拟无枝酸菌宿主构建及次级代谢基因簇异源表达

Construction of an Amycolatopsis sp.TNS106 derived host and heterologous expression of secondary metabolic gene clusters

为将生长快、发酵时间短、遗传操作便捷的稀有放线菌拟无枝酸菌TNS106开发成异源表达宿主,通过同源重组将内源的瑞斯托霉素生物合成关键基因rpsA替换为ΦC31和ΦBT1噬菌体细菌附着位点attB,清除代谢背景并引入整合位点,得到菌株HXR1;将含有来自天蓝色链霉菌的放线紫红素基因簇或来自刺糖多孢菌的多杀菌素基因簇的质粒转到HXR1进行异源表达,检测发酵产物。结果显示,HXR1成功表达放线紫红素和多杀菌素;与红色糖多孢菌宿主LJ161相比,放线紫红素的产生提前1 d,产量提高1.3倍。拟无枝酸菌异源表达宿主HXR1可为从链霉菌和稀有放线菌中发现新的次级代谢产物提供有用的平台。

Heterologous expression is an efficient approach to activate silent gene clusters of bioactive natural products.The rare actinomycetes strain Amycolatopsis sp.TNS106 is a producer of ristomycin A,which exhibits fast growth,short fermentation time and convenient genetic manipulation system.In order to develop this strain into a heterologous expression host for biosynthetic gene clusters(BGCs),the non-ribosomal peptide synthetase gene(rpsA)essential for the ristomycin A biosynthesis was replaced with a cassette containing the bacterial attachment sites attB^(ΦC31) and attB^(ΦBT1) via homologous recombination to construct a host with a clean background of secondary metabolism and two integrative sites.To test the obtained strain HXR1,integrative plasmids containing actinorhodin BGC from Streptomyces coelicolor or spinosad BGC from Saccharopolyspora spinosa were conjugated into HXR1.The results of fermentation and product analyses showed that actinorhodin and spinosad were successfully produced in HXR1.Compared with the Sac.erythraea-derived host LJ161 belonging to the non-Streptomyces actinomycete host,the actinorhodin production from HXR1 was approximately 1 day earlier and 1.3-fold higher.The Amycolatopsis sp.TNS106-derived host HXR1 will provide a useful platform for accelerating the discovery of novel secondary metabolites from Streptomyces and rare actinomycetes.