We all know vitamin C is a potent antioxidant and beneficial for humans to a great extent. Scientists from Japan have found that vitamin C is beneficial for plants too, as a sun block! Chloroplasts in plants have high levels of ascorbate (vitamin C) and this helps them overcome photoinhibition caused by extremely strong sunlight/light. The researchers have found the reason for high levels of ascorbate in the chloroplasts in plants. Ascorbate is synthesized in the mitochondria, the component which is the ‘power house’ of the cell. This study published in Nature Communications, shows that AtPHT4;4, a member of the phosphate transporter 4 family of Arabidopsis thaliana (a small flowering plant) works as a transporter of ascorbate in plants. This transporter facilitates the movement of ascorbate from the mitochondria, the site of synthesis, to the chloroplast helping the plants to use the high levels of ascorbate to protect them from light.
The AtPHT4;4 protein is expressed abundantly in the chloroplast envelope membrane. Knockout of this protein in plants results in decreased levels of ascorbate in the leaves and the heat dissipation process of excessive energy during photosynthesis is compromised. Hence, these proteins act as ‘sun-block’ in plants.
The original publication can be accessed here.
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