Protection against damage
DNA-damages occur on a regular basis. Now a new study from Chinese researchers in Science Advances shows that the stress hormone ABA stimulates plants to find DNA breaks.
Organisms do everything to prevent damage to their DNA, or otherwise to repair this as soon as possible. When this fails it orders the cell to die, to prevent mistakes from accumulating. At the same time researchers use DNA damage to introduce new traits. To do this more efficiently it helps to know how an organism deals with DNA damage.
There were suggestions that the stress hormone ABA could be involved in making plants more tolerant to DNA damage. The researchers decided to investigate this. The first thing they did was looking at cell death after exposure to DNA damaging substances. They noticed that when they gave the plants extra ABA during the exposure, less cells would die.
But how does ABA manage this? To answer this question the researchers studied the effect of a protein regulator, SnRK2. SnRK2 regulates proteins in name of ABA. When SnRK2 was absent at the time the researchers exposed the plant to DNA-damaging substances, then just as many cells died in the presence of ABA as in the absence of ABA.
ABA tells via SnRK2 and CLC2 the DNA-break searcher ADA2b to be extra alert
To find out which protein it was that SnRK2 is regulating in this case, the researchers used SnRK2 as bait. In this way the researchers found out that the protein CLC2 binds to SnRK2. Subsequently the researchers zoomed in at what happens inside the cell with those proteins after exposure of DNA damaging substances. Under normal circumstances CLC2 is localised at membranes in the cell. But after exposure of DNA damaging substances CLC2 is relocated to the nucleus. But only when SnRK2 can tell CLC2 that it is time to move to the nucleus.
The question that remained was what does CLC2 in the nucleus to prevent DNA damage? To find out the researchers checked with which proteins CLC2 is interacting. This turned out to be ADA2b, a protein of which it is known that it helps with the localization of DNA double strand breaks, so the plant can repair those. In plants without CLC2 or SnRK2 ADA2b has trouble finding the double strand breaks.
The researchers have not yet found out how exactly CLC2 helps ADA2b with finding double strand breaks. But clear is that ABA helps with finding those breaks. This can help the researchers with heling plants to better withstand mutagenesis treatments. And maybe also help with making gene editing more effective.
Literature
Jieming Jiang et al., Abscisic acid enhances DNA damage response through the nuclear shuttling of clathrin light chain 2 in plant cells.Sci. Adv.11, eadt2842 (2025). DOI: 10.1126/sciadv.adt2842
Plant en Zo 