Enhanced Photosynthesis
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Description and purpose of the technology
Photosynthesis enhancement is a theoretical geoengineering approach based on the idea that plants and algae could be genetically modified to exhibit “more efficient” photosynthetic traits, which could lead to more carbon dioxide being absorbed and metabolized. There are serious concerns that accompany all genetic engineering of plant life, involving unexpected side effects, risks of contamination in natural systems, poorly-understood long-term impacts on humans and ecosystems and corporate control of the technologies and their uses. According to critics of the approach, enhancing photosynthesis in this high-tech way is high-risk, with food security being most at risk. [1]
However, proponents usually justify research into genetically modifying plant photosynthesis with food security arguments—world population is growing, crop yields have reached a plateau and, given the growing demands for food and fuel in the face of climate change, we must find a way to increase crop yields. For proponents of the technology, “the key remaining route to increase the genetic yield potential of our major crops” [2] is enhancing photosynthesis. Increasingly, the potential for Carbon Dioxide Removal (CDR) is also being used as a major justification for this research, since increased crop yields through genetic modification would by design also remove more carbon dioxide from the atmosphere. The anticipated CDR potential of enhancing photosynthesis is based on the assumption that the additional carbon dioxide that would be absorbed by the genetically modified plants and algae would remain permanently stored in soils or at the bottom of the ocean.
Actors involved
The C4 Rice Project is a collaboration between scientists from Europe, North America and Asia. Kick-started in 2008, it has received at least US$ 25 million of support from the Bill and Melinda Gates Foundation so far. The project aims to transform the photosynthetic traits of rice from C3 photosynthesis to C4, which is a more efficient form of photosynthesis in warmer climates. This would, in theory, increase yields, enhance nitrogen use and water use efficiency, improve adaptation to hotter and drier climates and eventually remove more carbon dioxide from the atmosphere. The present funding phase aims to develop a prototype C4 photosynthesis rice. [3]
Critics question the wisdom of using rice as the target crop for such extreme genetic engineering in a time of water stress, when it is one of the world’s staple crops and when it is the central pillar of the livelihoods of billions of people. [4] Notwithstanding, some researchers consider rice “an ideal crop” to engineer because it was the first crop species to have its genome sequenced and there is therefore large amounts of physiological, genetic and genomic data available. Rice could pave the way to engineered C4 wheat, C4 cotton and C4 trees. [5] Proponents claim that enhancing the photosynthesis of major crops on a large scale would theoretically draw down large amounts of carbon dioxide.
The European Union funded its own “3To4” enhanced photosynthesis project from 2012 to 2016, involving a consortium of private and public-sector researchers, an overall budget of €8.9 million and practical support for the C4 Rice Project. While the researchers focussed initially on rice as a target crop, they “envisage rapid transfer of technological advances into mainstream EU crops, such as wheat and rape.” [6] Private-sector consortium members included Bayer Crop Science and Chemtex Italia (now Biochemtex).
The pan-European project BEEP (bio-inspired and bionic materials for enhanced photosynthesis) also looks at photosynthetic processes but in the marine environment, and aims to understand the mechanisms affecting photosynthetic efficiency, for example in marine bacteria and algae, with a view to “boosting photosynthesis in living organisms.” [7]
Other research is currently underway to explore how plant absorption of carbon dioxide could be increased synthetically. Synthetic biologists have built entirely novel biochemical processes into engineered organisms to speed up the carbon fixation process and make plants better at turning carbon dioxide into energy. For example, in 2016 a team of synthetic biologists at the Max Planck Institute for Terrestrial Microbiology in Marburg, Germany, stitched together 17 different enzymes from nine different organisms (e.g. gut bacteria, other microbes and plants) to achieve a proof-of-principle carbon dioxide fixation pathway in an engineered organism that exceeds what can be found in nature. The so-called CETCH cycle includes three engineered enzymes, among which is a new synthetic carbon dioxide-fixing enzyme that is nearly 20 times faster than the most prevalent naturally-occuring carbon dioxide-fixing enzyme. After demonstrating the process in vitro, the research team is now aiming to transplant the process into living cells. Future applications are also envisaged for higher biofuel and food production. [8]
In another study funded by the Bill and Melinda Gates Foundation, researchers enhanced crop productivity by reducing the time it takes plants to “recover” from detecting too much light. [9] By adding proteins to certain tobacco plants, the engineered plants grew up to 20% bigger, and the focus of the work is now on achieving the same results with crops like rice, sorghum and cassava.
