In plants, the natural aging process is called senescence, which involves all the changes that cause the death of cells, tissues, and the entire plant body. Senescence is usually associated with decay and mortality or decreased fertility.
Age-Reversing Mechanism
At the University of California Riverside, experts discovered the secret to reverse the aging process. In their paper "COG-imposed Golgi functional integrity determines the onset of dark-induced senescence." they described that a particular organelle in plant cells might be the key.
Led by Heeseung Choi from UCR's Botany and Plant Sciences Department, the research team determined the parts of the plant cells responsible for controlling their responses to stress from factors such as stress, too little light, or too much salt. They learned about an understudied protein responsible for maintaining the organelle by controlling the survival of plants being left too often in the dark.
This particular organelle, the Golgi body, is responsible for sorting the molecules in the cell to ensure they get to the right places. Meanwhile, the protein COG works by controlling and coordinating the movement of small sac "envelopes" that transport other molecules around the cell. The team discovered that the COG protein and the Golgi bodies work hand in hand, with the protein helping the organelle attach sugars to other proteins or lipids before they are sent to the parts of the plant where they are needed.
As Choi described, Golgi bodies are like the post office of the cell where the proteins and lipids are packed and sent out to where they are needed. A damaged Golgi body can create confusion and trouble in cellular activities, affecting how the cell works and stays healthy.
After finding out the importance of COG to plant health, the researchers decided to learn more about this protein's impact on plants' growth. By working with two groups of plants, the team modified some so they would not produce these proteins. As expected, the modified plants did not show issues growing under normal conditions and cannot be distinguished from unmodified plants.
In the dark, the COG mutants showed signs of aging that usually appear in wild, unmodified plants around day nine. On the other hand, these signs were delivered to the mutants in just three days. This is because depriving plants of light limits their access to solar energy that helps make the sugar needed for their growth.
According to UCR molecular biochemistry professor Katie Dehesh, their study allowed them to define the profound importance of an organelle in the cell not previously implicated in aging. It is exciting that the Golgi bodies are also present in humans and all eukaryotic organisms. Dehesh noted that this research will help find clues about human aging.
How Do Golgi Bodies Work?
The Golgi body is an organelle in a cell composed of a series of cup-shaped sacs covered in membranes. Named after its discoverer, Italian biologist and pathologist Camillo Golgi, it is the central organelle that mediates protein and lipid transport within the eukaryotic cell.
Golgi bodies work by processing the proteins made by the endoplasmic reticulum (ER) before sending them to the cell. Proteins enter the Golgi bodies on the side that faces the ER and exit on the opposite side, facing the cell's plasma membrane.
As the proteins move through this organelle, different chemical processes could happen. One of these is modifying carbohydrate groups and cutting secretory proteins at specific amino acid positions.
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