Increasing abiotic stress resistance of barley

Soil salinity and drought are major limitations for crop yield. Drought stress is the most severe yield-limiting factor for crop production and hazardous to worldwide food security; increased frequency of drought periods due to climatic changes require the design of better-adapted genotypes and drought-tolerant crop cultivars. Salinity is a widespread problem on irrigated land. Despite many efforts, the progress of conventional breeding to increase drought and salt tolerance has been limited, likely due to the complexity of these traits. A thorough physiological and molecular understanding of the processes is thus required to identify key processes and players, which then can be targeted individually by marker-assisted breeding or transgene technologies. Both drought and salt stress share an osmotic component due to decreased soil water availability. The plant responds to this challenge by regulating stomatal apertures, synthesising compatible osmolytes and increasing the capacity of ion uptake. The initiation of salt and drought tolerance mechanisms is controlled by an intricate signalling network involving the plant hormone abscisic acid (ABA) and numerous second messengers. Upon perception of the stress, one of the first responses is a transient elevation of cytosolic free calcium. Polyamines, in particular spermine, have been shown to improve tolerance and recovery from drought. However, the mechanism of action of spermine is yet unknown. There is strong evidence of an interference of spermine in cation channel gating. Interestingly, in vitro studies have shown that spermine modulates the TPC1 channel. We will investigate the crosstalk between polyamines and calcium signals in barley.