Objective  Members of the amaranth TCP gene family were identified based on the transcriptome database for an in-depth understanding on the roles they associated with the growth, development, and abiotic stress of the plant.

  Method  Members of the TCP gene family were identified by screening the transcriptome database on Dahong amaranth (Amaranthus tricolor L.) for a bioinformatics analysis. Amaranth seedlings were cultured under different conditions and their expressions under different treatments analyzed by qRT-PCR.

  Results  Amaranth TCP gene family has 14 members, all localized in the nucleus. The length of AtrTCP protein was in the range of 230–721 aa, the predicted relative molecular weight was 25.25–78.57 kD, the isoelectric point was 6.15–9.45, and it contained 15 conserved motifs. Except AtrTCP11, which was stable protein, all the other proteins were unstable. Two AtrTCP family members, AtrTCP2 and AtrTCP6, were predicted as miR319 target genes by miRNA. qRT-PCR showed differentiated expressions of the family members under salt solutions of varied concentrations (i.e., 0, 50, 100, and 200 mmol·L⁻¹). The expression of the upregulated AtrTCP10 reached a significant level under blue light, and so did those of the downregulated AtrTCP2, AtrTCP3, AtrTCP8, AtrTCP9, AtrTCP11, and AtrTCP13. Under different concentrations of ammonium nitrate ratio (0∶0, 0∶10, 3∶7, 5∶5, 7∶3, 10∶0) treatment, the expressions of the TCP genes differed. AtrTCP3 was shown to be involved in the entire nitrogen metabolism process. In tissues of amaranth, AtrTCP3 and AtrTCP12 were highly expressed in leaves, while the others in roots.

  Conclusion   Depending on the treatments, the expressions of the amaranth TCP gene family members differed. It suggested a broad spectrum of involvements by the members associated with abiotic stresses on amaranth.