Evolution and expression analyses of the MADS-box gene family in Brassica napus.
ABSTRACT: MADS-box transcription factors are important for plant growth and development, and hundreds of MADS-box genes have been functionally characterized in plants. However, less is known about the functions of these genes in the economically important allopolyploid oil crop, Brassica napus. We identified 307 potential MADS-box genes (BnMADSs) in the B. napus genome and categorized them into type I (M?, M?, and M?) and type II (MADS DNA-binding domain, intervening domain, keratin-like domain, and C-terminal domain [MIKC]c and MIKC*) based on phylogeny, protein motif structure, and exon-intron organization. We identified one conserved intron pattern in the MADS-box domain and seven conserved intron patterns in the K-box domain of the MIKCc genes that were previously ignored and may be associated with function. Chromosome distribution and synteny analysis revealed that hybridization between Brassica rapa and Brassica oleracea, segmental duplication, and homologous exchange (HE) in B. napus were the main BnMADSs expansion mechanisms. Promoter cis-element analyses indicated that BnMADSs may respond to various stressors (drought, heat, hormones) and light. Expression analyses showed that homologous genes in a given subfamily or sister pair are highly conserved, indicating widespread functional conservation and redundancy. Analyses of BnMADSs provide a basis for understanding their functional roles in plant development.
Project description:Plant life critically depends on the function of MADS-box genes encoding MADS-domain transcription factors, which are present to a limited extent in nearly all major eukaryotic groups, but constitute a large gene family in land plants. There are two types of MADS-box genes, termed type I and type II, and in plants these groups are distinguished by exon-intron and domain structure, rates of evolution, developmental function and degree of functional redundancy. The type I genes are further subdivided into three groups - M alpha, M beta and M gamma - while the type II genes are subdivided into the MIKCC and MIKC* groups. The functional diversification of MIKCC genes is closely linked to the origin of developmental and morphological novelties in the sporophytic (usually diploid) generation of seed plants, most spectacularly the floral organs and fruits of angiosperms. Functional studies suggest different specializations for the different classes of genes; whereas type I genes may preferentially contribute to female gametophyte, embryo and seed development and MIKC*-group genes to male gametophyte development, the MIKCC-group genes became essential for diverse aspects of sporophyte development. Beyond the usual transcriptional regulation, including feedback and feed-forward loops, various specialized mechanisms have evolved to control the expression of MADS-box genes, such as epigenetic control and regulation by small RNAs. In future, more data from genome projects and reverse genetic studies will allow us to understand the birth, functional diversification and death of members of this dynamic and important family of transcription factors in much more detail.
Project description:BACKGROUND:MADS-box genes play important roles in vegetative growth and reproductive development and are essential for the correct development of plants (particularly inflorescences, flowers, and fruits). However, this gene family has not been identified nor their functions analyzed in Brassica oleracea. RESULTS:In this study, we performed a whole-genome survey of the complete set of MADS-box genes in B. oleracea. In total, 91 MADS-box transcription factors (TFs) were identified and categorized as type I (M?, M?, M?) and type II (MIKCC, MIKC*) groups according to the phylogeny and gene structure analysis. Among these genes, 59 were randomly distributed on 9 chromosomes, while the other 23 were assigned to 19 scaffolds and 9 genes from NCBI had no location information. Both RNA-sequencing and quantitative real-time-PCR analysis suggested that MIKC genes had more active and complex expression patterns than M type genes and most type II genes showed high flowering-related expression profiles. Additional quantitative real-time-PCR analysis of pedicel and four flower whorls revealed that the structure of the B.oleracea MIKC genes was conserved, but their homologues showed variable expression patterns compared to those in Arabidopsis thaliana. CONCLUSION:This paper gives a detailed overview of the BolMADS genes and their expression patterns. The results obtained in this study provide useful information for understanding the molecular regulation of flower development and further functional characterization of MADS-box genes in B. oleracea.
