Stra Alice, Almarwaey Lamyaa O, Alagoz Yagiz, Moreno Juan C, Al-Babili Salim
The Bioactives Laboratory, Center for Desert Agriculture, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
Front Plant Sci. 2023 Jan 18;13:1072061. doi: 10.3389/fpls.2022.1072061. eCollection 2022.
Carotenoids are well-known isoprenoid pigments naturally produced by plants, algae, photosynthetic bacteria as well as by several heterotrophic microorganisms. In plants, they are synthesized in plastids where they play essential roles in light-harvesting and in protecting the photosynthetic apparatus from reactive oxygen species (ROS). Carotenoids are also precursors of bioactive metabolites called apocarotenoids, including vitamin A and the phytohormones abscisic acid (ABA) and strigolactones (SLs). Genetic engineering of carotenogenesis made possible the enhancement of the nutritional value of many crops. New metabolic engineering approaches have recently been developed to modulate carotenoid content, including the employment of CRISPR technologies for single-base editing and the integration of exogenous genes into specific "safe harbors" in the genome. In addition, recent studies revealed the option of synthetic conversion of leaf chloroplasts into chromoplasts, thus increasing carotenoid storage capacity and boosting the nutritional value of green plant tissues. Moreover, transient gene expression through viral vectors allowed the accumulation of carotenoids outside the plastid. Furthermore, the utilization of engineered microorganisms allowed efficient mass production of carotenoids, making it convenient for industrial practices. Interestingly, manipulation of carotenoid biosynthesis can also influence plant architecture, and positively impact growth and yield, making it an important target for crop improvements beyond biofortification. Here, we briefly describe carotenoid biosynthesis and highlight the latest advances and discoveries related to synthetic carotenoid metabolism in plants and microorganisms.
类胡萝卜素是植物、藻类、光合细菌以及几种异养微生物天然产生的著名类异戊二烯色素。在植物中，它们在质体中合成，在那里它们在光捕获以及保护光合装置免受活性氧（ROS）的侵害方面发挥着重要作用。类胡萝卜素也是称为阿朴类胡萝卜素的生物活性代谢物的前体，包括维生素A和植物激素脱落酸（ABA）及独脚金内酯（SLs）。类胡萝卜素生物合成的基因工程使得提高许多作物的营养价值成为可能。最近开发了新的代谢工程方法来调节类胡萝卜素含量，包括采用CRISPR技术进行单碱基编辑以及将外源基因整合到基因组中的特定“安全港”。此外，最近的研究揭示了将叶片叶绿体合成转化为有色体的选择，从而提高类胡萝卜素的储存能力并提高绿色植物组织的营养价值。此外，通过病毒载体的瞬时基因表达使类胡萝卜素在质体外积累。此外，利用工程微生物可以高效大量生产类胡萝卜素，这便于工业生产。有趣的是，类胡萝卜素生物合成的调控还可以影响植物结构，并对生长和产量产生积极影响，使其成为除生物强化之外作物改良的重要目标。在这里，我们简要描述类胡萝卜素的生物合成，并强调与植物和微生物中合成类胡萝卜素代谢相关的最新进展和发现。
