State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China.
Planta. 2021 Apr 17;253(5):107. doi: 10.1007/s00425-021-03626-z.
Importation of taxadiene synthase into chloroplasts is important for the efficient heterologous production of taxadiene. Taxadiene, the first committed precursor to taxol, is synthesized from geranylgeranyl pyrophosphate (GGPP) by action of taxadiene synthase (TS). Heterologous production of taxadiene could potentially rely on both cytosolic mevalonic acid (MVA) pathway and the plastidic methylerythritol phosphate (MEP) pathway. We suggest the compartmentalized engineering in chloroplast as an efficient approach for taxadiene production. In this study, we directly introduced the TS gene from Taxus brevifolia into the tobacco chloroplast genome and found that the transplastomic plants accumulated a low content of taxadiene, ~ 5.6 μg/g dry weight (DW). Moreover, we tried a combination of MEP and MVA pathways for taxadiene synthesis by nuclear transformation with a truncated version of TS (without encoding a transit peptide) into the transplastomic plants. However, this did not further improve the taxadiene production. In contrast, we found that taxadiene could be produced up to 87.8 μg/g DW in leaves of transgenic plants expressing TS with a chloroplast transit peptide, which was significantly higher than that in leaves of transplastomic plants. Thus, this study highlights the importance of TS importation into chloroplast for production of taxadiene.
将 taxadiene 合酶导入叶绿体对于 taxadiene 的高效异源生产非常重要。taxadiene 是紫杉醇的第一个关键前体，由 taxadiene 合酶（TS）作用于 geranylgeranyl pyrophosphate（GGPP）合成。taxadiene 的异源生产可能依赖于细胞质甲羟戊酸（MVA）途径和质体甲基赤藓醇磷酸（MEP）途径。我们建议在叶绿体中进行区室化工程，这是一种有效的 taxadiene 生产方法。在这项研究中，我们直接将来自 Taxus brevifolia 的 TS 基因导入烟草叶绿体基因组中，发现转基因植株积累了低含量的 taxadiene，约为 5.6μg/g 干重（DW）。此外，我们尝试通过核转化将 TS 的截断版本（不编码转运肽）与转基因植株结合，利用 MEP 和 MVA 途径合成 taxadiene。然而，这并没有进一步提高 taxadiene 的产量。相比之下，我们发现表达具有叶绿体转运肽的 TS 的转基因植物叶片中可生产高达 87.8μg/g DW 的 taxadiene，明显高于转基因植株叶片中的产量。因此，这项研究强调了将 TS 导入叶绿体对于 taxadiene 生产的重要性。
