Dynamic transcriptomic analysis uncovers key genes and mechanisms involved in seed priming-induced tolerance to drought in barley

Abstract Seed priming is an effective strategy to improve stress tolerance in plants. In spite of great efforts to clarify the molecular basis of primed acquired tolerance, molecular mechanism of priming is yet unclear. Priming with CaCl2 improved drought tolerance in sensitive and tolerant barley varieties. Therefore, in this study the time series transcriptome analyses of available microarray data in two primed barley varieties under drought stress was performed to clarify the mechanism of seed priming-induced drought tolerance and to identify the involved genes. Further analyses including gene ontology (GO) enrichment, clustering, and promoter analyses were performed. Besides, transcription factors and protein kinases were identified. As the results showed, 1388 and 725 differentially probe sets were identified in sensitive and tolerant genotypes respectively, which were then clustered into 7 and 6 profiles. Although four profiles (profiles 27, 20, 34, 19) were common between sensitive and tolerant genotypes, cluster 34 was the only cluster that consist of upregulated probe sets in primed seeds compared to non-primed. So, the genes which were identified in cluster 34 are introduced to have distinguished role in drought tolerance mediated by priming. The relative analysis also showed that ERF/AP2, C2C2-Dof and bHLH transcription factor families are regulatory important components of the transcriptional cascade involved in priming-induced tolerance. Taken together, the results provide a basic knowledge which can be used in barley manipulation programs for drought stress tolerance through priming process.