Climate dependent control of water loss in leaves | Umweltbundesamt

In Bavaria too, climate change is leading to more frequent periods of heat and drought. To counter this, the water management of crops is a size to be improved. Water loss occurs in plants via stomata in the leaves. The stoma opening width, due to the two involved guard cells (SZ), determines the water loss. An optimized water balance under drought stress is therefore crucially dependent on the reaction of the stomata. Here, the stress hormone abscisic acid (ABA) plays a key role.

The project showed that the stoma closure, a first response to ABA, works faster for barley than for non-grasses and is due to the interaction of closing and secondary cells (NZ). The elucidation of the communication between these two cell types should therefore ultimately help breeders to grow climate-adapted barley varieties. For this purpose, in the barley reference species "bark", the genes identified by a method called RNAseq were identified, which are used specifically in closing cells and those in secondary cells. The processes in the stoma movement in SZ and NZ are controlled in opposite directions.

Important candidates were then functionally characterized. Thus, a model for the nature and regulation of stomata in barley could be established. This model was then tested under stress and with ABA treatment and confirmed on breeding lines. In the field trial special stress-tolerant and sensitive breeding lines were found. By comparing genes used in these strains with the specific inclusion of ABA regulated genes, drought tolerance markers should be identified and made available to breeders.