Morelli Luca, García Romañach Laura, Glauser Gaetan, Shanmugabalaji Venkatasalam, Kessler Felix, Rodriguez-Concepcion Manuel
Institute for Plant Molecular and Cell Biology (IBMCP), CSIC-Universitat Politècnica de València, 46022 Valencia, Spain.
Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
Metabolites. 2023 Jan 28;13(2):193. doi: 10.3390/metabo13020193.
The enrichment of plant tissues in tocochromanols (tocopherols and tocotrienols) is an important biotechnological goal due to their vitamin E and antioxidant properties. Improvements based on stimulating tocochromanol biosynthesis have repeatedly been achieved, however, enhancing sequestering and storage in plant plastids remains virtually unexplored. We previously showed that leaf chloroplasts can be converted into artificial chromoplasts with a proliferation of plastoglobules by overexpression of the bacterial gene. Here we combined coexpression of with genes involved in tocopherol biosynthesis to investigate the potential of artificial leaf chromoplasts for vitamin E accumulation in leaves. We show that this combination improves tocopherol levels compared to controls without crtB and confirm that , , and genes are useful to increase the total tocopherol levels, while further leads to enrichment in α-tocopherol (the tocochromanol showing highest vitamin E activity). Additionally, we show that treatments that further promote plastoglobule formation (e.g., exposure to intense light or dark-induced senescence) result in even higher improvements in the tocopherol content of the leaves. An added advantage of our strategy is that it also results in increased levels of other related plastidial isoprenoids such as carotenoids (provitamin A) and phylloquinones (vitamin K1).
由于生育色原醇（生育酚和生育三烯酚）具有维生素E和抗氧化特性，提高其在植物组织中的含量是一个重要的生物技术目标。基于刺激生育色原醇生物合成的改进已多次实现，然而，增强其在植物质体中的隔离和储存几乎尚未得到探索。我们之前表明，通过过表达细菌基因，可以使叶片叶绿体转化为具有大量质体小球的人工有色体。在此，我们将crtB与参与生育酚生物合成的基因共表达，以研究人工叶片有色体在烟草叶片中积累维生素E的潜力。我们表明，与没有crtB的对照相比，这种组合提高了生育酚水平，并证实crtE、crtI、hpt和tHMG基因有助于提高总生育酚水平，而crtB进一步导致α-生育酚（具有最高维生素E活性的生育色原醇）富集。此外，我们表明，进一步促进质体小球形成的处理（例如，暴露于强光或黑暗诱导的衰老）会使叶片中的生育酚含量有更高的提高。我们策略的一个额外优势是，它还会导致其他相关质体类异戊二烯如类胡萝卜素（维生素A原）和叶绿醌（维生素K1）的含量增加。