A research project conducted by the Qingdao Institute of Bioenergy and Bioprocess Technology in China aims to combine carbon dioxide uptake, enhanced microalgal photosynthesis and biofuel production by genetically modifying the microalgae species Nannochloropsis oceanica. The objective is to improve microalgal tolerance to high levels of carbon dioxide in order to produce microalgae with flue gas from oil production. [10]
The California-based Salk Institute has announced plans to commercialize the Ideal Plant Project by 2025, which uses gene editing methods to enhance plant capacity to store carbon and to resist decomposition. It does this by increasing the amount of suberin, a plant-based substance comparable to cork, in plant roots.
The US company ZeaKal is currently developing and testing its “PhotoSeed” plants, in cooperation with chemical company Dow DuPont. According to ZeaKal, enzymatic reactions in PhotoSeed plants have been genetically modified in order to enhance photosynthesis and increase growth rates and carbon dioxide uptake. [11]
Impacts of the technology
The ability to manipulate photosynthesis implies control over just about everything that determines how and if a plant survives and thrives, including how efficiently it uses water and nutrients to grow and produce the biomass that we use for food, fibre and fuel, as well as how efficiently it fixes carbon dioxide and releases oxygen.
Genetically engineering plant life in order to enhance photosynthesis brings with it serious concerns. Jill E. Gready, Research Professor at the Australian National University, argues that the “pursuit and public promotion of some very high-tech solutions for photosynthesis improvement with high risk of failure… present a high-level risk to food security as they provide false confidence that the problem is being addressed, and, by diverting funds, lead to lost opportunity for R&D with greater likelihood of success and impact.” [12]
Cornell University’s Norman Uphoff, another critic of enhancing photosynthesis, has spearheaded an agroecological method of cultivating rice known as the System of Rice Intensification. He recently published data demonstrating that a change in farm management practices, such as wider spacing of plants and increased soil aeration, can dramatically increase rice yields beyond what has been thought possible, and without increased dependence on chemical inputs or genetic engineering. [13]
Reality check
Research into photosynthesis enhancement is well underway and projects are moving from engineering in vitro to engineering crop plants themselves, with a view to commercializing the engineered strains. However, the effectiveness of enhanced photosynthesis as a carbon dioxide removal method is still mostly theoretical, particularly because there are many uncertainties related to the permanence of the absorbed carbon in soils or the deep ocean.
Further reading
ETC Group and Heinrich Böll Foundation, “Outsmarting Nature? Synthetic Biology and Climate Smart Agriculture”: http://www.etcgroup.org/content/outsmarting-nature/report
This video summarizes what the researchers are trying to achieve through photosynthesis enhancement but doesn’t discuss the potential impacts: www.youtube.com/watch?v=Av0dTk9KzlY
End notes
[1] Gready (2014) Best-fit options of crop staples for food security: productivity, nutrition and sustainability, in: Jha, et al. (2014) Handbook on Food, chapter 15, page 406
[2] Long, et al. (2015) Meeting the Global Food Demand of the Future by Engineering Crop Photosynthesis and Yield Potential, in: Cell, Vol. 161:56-66, https://doi.org/10.1016/j.cell.2015.03.019
[3] ETC Group and Heinrich Böll Foundation (2020) Geoengineering Map, https://map.geoengineeringmonitor.org
[4] ETC Group and Heinrich Böll Foundation (2015) Outsmarting Nature? Synthetic Biology and Climate Smart Agriculture, Communiqué 114, https://www.boell.de/en/2015/11/30/outsmarting-nature-synthetic-biology-and-climate-smart-agriculture
[5] Zhu, et al. (2010) C4 Rice – an ideal arena for systems biology research, in: J Integr Plant Biol., Vol. 52(8):762 – 770, https://doi.org/10.1111/j.1744-7909.2010.00983.x
[6] CORDIS (2016) 3to4: Converting C3 to C4 photosynthesis for sustainable agriculture, CORDIS project database of the European Union, accessed: February 2020, https://cordis.europa.eu/project/id/289582; ETC Group and Heinrich Böll Foundation (2020)
[7] ETC Group and Heinrich Böll Foundation (2020)
[8] Schwander, et al. (2016), A synthetic pathway for the fixation of carbon dioxide in vitro, in: Science, Vol. 354(6314):900 – 904, http://doi.org/10.1126/science.aah5237; ETC Group and Heinrich Böll Foundation (2020)
[9] Kromdijk, et al. (2016) Improving photosynthesis and crop productivity by accelerating recovery from photoprotection, in: Science, Vol. 354(6314): 857 – 861, http://doi.org/10.1126/science.aai8878
[10] ETC Group and Heinrich Böll Foundation (2020)
[11] ETC Group and Heinrich Böll Foundation (2020)
[12] Gready (2014)
[13] Uphoff (2013) Rethinking the concept of ‘yield ceiling’ for rice: implications of the System of Rice Intensification (SRI) for agricultural science and practice, in: Journal of Crop and Weed, Vol. 9(1):1 – 19, http://www.cropandweed.com/vol9issue1/1.1.html
Enhanced Photosynthesis
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Descripción y propósito de la tecnología
Photosynthesis enhancement is a theoretical geoengineering approach based on the idea that plants and algae could be genetically modified to exhibit “more efficient” photosynthetic traits, which could lead to more carbon dioxide being absorbed and metabolized. There are serious concerns that accompany all genetic engineering of plant life, involving unexpected side effects, risks of contamination in natural systems, poorly-understood long-term impacts on humans and ecosystems and corporate control of the technologies and their uses. According to critics of the approach, enhancing photosynthesis in this high-tech way is high-risk, with food security being most at risk. [1]
However, proponents usually justify research into genetically modifying plant photosynthesis with food security arguments—world population is growing, crop yields have reached a plateau and, given the growing demands for food and fuel in the face of climate change, we must find a way to increase crop yields. For proponents of the technology, “the key remaining route to increase the genetic yield potential of our major crops” [2] is enhancing photosynthesis. Increasingly, the potential for Carbon Dioxide Removal (CDR) is also being used as a major justification for this research, since increased crop yields through genetic modification would by design also remove more carbon dioxide from the atmosphere. The anticipated CDR potential of enhancing photosynthesis is based on the assumption that the additional carbon dioxide that would be absorbed by the genetically modified plants and algae would remain permanently stored in soils or at the bottom of the ocean.
