东北红豆杉野生种与栽培种类黄酮代谢网络多组学比较

Multi-omics comparative study on flavonoid metabolic networks between wild and cultivated Taxus cuspidata Sieb. et Zucc. species

  • 摘要: 【目的】 开展东北红豆杉野生种和栽培种类黄酮代谢网络比较研究,为深入解析东北红豆杉次生代谢进化模式及药用植物代谢网络,选育药用活性成分定向富集的东北红豆杉优良品种提供参考依据。【方法】 以东北红豆杉2份野生种资源分别来自辽宁丹东(W1)和吉林汪清(W2)和3份栽培种资源日本矮紫杉(C1)、东北红豆杉×日本矮紫杉杂交种(C2)和金叶红豆杉(C3)为研究对象,对红豆杉野生种和栽培种的嫩叶样品进行代谢组学和转录组学分析,对样品中的代谢物进行主成分分析(PCA)。采用液相色谱—串联质谱法(LC-MS/MS)检测样品中代谢物的相对浓度,基于Illumina Novaseq 6000平台,以P<0.05且差异倍数(Fold Change)≥1.5为标准筛选差异表达基因(DEGs),对代谢物进行KEGG代谢通路富集分析。通过代谢组和转录组联合分析构建类黄酮生物合成通路网络,对关键基因的转录组测序数据进行实时荧光定量PCR验证。【结果】 野生种和栽培种东北红豆杉在代谢物组成上呈高度群体特异性分离模式。第一主成分(PC1)解释54.2%的变异,第二主成分(PC2)解释22.2%的变异。KEGG代谢通路富集分析结果显示,栽培种和野生种东北红豆杉比较组中的代谢物谱存在显著差异,包括新陈代谢、人类疾病、生物系统、环境信息处理和细胞过程五大类,富集到排名前20种的代谢通路分别有11、4、3、1和1种;在新陈代谢分类中,富集到异黄酮生物合成代谢通路、甾体激素生物合成和类黄酮生物合成通路。与野生种相比,东北红豆杉栽培种显著富集了以类黄酮为主、涉及营养和形态建成的次生代谢物相关通路。DEGs分布数量在不同比较组中呈两极分化,其中在W2 vs C1比较组中获得的DEGs数量最多,为851个,占比50.38%;W1 vs C1比较组次之,为491个,占比29.07%。东北红豆杉栽培种的高表达簇DEGs富集了有关植物生长发育调控、营养物质积累与转运、器官发育与形态建成、品质改良和促进生长的激素信号转导相关基因;野生种高表达簇DEGs则富集了环境感知、资源高效利用、繁殖策略调控、种间竞争和多重抗性相关基因。东北红豆杉栽培种和野生种间类黄酮物质的相对浓度存在明显差异,除橙皮素-7-O-葡萄糖苷外,其余6种类黄酮物质的相对浓度均表现为3份栽培种东北红豆杉显著高于2份野生种东北红豆杉(P<0.05,下同)。东北红豆杉野生种和栽培种在苯丙氨酸至类黄酮代谢通路关键基因的表达上存在明显差异,在细胞色素P450家族基因中,栽培种CYP75A3基因表达量较野生种下调,而栽培种CYP75B137基因表达量较野生种上调。与东北红豆杉野生种相比,R2R3-MYB、bHLH和WD40转录因子相关基因的表达量在栽培种中明显上调。9个基因的实时荧光定量PCR检测结果与转录组测序数据较为一致。【结论】 人工栽培驯化使东北红豆杉类黄酮代谢网络发生定向重塑,栽培种通过“上游供给强化+支路阀门调控+MBW转录网络协同”形成高效通量模式,推动功能性类黄酮物质定向富集,野生种则保持更高的类黄酮结构多样性,以支撑其对复杂胁迫的广谱适应性。

     

