Engineered plants could be green chemical factories of the future
Synthetic biology aims to modify existing organisms by designing biological systems based on IT and engineering. One key approach is to design and then introduce synthetic genomes into cells. Genomes provide an organism with all its genetic information. “Plants are particularly attractive targets of synthetic biology,” explains GENEVOSYN project coordinator Ralph Bock, director at the Max Planck Institute of Molecular Plant Physiology in Germany. “First, their genomes can be manipulated relatively easily. Second, plants can tolerate even large changes to their genomes. Third, and most importantly, all life on our planet depends on plants. They produce the oxygen we breathe and the food we eat.” “In view of the growing world population and the challenges that come with climate change, agricultural productivity must double by 2050,” notes Bock. “New renewable sources of chemicals and fuels must be found. We urgently need new technologies, and here synthetic biology can play an important role.”
Applying genomic engineering
The GENEVOSYN project, supported by the European Research Council, is built on Bock’s groundbreaking work in developing tools to engineer the genomes of two cell organelles – structures that perform specific functions in cells – called chloroplasts and mitochondria. The genomes of these two organelles are much smaller than the genome in the nucleus of the plant cell. “This makes chloroplasts and mitochondria particularly amenable to large-scale genome engineering with high precision,” explains Bock. “This allows us to apply synthetic biology approaches that are currently not feasible in the nuclear genome.” The project had a number of aims. First, Bock wanted to engineer a new metabolic pathway in the chloroplast, to allow for the synthesis of an antimalarial drug called artemisinin. Second, he wanted to develop methods to make the mitochondrial genome more accessible to genetic manipulations. “Finally, we wanted to build on our discovery that entire genomes can be transferred between plant species by grafting,” says Bock. “Our idea was to exploit this process to generate new synthetic plant species.”
Plants as factories
The project, completed in March 2021, successfully introduced the artemisinin pathway into chloroplasts. Bock and his team were able to show that this much-needed drug, which has the potential to save thousands of lives, can be produced to high levels in tobacco leaves. “The strategies and tools we developed in this project are now ready to be applied to other metabolic pathways,” adds Bock. The team also made some progress with mitochondrial genome engineering. “There are still a number of technical obstacles that need to be overcome before we can put additional genes into the mitochondrial genome,” says Bock. Finally, the project succeeded in generating several synthetic species, and the team is currently analysing their genetics, physiology and metabolism. “We found that grafting can promote the transfer of genetic material between different species,” remarks Bock. “This provides plant breeders with a new method for producing new crop species with novel properties.” Overall, the GENEVOSYN project has underlined the potential of synthetic biology in strengthening food security, and in the use of plants as factories for the efficient synthesis of green chemicals, biopharmaceuticals and other useful compounds. Bock believes this is only the beginning. “Future challenges that can be addressed through synthetic biology include, for example, the improvement of photosynthesis, and the engineering of plants that can use the nitrogen in the air as fertiliser,” he concludes.
Keywords
GENEVOSYN, agriculture, chemicals, biopharmaceuticals, genetic, synthetic, biology