Application Research On Rapid Monitoring Of Tai Lake Fish By Environmental DNA Metabarcoding

The loss of biodiversity is a global environmental crisis faced by all mankind in the 21 st century.It has a major impact on the ecosystem services and ecological health of the planet.It is of great significance and value to strengthen the monitoring and assessment of changes in ecosystem biodiversity.The freshwater ecosystem is an important part of the global ecosystem.Due to the destruction of dams,environmental pollution,soil erosion and other damages in recent years,it has increasingly affected human survival and development.As a species on the top of the food chain in freshwater ecosystems,fishes not only affect the structure and function of aquatic ecosystems,but also reflect the health status of aquatic ecosystems,and have a good comprehensive indication of the influence of natural environmental factors and human interference on aquatic ecosystems significance.Traditional fish diversity monitoring methods such as electric fish have greatly damaged natural habitats.Traditional species identification requires careful visual observation,morphological comparison,and empirical judgment.The traditional method requires high professional equipment and experience skills of researchers,but the efficiency is not optimistic.These limitations of traditional biodiversity monitoring have created a need for alternative methods of fish diversity monitoring.With the development of second-generation sequencing technology,environmental DNA metabarcoding technology provides a new method for biological monitoring of fish.With the help of environmental DNA metabarcoding technology,the situation of traditional biodiversity monitoring is expected to be significantly improved.However,in the advancement of technology development,research methods differ from country to country.This study aims to establish a set of environmental DNA metabarcoding monitoring methods suitable for native fish in the Tai Lake Basin.The main objectives of this study are: 1)To establish a local fish barcoding database in the Tai Lake: to screen the DNA barcoding area for species establishment based on the molecular genetic evolution characteristics of fish in the Tai Lake;On the basis of identification,the DNA barcodes of species are amplified and sequenced,a standardized species barcoding database entry format is established,and a barcode database of native species in the Tai Lake is established.2)Screening of metabarcoding monitoring primers suitable for local fish in Tai Lake: The lack of uniform technical standards makes the reliability of DNA metabarcoding technology research controversial.How to select the appropriate PCR amplification primer is DNA the key to Environmental DNA metabarcoding.3)Environmental DNA metabarcoding monitoring Tai Lake fish diversity: using environmental DNA metabarcoding monitoring Tai Lake fish diversity to compare with traditional traditional aquatic organisms monitoring to verify the feasibility of rapid environmental DNA metabarcoding monitoring method.This study can achieve fast,convenient and highthroughput biological monitoring.And gradually standardize and standardize,promote the commercialization of aquatic organism monitoring,so that its role in aquatic ecological environment management can be fully exerted and reflected,providing support for management decisions.The main results and conclusions of this study are: 1)The establishment of a fish genetic barcode database in the Tai Lake.After morphological identification of the collected fish samples,DNA extraction and Sanger sequencing were performed one by one to obtain the characteristic barcode sequences of 35 fish species in Tai Lake.2)Design 10 pairs of metabarcoding primers according to the characteristic barcode sequences of Taihu fish,which mainly cover the 12 S r RNA and 16 S r RNA genes of fish mitochondria.Through computer simulation and experimental evaluation,it was found that the meta F1 primer can effectively amplify more than 90% of the fish,and the product length is 196 bp,which is most suitable for gene amplification of Taihu fish.3)Exploring the technical steps of rapid monitoring of metabarcodings of fish environment DNA in Tai Lake,and determining the rapid monitoring including pretreatment and sampling methods: the collection of 1L of surface water,and the use of a filter membrane with a pore size of 0.45 microns for filtration and enrichment.4)The use of environmental DNA metabarcodings to monitor the biodiversity of fish in Tai Lake and the comparison of fish communities with traditional fishing methods.The study found that the detection rate of fish using environmental DNA metabarcoding technology at 23 sampling sites Both are higher than traditional fishing methods,and the detection rate of common sites reaches 68%,which can effectively represent the fish diversity in Tai Lake.Finally,the purpose of this study is to establish a standardized fishery DNA metabarcoding survey program to detect complex and large-scale fish communities in Tai Lake.The results of this study will contribute to the design of future surveys of DNA metabarcoding monitoring of fish environments and the development of rapid and non-invasive methods for surveying freshwater fish species.Form a complete,scientific,reasonable and feasible monitoring technology system to provide technical reference for environmental management departments.