquae had a regular annual cycle; it began appearing in late autumn and it reached a peak in late spring.

Key Words::

• cpcBA-IGS
• Cyanobacteria
• Dolichospermum flos-aquae
• Real-time PCR
• Taihu Lake

ACKNOWLEDGEMENTS

This work was supported by NSFC-JST joint project (No. 41261140337) and the State Key Basic Research and Development Plan of China (No. 2008CB418002).

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found online at http://dx.doi.org/10.2216/12-125.1.s1.