茉莉酸甲酯对三七叶总黄酮含量及其应答基因表达量的影响

Effect of methyl jasmonate on total flavonoids content and expression of responsive genes in Panax notoginseng leaves

目的 研究茉莉酸甲酯(methyl jasmonate,MeJA)对三七叶总黄酮含量的影响,探究其在转录水平上对类黄酮生物合成以及茉莉酸(jasmonate,JA)信号通路关键酶基因的调控模式。方法 使用不同浓度(0、200、400、800μmol/L)的MeJA喷施一年生三七叶片7d,测定植株生物量以及叶片总黄酮含量;基于MeJA处理的一年生三七叶转录组数据,挖掘类黄酮生物合成与JA信号通路中关键酶基因,并分析它们在200μmol/L的MeJA处理7、14 d后的表达模式;使用200μmol/L的MeJA喷施一年生三七叶片,采用实时荧光定量PCR(q PCR)检测类黄酮生物合成与JA信号通路中关键酶基因在处理0、2、4、6、10、14h后的相对表达量。结果 不同浓度MeJA处理均显著提高一年生三七叶总黄酮的含量,但对其生物量的影响并未达到显著水平。外源MeJA诱导了三七中类黄酮生物合成和JA信号通路关键酶基因的表达。其中,类黄酮生物合成基因PAL、C4H、4CL、F3H、FLS和IFS呈现上调表达,而CHS和CHI呈下调表达;JA信号通路基因LOX、AOS、AOC、OPR、ACX、MEP、KAT、JAR1、JAZ和MYC都呈上调表达。研究发现,当三七受到外源MeJA诱导时,JAZ阻遏蛋白介导了JA信号对类黄酮生物合成基因表达模式的影响。结论 外源MeJA对一年生三七叶总黄酮含量的正向调控主要是通过增强JA信号通路基因JAZ和MYC,以及类黄酮生物合成基因PAL、C4H、4CL和IFS的表达来实现的。

Objective To study the effect of methyl jasmonate(MeJA) on total flavonoids content in Panax notoginseng leaves and explore the transcriptional regulation mode of MeJA on key enzyme genes in flavonoid biosynthesis and jasmonate(JA) signaling pathway. Methods Different concentrations(0, 200, 400, 800 μmol/L) of MeJA were used to spray one-year-old P. notoginseng leaves for 7 d to determine biomass and total flavonoids content in leaves;Based on the transcriptome data of one-year-old P.notoginseng leaves treated with MeJA, the key enzyme genes in flavonoid biosynthesis and JA signaling pathway were mined, the expression patterns of which were analyzed after treatment with 200 μmol/L MeJA for 7 and 14 d;The one-year-old P. notoginseng leaves were sprayed with 200 μmol/L MeJA, and the relative expression levels of key enzyme genes in flavonoid biosynthesis and JA signaling pathway were detected by real-time quantitative PCR(qPCR) at 0, 2, 4, 6, 10 and 14 h after treatment. Results Different concentrations of MeJA significantly increased the content of total flavonoids in one-year-old P. notoginseng leaves, but the effect on biomass was not significant. Exogenous Me JA induced the expression of key enzyme genes in flavonoid biosynthesis and JA signal pathway in P. notoginseng. Among them, the flavonoid biosynthetic genes PAL, C4H, 4CL, F3H, FLS and IFS were up-regulated, while CHS and CHI were down-regulated;LOX, AOS, AOC, OPR, ACX, MEP, KAT, JAR1, JAZ and MYC involved in the JA signaling pathway were all up-regulated. These results found that JAZ repressor mediated the effect of JA signal on the expression pattern of flavonoid biosynthetic genes when P. notoginseng was induced by exogenous MeJA. Conclusion The positive regulation of exogenous Me JA on total flavonoid content in one-year-old P. notoginseng leaves was mainly achieved by enhancing the expression of JAZ and MYC involved in JA signaling pathway and flavonoid biosynthetic genes PAL, C4H, 4CL and IFS.