The circadian clock and stress adaptation in barley

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The scarcity of water is the greatest problem facing agriculture in the Middle East today. The development of drought resistant crops is a major prerequisite to sustain food production under limited water conditions. Recent studies in Arabidopsis have shown that the circadian clock is an important mechanism controlling stress adaptation in plants by regulating key physiological and metabolic pathways. However, the impact of circadian traits on adaptation and yield potential in a crop has not yet been analyzed. The aims of the proposed project are to elucidate the adaptive significance of variation in the circadian clock in barley and 2) to gain a mechanistic understanding of the barley circadian clock and its interrelationship with the metabolome and abiotic stress. In the first phase of the project, we have successfully established a high-throughput system to measure circadian rhythmicity based on changes in fluorescence (F) and identified clock mutants in the wild barley collection B1K. In the second phase of the project we propose to use the identified clock variants to a) define output traits of the clock such as physiological and agronomic performance (yield) in the field and under controlled conditions and b) to define input pathways into the clock by testing plasticity of the clock in response to abiotic stresses. In addition, we propose to analyse circadian changes in global gene expression, carbon metabolism and physiology to reveal how the clock regulates responses to environmental changes in barley. Variation in global gene expression, carbon metabolism and physiology will be integrated in a comprehensive network to identify causal relationships, input signals and output parameters of the clock and its effects on performance. Novel genes/alleles and germplasm resources can be used for marker assisted selection of barley adapted to dry environments in the Middle East and will be also valuable for precision breeding of barley adapted to climate change in temperate latitudes.