Transcriptomic analysis reveals adaptive strategies to chronic low nitrogen in Tibetan wild barley

Abstract

Background: Development of crop cultivars with high low nitrogen (LN) tolerance or nitrogen use efficiency (NUE) is imperative for sustainable agriculture development. Tibetan wild barley is rich in genetic diversity and may provide elite genes for LN tolerance improvement. Little has been known about transcriptional responses of the wild barley to chronic LN stress. Results: In this study, transcriptomic profiling of two Tibetan wild barley genotypes, LN- tolerant XZ149 and LN-sensitive XZ56 has been conducted using RNA-Seq to reveal the genotypic difference in response to chronic LN stress. A total of 520 differentially expressed genes (DEGs) were identified in the two genotypes at 12 d after LN stress, and these DEGs could be mainly mapped to 49 metabolism pathways. Chronic LN stress lead to genotype-dependent responses, and the responsive pattern in favor of root growth and stress tolerance may be the possible mechanisms of the higher chronic LN tolerance in XZ149. Conclusion: There was a distinct difference in transcriptional profiling between the two wild barley genotypes in response to chronic LN stress. The identified new candidate genes related to LN tolerance may cast a light on the development of cultivars with LN tolerance.