Seasonal Changes And Community Structure And Diversity Of Aerobic Anoxygenic Phototrophic Bacteria In The Surface Seawater Of The Dongji Island Mussel Aquaculture Area

Marine microorganisms widely distributed and have a very high abundance in the ocean,and they play a vital role in the bio-geochemical cycle of energy flows or in many material circulations.They have always been hot issues in marine ecology research.In recent years,as the global warming and marine environmental pollution intensified,many countries of the world were committed to the marine carbon storage,pollution control and other functional microbial application research,aerobic anoxygenic phototrophic bacteria(AAPB)is one of the most studied and typical microorganisms.They are a kind of heterotrophic photosynthetic microorganisms which were widely distributed in various marine environments and have a potentially important role in the biogeochemical cycles of microbial ecology,ocean carbon sinks and marine ecosystems.In this study,the diversity and interaction relationship between community structure distribution and environmental factors of AAPB in the aquaculture area and non-aquaculture area of the Qingbang Island of China were analyzed by molecular biology methods such as TA clone and high-throughput sequencing.We sampled surface seawater of 0.5m in the study area in October 2015,January 2016,April 2016 and July 2016,respectively.And detected water temperature,salinity and other water quality parameters of samples simultaneously.After water samples were collected through the membrane filtration process,then the total genomic DNA of planktonic microorganisms were extracted and amplify the small subunit pufM gene encoding the photoreaction center.By constructing a clone library for validation experiments,and the high-throughput sequencing technique was used to analyze the diversity and community structure of AAPB.A total of 755,040 high quality sequences,and they fell into 18,673 OTUs.There were 161 genera were found by high throughput sequencing of seawater samples.Acording to the results of the Chao index of each sample,we conclude that the order of abundance of each sample is: DD1> DC1> DX1> DQ2> DQ1> DD2> DC2> DX2,and the Shannon index and Simpson index show that each site microbes.The result of the diversity ordering is: DD1> DQ2> DC1> DQ1> DD2> DC2> DX1> DX2.The values of the coverage of all samples were above 0.9,indicating that the sequencing depth is sufficient and the coverage is high.The library can be used to assess the diversity of AAPB.In the mussel aquaculture area and non-aquaculture area of Qingbang Island,the analysis results of bacterial groups in the four seasons of seawater included Actinobacteria,Bacteroidetes,Cyanobacteria,DeinococcusThermus,Euryarchaeota,Phytophthora,Proteobacteria and unclassified unclassified bacteria.Microbes shared in this 8 samples were the myostatic bacteria and Firmicutes,among which the strain was the most dominant flora,followed by Firmicutes.Proteins of the genus Methylobacterium,Sphingomonas,Rhodobacter and Brevundimonas in the Alphaproteobacteria(Proteobacteria)of the Proteobacteria are higher in all samples,indicating the space in which these bacteria are suitable for survival and The time range is relatively wide,so it also shows that the ability of bacteria to adapt to the environment and the distribution of the range is very wide.The results of the clustering tree analysis were the most similar to the time and space scale,the autumn aquaculture area and the winter non-aquaculture community.According to the results of PCA analysis,evolution distance of four samples in spring,summer,autumn and winter were close,and the samples from summer,autumn and spring were close,which indicated that the composition of these samples was comparable.The samples in the winter area,the summer and the winter,show that in the spring,summer and winter,the samples in the same season are located in the spring,summer and winter.In the spring,summer and winter,the microbial community structure of the two seas were similar.RDA analysis is based on a linear model,the analysis can detect the relationship among environmental factors,samples and microorganisms.RDA analysis showed that DO,salinity,DIN(dissolved inorganic nitrogen).SiO32-(silicate)and T(temperature)were some of the most important environmental factors affecting the distribution of AAPB genus.Since PO43-(phosphate)at the zero point,the ray is expected to be very short,so there is no correlation between the distribution of AAPB community.In these environmental variables,temperature and salinity are longer than several other factors,indicating that these two factors are the most important environmental factors that affect the distribution of AAPB's community.All physical and chemical factors may play a single or synergistic role in constructing the AAPB population structure.The data suggest that different AAPB populations are controlled by various complex ecological factors,which may explain why it was difficult to accurately predict the total AAPB distribution in the aquatic environment.The results of this study showed that the Qingbang Island waters contained a rich AAPB group,which was the basis for comprehensive understanding of AAPB diversity and abundance in special functional waters.