Photosynthesis is a process that plants and other organisms use to convert light energy into chemical energy that can then be released to fuel the organism’s activities via cellular respiration. Photosynthesis is critical for climate processes because it absorbs carbon dioxide from the atmosphere and then binds it in plants, soils, and harvested products.
Researchers using CRISPR/Cas9 have finally solved the mystery of the unclear biological significance of the ferredoxin/thioredoxin pathway in plants. The pathway is important for light-dependent enzyme activation, photosynthesis in leaves, and normal plant growth, according to the researchers.
Photosynthesis is one of the most important chemical reactions, not only for plants but also for the entire world. The significance of photosynthesis cannot be overstated. As a result, it’s no surprise that science has long been fascinated by the reactions and physical phenomena that occur during photosynthesis. One of these phenomena is the ferredoxin/thioredoxin (Fd/Trx) pathway.
The insights we gained from this study into the working and importance of the Fd/Trx pathway in plants has given us a deeper understanding of the complex mechanisms that occur within plants, and this research also pushes us to look deeper and answer many other questions related to the photosynthesis process so that we can fully understand this awe-inspiring process that powers the entire world.
Dr. Yoshida
The Fd/Trx pathway, discovered around a half-century ago, has long been credited with regulating many light-dependent reactions in chloroplasts, the organ in the leaf where photosynthesis occurs. The Fd/Trx pathway has long been thought to be extremely important to plants because it activates several enzymes in chloroplasts in response to light. However, these assumptions have been called into question for two reasons. The first is because other pathways in the leaf have been discovered that could also activate chloroplast enzymes. The second reason is that no studies have been conducted to investigate how suppression of the Fd/Trx pathway affects plants.
To solve this problem a team of researchers from the Tokyo Institute of Technology (Tokyo Tech) led by Associate Professor Keisuke Yoshida, used CRISPR/Cas9 technology to create a mutated specimen of the plant Arabidopsis thaliana. This specimen was genetically engineered to make their Fd/Trx pathway completely defective. According to Dr. Yoshida, “By creating a model with a defective Fd/Trx pathway, we were able to uncover its actual biological significance in plants, which has led to some exciting discoveries.” The paper was published in Journal of Biological Chemistry.
The researchers compared the new mutant specimens to the unmutated plants to see what was different and thus understand the impact of the Fd/Trx pathway. The researchers examined the states of enzymes in the chloroplast after shining different intensities of light on the plants to assess the role of the pathway in activating light dependent reactions in the chloroplast. The enzymes in the wild, unmutated plant had shifted from an oxidized to a reduced state. In the mutated plants, however, none of the enzymes had changed their state.
The mutated plants also showed abnormally developed chloroplasts and reduced ability to photosynthesize. ATP synthase was the only enzyme that showed a reducing response in the mutant strain. This enzyme is key to the synthesis of ATP, the energy storage molecule for all living beings. ATP synthase activation occurred through various pathways and was not affected much by the defective Fd/Trx pathway.
To summarize, the researchers discovered that the Fd/Trx pathway is required for many light-dependent enzyme activation reactions in leaves. The Fd/Trx pathway is also required for efficient photosynthesis, which is necessary for normal plant growth.
“The insights we gained from this study into the working and importance of the Fd/Trx pathway in plants has given us a deeper understanding of the complex mechanisms that occur within plants,” says Dr. Yoshida, “and this research also pushes us to look deeper and answer many other questions related to the photosynthesis process so that we can fully understand this awe-inspiring process that powers the entire world.”
