Cells (red units) in the root tips of Arabidopsis thaliana plants under environmental stress. The proteins stabilized by ANAC044 and ANAC085 are shown in green, and their presence in a cell indicates that the cell cycle has come to a pause. Image credit: Takahashi et al. (CC BY 4.0)
During environmental stresses, such as high light or a drought, plants do not have the opportunity to up and leave. Instead, they need to buy time and energy by pausing their growth, which means stopping their cells from dividing. In this case, the cell cycle, a series of stages during which a cell prepares itself for division, must be halted.
If the genetic information in cells is damaged, often under the influence of the environment, plants stop their cell cycle in the step just before division. However, it is still unclear how this process takes place, and which proteins participate in it. Researchers also do not know whether environmental stresses can directly trigger this mechanism.
To investigate, Takahashi et al. conducted a series of genetic experiments on a common plant known as Arabidopsis thaliana, and they identified two proteins, ANAC044 and ANAC085, which could stop the cell cycle when the genetic information is damaged. In particular, ANAC044 and ANAC085 worked by stabilizing other proteins that turn off certain genes that the cell needed to divide. Additional experiments showed that other types of stresses, such as heat, halted the cell cycle using the ANAC044 and ANAC085 pathway. This suggests that this mechanism may be a central ‘hub’ that responds to various stress signals from the environment to prevent cells from dividing.
In the field, environmental stresses stop plants from growing, which reduces crop yields; ultimately, manipulating ANAC044 or ANAC085 might help to boost plant productivity even when external conditions fluctuate.
