While bioactive properties of Centaurium erythraea Rafn secoiridoid glucosides (SG) are widely recognized, many aspects related to their biochemistry, metabolism and relationship to the overall plant physiology are not yet understood. Here we present for the first time an insight into the molecular background of organ-specific and genotype-dependent constitutive biosynthesis of secoiridoids in C. erythraea, by comparing chemical profiles and secoiridoid glucosides-related gene expression. Genes encoding enzymes for intermediate steps of secoiridoids biosynthesis up to secologanin have been identified by analysing transcriptomic data from C. erythraea leaves. Results suggest an organ-specific capacity for the production and accumulation of secoiridoid glucosides, and highlight leaves as the main biosynthesis site. They also point out that significant differences in SG content among various C. erythraea genotypes, are, at least partially, determined by different expression patterns of SG-related genes. The biosynthesis of SG in C. erythraea leaves is enhanced upon treatments with methyl jasmonate (MeJA), which causes reprogramming of SG-related gene expression, leading to an increased production of valuable bioactive compounds. The present study unveiled several rate-limiting genes (encoding GES, G8O, 8HGO, IS and 7DLGT) in SG biosynthesis. SLS and CPR are highlighted as important genes/enzymes that might regulate biosynthetic flux through SG pathway. Information gathered within this study will help us gain deeper insight into the SG metabolism and develop strategies for enhanced biosynthesis of specific secoiridoid glucosides in homologous or heterologous systems.

中文翻译：

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Centaurium erythraea Rafn 中二环环烯醚萜苷的器官特异性和基因型依赖性组成型生物合成，及其与茉莉酸甲酯的诱导

虽然 Centaurium erythraea Rafn secoiridoid glucosides (SG) 的生物活性特性已得到广泛认可，但与它们的生物化学、代谢和与整体植物生理学的关系相关的许多方面尚不清楚。在这里，我们首次通过比较化学特征和类环烯醚萜苷相关基因表达，深入了解 C. erythraea 中类环烯醚萜类器官特异性和基因型依赖性组成性生物合成的分子背景。通过分析来自 C. erythraea 叶子的转录组学数据，已经确定了编码酶的基因，这些酶用于 secoiridoids 生物合成的中间步骤直到 secologanin。结果表明产生和积累类环烯醚萜苷的器官特异性能力，并突出叶子作为主要的生物合成位点。他们还指出，不同 C. erythraea 基因型之间 SG 含量的显着差异，至少部分是由 SG 相关基因的不同表达模式决定的。用茉莉酸甲酯 (MeJA) 处理后，C. erythraea 叶子中 SG 的生物合成得到增强，这会导致 SG 相关基因表达的重编程，从而导致有价值的生物活性化合物的产生增加。本研究揭示了 SG 生物合成中的几个限速基因（编码 GES、G8O、8HGO、IS 和 7DLGT）。SLS 和 CPR 被强调为可能通过 SG 途径调节生物合成通量的重要基因/酶。