Transcriptome analysis of two near-isogenic lines with different NUE under normal nitrogen conditions in wheat

Nitrogen (N) is an essential nutrient element for crop productivity. Unfortunately, the nitrogen use efficiency (NUE) of crop plants gradually decreases with the increase of the nitrogen application rate. Nevertheless, little has been known about the molecular mechanisms of differences in NUE among genotypes of wheat. The use of near-isogenic lines (NILs) in transcriptome analysis can reduce genetic background noise. In this study, we used RNA-Sequencing (RNA-Seq) to compare the transcriptome profiling in NILs (1Y, high-NUE, and 1W, low-NUE) under normal nitrogen conditions. The results showed that 7,023 DEGs (4,738 up-regulated and 2,285 down-regulated) were identified in the 1Y vs 1W comparison. The responses of 1Y and 1W to normal nitrogen differed significantly in the transcriptional regulation mechanisms. Several genes belonging to the GS and GOGAT gene families were up-regulated in 1Y compared with 1W, and the enhanced carbon metabolism might lead 1Y to produce more C skeletons, metabolic energy, and reductants for nitrogen metabolism. A subset of transcription factors (TFs) family members such as ERF, WRKY, NAC, and MYB were also identified. Collectively, these identified candidate genes provided new information for a further understanding of the genotypic difference in NUE A total of twelve samples, including two treatments (N1 and N0). Each treatment was detected at a time point with 3 replicates. Two forms of Nitrogen fertilizers treatments: normal nitrogen (1.6g pot–1), which is referred to as N1, and a control (no nitrogen application), which is referred to as N0.