Objective  The composition, structure, and evolution of each member of the growth-interacting factors (GIF) of the growth-regulating factors (GRF) and the transcription cofactors that closely associate with the growth, development, and stress response of plants in Setaria italica were analyzed.

  Method  Based on the S. italica genome database and bioinformatics, the structure, characteristics, position on the chromosome, proteins similarity, secondary structure, transmembrane domain, and phosphorylation sites of the GIF genes were obtained.

  Result  The 3 SiGIFs in S. italica genome contained 4 exons locating on the 3, 8, and 9 chromosomes. The greatest similarity between SiGIF1 and SiGIF2 was 72.04%, while the lowest was 37.08% between SiGIF1 and SiGIF3. The secondary structure consisted of 41.56%～56.60% random coils, 34.43%～35.50% alpha helix, 5.19%～11.69% beta turns and 3.23%～11.26% extended strands. The TMHMM transmembrane domain analysis showed no transmembrane domain in SiGIFs. MEME indicated that all SiGIFs contained conserved SSXT (PF05030) domain. And potential phosphorylation sites in the GIFs were predicted by analysis.

  Conclusion   The bioinformatics revealed information on the structure, phosphorylation sites of SiGIF gene family provided crucial insights for the studies on the growth and development of plants.