Lysogenic Bacterioplankton Distribution And Genetic Diversity In Wetland

In this study,the investigations on the lysogenic bacterioplankton abundance in different lakes,rivers,reservoirs,ponds and other types of natural wetlands were conducted,and the impact of environmental factors on them were discussed.Meanwhile, the genetic diversity of some bacterioplankton samples was determined,and some species of lysogenic bacteria that easy to be induced were identified.These results will possibly help us further understand the relationship between bacterioplankton and virioplankton,as well as the effect of environmental factors on them.A series of samples was collected from eutrophic fresh water lakes of different nutritional levels in Hubei Province during May 2006 to January 2007.These samples were treated with mitomycin C to stimulated prophage induction,and the bacterioplankton abundance and environmental factors were measured at the same time. It was observed that the frequency of lysogenic cells(FLC)was no significant difference between summer and winter of the year in the eutrophic lakes.But the FLC in hyper eutrophic lakes(74-78%)was significantly higher than that of light eutrophic lakes (21-66%).Across all investigated lakes,FLC was significant positive related to TLI and COD(p＜0.01).It appeared that there was no correlation between FLC and total plankton abundance,and the same result was observed between FLC and temperature.It was the nutrient level of eutrophication that was the decisive factor in FLC.The community structure of bacterioplankton in different seasons,different nutritional levels of the lake-type wetlands and its changes after the prophages induction were investigated using PCR-DGGE technology.The experimental results showed that the community structure of each site sample changed little with season,but.the abundance of species might be variance in different seasons.There were certain changes in the community structure after the prophage induction.In addition,the results of optimal conditions experiment showed that electrophoresis conditions on the DGGE would have a direct impact on the results,and the degeneration of gradient and the concentration of PCR products also affected the results.The number of bacteriaplankton stains isolated from each lakes were 10 of the Nanhu Lake,15 of Chaohu Lake,17 of Miaohu Lake,10 of Shuiguo Lake,12 of Fenghuotai Lake.The 16S rRNA genes from 16 stains were sequenced,among which 14 strains were most easily induced and 2 strains were easily induced.The induction results of bacteria isolated corresponded to the results of FLC ecological surveys.The sequencing results show thatγ-Proteobacteria and Bacillus may be the main lysogenic bacterial groups in the lakes.