    Abstract: 【Objective】 The aim of the study was to compare the flavonoid metabolic networks of wild and cultivated Taxus cuspidata Sieb. et Zucc. species,deeply analyze the secondary metabolic evolution pattern of Taxus cuspidata Sieb. et Zucc. and the metabolic network of medicinal plants, which could provide reference basis for the selection of high-quality varieties of Taxus cuspidata Sieb. et Zucc. with targeted enrichment of medicinal active components.【Method】 Two wild Taxus cuspidata Sieb. et Zucc. species from Dandong,Liaoning(W1)and Wangqing,Jilin(W2) and three cultivated species Taxus cuspidata var. nana(C1),Taxus cuspidata Sieb. et Zucc.×Taxus cuspidata var. nana cuspidata var. nana hybrid(C2),and golden yew(C3) were used as research object. Metabolomics and transcriptomics analysis were conducted on the young leaves of wild and cultivated Taxus cuspidata Sieb. et Zucc. species, and principal component analysis (PCA) was performed on the metabolites in the samples. The relative concentrations of metabolites in the samples were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Based on Illumina Novaseq 6000 platform, differentially expressed genes (DEGs) were screened according to the criteria of P<0.05 and fold change≥1.5. KEGG metabolic pathway enrichment analysis was conducted for the metabolites. The flavonoid biosynthesis pathway network was constructed through the combined analysis of metabolomics and transcriptomics, and the transcriptional sequencing data of key genes were verified by real-time fluorescence quantitative PCR.【Result】 Wild and cultivated Taxus cuspidata Sieb. et Zucc. species showed highly clear group-specific separation in metabolite composition,with principal component 1 (PC1) and principal component 2 (PC2) explaining 54.2% and 22.2% of the variation respectively. KEGG metabolic pathway enrichment analysis results showed that there were significant difference in the metabolite spectra between the cultivated and wild Taxus cuspidata Sieb. et Zucc. species comparison groups. These differences were observed in five major categories: metabolism, human diseases, biological systems, environmental information processing, and cellular processes. The top 20 enriched metabolic pathways included 11, 4, 3, 1, and 1 pathways respectively; in the metabolism category, the enriched metabolic pathways included isoflavone biosynthesis, steroid hormone biosynthesis, and flavonoid biosynthesis. Compared with the wild resources, the cultivated Taxus cuspidata Sieb. et Zucc. species significantly enriched the pathways related to secondary metabolites mainly composed of flavonoids, which were involved in nutrient and morphogensis. The distribution quantity of DEGs showed a polarized pattern in different comparison groups. Among them, the number of DEGs obtained in the W2 vs C1 comparison group was the largest (851), accoun-ting for 50.38%; followed by W1 vs C1 comparison group (491), accounting for 29.07%. The highly expressed cluster DEGs of the cultivated Taxus cuspidata Sieb. et Zucc. species enriched genes related to plant growth and development regulation, nutrient accumulation and transport, organ development and morphological formation, quality improvement, and hormone signal transduction for promoting growth; while the highly expressed cluster DEGs of the wild Taxus cuspidata Sieb. et Zucc. species enriched genes related to environmental perception, efficient resource utilization, reproductive strategy regulation, interspecific competition, and multiple resistances. There were great difference in the relative concentrations of flavonoid substances between the cultivated and wild Taxus cuspidata Sieb. et Zucc. species. Except for naringenin-7-O-glucoside, the relative concentrations of the other six flavonoid substances were significantly higher in the three cultivated Taxus cuspidata Sieb. et Zucc. species than in the two wild Taxus cuspidata Sieb. et Zucc. species (P<0.05, the same below). There are great difference in the expression of key genes in the phenylalanine to flavonoid metabolic pathway between the wild and cultivated Taxus cuspidata Sieb. et Zucc. species. Among cytochrome P450 family genes, the expression level of the cultivated Taxus cuspidata Sieb. et Zucc. species CYP75A3 gene was lower than that of wild Taxus cuspidata Sieb. et Zucc. species, while the expression level of the cultivated Taxus cuspidata Sieb. et Zucc. species CYP75B137 gene was higher than that of wild Taxus cuspidata Sieb. et Zucc. species. Compared with the wild Taxus cuspidata Sieb. et Zucc. species, the expression levels of genes related to R2R3-MYB, bHLH, and WD40 transcription factors were significantly up-regulated in the cultivated Taxus cuspidata Sieb. et Zucc. species. The results of real-time fluorescence quantitative PCR for nine genes were consistent with the transcriptome sequencing data.【Conclusion】 Artificial cultivation and domestication directionally reshape the flavonoid metabolic network of Taxus cuspidata Sieb. et Zucc. Cultivated Taxus cuspidata Sieb. et Zucc. species form an efficient metabolic flux pattern through enhanced upstream supply + branch-point regulation + coordinated MBW transcriptional control,thereby promoting the targeted accumulation of functional flavonoids,whereas wild Taxus cuspidata Sieb. et Zucc. maintain greater flavonoid structural diversity to support broad adaptation to complex environmental stresses.

     

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