Comparison Of Bacterial And T4-type Phage Diversity Between Two Sanjiang Natural Wetlands And A Paddy Field In The Nearby In Northeast China

To illustrate the effects of the exploitation on bacterial community structure anddiversity in Sanjiang wetlands, and explore the diversity characteristic of T4-type phages inwetlands and paddy ecosystem as well, Molecular biology techniques were used to investigatethe community of bacteria and T4-type phages.Bacterial16S rRNA gene clone libraries were constructed, and300clones were obtainedfrom three libraries (paddy, Carex lasiocarpa and Deyeuxia platyphylla wetlands) in total.Unique phylotypes were defned as OTUs with≤97%16S rRNA gene sequences similarity,and we obtained70,75,75OTUs from paddy, Carex lasiocarpa and Deyeuxia platyphyllawetlands, respectively. The coverages of clone libraries were49%,44%and42%, whichexplain approximately half of the total bacterial species in the study sites. Shannon index andspecies richness index Schao1show that bacterial diversity in wetlands is higher than that inpaddy. Proteobacteria, Firmicutes, Actinobacteria, Verrucomicrobia, Acidobacteria,Planctomycetes, Bacteroidetes, Chloroflexi and Armatimonadetes were identified among the300clones. And Proteobacteria, Firmicutes, Actinobacteria, Verrucomicrobia, Acidobacteria,Chloroflexi were the shared bacterial Phylums among the three libraries. Significant increasein the number and diversity of proteobacteria in the soil has been found after the exploitationfrom wetlands to paddy. Composition analysis result shows that the proportion ofProteobacteria is37%,17%and24%in paddy, Carex lasiocarpa and Deyeuxia platyphyllawetlands, respectively. There are4Proteobacteria classes (α-, β-, γ-, δ-)in paddy, while only2classes(α-, δ-) in wetlands. Results of principal component and community similarity analysisindicate that bacterial communities from the three libraries is divergence in general, bacterialcommunities in Carex lasiocarpa wetland is similar to that in Deyeuxia platyphylla wetland,similarity of bacterial communities between paddy and wetlands is relatively low. The lowerproportion of Acidobacteria obtained in this study inferred that the bacterial communities inwetlands in Sanjiang plain were unique and differed with those found in other wetlandsaround the world. We concluded that vegetation and wetland type will affect the diversity ofbacterial communities. The number of Firmicutes didn't fluctuate obviously between paddyand Carex lasiocarpa wetland, however, much higher than that in Deyeuxia platyphyllawetland. And Verrucomicrobia in Deyeuxia platyphylla wetland is much higher than that inpaddy and Carex lasiocarpa wetland. In our study, Planctomycetes was found in paddy andCarex lasiocarpa wetland, which didn't exist in Deyeuxia platyphylla Wetland. We also foundBacteroidetes in paddy and Deyeuxia platyphylla wetland, which didn't exist in Carex lasiocarpa wetland.Based on the analysis of Phylogenetic tree and UniFrac, We found novol group of g23sequences in waters in the wetlands and the paddy field. The distribution of g23sequences inthe wetlands was distinctly differed with those from aquatic environments and upland blacksoils, but similar with those from the paddy fields. Unifrac analysis shows that the T4-typebacterial viruses between soil and water in wetland ecosystem changed significantly. Greatertemporal change of T4-type phage communities in waters than in soils was discovered in thisstudy. Heterogeneous of T4-type phage communities in the wetlands is much more than thosein lake freshwater, upland black soils and paddy field soils.