Krugman, T., Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel
Peleg, Z., Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel, Department of Plant Sciences, University of California, Davis, CA 95616, United States
Quansah, L., Blaustein Institute for Desert Research, Department of Dryland Biotechnology, Ben Gurion University of the Negev, Midreshet Ben Gurion 84990, Israel
Chagué, .V., Organisation and Evolution of Plant Genomes, Unité de Recherche en Génomique Végétale (URGV), 91057 Evry, France
Korol, A.B., Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel
Nevo, E., Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel
Saranga, Y., Robert H. Smith Institute of Plant Science and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel
Fait, A., Blaustein Institute for Desert Research, Department of Dryland Biotechnology, Ben Gurion University of the Negev, Midreshet Ben Gurion 84990, Israel
Chalhoub, B., Organisation and Evolution of Plant Genomes, Unité de Recherche en Génomique Végétale (URGV), 91057 Evry, France
Fahima, T., Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Mt. Carmel, Haifa 31905, Israel

Transcriptomic and metabolomic profiles were used to unravel drought adaptation mechanisms in wild emmer wheat (Triticum turgidum ssp. dicoccoides), the progenitor of cultivated wheat, by comparing the response to drought stress in roots of genotypes contrasting in drought tolerance. The differences between the drought resistant (R) and drought susceptible (S) genotypes were characterized mainly by shifts in expression of hormonerelated genes (e.g., gibberellins, abscisic acid (ABA) and auxin), including biosynthesis, signalling and response; RNA binding; calcium (calmodulin, caleosin and annexin) and phosphatidylinositol signalling, in the R genotype. ABA content in the roots of the R genotype was higher in the wellwatered treatment and increased in response to drought, while in the S genotype ABA was invariant. The metabolomic profiling revealed in the R genotype a higher accumulation of tricarboxylic acid cycle intermediates and drought-related metabolites, including glucose, trehalose, proline and glycine. The integration of transcriptomics and metabolomics results indicated that adaptation to drought included efficient regulation and signalling pathways leading to effective bio-energetic processes, carbon metabolism and cell homeostasis. In conclusion, mechanisms of drought tolerance were identified in roots of wild emmer wheat, supporting our previous studies on the potential of this genepool as a valuable source for novel candidate genes to improve drought tolerance in cultivated wheat. © Springer-Verlag 2011.