Metageneomic Analysis Of Diversity Of Viral Communities In Yunnan Eutrophic Lakes

In recent years,with the rapid development of economy and increasing of human activities,the eutrophication of ocean and lake become serious.The red tides and cyanobacteria bloom occurred frequently which seriously influence people production and living.Virioplankton is the most abundant and active organism in aquatic ecosystems which closely related to host material cycle and gene transfer.At present,many researches of virioplankton have focus on marine environments.However,little is known about their biodiversity in freshwater.In this paper,the plateau eutrophication lake Dianchi,Erhai and Xingyun in Yunnan were taken as the research objects.The species composition and the function of virioplankton community in different seasons of Dianchi,the influence of seasonal changes to the structure and function of virioplankton community were studied.In addition,the community and functional of virioplankton from different plateau lakes in Lake Dianchi,Erhai and Xingyun were also studied for further analysis the effects of regional changes on structure and function of virioplankton community,and provide reference data for the specific recognition of virus in different environment.This study can provide the theoretical basis for water pollution control and water ecological balance.The main research contents and results are as follows:1.In the study,the key of metagenomic is enriching the virus particles in order to reach the requirement construction sequencing.The Protease-SDS-precipitation method as the optimal extraction method of total DNA was determined and this can reach the relevant requirements of molecular biology and basis for subsequent metagenomic analysis.2.The virioplankton community and function in different seasons of plateau lakes Dianchi were researched.The studies showed virioplankton in Lake Dianchi consist of phage,cyanophage,animal viruses and phycovirus.Most of the virus-like sequences belonged to Styloviridae and Synechococcus phage S-CBS3 is widely distributed in Lake Dianchi and the most abundant in spring.We research the virioplankton community and functional from plateau lakes in different plateau lakes of Lake Dianchi,Erhai and Xingyun.The study showed that the composition and function of virioplankton community in Lake Dianchi,Erhai and Xingyun consist of phage,cyanophage,animal viruses and phycovirus.Most of the virus-like sequences belonged to Styloviridae and Synechococcus phage S-CBS3 is widely distributed in Lake Dianchi,Erhai and Xingyun.Synechococcus phage S-CBS4 is the most abundant in Lake Erhai and Xingyun.3.The seasonal changes of virioplankton in eutrophication plateau lake Dianchi were investigated.The results showed that virioplankton communities emerged a seasonal variation trend,and there was no significant difference of diversity index between spring and winter.In different lakes,there was a regional difference in the study of the virioplankton,and the diversity index of Erhai was the highest among three plateau lakes.4.Phylogenetic analysis of TerL gene for virioplankton in plateau lakes Dianchi,Erhai and Xingyun indicated that our sequences were more closely related to those from marine virus,Synechococcus phage,Prochlorococcus phage,Lester phage and Burkholderia virus.In addition,many unknown virioplankton sequences were found.5.Functional analysis showed that the most represented categories were mino acid metabolism in Lake Dianchi.The main metabolic pathways were Amino acid metabolism and carbohydrate metabolism in Lake Dianchi.Functional gene annotation showed that the virus activity was strongest in spring.Functional analysis of COG and KEEG showed that the most represented categories was amino acid metabolism in Lake Dianchi,Erhai and Xingyun.The Main metabolic pathways were Amino acid metabolism and carbohydrate metabolism in three lakes.6.We research the differences from virioplankton community and functional of different seasons and lakes.The diversity of virioplankton community in Lake Dianchi,Erhai,Xingyun has significant differences.The virioplankton community has higher diversity in spring and winter in Lake Dianchi.In the further study showed,environmental factors(pH value and Chl-a)were played important roles in the species and genetic diversity of virioplankton.