Actores involucrados
The C4 Rice Project is a collaboration between scientists from Europe, North America and Asia. Kick-started in 2008, it has received at least US$ 25 million of support from the Bill and Melinda Gates Foundation so far. The project aims to transform the photosynthetic traits of rice from C3 photosynthesis to C4, which is a more efficient form of photosynthesis in warmer climates. This would, in theory, increase yields, enhance nitrogen use and water use efficiency, improve adaptation to hotter and drier climates and eventually remove more carbon dioxide from the atmosphere. The present funding phase aims to develop a prototype C4 photosynthesis rice. [3]
Critics question the wisdom of using rice as the target crop for such extreme genetic engineering in a time of water stress, when it is one of the world’s staple crops and when it is the central pillar of the livelihoods of billions of people. [4] Notwithstanding, some researchers consider rice “an ideal crop” to engineer because it was the first crop species to have its genome sequenced and there is therefore large amounts of physiological, genetic and genomic data available. Rice could pave the way to engineered C4 wheat, C4 cotton and C4 trees. [5] Proponents claim that enhancing the photosynthesis of major crops on a large scale would theoretically draw down large amounts of carbon dioxide.
The European Union funded its own “3To4” enhanced photosynthesis project from 2012 to 2016, involving a consortium of private and public-sector researchers, an overall budget of €8.9 million and practical support for the C4 Rice Project. While the researchers focussed initially on rice as a target crop, they “envisage rapid transfer of technological advances into mainstream EU crops, such as wheat and rape.” [6] Private-sector consortium members included Bayer Crop Science and Chemtex Italia (now Biochemtex).
The pan-European project BEEP (bio-inspired and bionic materials for enhanced photosynthesis) also looks at photosynthetic processes but in the marine environment, and aims to understand the mechanisms affecting photosynthetic efficiency, for example in marine bacteria and algae, with a view to “boosting photosynthesis in living organisms.” [7]
Other research is currently underway to explore how plant absorption of carbon dioxide could be increased synthetically. Synthetic biologists have built entirely novel biochemical processes into engineered organisms to speed up the carbon fixation process and make plants better at turning carbon dioxide into energy. For example, in 2016 a team of synthetic biologists at the Max Planck Institute for Terrestrial Microbiology in Marburg, Germany, stitched together 17 different enzymes from nine different organisms (e.g. gut bacteria, other microbes and plants) to achieve a proof-of-principle carbon dioxide fixation pathway in an engineered organism that exceeds what can be found in nature. The so-called CETCH cycle includes three engineered enzymes, among which is a new synthetic carbon dioxide-fixing enzyme that is nearly 20 times faster than the most prevalent naturally-occuring carbon dioxide-fixing enzyme. After demonstrating the process in vitro, the research team is now aiming to transplant the process into living cells. Future applications are also envisaged for higher biofuel and food production. [8]
In another study funded by the Bill and Melinda Gates Foundation, researchers enhanced crop productivity by reducing the time it takes plants to “recover” from detecting too much light. [9] By adding proteins to certain tobacco plants, the engineered plants grew up to 20% bigger, and the focus of the work is now on achieving the same results with crops like rice, sorghum and cassava.
