Climate change is a major environmental stress threatening biodiversity and human civilization. The best hope to secure staple food for humans and animal feed by future crop improvement depends on wild progenitors. We examined 10 wild emmer wheat (Triticum dicoccoides Koern.) populations and 10 wild barley (Hordeum spontaneum K. Koch) populations in Israel, sampling them in 1980 and again in 2008, and performed phenotypic and genotypic analyses on the collected samples. We witnessed the profound adaptive changes of these wild cereals in Israel over the last 28 y in flowering time and simple sequence repeat allelic turnover. The revealed evolutionary changes imply unrealized risks present in genetic resources for crop improvement and human food production.climate warming | phenotypic and genotypic diversity | plant genetic resources I n recent decades there have been increasing concerns about the future of food production influenced by climate change (1-7) to feed a fast growing world population reaching 9-10 billion by 2050 (8). Aridization has alarmingly increased in summer, resulting in dry regions of wheat growing areas, particularly in the Americas, Asia, and Africa, and in the area of origin and diversity of wild emmer wheat in the Near East (9). Cultivated wheat, the number one world food staple, is genetically impoverished by long-term selective breeding (10). The wild progenitors of cultivated cereals, especially wild emmer wheat Triticum dicoccoides Koern. (TD) (9) and wild barley Hordeum spontaneum K. Koch (HS) (11), have become eroded by urbanization and agriculture (12). Both progenitors are rich in genetic resources adapted to abiotic (e.g., solar radiation, temperature, drought, and mineral poverty) and biotic (e.g., pathogens and parasites) stresses. These progenitors are the best genetic hope for improving genetically impoverished cultivars for human food production (9-17). Thus, it is crucial to evaluate the evolutionary adaptation in natural populations of the progenitors under climate change and to understand the hidden risk in human food security. Here we examined 10 TD populations and 10 HS populations in Israel from 1980 and again in 2008 and performed phenotypic and genotypic analyses on the collected samples. We witnessed the profound adaptive changes of these wild cereals in Israel over the last 28 y in flowering time (FT) and simple sequence repeat (SSR) allelic turnover. ResultsPhenotypic Analysis. In a greenhouse experiment, we compared the time from germination until flowering of ∼800 genotypes in 20 natural populations from different habitats and climates that were subjected to 28 y of climate change. The sampled populations (16, 17) were distributed across 350 km of their Israeli range (SI Appendix, Fig. S1 and Table S1). A total of 57 independent pair-wise comparisons were made under dry (300 mm) and wet (600 mm) irrigation regimes. Dramatically, in all TD and HS populations, without exception, the 2008 populations reached FT earlier than those collected in 1980 (Sign test, P < 1...

Evolution of genome size in geophytes is closely related to their ecology and phenology and is also associated with remarkable changes in DNA base composition. Although geophytism together with producing larger cells appears to be an advantageous strategy for fast development of an organism in seasonal habitats, the drought sensitivity of large stomata may restrict the occurrence of geophytes with very large genomes to regions not subject to water stress.

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BackgroundAll plants in nature harbor a diverse community of rhizosphere bacteria which can affect the plant growth. Our samples are isolated from the rhizosphere of wild barley Hordeum spontaneum at the Evolution Canyon (‘EC’), Israel. The bacteria which have been living in close relationship with the plant root under the stressful conditions over millennia are likely to have developed strategies to alleviate plant stress.Methodology/Principal FindingsWe studied distribution of culturable bacteria in the rhizosphere of H. spontaneum and characterized the bacterial 1-aminocyclopropane-1-carboxylate deaminase (ACCd) production, biofilm production, phosphorus solubilization and halophilic behavior. We have shown that the H. spontaneum rhizosphere at the stressful South Facing Slope (SFS) harbors significantly higher population of ACCd producing biofilm forming phosphorus solubilizing osmotic stress tolerant bacteria.Conclusions/SignificanceThe long-lived natural laboratory ‘EC’ facilitates the generation of theoretical testable and predictable models of biodiversity and genome evolution on the area of plant microbe interactions. It is likely that the bacteria isolated at the stressful SFS offer new opportunities for the biotechnological applications in our agro-ecological systems.