The Structural Characteristics Of The Attached Bacterial Community In Typical Submerged Plants In Shallow Lakes

Aquatic macrophytes is the key species in shallow lake ecosystem,epiphytes bacteria attached on it is not only affect the growth of macrophytes directly,but also relate with biogeochemical cycle process of nutrients,It is of significance to have a deep understanding of structure and functions of the eutrophical lake ecosystem.With the typical aquatic macrophytes in Hongze lake and Taihu lake as the study objects.Molecular biology methods such as TRFLP and high-throughput sequencing were applied to investigate the impact of the patotipo,instar,spatial factors of the host macrophytes on epiphytes bacteria and bacterioplankton.Results were as follows:(1)38 species of bacteria phyla and 361 species of bacteria genera were detected from epiphytes bacteria attached on Potamogeton pectinatus in different growth stages.Proteobacteria was the main category of bacteria with the relative abundance about 59%,When the macrophytes were in decline phase,the relative abundance of Gammaproteobacteria was more than 42.3%.In addition,the relative abundance of Bacteroidetes(11.1%),Actinobacteria(9.7%),Firmicutes(7.7%),Cyanobacteria(7.2%)were higher in this study.Pseudomonas(11.8%-22.00%)and Flavobacterium(5.40%-7.80%)were the dominant bacteria genera.(2)52 species of bacteria phyla and 488 species of bacteria genera were detected from epiphytes bacteria attached on Ceratophyllum demersum both in Hongze Lake and Taihu Lake.Predominant epiphytes bacteria in Hongze Lake were Gammaproteobacteria(29.8%),then Actinobacteria(16.8%),Alphaproteobacteria(11.7%),Betaproteobacteria(10.1%)respectively.Predominant epiphytes bacteria in Taihu Lake were Cyanobacteria(29.7%),Actinobacteria(13.4%),Betaproteobacteria(12.7%),Alphaproteobacteria(10.9%).Pseudomonas(6.20%),Flavobacterium(5.34%),Synechococcus(1.04%),Rheinheimera(0.91%),Bacillus(0.84%)were the abundance of bacteria genera in Taihu Lake.Flavobacterium(4.64%),Pseudomonas(3.96%),Bacillus(1.59%),Clostridium(1.10%),Rhodobacte(0.89%)were the abundance of bacteria genera in Hongze Lake.(3)Diversity of epiphytic bacteria was related to temporal difference,spatial difference and vegetation types and so on.Duting each growth stage of Potamogeton pectinatus,the diversity of epiphytic bacteria exibited as follows:beginning of the decline stage>florescence>young seedling>completely decline stage;Diversity of epiphytic bacteria on different submerged macrophytes in Hongze Lake were Potamogeton pectinatus>Potamogeton crispus>Ceratophyllum demersum;The diversity of epiphytic bacteria of Ceratophyllum demersum and surrounding bacterioplankton in Hongze Lake was higher than it in Taihu Lake whether in July or in October.(4)Variation analysis of bacterial community structure based on T-RFs and OUT numbers.With the growth of Potamogeton pectinatus,epiphytic bacteria community structure with high similarity except in young seedling stage.Because biological membrane has not formed in seedling stage.Epiphytic bacteria community structure of Potamogeton pectinatus and Potamogeton crispus were more similar than Ceratophyllum demersum.Different macrophyte types of epiphytic bacteria showed certain host selectivity in this study.Through community structure of epiphytic bacteria and surrounding bacterioplankton in two lakes,Bacterioplankton were more sensitive than epiphytic bacteria to spatial and seasonal disparities.