Genetic Diversity Of T4 Type Virioplankton In Freshwater Lakes

Virioplankton is the most diverse and abundant living form in freshwaters, and in this study, we checked its diversity in freshwater lakes of Wuhan mainly with 3 different methods.RAPD method:comparing profiles from different lakes, we know the general virioplankton diversity of different samples. To the same season, with the increase of nutrition, virioplankton seems to be more diverse and abundant. Each lake shows different trend from winter to summer.DGGE method:we amplified g23 gene of 22 samples (11 lakes, in winter and summer) to identify T4 virioplankton diversity, and get the following results. More efficient PCR products can be easily got in summer samples, and the bands from electrophoresis image of summer samplesare much more than bands of winter samples. The same result with RAPD is that diversity of virioplankton is higher in eutrophic samples. Summer image showed significant universal and special bands.Metagenome method:312 sequences were aquired from 11 different nutrient condition lakes in summer and winter. We divide all the lakes into 4 different goups according to their nutrient level. Average evolutionary divergence over sequence pairs within groups alalysis showde that nutrient level and seasonal change can do great to virioplankton community structure in lakes. Furthermore, the phylogenetic analysis of all the sequences revealed 7 special clusters, C1-C7, and proved that anthropology forcing could influence the genetic diversity of T4 phage in some freshwater lakes.