磷胺霉素处理对丹参毛状根合成丹参酮类化合物的影响

Effects on Salvia miltiorrhiza hairy roots of tanshinones content accumulation after treated with fosmidomycin

使用萜类物质合成MEP途径中关键酶DXR的有效抑制剂磷胺霉素(100μmol·L-1)处理丹参毛状根,在处理后2,4,6,8,10,16,21 d收获毛状根,检测处理组和对照组毛状根中SmDXR基因的mRNA水平以及丹参酮类物质含量的变化情况。结果发现,随着磷胺霉素处理时间延长,丹参毛状根颜色与对照组相比明显变浅;毛状根中SmDXR基因的mRNA水平呈抛物线型变化,在处理后第6天达到最高值,随后逐渐降低;检测了4种丹参酮类化合物含量,其中丹参酮Ⅰ的含量变化不显著,而二氢丹参酮Ⅰ、隐丹参酮、丹参酮ⅡA的含量随处理时间延长而逐渐降低,第21天时对照组毛状根中总丹参酮含量是处理组的5.63倍。上述结果表明,丹参DXR基因对于MEP途径丹参酮类化合物的积累具有重要作用,抑制SmDXR基因表达将对该途径次生代谢产物积累产生显著影响。

Fosmidomycin （ 100 μmol · L^-1 ） which is the effective inhibitor of DXR, key enzyme in terpenoid MEP pathway, was used to treat with hairy roots of Salvia miltiorrhiza. The treated roots were harvested at 2, 4, 6, 8, 10, 16 and 21 d, mRNA level of SmDXR and tanshinone content in treated and negative control groups were detected. Results found that, after treated with fosmidomycin, color of S. miltiorrhiza hairy roots grew pale gradually comparing with controls ; mRNA level of SmDXR in hairy roots varied as a shape of parabolic and the highest value achieved at the sixth day after treatment, then it decreased gradually; Content of four kinds of tanshinones were detected. Among of the four kinds of tanshinones, Tanshinone Ⅰ content changed relatively little, while content of dihydrotanshinone Ⅰ, cryptotanshinone and tanshinone Ⅱ A decreased gradually in 21 days. The content of total tanshinones in NC groups was 5.63 times more than FOS-treated roots in the 21th day. The previous results showed that SmDXR played an important role in the accumulation of tanshinone content in MEP pathway. Once the mRNA level of SmDXR was suppressed, the accumulation of secondary metabolites will be significantly affected.