When plants photosynthesize, the stomata on the leaves open to absorb carbon dioxide.
However, prolonged stomatal opening can also expose plants to the threat of internal water loss.
Understanding how plants sense their environment and control stomatal opening times is important for addressing future climate change.
Recently, a study in Science Advances has identified a new molecular pathway for plants to sense CO2 and control their “breathing”.
Scientists have found that in low CO2 environments, a protein called HT1 activates CBC1 kinase in plants, causing the guard cells on both sides of the stomata to swell and keep the stomata open for a long time in order to obtain enough CO2 for photosynthesis.
As CO2 levels rise, the MAP kinase MPK4/MPK12 inhibits the activity of HT1, causing the stomata to close.
This study may help improve the efficiency of photosynthesis in crops and other plants.