Comprehensive expression profiling analysis to investigate salt and drought responding genes in wild barley (Hordeum spontaneum L.)

Drought and salinity are among the most affecting abiotic stress factors that limit the productivity in economically important plants. Understanding drought and salt tolerance mechanism is pivotal for developing drought and salt tolerant crop cultivars. Here, we monitored the changes in gene expression profiles of leaf and root tissues of two wild barley (Hordeum spontaneum L.) accessions after treatment with salt and drought stresses. We identified a total of 641 DEGs across 24 conditions (2 accessions, 2 stress conditions, 2 tissues and 3 time-points). Interestingly, there was a relatively little overlap between the leaf and the root stress responsive gene expression patterns, suggesting that different stress associated processes might be operating in these tissues during stress adaptation. In hierarchical clustering, the genes with distinct expression patterns were nearly half found in Cluster 1 and Cluster 9 and DEGs found in Cluster 9 were significantly enriched for metabolic processes and organic substance metabolic process. Gene ontology (GO) annotations of biological process of salt and drought analysis identified genes in categories including, catabolic processes, oxidation-reduction and organic substance metabolic process. Molecular function analyses significantly detected transcripts associated with oxidoreductase activity and nucleotide binding. Overall, our results revealed a number of candidate genes and plant processes associated with stress tolerance in wild barley. Determination of responsive genes will shed light on other barley studies aiming to elucidate molecular mechanism of drought or salt tolerance.