Project description:BACKGROUND:MADS-box genes encode transcription factors that are known to be involved in several aspects of plant growth and development, especially in floral organ specification. To date, the comprehensive analysis of potato MADS-box gene family is still lacking after the completion of potato genome sequencing. A genome-wide characterization, classification, and expression analysis of MADS-box transcription factor gene family was performed in this study. RESULTS:A total of 153 MADS-box genes were identified and categorized into MIKC subfamily (MIKCC and MIKC*) and M-type subfamily (M?, M?, and M?) based on their phylogenetic relationships to the Arabidopsis and rice MADS-box genes. The potato M-type subfamily had 114 members, which is almost three times of the MIKC members (39), indicating that M-type MADS-box genes have a higher duplication rate and/or a lower loss rate during potato genome evolution. Potato MADS-box genes were present on all 12 potato chromosomes with substantial clustering that mainly contributed by the M-type members. Chromosomal localization of potato MADS-box genes revealed that MADS-box genes, mostly MIKC, were located on the duplicated segments of the potato genome whereas tandem duplications mainly contributed to the M-type gene expansion. The potato MIKC subfamily could be further classified into 11 subgroups and the TT16-like, AGL17-like, and FLC-like subgroups found in Arabidopsis were absent in potato. Moreover, the expressions of potato MADS-box genes in various tissues were analyzed by using RNA-seq data and verified by quantitative real-time PCR, revealing that the MIKCC genes were mainly expressed in flower organs and several of them were highly expressed in stolon and tubers. StMADS1 and StMADS13 were up-regulated in the StSP6A-overexpression plants and down-regulated in the StSP6A-RNAi plant, and their expression in leaves and/or young tubers were associated with high level expression of StSP6A. CONCLUSION:Our study identifies the family members of potato MADS-box genes and investigate the evolution history and functional divergence of MADS-box gene family. Moreover, we analyze the MIKCC expression patterns and screen for genes involved in tuberization. Finally, the StMADS1 and StMADS13 are most likely to be downstream target of StSP6A and involved in tuber development.
Project description:MADS-box genes encode transcription factors that participate in various plant growth and development processes, particularly floral organogenesis. To date, MADS-box genes have been reported in many species, the completion of the sequence of the willow genome provides us with the opportunity to conduct a comprehensive analysis of the willow MADS-box gene family. Here, we identified 60 willow MADS-box genes using bioinformatics-based methods and classified them into 22 M-type (11 M?, seven M? and four M?) and 38 MIKC-type (32 MIKCc and six MIKC*) genes based on a phylogenetic analysis. Fifty-six of the 60 SsMADS genes were randomly distributed on 19 putative willow chromosomes. By combining gene structure analysis with evolutionary analysis, we found that the MIKC-type genes were more conserved and played a more important role in willow growth. Further study showed that the MIKC* type was a transition between the M-type and MIKC-type. Additionally, the number of MADS-box genes in gymnosperms was notably lower than that in angiosperms. Finally, the expression profiles of these willow MADS-box genes were analysed in five different tissues (root, stem, leave, bud and bark) and validated by RT-qPCR experiments. This study is the first genome-wide analysis of the willow MADS-box gene family, and the results establish a basis for further functional studies of willow MADS-box genes and serve as a reference for related studies of other woody plants.
