Abstract:MADS-box gene family is a significant transcription factor family that plays a crucial role in regulating plant growth, development, signal transduction, and other processes. In order to study the characteristics of MADS-box gene family in Docynia delavayi (Franch.) Schneid. and its expression during different stages of seed germination, this study used seedlings at different stages of germination as materials and screened MADS-box transcription factors from the transcriptome database of D. delavayi using bioinformatics methods based on transcriptome sequencing. The physical and chemical properties, protein conservative motifs, phylogenetic evolution, and expression patterns of the MADS-box transcription factors were analyzed. Quantitative real-time PCR (qRT-PCR) was used to verify the expression of MADS-box gene family members during different stages of seed germination in D. delavayi. The results showed that 81 genes of MADS-box gene family were identified from the transcriptome data of D. delavayi, with the molecular weight distribution ranged of 6 211.34-173 512.77 Da and the theoretical isoelectric point ranged from 5.21 to 10.97. Phylogenetic analysis showed that the 81 genes could be divided into 15 subgroups, among which DdMADS27, DdMADS42, DdMADS45, DdMADS46, DdMADS53, DdMADS61, DdMADS76, DdMADS77 and DdMADS79 might be involved in the regulation of ovule development in D. delavayi. The combination of the transcriptome data and the qRT-PCR analysis results of D. delavayi seeds indicated that DdMADS25 and DdMADS42 might be involved in the regulation of seed development, and that DdMADS37 and DdMADS38 might have negative regulation effects on seed dormancy. Previous studies have reported that the MIKC* subgroup is mainly involved in regulating flower organ development. For the first time, we found that the transcription factors of the MIKC* subgroup exhibited a high expression level at the early stage of seed germination, so we speculated that the MIKC* subgroup played a regulatory role in the process of seed germination. To verify the accuracy of this speculation, we selected DdMADS60 and DdMADS75 from the MIKC* subgroup for qRT-PCR experiments, and the experimental results were consistent with the expression trend of transcriptome sequencing. This study provides a reference for further research on the biological function of D.delavayi MADS-box gene family from the perspective of molecular evolution.
