Analysis Of The Mussel And Fish Diversity In Poyang Lake Using Environmental DNA Metabarcoding

Environmental DNA(eDNA)surveys are increasingly being used for biodiversity monitoring,principally because they are sensitive and can provide high resolution community composition data.Since the advent of environmental DNA technology,it has been used in biological monitoring of aquatic organisms,invasive biology(detection of early species,passive surveillance)and biodiversity.The research of environmental DNA for biodiversity more widely,on the standardization process of environment DNA metabarcoding technology,this study explores the suitable universal primers of mussels for environmental DNA.Environmental DNA metabarcoding technology is applied to mussels biodiversity study in Poyang lake,compared with the traditional method,the effectiveness and feasibility of the proposed method are verified.The technique is also applied to the study of fish biodiversity,providing more theory basis for their resources protection and scientific management.The sequencing volume of this study was about 100,000 reads per sample.The results are as follows.(1)Selecting suitable metabarcoding primers for freshwater mussel's environmental DNA biodiversity research,The result shows:it was found that 8mussels species belonging to 6 genera were annotated by 16S r RNA³⁴⁰*which accounted for 26.69%of the total sequences,and 6 mussels species belonging to 4genera were annotated by cyt b*which accounted for 6.60%of the total sequences.The primer 16S r RNA³⁴⁰*was more suitable used for metabarcoding primer for the research of environmental DNA biodiversity in freshwater mussels.Then,16SPP¹⁴⁷and 16SP³⁰⁰primers were used for studing diversity of mussels in water samples,and compared with the traditional method,the results showed that 16SPP¹⁴⁷primers detected more species,covering 7 species detected by the traditional method,the rare species-Lamprotula cornuum-lunae and endangered species-Sinosolenaia carinata was detected.(2)In this study,an environmental DNA metabarcoding mussel database was established.After morphological identification,the collected mussel samples were sequenced by mitochondrial genome,and the mussel sequences were downloaded from NCBI.A total of 53 barcode sequences were obtained,including 16 M type and37 F type.It includes 35 mussels and 1 Cobicula fluminea.(3)We used"16SPP¹⁴⁷"primer explore the effectiveness of the technology in the detection of mussel diversity in Poyang Lake.In this study,the diversity of mussels in Poyang Lake(in the channel connecting the Poyang Lake and the Yangtze River,main lake area of Poyang Lake,Junshan Lake and Qinglan Lake)was studied,and the mussel species were collected by traditional methods at similar points for comparison.The results showed that the mussel identified by environmental DNA metabarcoding technique including traditional methods.(4)Through a standardized analysis process by environmental DNA metabarcoding.14 families and 52 species of fish detected from 40 samples in 7habitats(Jiangxi section of the mainstream of Yangtze River,in the channel connecting the Poyang Lake and the Yangtze River-Hereinafter referred to as the channel,main lake area of Poyang Lake,Nanjishan Nature Reserve,Junshan Lake,Qinglan Lake and Sha Hu).Cyprinidae is the main taxa of fish.Among all habitats,lake limnicolous fishes accounted for the highest proportion,while river-sea migratory fish accounted for the least.The proportion of omnivorous fish was the highest in all habitats,and the proportion of detrital fish was the least.The proportion of fish habitats in each water layer was similar.Small fish are dominant,and medium fish are the least,the result consistent with the traditional fish resources survey.Alpha diversity analysis showed that the diversity index of Junshan Lake was high,indicating that the water quality of Junshan Lake is good and species diversity is high.Beta diversity analysis showed that the community structure of Qinglan Lake was significantly different from that of the other six habitats,which also indicated that there was population barrier between the sub-lake and the main lake.Correlation analysis of environmental factors showed that water temperature and p H had a significant positive correlation with the fish community in Poyang Lake.(5)Environmental DNA sampling methods were also discussed.After collecting water samples and sediment from the same location in Poyang Lake,We investigated fish diversity using environmental DNA water sample and mud sample,and the two approaches were compared.The results showed that the largest number of fish species(18 species)were detected in the mud samples,with the combination of the two methods,the identified fish taxa included 8 species.Alpha diversity and beta diversity analysis showed that there were significant differences in fish community structure between the two methods,and the mud samples were more convenient and identified more species than the water samples.