Study On Bacteria And Virus Population Structure Of Napahai Plateau Wetland Based On Metagenome

Virus is the most abundant entity on Earth,and is widely distributed in various natural environments.Virus plays important roles in regulating microbial community structure and function,promoting biogeochemical cycle,and horizontal gene transfertation.At present,the research on environmental virus ecology mainly focuses on marine and freshwater lake ecosystem,but the research of plateau wetland is limited.Metagenomics was used to analyze the microorganisms in Napahai plateau wetland,which is unique wetland in China in order to explore the ecological relationship and ecological role of viruses and prokaryotes in the plateau wetland environment.The main results are as follows:1.For prokaryotic microorganisms,210 families and 3,341 genera were identified.The bacterial domain included 184 gates,among which the Proteobacteria was the most abundant,followed by Acidobacteria and Actinobacteria.The Proteobacteria and Bacteroidetes in water were significantly higher than that in soil,while Acidobacteria,Actinobacteria,Verrucomicrobia,Candidatus Rokubacteria were higher than that in water.Among 3,262 bacteria,Bradyrhizobium in soil is the dominant genus,and Curvibacter,Methylophilus and Methylotenera are the main dominant genera in water.13 phylum and 32 genera were identified in Archaea.13 phylum and 47 genera were identified in Eukaryote.2.The analysis of genome function showed that the most representative gene function was amino acid transport and metabolism,followed by energy production and conversion function,coenzyme transport and metabolism function,lipid transport and metabolism function,signal transduction mechanism function.3.It showed that the carbon and nitrogen metabolism genes in Napahai plateau wetland were rich.The carbon fixation pathway was mainly Calvin cycle,reductive tricarboxylic acid cycle and 3-hydroxypropionic acid cycle,while the Proteobacteria,Chloroflexi and Crenarchaeota are the main carbon fixing bacteria;for nitrogen cycling,the reduction process of nitrogen fixation and dissimilated nitrate was the main process in water,while the soil was nitrification and denitrification.Proteobacteria,Nitrospirae,Verrucomicrobia,Actinobacteria,Thaumarchaeota and Euryarchaeota were in the important process of nitrogen metabolism.4.DNA virus accounted for 99.4%,RNA virus 0.6% and phage in DNA virus accounted for 47.95%.The level annotation of the viridae showed that Siphovridae,Myoviridae,Genomoviridae,Herpesviridae,Phycodnaviridae and Mimiviridae were the dominant virus families.5.The predicted host abundance of viruses in the Napahai Plateau Wetland is basically consistent with the prokaryote abundance calculated by metagenome sequencing.Proteobacteria and Actinobacteria are still the main dominant flora in Napahai Plateau Wetland.Firmicutes have relatively high abundance in virus prediction.There were significant differences in the distribution and composition of virus community and prokaryotic host community between water and soil samples,while there were little differences in the structure of virus community and prokaryotic host community between soil samples.6.The correlation analysis between virus community and environmental factors showed that the non biological environmental factors affecting the virus community were TN,water temperature,Chl-a and Zn.In addition,the distribution of four dominant viruses in Napahai plateauwetland was uneven,and the Mimiviridae was mainly distributed in the downstream soil;most of the Siphovridae were distributed in the upstream soil samples;the Phycodnaviridae and Herpesoviidae were mainly distributed in water.7.Phylogenetic analysis of algal DNA viruses showed that cyanophages were rich,including all six known genera,and a small number of sequences were different,which may indicate that there are new algal DNA viruses.The abundance of algal viruses might be related to its unique geographical formation.It is one of the largest freshwater lakes in the upper reaches of the Yangtze River in China.It has both land and water characteristics and is rich in biodiversity.8.The viral metabolizing genes in Napahai plateau wetland mainly included psb A gene related to photosynthesis,ATPase gene related to photosynthetic electron transport,pfk,pgk,tpi A and pyk genes related to carbon metabolism,nif U and nifr R genes related to nitrogen metabolism,cob S,maz G and pur M genes related to DNA biosynthesis,Tus,Moa,This,Thi F and nif S genes related to sulfur metabolism,pho H,pst S genes related to phosphate metabolism and heat metabolism genes hsp,UDP thioquinolone synthase UDP-SQ and so on.These metabolizing genes regulate key metabolic processes in host cells,such as photosynthesis,pentose phosphate cycle pathway,carbon cycle pathway,iron sulfur cluster synthesis,DNA biosynthesis and so on.The maintenance and inhibition of AMGs on some key metabolic reactions of the host help the cyanophage get more chances of infection and increase the probability of infection,and help the cyanophage release more offspring.In this study,the diversity data of microbial community in Napahai plateau wetland was obtained,and the carbon fixation pathway,nitrogen metabolism pathway the virus population structure pattern and the auxiliary metabolic genes in the virus genome were were preliminarily analyzed.It helps to understand the influence between virus and virus,virus and host,virus and environment.It provides the reference for the comprehensive management and protection of wetland environment in China,and provides basic data for the study on biogeochemical cycle.