Study On Biosynthetic Potential Of Natural Products From Polar Marine Actinobacteria And Their Gene Cluster Mining

In recent years,actinobacteria from marine and extreme environments may evolve unique genetic properties and natural products during the process of adapting to special environments,and have become important objects for discovery of novel natural products.This study,started from genome,and through bioinformatics techniques,analysed the biosynthetic potential of natural products from five polar marine actinobacteria,and performed research of the representative gene clusters mining.These five polar marine actinobacteria chosen in this study covered the genus Streptomyces and the genus of three rare actinobacteria:Nocardiopsis,Brachybacterium and Marisediminicola.Through the analysis of genomes,the number of natural product biosynthetic gene clusters has a significant positive correlation with the size of the genome.The genomes of strains of Streptomyces and Nocardiopsis encoding the most abundant and diverse natural product biosynthetic gene clusters,which showed these strains have a good potential for gene clusters mining.The other two strains of rare actinobacteria have relatively small genomes and encode fewer natural product biosynthetic gene clusters.Therefore,two strains of polar Streptomyces(Streptomyces sp.604F and Streptomyces sp.R15-527F)and one strain of polar rare actinobacteria(Nocardiopsis sp.502F)were selected for further analysis of their biosynthetic potential of natural products,and one representative gene cluster was respectively selected(604F27,527F15 and 502F10)to perform research of gene cluster mining.The gene cluster 604F27 contained two Type ? PKSs,one Type ? PKS,one NRPS and one halogenase gene,which could produce the halogen-containing PK-NRP hybrid compound.The gene cluster 527F15 contained all key genes responsible for the biosynthesis of lasso peptide,which predicted to produce a lasso peptide with molecular weight of 2020 Da.The type of gene cluster 502F10 was terpene-bacteriocin.These three gene clusters were cloned into appropriate vectors using the RecE/T and Red?/? cloning techniques and successfully transformed into the chromosome of Streptomyces coelicolor M1154 engineering strain for heterologous expression by intergeneric conjugal transfer system.Based on the detection of RT-PCR,the key genes of these three gene clusters got expression with varying degrees.However,due to low expression of key genes,different expression levels among key genes,and unknown products,etc.,the predicted biosynthetic products have not been discovered.This study preliminary revealed the biosynthetic potential of natural products from polar marine actinobacteria has difference among species,and the most studied genus Streptomyces still has the potential to biosynthesize novel natural products.In addition,this study can quickly discover the biosynthetic potential of natural products through genome analysis,which is more efficient than traditional separation and identification of compounds.The RecE/T and Red ?/? cloning techniques can be used as a choice for discovery of novel natural products,and provide a technical idea for the targeted development of natural products mining from polar marine actinobacteria in the future.However,the expression and analysis of the products involved in this study still need in-depth research.