Making small molecules in plants: A chassis for synthetic biology‐based production of plant natural products

Abstract

Plant natural products have been extensively exploited in food, medicine, flavor, cosmetic, renewable fuel, and other industrial sectors. Synthetic biology has recently emerged as a promising means for the cost‐effective and sustainable production of natural products. Compared with engineering microbes for the production of plant natural products, the potential of plants as chassis for producing these compounds is underestimated, largely due to challenges encountered in engineering plants. Knowledge in plant engineering is instrumental for enabling the effective and efficient production of valuable phytochemicals in plants, and also paves the way for a more sustainable future agriculture. In this manuscript, we briefly recap the biosynthesis of plant natural products, focusing primarily on industrially important terpenoids, alkaloids, and phenylpropanoids. We further summarize the plant hosts and strategies that have been used to engineer the production of natural products. The challenges and opportunities of using plant synthetic biology to achieve rapid and scalable production of high‐value plant natural products are also discussed.

MYC2: A Master Switch for Plant Physiological Processes and Specialized Metabolite Synthesis

“…Chassis cells are the hardware foundation of synthetic biology [ 125 ]. However, the construction of chassis cells for plant natural-product synthesis remains challenging [ 126 ]. The development of life sciences has made available complete genome sequences, has provided valuable bioinformatics and genetic resources, and has deepened our understanding of the biosynthesis of natural products and the regulatory mechanisms at play [ 127 , 128 , 129 , 130 ].…”

“…The use of plants as a specialized-metabolite production chassis has many advantages, including the presence of photosynthetic systems, extremely rich enzyme repertoires, and various cellular compartments [ 138 , 144 , 145 ]. Plant cellular compartments can decompose complete pathways into independent parts, and various conditions, such as reactions and precursor compounds, can be optimized in each cellular compartment; therefore, using plants as a chassis has great potential for production applications [ 126 ]. The commonly used plant chassis for heterologous synthesis is Nicotiana benthamiana , and various natural products, including alkaloid terpenoids, paclitaxel, and artemisinin, have transiently been expressed in N. benthamiana [ 146 , 147 , 148 ].…”

When green carbon plants meet synthetic biology

“…84 Furthermore, the engineering of targeted pathways will interfere due to the strict metabolic regulation and complex feedback regulation mechanism in plants. 28 Although mathematical models can help manage the complexity of plant CO 2 fixation, a lack of knowledge of the relevant components commonly compromises accurate predictions. 84 The transcriptome and metabolome of transgenic plants with different pathways could be determined to explain the transcriptional basis and signal transduction and help elucidate metabolic crosstalk.…”

“…27 Compared with microbial chassis, plant chassis can be engineered at the level of its cells, tissues or the whole plant. 28 Especially, the plant chassis could provide appropriate platform to express plant originated genes. Moreover, the photosynthesis of plants naturally fixes 105 billion tonnes of carbon per year and directly generates 210 billion tonnes of biomass.…”

“…Since plants have evolved differentiated cells and tissues, the complex structure and gene regulation could affect the functions of the introduced genes. 28 Thus, adding, removing or modifying the targeting peptides could alter the subcellular location of heterologous proteins in the artificial pathway and affect the resulting CO 2 fixation. 98 The targeting peptides are short chains of 3-70 amino acids that direct peptide and protein transport to specific regions in cells.…”