Comparative Analysis of Root Transcriptome of High-NUE Mutant and Wild-Type Barley under Low-Nitrogen Conditions

Although nitrogen (N) deficiency greatly affects N absorption and metabolism in barley, the global transcriptomic changes in morphological and physiological adaptation to altered N availability remains largely unclear. We conducted a comparative transcriptome analysis of roots in A9-29 (low N tolerant line of barley) and Hua 30 (low N-sensitive variety of barley) under low N conditions to elucidate the responses and the underlying molecular mechanism. The results demonstrated that the root architecture was strongly influenced and that the root morphological indexes (total root length, total root area surface, and root volume) were remarkably promoted in A9-29 compared to Hua30 under low N stress. The transcriptome analysis of roots identified 1779 upregulated differentially expressed genes (DEGs) and 1487 downregulated DEGs specifically expressed in A9-29 under low N stress. Specific DEGs in A9-29 were largely enriched in energy metabolism, lipid metabolism, and the metabolism of other amino acids. In addition, transcription factor genes ERFs and IAA-related genes were specifically expressed in A9-29. To conclude, this study could provide a foundation for improving low N tolerance in barley.