多种激素对喜树悬浮细胞中喜树碱合成关键酶基因的影响

Effects of Plant Hormones on Key Genes of Camptothecin Biosynthesis in Camtoptheca acuminata

喜树中抗肿瘤活性成分喜树碱的生物合成调控具有重要的理论意义与应用价值。基于喜树碱生物合成途径的复杂性及其积累的时间、空间特异性,本研究选择生理状态的均一的喜树悬浮细胞作为研究材料,分析植物激素茉莉酸甲酯(methyl jasmonate, MeJA)、脱落酸(abscisic acid, ABA)、赤霉素(gibberellin, GA)以及水杨酸(salicylic acid, SA)对喜树碱合成途径中关键酶基因转录水平的调控。实时荧光定量PCR (RT-qPCR)检测结果显示,MeJA、ABA、GA以及SA均可促进喜树碱合成色胺途径中关键酶基因CaTDC1以及下游CaSTR的表达,且在处理2 h左右达到峰值;MeJA、GA、SA主要调控环烯醚萜途径中关键酶基因Ca7DLGT、CaG8O、CaCYC1的表达,而ABA则显著调控色胺途径关键酶基因CaTDC1以及下游CaSTR的转录水平;4种激素中SA调控效果与其他激素相比极其显著。本实验排除了喜树碱合成时间、空间特异性影响以及植物向重性、激素浓度梯度等干扰因素,准确地分析了4种激素对喜树碱合成途径关键酶基因的调控,为后续研究植物激素调控喜树碱等次生代谢产物的积累的分子机制提供依据,对于有效提高喜树碱等代谢产物的高效生产以及积累提供了科学依据。

The regulation of campt othecin biosynthesis in Camptotheca acuminata has important theoretical significance and application value. Based on the complexity of camptothecin biosynthesis pathway and the temporal and spatial specificity of its accumulation, the study selected physiological homogeneous camptothecin suspension cells as research materials to analyze the plant hormones methyl jasmonate(MeJA), abscisic acid(ABA),gibberellin(GA), and salicylic acid(SA) regulates the transcription of key enzyme genes in camptothecin biosynthesis pathway. Real time quantitative PCR(RT-qPCR) results showed that MeJA, ABA, GA and SA could promote the expression of key enzyme gene CaTDC1 and downstream CaSTR in the tryptamine synthesis pathway of camptothecin MeJA, GA and SA mainly regulate the expression of key enzyme genes Ca7DLGT, CaG8O and CaCYC1in iridoid pathway, while ABA significantly regulates the transcription of key enzyme genes CaTDC1 and downstream CaSTR in tryptamine pathway;among the four hormones, SA has extremely significant regulatory effect compared with other hormones. In this study, we excluded the influence of time and space specificity of cam ptothecin synthesis, plant gravitropism, hormone concentration gradient and other interference factors, accurately analyzed the regulation of four hormones on the key enzyme genes of camptothecin synthesis pathway, providing a basis for subsequent research on the molecular mechanism of plant hormones regulating the accumulation of camptothecin and other secondary metabolites. It provided a scientific basis for improving the efficient production and accumulation of camptothecin and other metabolites.