Genomics Analysis Of Mobile Genetic Factors Isolated From Shenzhen Offshore Waters

Due to the influence of human activities,the offshore environment is prone to change the composition of bacteria.Residues of agricultural and veterinary drugs in farms and livestock farms,heavy metals in industrial areas,and organic compounds in domestic wastewater lead to the evolution of bacteria in the environment to adapt to this pressure.Movable genetic factors in bacterial communities mainly include plasmids and bacteriophages.Plasmids can carry special genes between bacterial communities by horizontal gene transfer,which is one of the most important ways of bacterial evolution.In this study,samples were collected from different waters,and different pressure conditions were simulated by using extracts of chloramphenicol,kanamycin,penicillin,naphthalene and yeast extract.Explore the distribution of bacteria and plasmids through bioinformatics strategies,analyze the distribution of related genes,and reveal the correlation between environment,bacteria,plasmids and genes.We collected samples from Dasha River,Shenzhen Bay and Shekou Port.The 16 S rRNA analysis showed that the composition of bacteria in different experimental groups showed certain regularity.Pseudomonas is more likely to survive in chloramphenicol and naphthalene enrichment groups.Escherichia were more likely to accumulate in Kanamycin and penicillin enrichment groups of Shekou Port and Shenzhen Bay samples.And Flavobacteriaceae showed a certain degree of specificity for the selection of stress environment.A total of 20 different types of plasmids were found,which demonstrate the diversity of plasmid replication modules in the sampling site.The diversity of plasmids helps the plasmid adapt to a variety of stressful environments,providing a guarantee for the horizontal transfer of genes in bacterial communities.Resistance genes make bacteria resistant to antibiotics.Horizontal transmission of antibiotic resistance genes carried by plasmids in bacterial communities can lead to evolution of bacterial communities in stressful environments.Through the analysis of the distribution of antibiotic resistance genes,it is found that the resistance genes may be evolving incross-resistance.The problem of bacterial resistance is becoming more and more serious,and an effective measure is urgently needed to solve the problem of bacterial resistance.It is generally believed that virulence factors mainly play a role in pathogenicity of bacteria.Through the analysis of virulence factors,we found that virulence factors related to invasiveness may also increase the competitive advantage of hosts in different pressure environments,and improve the ability of bacteria to adapt to the environment and maintain their own survival.By analyzing the correlation between plasmids and host bacteria and enrichment environment,it was found that Pseudomonas tended to survive under strong pressure and preferred to carry SSB and KfrA_N plasmids.Shewanella,Vibrio and Psychrobacter tend to survive in a stress-free environment and are prone to carry plasmids of Rep₃type.Escherichia and Salmonella have the highest abundance in relatively low pressure environment,but they are also found in the other two environments.These two bacteria have a wider range of adaptability to the environment.There seems to be no obvious preference for carrying different plasmid types.The characteristics of carrying plasmid types are relatively rich types and average abundance.The discovery of plasmid characteristics in this study plays an important role in judging environmental pollution.Compared with the whole genome of bacteria,the genome of plasmid is smaller,and the genetic manipulation and sequence analysis are simple and fast.Developing and utilizing plasmids as environmental pollution markers to assess the environmental pollution situation in China's offshore waters is of great significance for the future pollution control planning of Shenzhen offshore waters.