A research project conducted by the Qingdao Institute of Bioenergy and Bioprocess Technology in China aims to combine carbon dioxide uptake, enhanced microalgal photosynthesis and biofuel production by genetically modifying the microalgae species Nannochloropsis oceanica. The objective is to improve microalgal tolerance to high levels of carbon dioxide in order to produce microalgae with flue gas from oil production. [10]
The California-based Salk Institute has announced plans to commercialize the Ideal Plant Project by 2025, which uses gene editing methods to enhance plant capacity to store carbon and to resist decomposition. It does this by increasing the amount of suberin, a plant-based substance comparable to cork, in plant roots.
The US company ZeaKal is currently developing and testing its “PhotoSeed” plants, in cooperation with chemical company Dow DuPont. According to ZeaKal, enzymatic reactions in PhotoSeed plants have been genetically modified in order to enhance photosynthesis and increase growth rates and carbon dioxide uptake. [11]
Impactos de la tecnología
The ability to manipulate photosynthesis implies control over just about everything that determines how and if a plant survives and thrives, including how efficiently it uses water and nutrients to grow and produce the biomass that we use for food, fibre and fuel, as well as how efficiently it fixes carbon dioxide and releases oxygen.
Genetically engineering plant life in order to enhance photosynthesis brings with it serious concerns. Jill E. Gready, Research Professor at the Australian National University, argues that the “pursuit and public promotion of some very high-tech solutions for photosynthesis improvement with high risk of failure… present a high-level risk to food security as they provide false confidence that the problem is being addressed, and, by diverting funds, lead to lost opportunity for R&D with greater likelihood of success and impact.” [12]
Cornell University’s Norman Uphoff, another critic of enhancing photosynthesis, has spearheaded an agroecological method of cultivating rice known as the System of Rice Intensification. He recently published data demonstrating that a change in farm management practices, such as wider spacing of plants and increased soil aeration, can dramatically increase rice yields beyond what has been thought possible, and without increased dependence on chemical inputs or genetic engineering. [13]
Visión realista
Research into photosynthesis enhancement is well underway and projects are moving from engineering in vitro to engineering crop plants themselves, with a view to commercializing the engineered strains. However, the effectiveness of enhanced photosynthesis as a carbon dioxide removal method is still mostly theoretical, particularly because there are many uncertainties related to the permanence of the absorbed carbon in soils or the deep ocean.
Lectura complementaria
ETC Group and Heinrich Böll Foundation, “Outsmarting Nature? Synthetic Biology and Climate Smart Agriculture”: http://www.etcgroup.org/content/outsmarting-nature/report
This video summarizes what the researchers are trying to achieve through photosynthesis enhancement but doesn’t discuss the potential impacts: www.youtube.com/watch?v=Av0dTk9KzlY
Notas finales
[1] Gready (2014) Best-fit options of crop staples for food security: productivity, nutrition and sustainability, in: Jha, et al. (2014) Handbook on Food, chapter 15, page 406
[2] Long, et al. (2015) Meeting the Global Food Demand of the Future by Engineering Crop Photosynthesis and Yield Potential, in: Cell, Vol. 161:56-66, https://doi.org/10.1016/j.cell.2015.03.019
[3] ETC Group and Heinrich Böll Foundation (2020) Geoengineering Map, https://map.geoengineeringmonitor.org
[4] ETC Group and Heinrich Böll Foundation (2015) Outsmarting Nature? Synthetic Biology and Climate Smart Agriculture, Communiqué 114, https://www.boell.de/en/2015/11/30/outsmarting-nature-synthetic-biology-and-climate-smart-agriculture
[5] Zhu, et al. (2010) C4 Rice – an ideal arena for systems biology research, in: J Integr Plant Biol., Vol. 52(8):762 – 770, https://doi.org/10.1111/j.1744-7909.2010.00983.x
[6] CORDIS (2016) 3to4: Converting C3 to C4 photosynthesis for sustainable agriculture, CORDIS project database of the European Union, accessed: February 2020, https://cordis.europa.eu/project/id/289582; ETC Group and Heinrich Böll Foundation (2020)
[7] ETC Group and Heinrich Böll Foundation (2020)
[8] Schwander, et al. (2016), A synthetic pathway for the fixation of carbon dioxide in vitro, in: Science, Vol. 354(6314):900 – 904, http://doi.org/10.1126/science.aah5237; ETC Group and Heinrich Böll Foundation (2020)
[9] Kromdijk, et al. (2016) Improving photosynthesis and crop productivity by accelerating recovery from photoprotection, in: Science, Vol. 354(6314): 857 – 861, http://doi.org/10.1126/science.aai8878
[10] ETC Group and Heinrich Böll Foundation (2020)
[11] ETC Group and Heinrich Böll Foundation (2020)
[12] Gready (2014)
[13] Uphoff (2013) Rethinking the concept of ‘yield ceiling’ for rice: implications of the System of Rice Intensification (SRI) for agricultural science and practice, in: Journal of Crop and Weed, Vol. 9(1):1 – 19, http://www.cropandweed.com/vol9issue1/1.1.html