Project description:The Orchidaceae family, which is one of the most species-rich flowering plant families, includes species with highly diversified and specialized flower shapes. The aim of this study was to analyze the MADS-box genes expressed in the inflorescence of Orchis italica, a wild Mediterranean orchid species. MADS-box proteins are transcription factors involved in various plant biological processes, including flower development. In the floral tissues of O. italica, 29 MADS-box genes are expressed that are classified as both class I and II. Class I MADS-box genes include one M?-type gene, thereby confirming the presence of this type of MADS-box genes in orchids. The class II MIKC* gene is highly expressed in the column, which is consistent with the conserved function of the MIKC* genes in gametophyte development. In addition, homologs of the SOC, SVP, ANR1, AGL12 and OsMADS32 genes are expressed. Compared with previous knowledge on class II MIKCC genes of O. italica involved in the ABCDE model of flower development, the number of class B and D genes has been confirmed. In addition, 4 class A (AP1/FUL) transcripts, 2 class E (SEP) transcripts, 2 new class C (AG) transcripts and 1 new AGL6 transcript have been identified. Within the AP1/FUL genes, the sequence divergence, relaxation of purifying selection and expression profiles suggest a possible functional diversification within these orchid genes. The detection of only two SEP transcripts in O. italica, in contrast with the 4 genes found in other orchids, suggests that only two SEP genes could be present in the subfamily Orchidoideae. The expression pattern of the MIKCC genes of O. italica indicates that low levels at the boundary of the domain of a given MADS-box gene can overlap with the expression of genes belonging to a different functional A-E class in the adjacent domain, thereby following a "fading borders" model.
Project description:The repertoire and functions of MADS-box family transcription factors (TFs) largely remains unexplored with respect to floral organogenesis of Momordica dioica Roxb. Degenerative PCR followed by rapid amplification of cDNA ends was employed in the present study to clone and characterize 17 MADS-box genes (designated as MdMADS01 to MdMADS17) from the floral buds of M. dioica. The cloned genes were clustered into three subgroups (11 MIKCC, 4 MIKC* and 2 M?) based on phylogenetic relationships with the MADS-box genes from Cucumis sativus, Cucumis melo and Arabidopsis thaliana. Southern hybridization showed that all the isolated genes were represented by single copy locus in the M. dioica genome. Gene structure analysis revealed 1-8 exons in MdMADS-box genes with the number of exons in MIKC greatly exceeding from that in M-type genes. Motif elicitation of the MdMADS-box genes indicated the presence of additional domains with MIKC type, suggesting that they had more complex structures. Expression analysis of MdMADS genes in six M. dioica transcriptome suggested that, 11 MIKCC-type genes are associated with floral homeotic functions, 4 MIKC*-type genes (MdMADS12 to MdMADS15) controlled the growth of male gametophyte, while the two M-type genes (MdMADS16 and MdMADS17) played significant role in female gametogenesis and seed development. Overall, these are the first set of MADS-box genes from M. dioica exhibiting a differential expression pattern during floral development. The results from this study will provide valuable information for further functional studies of candidate MADS-box genes in the sexual dimorphism of this economically important dioecious cucurbit.
Project description:Proteins encoded by MADS-box genes are important transcription factors involved in the regulation of flowering plant growth and development. Currently, no systematic information exists regarding the MADS-box family in the important tropical fruit banana. Ninety-six MADS-box genes were identified from the banana (Pahang) A genome. Phylogenetic analysis indicated that Musa acuminata MCM1-AGAMOUS- DEFICIENS-SRF (MaMADS) could be divided into MIKCc, MIKC*, M?/? and M? groups. MIKCc could be further divided into 11 subfamilies, which was further supported by conserved motif and gene structure analyses. Transcriptome analysis on the Feng Jiao (FJ) and BaXi Jiao (BX) banana cultivars revealed that MaMADS genes are differentially expressed in various organs, at different fruit development and ripening stages, indicating the involvement of these genes in fruit development and ripening processes. Interactive network analysis indicated that MaMADS24 and 49 not only interacted with MaMADS proteins themselves, but also interacted with hormone-response proteins, ethylene signal transduction and biosynthesis-related proteins, starch biosynthesis proteins and metabolism-related proteins. This systematic analysis identified candidate MaMADS genes related to fruit development and ripening for further functional characterization in plants, and also provided new insights into the transcriptional regulation of MaMADS genes, facilitating the future genetic manipulation of MADS-mediated fruit development and ripening.
