The Research On Diversity Of Virioplankton In The Pearl River Estuary And Its Potential Role On Ecology

This research utilizes metagenomic sequencing technology and Denovo identification technology,on the background of Pearl River Estuary,studied under salinity gradient,the composition,distribution,diversity,function of the virus and its regulation on the prokaryotes and eukaryotes of the micro and small organisms,is of great significance on the knowledge of the virus and its ecological effect.The main results of this study include the following three parts.(?)The first study on the diversity and distribution of micro and small plankton communities in the pearl river estuary,preparing statistics for the viral ecology role,shows that:(1)the prokaryotic and eukaryotic microbiological diversity in the low-salt water zone of the estuary was the highest,and the diversity gradually decreased along with the increase of salinity gradient.The unique species in the low-salinity water area of the estuary are the most and decrease with the increase of salinity gradient;(2)in the prokaryotes of the estuary,the relative abundance of proteobacteria accounts for the majority,among which the relative abundance of proteobacteria increases with the increase of salinity.Among the eukaryotic micro and small organisms in the Pearl River Estuary,the relative abundance of Coscinodiscophyceae accounted for the majority in the low-salinity area and decreased with the salinity gradient.Appendiculariae is a major component in high salinity and increases with salinity;(3)dissolved oxygen,salinity,ammonia nitrogen,chlorophyll a,temperature,nitrate,phosphate and nitrite are important factors affecting prokaryotes in the Pearl River Estuary.Dissolved oxygen,salinity,chlorophyll a,temperature,nitrate,phosphate,nitrite are important factors affecting eukaryotic micro and small organisms.(?)The study on the composition and diversity of pearl river estuary viruses shows that:(1)the main viral groups in the pearl river estuary were Myoviridae and Siphoviridae,and the relative abundance decreased with the increase of salinity.(2)compared with fresh water and ocean,estuary viruses are highly unique,and saltwater areas in estuaries have higher virus diversity;(3)not only do salinity,temperature,chlorophyll a and dissolved oxygen significantly affect the distribution of virus community,but nutrient salts are also important factors.(?)Studies on the potential role of the pearl river estuary viruses in the food web and biogeochemical cycle have shown that:(1)the “Kill the Winner” model hypothesis and the “Piggyback-the-Winner” hypothesis of the virus were verified by CCA,VPA and PLSPM analysis,indicating that the virus potentially regulated the host community structure by the dual role of the lysogeny-lytic model;(2)viruses potentially play an important role in the carbon metabolic cycle of estuarine environment,and its role in carbohydrate anabolism is greater than that of degradation.