海洋放线菌SCSIO 07745中红霉素衍生物的分离、鉴定和生物合成基因簇的分析

目的：对从中国南海沉积物样品中分离的放线菌SCSIO 07745中抑菌活性次级代谢产物进行研究,并对相应产物的生物合成基因簇进行分析。方法：提取菌株SCSIO 07745基因组DNA,利用Illumina Hiseq和PacBio SMRT技术进行基因组测序；通过对16S rDNA序列进行分析构建系统发育进化树以鉴定菌种；以有机溶剂萃取得到发酵产物并利用正相反相柱层析等色谱手段进行分离纯化；通过波谱数据分析对化合物进行结构鉴定。利用生物信息学技术对基因组进行注释并对合成该化合物的基因簇进行定位分析,推导其生物合成途径。结果：该放线菌被鉴定为糖多孢红霉菌Saccharopolyspora erythraea,从其发酵产物中分离鉴定了2个大环内酯类化合物sporeamicin A(1)和erythromycin A enol ether(2)。全基因组序列测序发现该菌株基因组DNA为线状,含有31个次级代谢产物生物合成基因簇,其中基因簇3可能负责红霉素衍生物的生物合成,并对其生物合成途径进行了推导。结论：筛选得到了1株产生红霉素类化合物的海洋糖多孢红霉菌S. erythraea SCSIO 07745,为红霉素类抗生素的开发提供了新的菌株资源。同时,该菌株的全基因组序列为其蕴藏的次级代谢产物的挖掘奠定了基础。

Study on the secondary metabolites and identification of the sporeamicin biosynthetic gene cluster from marine-derived Saccharopolyspora erythraea SCSIO 07745

Objective To identify and obtain the genome information of strain SCSIO 07745 isolated from a sediment sample collected from South China Sea. To identify the biosynthetic gene cluster responsible for its main active antibacterial product. Methods The genomic DNA of the strain was extracted and identified using the second generation Illumina Hiseq and the third generation PacBio SMRT technology. The strain was identified by the phylogenetic tree based on the 16S rDNA sequences. The purification was performed by solvent extraction, normal and reverse phase silica gel chromatopgraphy; and the structures were elucidated by spectroscopic data. The biosynthetic gene cluster of secondary metabolites was annotated by bioinformatics approach and the pathway was proposed. Results The strain was identified as S. erythraea SCSIO 07745 and two compounds sporeamicin A (1) and erythromycin A enol ether (2) were isolated. The whole genome sequence includes a circle chromosome and 31 secondary metabolites biosynthetic gene cluster which was revealed by the antiSMASH annotation results. The biosynthetic pathway of sporeamicin was identified. Conclusion We have discovered a marine-derived S. erythraea SCSIO 07745 which produces sporeamicin. We have also identified the sporeamicin biosynthetic gene cluster and proposed the sporeamicin biosynthetic pathway.