A Pathway Is Essential for Light-Dependent Enzyme Activation, Photosynthesis in Leaves, Normal Plant Growth [Study]

Photosynthesis is one of the most essential chemical reactions, not only for plants, but for the entire planet. The impact, and thus the significance, of photosynthesis cannot be overstated.

As a result, it's not surprising that scientific research has long been captivated by the responses and physical phenomena that occur during photosynthesis.

The ferredoxin/thioredoxin (Fd/Trx) pathway is one of these.

Shining a new light on the importance of a critical photosynthesis

(Photo : Vadim L/Unsplash)

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, as per ScienceDaily.

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 address this issue, a team of Tokyo Institute of Technology (Tokyo Tech) researchers led by Associate Professor Keisuke Yoshida used CRISPR/Cas9 technology to create a mutant specimen of the plant Arabidopsis thaliana.

This specimen was genetically modified to have a completely defective Fd/Trx pathway.

"By developing 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," said Dr. Yoshida.

The paper was published in the 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 changed their state.

In addition, the mutated plants had abnormally developed chloroplasts and a reduced ability to photosynthesize.

In the mutant strain, ATP synthase was the only enzyme that showed a reducing response.

This enzyme is essential for the synthesis of ATP, the molecule that stores energy in all living things. Activation of ATP synthase occurred via multiple pathways and was unaffected by the defective Fd/Trx pathway.

In summary, 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 important for photosynthesis, which is required for normal plant growth.

Also Read: Tree Growth is Not Entirely Dependent on Photosynthesis: New Study

The important role of photosynthesis

Photosynthesis' primary function is to convert solar energy into chemical energy and then store that chemical energy for later uses, as per Michigan University.

This process powers the majority of the planet's living systems. It is inefficient by human engineering standards, but it does the job.

Photosynthesis occurs in chloroplasts, which are parts of the cell. Chemistry and physics are intricate.

It's humbling to think that the energy in our bodies travels 93 million miles in just over eight minutes, and that life has tapped into that energy stream.

That energy is bound up in biological systems for a short time before continuing on its merry way into the darkness of space.

The process of respiration, interestingly and not by chance, breaks apart the glucose molecule. Respiration occurs in nearly all living things' cells.

The released energy is then used for various metabolic activities, including the energy required to read this article.

Respiration occurs in mitochondrial regions of cells. The chemical reactions are the inverse of photosynthesis, with six oxygen molecules (12 atoms) as inputs.

Energy, as well as carbon dioxide and water, are released.

Oxygen is a byproduct of photosynthesis, and carbon dioxide is a byproduct of respiration. Trees are frequently cited as the primary source of oxygen for the planet, but this is incorrect.

Water covers the majority of the planet, and the collective photosynthesis of lowly algae is the true oxygen machine.

Nonetheless, trees and forests are important oxygen producers. However, if the only benefit of trees and forests was oxygen, we could easily live without them.

Furthermore, some forests produce more carbon dioxide than oxygen.

Fortunately, the benefits of trees and forests extend far beyond the production of oxygen.

Related article: Researchers Reveal the Most Detailed Process of Photosynthesis