Abstract
Plants uptake and assimilate nitrate and ammonium, and then biosynthesize various compounds involving nitrogen, including amino acids, protein and nucleotides. Nitrogen supply not only directly induces expression of nitrogen-responsive genes but also elevates the levels of assimilated products, triggering the secondary responses. To comprehensively investigate alterations in metabolite contents and gene expression pattern, we performed metabolic profiling and microarray analyses, using rice seedlings that were treated with 10 mM ammonium nitrate for different periods. Results of the analyses revealed different alterations in shoots and roots, and also allow us to identify both transcription factors that were induced rapidly and transcription factors that were induced in parallel with an increase of glutamine. Such transcription factors were members of the AP2-EREBP, the MYB, the NAC, the WRKY, or the zinc-finger family. We are currently attempting to identify the target genes of the transcription factors.
