洛蒙德链霉菌S015中cutR/cutS双组分调控系统对洛蒙真菌素合成的调控

Function of cutR/cutS two component system in lomofungin biosynthesis in Streptomyces lomondensis S015

摘要:

【背景】cutR/cutS双组分调控系统在链霉菌次级代谢过程中起重要作用。【目的】通过同源重组的方法在野生型S015菌株中分别敲除cutR和cutS，构建单基因缺失突变株，研究cutR/cutS双组分调控系统对洛蒙真菌素合成的调控。【方法】对突变株及野生型菌株的发酵产物进行高效液相色谱法(High performance liquid chromatography，HPLC)分析，通过qPCR测定基因表达量的变化。【结果】HPLC产物分析发现，S015ΔcutR和S015ΔcutS中洛蒙真菌素产量分别达到了128.1±26.4 mg/L和61.8±4.5 mg/L，分别为野生型S015产量的11.5倍和5.5倍。qPCR检测发现，S015ΔcutR突变株中lomo14、lomo10、lphzB、lphzC、lphzE和lphzG的表达量分别达到野生型的1 151.7±88.8、110.5±5.8、129.3±7.7、380.2±34.6、348.2±42.1和299.8±38.2倍；S015ΔcutS突变株中lomo14、lomo10、lphzB、lphzC、lphzE和lphzG的表达量分别达到野生型的4.3±0.5、2.2±0.2、9.3±0.9、10.3±0.6、20.7±1.5和20.4±0.8倍。【结论】cutR/cutS双组分调控系统在洛蒙德链霉菌的洛蒙真菌素合成过程中对其合成途径核心基因和侧链修饰基因的表达有抑制作用，从而抑制其合成。

Abstract:

[Background] The cutR/cutS two component system plays a significant role in secondary metabolite in Streptomyces. [Objective] The aim of the study is to investigate the function of the cutR/cutS two component system in the production of lomofungin in Streptomyces lomondensis S015. [Methods] HPLC was used to analysis fermentation production, meanwhile accessing quantitative real-time PCR to monitor the levels of gene expression. [Results] HPLC results indicated that the yield of lomofungin in S015ΔcutR and S015ΔcutS reach the total amount of 128.1±26.4 mg/L and 61.8±4.5 mg/L respectively, that is 11.5 and 5.5 times of the yield of wild type. Results of qPCR indicated that in S015ΔcutR mutant the relative gene expression of lomo14, lomo10, lphzB, lphzC, lphzE and lphzG reached respectively 1 151.7±88.8, 110.5±5.8, 129.3±7.7, 380.2±34.6, 348.2±42.1 and 299.8±38.2 times of the wild type, and in S015ΔcutS mutant the relative gene expression of lomo14, lomo10, lphzB, lphzC, lphzE and lphzG were respectively 4.3±0.5, 2.2±0.2, 9.3±0.9, 10.3±0.6, 20.7±1.5 and 20.4±0.8 times. [Conclusion] The study shows that the cutR and cutS negatively regulate several main synthetic genes and side-chain modification genes of lomofungin production in S. lomondensis, thereby reducing the production.