Study Of Secondary Metabolite Biosynthesis Gene Clusters In The Metagenomes Of Fresh Waters System At Wuhan

Antibiotics are the most representative secondary metabolites of microorganisms and have been widely used in many fields such as agriculture,medicine and scientific research.As the antibiotic resistance becomes more severe,the demand for new antibiotics gradually increases.The study of clusters of genes associated with microbial secondary pathway synthesis is one of the methods for predicting and discovering novel antibiotics.In this paper,the freshwater waters of Wuhan City have been used as the research object.The ketosynthase(KS)domain of the polyketide synthesis pathway and the adenylation(AD)domain of the non-ribosome peptide synthesis pathway have been sequenced by the PacBio RS II sequencing platform.The data has been analyzed through comparison with the MIBiG database and the NCBI nr database.The diversity of the gene clusters and the potential of secondary metabolic have been evaluated according to the gene cluster code.Besides,secondary metabolic abundances of each water has been compared.The results were shown below:First,we have collected water samples from 10 waters in Wuhan.There were 1,420 AD domain sequences and 1,436 KS domain sequences with significant similarity to the MIBiG database.In comparison with the NR database,the number of AD and KS domain sequences were finally 1263 and 1449,respectively.Second,according to the comparison result from MIBiG database,the water sample(C)is with the highest secondary metabolic abundance,and the water sample(D)is with the highest abundance in the KS domain.After deduplication,we have obtained 175(from 129 gene clusters)and 205(from 141 gene clusters)protein sequences associated with the AD domain and the KS domain.Among them,42 gene clusters are very likely to participate in PKS-NRPS synthesis pathway.Third,in addition,we also have constructed a phylogenetic tree of AD domains and KS domains.It was found that each water area does not differ greatly in the secondary metabolic species.This study shows that there are abundant secondary metabolic gene resources in freshwater waters in Wuhan,which lays a good foundation for subsequent research.