Comparative de novo transcriptome analysis of barley varieties with different malting qualities.

Barley is one of the most important crops in the world. Barley is used as both food and feed and is important for malt production. Demands for malting quality differ among countries and customs. Malting quality is a complex characteristic involving barley genetics, the environmental conditions during barley growth, and the technological parameters of the malting process. In this study, the hypothesis was that there were no differences between two groups of barley varieties with different but defined malting qualities, which was tested using RNA sequencing during selected stages of malting. In total, 919 differentially transcribed genes between the two barley groups were identified and annotated. Differentially expressed genes (DEGs) were primarily assigned to gene ontology (GO) terms of oxidation-reduction process - oxidoreductase activity, response to stress, carbohydrate metabolic process, and proteolysis - hydrolase activity, and metal ion binding. Genes connected with the plasma membrane and its integral components also play important roles in malting quality. DEG profiles of selected genes in the three malting stages indicate a complex character of malting quality. Many single-nucleotide polymorphisms (SNPs) and insertions and deletions (indels) were identified. SNPs and indels with the best quality were used for primer design. After optimization and validation, five molecular markers were developed for use in barley breeding.