Phenolic acids and tanshinones are major bioactive ingredients in Salvia miltiorrhiza, which possess pharmacological activities with great market demand. However, transcriptional regulation of phenolic acid and tanshinone biosynthesis remains poorly understood. Here, a basic leucine zipper transcription factor (TF) named SmbZIP1 was screened from the abscisic acid (ABA)-induced transcriptome library. Overexpression of SmbZIP1 positively promoted phenolic acid biosynthesis by enhancing expression of biosynthetic genes such as cinnamate-4-hydroxylase (C4H1). Furthermore, biochemical experiments revealed that SmbZIP1 bound the G-Box-like1 element in the promoter of the C4H1 gene. Meanwhile, SmbZIP1 inhibited accumulation of tanshinones mainly by suppressing the expression of biosynthetic genes including geranylgeranyl diphosphate synthase (GGPPS) which was confirmed as a target gene by in vitro and in vivo experiments. In contrast, the phenolic acid content was reduced and tanshinone was enhanced in CRISPR/Cas9 [clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein 9]-mediated knockout lines. In addition, the previously reported positive regulator of tanshinone biosynthesis, SmERF1L1, was found to be inhibited in SmbZIP1 overexpression lines indicated by RNA sequencing, and was proven to be the target of SmbZIP1. In summary, this work uncovers a novel regulator and deepens our understanding of the transcriptional and regulatory mechanisms of phenolic acid and tanshinone biosynthesis, and also sheds new light on metabolic engineering in S. miltiorrhiza.

中文翻译：

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ABA反应性SmbZIP1参与调节丹参中酚酸和丹参酮的生物合成。

酚酸和丹参酮主要生物活性成分丹参，其拥有具有很大的市场需求药理活性。然而，酚酸和丹参酮生物合成的转录调控仍然知之甚少。在这里，从脱落酸（ABA）诱导的转录组文库中筛选了一个名为SmbZIP1的基本亮氨酸拉链转录因子（TF）。SmbZIP1的过表达通过增强生物合成基因（如肉桂酸4-羟化酶（C4H1））的表达，积极地促进了酚酸的生物合成。此外，生化实验表明，SmbZIP1结合了C4H1启动子中的G-Box-like1元素。基因。同时，SmbZIP1主要通过抑制生物合成基因的表达来抑制丹参酮的积累，该基因已被体外和体内实验确认为目标基因，其中包括香叶基香叶基二磷酸合酶（GGPPS）。相反，在CRISPR / Cas9 [聚簇的规则间隔的回文重复（CRISPR）/ CRISPR相关蛋白9]介导的敲除品系中，酚酸含量降低，丹参酮含量提高。此外，先前报道的丹参酮生物合成的正调节剂SmERF1L1在SmbZIP1中受到抑制。RNA测序表明过表达谱系，并被证明是SmbZIP1的靶标。总而言之，这项工作揭示了一种新型的调节剂，加深了我们对酚酸和丹参酮生物合成的转录和调节机制的理解，也为乳链球菌的代谢工程学提供了新的思路。