Enhancing Photosynthesis with GPT2 and SBPase Genes
By Izabela Ninu
Photosynthesis
Photosynthesis, the process by which plants convert sunlight into chemical energy, is fundamental to life on Earth. It not only provides the oxygen we breathe but also forms the basis of our food chain. However, the efficiency of photosynthesis is not optimal and can be improved, including the multiple reactions and the Calvin cycle. As such, not all the sunlight that reaches a plant is used for photosynthesis. In fact, plants typically convert only about 1% to 2% of the incident sunlight into chemical energy.
The Calvin cycle
The Calvin cycle, also known as the Calvin-Benson-Bassham (CBB) cycle, is the set of chemical reactions that take place in chloroplasts during photosynthesis. The cycle is light-independent: it takes place after the energy has been captured from sunlight.
The Calvin cycle is crucial for life on earth because it is the process by which plants convert carbon dioxide and sunlight into glucose, thereby providing essential energy for life processes.
GPT2
GPT2 (Glucose-6-phosphate/phosphate translocator 2) is involved in the transport of glucose-6-phosphate from the cytosol (the fluid present in the cell and is a constituent of the cytoplasm) into the chloroplast stroma, where it is converted into glucose via the process of gluconeogenesis. This is an important step in the Calvin cycle: it ensures a steady supply of glucose, which is the primary product of photosynthesis.
SBPase
On the other hand, SBPase (Sedoheptulose-1,7-bisphosphatase) plays a key role in the regeneration phase of the Calvin cycle.
It catalyzes the dephosphorylation of sedoheptulose 1,7-bisphosphate to sedoheptulose 7-phosphate, a critical step that leads to the regeneration of the CO2 acceptor molecule.
Increasing the Activity of GPT2
One way to enhance the Calvin cycle is by increasing the activity of GPT2 (Glucose-6-phosphate/phosphate translocator 2). GPT2 is responsible for the transport of glucose-6-phosphate from the cytosol into the chloroplast stroma, where it is converted into glucose for the Calvin cycle.
By using CRISPR to edit the genes that code for GPT2, we could increase its activity. This would enable a more efficient transport of glucose-6-phosphate into the chloroplast, thereby rendering a steady supply of glucose for the Calvin cycle.
Enhancing the Activity of SBPase
Another way to enhance the Calvin cycle is by enhancing the activity of SBPase (Sedoheptulose-1,7-bisphosphatase).
By using CRISPR to edit the genes that code for SBPase, we can speed up the regeneration of the CO2 acceptor molecule, leading to a faster Calvin cycle and, consequently, a higher rate of carbon fixation in the plant
Implications for Crop Yields
These modifications can result in increased photosynthetic efficiency and, ultimately, higher crop yields. This is particularly important in the context of global food security, as the world’s population continues to grow and climate change threatens agricultural productivity.
