Genetic Diversity of Bloom-Forming Microcystis (Cyanobacteria) Populations in a Hyper-Eutrophic Pond in Central China

Sequencing the environmental rRNA genes of Microcystis populations, such as by internal transcribed spacer (ITS), has been proven to provide a new insight into the genetic diversity of Microcystis in freshwater. In this study, a 19-month monitoring of Microcystis populations in a hyper-eutrophic pond in Wuhan city, China was conducted through molecular method by sequencing ITS fragments from the environmental DNA library. Three hundred twenty ITS genotypes of Microcystis in this pond were identified from a total of 563 sequences, thus exhibiting high genetic diversity of Microcystis in the pond. Dramatic changes and succession in ITS genotypes were also found during the survey period. Despite the absence of significant dominant ITS genotypes in the pond, several main genotypes were found to have been dominated for a short term. However, Microcystis ITS genotype patterns from 2007 to 2008 presented a complicated situation in this pond. The parsimony network (TCS) analysis showed that two groups were formed based on ITS genotypes.