Department of Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
Department of Plant and Environmental Sciences, Weizmann Institute of Science, 234 Herzl Street, Rehovot, 7610001, Israel.
New Phytol. 2019 Dec;224(4):1472-1478. doi: 10.1111/nph.15973. Epub 2019 Jul 11.
Betalains are nitrogenous red and yellow pigments found in a single order of plants, the Caryophyllales, and in some higher fungi. They are responsible for the colors observed in many ornamental plants, as well as in various food products, where they are used as natural colorants. Their nutritional properties and attractive colors make them an appealing target for metabolic engineering. This is further heightened by the limited availability of natural betalain sources, arising from their relative scarcity in the plant kingdom, particularly in edible plants. Recent progress in decoding their biosynthetic pathway has facilitated stable heterologous production of betalains in several plant and microbial systems. Here, we provide a brief review of recent advances and discuss current approaches and possible future directions in betalain metabolic engineering, including expanding the chemical diversity of betalains and increasing their yield, exploring new host organisms for their heterologous production, and engineering their secretion from the cell.
甜菜红素是一种含氮的红色和黄色素，仅存在于石竹目这一单系植物中，以及一些高等真菌中。它们使许多观赏植物以及各种食品呈现出人们所观察到的颜色，这些食品将甜菜红素作为天然着色剂使用。其营养特性和诱人的颜色使它们成为代谢工程的一个有吸引力的目标。由于它们在植物界，特别是在食用植物中相对稀缺，导致天然甜菜红素来源有限，这进一步加剧了这种情况。它们生物合成途径的解码方面的最新进展促进了在几种植物和微生物系统中稳定异源生产甜菜红素。在这里，我们简要回顾了最近的进展，并讨论了甜菜红素代谢工程的当前方法和可能的未来方向，包括扩大甜菜红素的化学多样性并提高其产量，探索用于其异源生产的新宿主生物，以及对其进行细胞分泌工程改造。
