茉莉酸甲酯对川续断根中川续断皂苷Ⅵ合成积累的影响

Methyl jasmonate stimulates the synthesis and accumulation of asperosaponin VI in the roots of Dipsacus asper

通过分析茉莉酸甲酯(MeJA)对川续断根中川续断皂苷Ⅵ积累及相关基因表达的影响,为深入研究MeJA调控川续断皂苷Ⅵ的合成奠定基础。本研究以川续断幼苗为实验材料,分别添加浓度为50、100、150、200、300μmol·L^(-1)的MeJA进行处理,在处理后1、3、5天不同时间点取样。分析根中川续断皂苷Ⅵ和超氧化物阴离子的含量、叶片中丙二醛(MDA)的含量、超氧化物歧化酶(SOD)活性以及川续断皂苷Ⅵ合成路径相关基因转录表达水平的动态变化。结果表明,采用浓度为150μmol·L^(-1)的MeJA处理川续断能显著增加根中川续断皂苷Ⅵ的积累,处理3天后川续断皂苷Ⅵ的含量最高,是对照组的2.16倍。MeJA处理后叶片中SOD活性降低,MDA的含量升高,根中超氧化物阴离子含量升高。同时根中川续断皂苷Ⅵ合成关键酶基因鲨烯环氧酶(DaSE1)、牻牛儿基二磷酸合成酶(DaGPS)的表达量与对照组相比上调表达。以上研究表明MeJA 150μmol·L^(-1)是促进川续断皂苷Ⅵ积累的适宜浓度,通过上调川续断皂苷Ⅵ合成关键酶基因的表达增加川续断皂苷Ⅵ的积累,从而抵抗MeJA对川续断造成的逆境胁迫。

We investigated the effect of methyl jasmonate(MeJA)on the content of asperosaponin VI and the expression of genes involved in its synthesis.Dipsacus aspero seedlings were treated with MeJA at different concentrations of 50,100,150,200 and 300μmol·L^(-1),and leaves and roots were sampled following treatment for 1,3 and 5 days.The content of asperosaponin VI and superoxide anion in the roots,malondialdehyde(MDA)content in leaves and superoxide dismutase were determined.The results show that 150μmol·L^(-1)MeJAsignificantly increased the accumulation of asperosaponin VI in roots.The content of asperosaponin VI was greatest after treatment for 3 days,and was 2.16 times higher than the control.After MeJA treatment,SOD activity decreased and MDA content increased in leaves.Moreover,superoxide anion content in roots increased.The expression of squalene epoxidase(DaSE1)and geranyl diphosphate synthase(DaGPS),key enzymes in the synthesis of asperosaponin VI,were up-regulated compared with the control group.These results indicate that an optimal concentration of 150μmol·L^(-1) MeJA increases the accumulation of asperosaponin VI by up-regulating the expression of key enzymes involved in the synthesis of asperosaponin VI,which facilitates resistance to adversity stress stimulated by MeJA.