Scientists have recently found new information about how young plants survive before they can use sunlight. Their study is published in Nature Communications.Most plants make food through photosynthesis. They use sunlight to produce sugars for energy. But a seed cannot do this when it first begins to grow. At this stage, the young plant cannot take in light. So the young plant uses energy stored inside the seed. This stored energy keeps it alive at the start.
The main energy source is fatty acids. These are broken down inside small cell parts called peroxisomes. Peroxisomes exist in both plant and human cells. Researchers often use plant cells to study this process. Plant cells are easier to see and study. In a small plant called Arabidopsis, the cells are large enough to observe clearly under a light microscope. This helps scientists track changes over time. They discovered that peroxisomes grow larger during early growth. When the plant begins photosynthesis, these structures return to their normal size. A research team wanted to understand what controls these size changes.
They focused on a protein called PEX11. This protein was already known to help peroxisomes divide. But the team suspected it might have another role as well. To study this function, they needed to change the genes that produce PEX11. The task was not easy. The protein is made by five different genes.
Changing one gene did not do much. But removing all five genes killed the plant. To study the effect, scientists used advanced gene-editing tools. They turned off different combinations of the five genes. This helped them understand what PEX11 really does. They also made two special types of plants with changed PEX11 genes.
In both cases, the peroxisomes still grew during the early stage, just like in normal plants. But something unusual happened afterward. Instead of shrinking back, some peroxisomes kept growing larger and larger. In extreme cases, these structures became so big that they stretched across the entire cell. This showed that PEX11 plays an important role in controlling the size of peroxisomes. The researchers also found another important difference. In normal cells, small bubble-like structures called vesicles form inside peroxisomes.
These vesicles help process fatty acids and to remove small parts of the outer membrane as they form. This process may help limit how big the peroxisome becomes. But in the modified plants, these vesicles were either missing or minimal. Without enough vesicles, the peroxisomes kept growing without control. This finding suggests that PEX11, a protein involved in the formation of cellular structures, may help create these vesicles. Without it, the balance inside the cell is disturbed.
The scientists then asked another question. Could this protein work the same way in other organisms? To test this, they used a version of the protein from yeast. Yeast is very different from plants and has been evolving separately for over a billion years. The researchers placed the yeast protein into the modified plant cells. The result was surprising.
The yeast protein was able to address the problem. The peroxisomes returned to their normal size and behavior. This evidence shows that the function of this protein has remained almost unchanged over a very long time. Scientists call this a “conserved” function. The protein likely works in a similar way in many living things, including humans. This discovery is important for several reasons. Peroxisomes take part in many processes inside cells. They are also linked to some human diseases. Understanding how they grow and work can help scientists learn more about these conditions. This knowledge could also be useful in biotechnology.
Scientists try to engineer cells to produce useful substances. To do this better, they need to control parts of the cell like peroxisomes. This study shows that a small protein helps control an important part of the cell. It also shows that studying plants can teach us things that apply to many living organisms.
