Polarity proteins shape efficient ‘breathing’ pores in grasses – Zoo House News
A research group from the University of Bern is investigating how plants “breathe”. They have gained new insights into how grasses develop efficient “respiratory pores” on their leaves. If important groundbreaking components are missing in this development process, the gas exchange between the plant and the atmosphere is impaired. The results are also important with regard to climate change.
Grasses have “respiratory pores” (called stomata) that open and close to regulate both the uptake of carbon dioxide for photosynthesis and the loss of water through transpiration. In contrast to many other plants, stomata in grasses form lateral “helper cells”. Thanks to these cells, the stomata of grasses can open and close faster, which optimizes gas exchange between the plant and the atmosphere and thus saves water.
For the current study, Prof. Dr. Michael Raissig, Dr. Heike Lindner and co-author Roxane Spiegelhalder from the Institute of Plant Sciences (IPS) at the University of Bern study the development of helper cells in the grass Brachypodium distachyon. They discovered two proteins that accumulate on opposite sides of a cell and act like a “compass” for the correct development of helper cells in grasses. The research results were published in the journal eLife.
A cell compass for the development of helper cells
Helper cells are formed by unequal, asymmetric cell division. A cell divides into a small cell, the helper cell, and a larger neighboring cell. In order for this division to occur in the correct proportion and orientation, the cell needs landmarks. These landmarks serve as landmarks and are given by what are known as polarity proteins, which accumulate on opposite sides of the cell and can thus define, for example, left and right or up and down. In this study, the Bern researchers discovered two polarity proteins that accumulate on two opposite sides. “The two proteins act as a sort of cellular compass, directing the direction of cell division and the development of helper cells. We have found that helper cells do not form properly if one of these proteins is missing,” explains project leader Michael Raissig.
Plant respiratory pores and climate change
“I’m always fascinated by the fact that the lack of a cell compass for a single cell type can affect the gas exchange dynamics and efficiency of the entire system,” says Michael Raissig. This is particularly relevant given climate change, which is causing prolonged periods of drought and excessive heat. Grasses play a central role in human food security; Grains like corn, rice, and wheat are all grasses and together provide more than half of the calories consumed by humans. “It is therefore of utmost importance to understand how plants ‘breathe’ and how and why grasses form more efficient ‘breathing’ pores,” adds Raissig.
Although this study mainly focuses on developmental biology, these results could still be relevant for the improvement of agricultural crops. “Stomata are the cellular gatekeepers between the leaf and the environment and are the first to react to climate changes,” says PhD student and co-author Roxane Spiegelhalder. Therefore, it is important to understand how and why grasses form the most efficient “gatekeepers” to “breathe” more water efficiently. How and whether these findings can be transferred to other crops requires further research, concludes Spiegelhalder.
Materials provided by the University of Bern. Note: Content can be edited for style and length.