Taxus stem barks can be used for extraction of paclitaxel. However, the composition of taxoids across the whole stem and the stem tissue‐specificity of paclitaxel biosynthesis‐related enzymes remain largely unknown. We used cultivated Taxus media trees for analyses of the chemical composition and protein of major stem tissues by an integrated metabolomic and proteomic approach, and the role of TmMYB3 in paclitaxel biosynthesis was investigated. The metabolomic landscape analysis showed differences in stem tissue‐specific accumulation of metabolites. Phytochemical analysis revealed that there is high accumulation of paclitaxel in the phloem. Ten key enzymes involved in paclitaxel biosynthesis were identified, most of which are predominantly produced in the phloem. The full‐length sequence of TmMYB3 and partial promoter sequences of five paclitaxel biosynthesis‐related genes were isolated. Several MYB recognition elements were found in the promoters of TBT , DBTNBT and TS . Further in vitro and in vivo investigations indicated that TmMYB3 is involved in paclitaxel biosynthesis by activating the expression of TBT and TS . Differences in the taxoid composition of different stem tissues suggest that the whole stem of T. media has potential for biotechnological applications. Phloem‐specific TmMYB3 plays a role in the transcriptional regulation of paclitaxel biosynthesis, and may explain the phloem‐specific accumulation of paclitaxel.

中文翻译：

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横跨红豆杉茎干的组织特异性研究鉴定了韧皮部特异性TmMYB3，参与了紫杉醇生物合成的转录调控。

红豆杉茎皮可用于提取紫杉醇。但是，整个类紫杉醇的组成和紫杉醇生物合成相关酶的茎组织特异性仍然未知。我们使用栽培的红豆杉培养基树，通过整合的代谢组学和蛋白质组学方法对主要干组织的化学组成和蛋白质进行了分析，并研究了TmMYB3在紫杉醇生物合成中的作用。代谢组学景观分析显示，干细胞特异性代谢产物的积累存在差异。植物化学分析表明，韧皮部中紫杉醇的含量较高。鉴定了参与紫杉醇生物合成的十种关键酶，其中大多数主要在韧皮部中产生。的全长序列分离了5个紫杉醇生物合成相关基因的TmMYB3和部分启动子序列。在TBT，DBTNBT和TS的启动子中发现了几种MYB识别元件。进一步在体外和体内研究表明，TmMYB3通过激活的表达参与紫杉醇生物合成的TBT和TS。在不同的干组织的紫杉烷成分的差异表明，全干T.媒体具有生物技术应用潜力。韧皮部特异的TmMYB3在紫杉醇生物合成的转录调控中起作用，并可能解释了韧皮部特异的紫杉醇积累。