Transcriptome profiling reveals major structural genes, transcription factors and biosynthetic pathways involved in leaf senescence and nitrogen remobilization in rainfed spring wheat under different nitrogen fertilization rates

The present study was undertaken to profile transcriptional changes in flag leaves between anthesis and end of grain filling stages of rainfed spring wheat cultivar under varying nitrogen (N) application rates: 0 kg/ha (NN), 52.5 kg/ha (LN), and 210 kg/ha (HN). A total of 4485 and 4627 differentially expressed genes (DEGs) were detected in LN and HN, respectively. The differential application of N altered several pathways; including plant hormone signal transduction, mitogen-activated protein kinase signaling pathway-plant, photosynthesis, phenylpropanoid biosynthesis and ATP-binding cassette transporters. Jasmonic acid, abscisic acid, salicylic acid and brassinosteroid related genes promoted leaf senescence in NN or LN, whereas auxin, gibberellin acid and cytokinins genes inhibited leaf senescence in HN. Major transcription factors: auxin/indole-3-acetic acid (AUX/IAA), no apical meristem (NAC) and WRKY expressed higher in either HN or LN than NN. The DEGs, pathways and transcription factors provide valuable insight for manipulation of leaf senescence and N remobilization in wheat. •N fertilizer altered leaf senescence and N remobilization in spring wheat.•Phytohormones: jasmonic acid, abscisic acid, salicylic acid and brassinosteroid related genes promoted leaf senescence under N limited conditions.•Whereas phytohormones such as auxin, gibberelin acid and cytokinins related genes inhibited leaf senescence in high N condition.•Carotenoid biosynthetic genes were highly expressed under N limited conditions than high N condition.