Identification and expression analysis of MADS-box gene family in Docynia delavayi (Franch.) Schneid / 生物工程学报

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.

Phylogenetic and expression analysis of SEPALLATA-like gene in Brassica oleracea L. var. acephala / 生物工程学报

The E class MADS-box genes SEPALLATA (SEP)-like play critical roles in angiosperm reproductive growth, especially in floral organ differentiation. To analyze the sequence characteristics and spatio-temporal expression patterns of E-function MADS-box SEP-like genes during kale (Brassica oleracea L. var. acephala) flower development, BroaSEP1/2/3 (GenBank No. KC967957, KC967958, KC967960) homologues, three kale SEP MADS-box gene, were isolated from the kale variety 'Fourteen Line' using Rapid amplification of cDNA ends (RACE). Sequence and phylogenetic analysis indicated that these three SEP genes had a high degree of identity with SEP1, SEP2, SEP3 from Brassica oleracea var. oleracea, Brassica rapa, Raphanus sativus and Brassica napus, respectively. Alignment of the predicted amino acid sequences from these genes, along with previously published subfamily members, demonstrated that these genes comprise four regions of the typical MIKC-type MADS-box proteins: the MADS domain, intervening (I) domain and keratin-like (K) domain, and the C-terminal domain SEPⅠ and SEP Ⅱ motif. The longest open reading frame deduced from the cDNA sequences of BroaSEP1, BroaSEP2, and BroaSEP3 appeared to be 801 bp, 759 bp, 753 bp in length, respectively, which encoded proteins of 266, 252, and 250 amino acids respectively. Expression analyses using semi-quantitative RT-PCR and quantitative real-time PCR indicate that BroaSEP1/2/3 are specifically expressed in floral buds of kale during flower development process. The expression levels of the three genes are very different at different developmental stages, also in wild type, mutant flower with increased petals, and mutant flower with decreased petals. These different patterns of gene expression maybe cause the flowers to increase or decrease the petal number.