Project description:MADS-box transcription factors widely regulate all aspects of plant growth including development and reproduction. Although the MADS-box gene family genes have been extensively characterized in many plants, they have not been studied in closely related species. In this study, 73 and 74 MADS-box genes were identified in European pear (Pyrus communis) and Chinese pear (Pyrus bretschneideri), respectively. Based on the phylogenetic relationship, these genes could be clustered into five groups (M?, M?, Mr, MIKCC, MIKC*) and the MIKCC group was further categorized into 10 subfamilies. The distribution of MADS-box genes on each chromosome was significantly nonrandom. Thirty-seven orthologs, twenty-five PcpMADS (P. communis MADS-box) paralogs and nineteen PbrMADS (P. bretschneideri MADS-box) paralogs were predicted. Among these paralogous genes, two pairs arose from tandem duplications (TD), nineteen from segmental duplication (SD) events and twenty-three from whole genome duplication (WGD) events, indicating SD/WGD events led to the expansion of MADS-box gene family. The MADS-box genes expression profiles in pear fruits indicated functional divergence and neo-functionalization or sub-functionalization of some orthologous genes originated from a common ancestor. This study provided a useful reference for further analysis the mechanisms of species differentiation and biodiversity formation among closely related species.
Project description:MADS-box genes encode transcription factors that are involved in plant development control (particularly in floral organogenesis) and signal transduction pathways, though a comprehensive analysis of MADS-box family proteins in Chinese jujube (Ziziphus jujuba Mill.) is still missing. Here, we report a genome-wide analysis of the MADS-box gene family in Chinese jujube. Based on phylogenetic analyses, 52 jujube MADS-box genes were classified into 25 MIKCC-type, 3 MIKC*-type, 16 M?, 5 M? and 3 M? genes. 37 genes were randomly distributed across all 12 putative chromosomes. We found that the type II genes are more complex than the type I genes and that tandem duplications have occurred in three groups of MADS-box genes. Meanwhile, some gene pairs in the same clade displayed similar or distinct expression profiles, suggesting possible functional redundancy or divergence. MIKCC-type genes exhibited typical temporal and spatial expression patterns in the four whorls of floral tissues. The expressions of B, C/D and E-type genes were significantly suppressed in phyllody as compared to flower, providing valuable evidence for their involvement in flower development. This study is the first comprehensive analysis of the MADS-box family in jujube, and provides valuable information for elucidating molecular regulation mechanism of jujube flower development.
Project description:BACKGROUND:MADS-box genes play crucial roles in plant floral organ formation and plant reproductive development. However, there is still no information on genome-wide identification and classification of MADS-box genes in some representative plant species. A comprehensive investigation of MIKC-type genes in the orchid Dendrobium officinale is still lacking. RESULTS:Here we conducted a genome-wide analysis of MADS-box proteins from 29 species. In total, 1689 MADS-box proteins were identified. Two types of MADS-box genes, termed type I and II, were found in land plants, but not in liverwort. The SQUA, DEF/GLO, AG and SEP subfamilies existed in all the tested flowering plants, while SQUA was absent in the gymnosperm Ginkgo biloba, and no genes of the four subfamilies were found in a charophyte, liverwort, mosses, or lycophyte. This strongly corroborates the notion that clades of floral organ identity genes led to the evolution of flower development in flowering plants. Nine subfamilies of MIKCC genes were present in two orchids, D. officinale and Phalaenopsis equestris, while the TM8, FLC, AGL15 and AGL12 subfamilies may be lost. In addition, the four clades of floral organ identity genes in both orchids displayed a conservative and divergent expression pattern. Only three MIKC-type genes were induced by cold stress in D. officinale while 15 MIKC-type genes showed different levels of expression during seed germination. CONCLUSIONS:MIKC-type genes were identified from streptophyte lineages, revealing new insights into their evolution and development relationships. Our results show a novel role of MIKC-type genes in seed germination and provide a useful clue for future research on seed germination in orchids.