Genome-Wide Analysis of the MADS-Box Gene Family in Maize: Gene Structure, Evolution, and Relationships

Evolutionary analysis of MADS-box genes in buckwheat species and functional study of FdMADS28 in flavonoid metabolism

The MADS-box gene family is a transcription factor family that is widely expressed in plants. It controls secondary metabolic processes in plants and encourages the development of tissues like roots and flowers. However, the phylogenetic analysis and evolutionary model of MADS-box genes in Fagopyrum species has not been reported yet. This study identified the MADS-box genes of three buckwheat species at the whole genome level, and conducted systematic evolution and physicochemical analysis. The results showed that these genes can be divided into four subfamilies, with fragment duplication being the main way for the gene family expansion. During the domestication process from golden buckwheat to tartary buckwheat and the common buckwheat, the Ka/Ks ratio indicated that most members of the family experienced strong purification selection pressure, and with individual gene pairs experiencing positive selection. In addition, we combined the expression profile data of the MADS genes, mGWAS data, and WGCNA data to mine genes FdMADS28/48/50 that may be related to flavonoid metabolism. The results also showed that overexpression of FdMADS28 could increase rutin content by decreasing Kaempferol pathway content in hairy roots, and increase the resistance and growth of hairy roots to PEG and NaCl. This study systematically analyzed the evolutionary relationship of MADS-box genes in the buckwheat species, and elaborated on the expression patterns of MADS genes in different tissues under biotic and abiotic stresses, laying an important theoretical foundation for further elucidating their role in flavonoid metabolism.

MADS-Box Family Genes in Lagerstroemia indica and Their Involvement in Flower Development

MADS-box is a key transcription factor regulating the transition to flowering and flower development. Lagerstroemia indica 'Xiang Yun' is a new cultivar of crape myrtle characterized by its non-fruiting nature. To study the molecular mechanism underlying the non-fruiting characteristics of 'Xiang Yun', 82 MADS-box genes were identified from the genome of L. indica. The physicochemical properties of these genes were examined using bioinformatics methods, and their expression as well as endogenous hormone levels at various stages of flower development were analyzed. The results showed that LiMADS genes were primarily classified into two types: type I and type II, with the majority being type II that contained an abundance of cis-acting elements in their promoters. By screening nine core proteins by predicted protein interactions and performing qRT-PCR analysis as well as in combination with transcriptome data, we found that the expression levels of most MADS genes involved in flower development were significantly lower in 'Xiang Yun' than in the wild type 'Hong Ye'. Hormonal analysis indicated that 'Xiang Yun' had higher levels of iP, IPR, TZR, and zeatin during its early stages of flower development than 'Hong Ye', whereas the MeJA content was substantially lower at the late stage of flower development of 'Hong Ye'. Finally, correlation analysis showed that JA, IAA, SA, and TZR were positively correlated with the expression levels of most type II genes. Based on these analyses, a working model for the non-fruiting 'Xiang Yun' was proposed. During the course of flower development, plant hormone response pathways may affect the expression of MADS genes, resulting in their low expression in flower development, which led to the abnormal development of the stamen and embryo sac and ultimately affected the fruiting process of 'Xiang Yun'.

Genome-Wide Characterization and Phylogenetic and Stress Response Expression Analysis of the MADS-Box Gene Family in Litchi (Litchi chinensis Sonn.)

The MADS-box protein is an important transcription factor in plants and plays an important role in regulating the plant abiotic stress response. In this study, a total of 94 MADS-box genes were predicted in the litchi genome, and these genes were widely distributed on all the chromosomes. The LcMADS-box gene family was divided into six subgroups (Mα, Mβ, Mγ, Mδ, MIKC, and UN) based on their phylogenetical relationships with Arabidopsis, and the closely linked subgroups exhibited more similarity in terms of motif distribution and intron/exon numbers. Transcriptome analysis indicated that LcMADS-box gene expression varied in different tissues, which can be divided into universal expression and specific expression. Furthermore, we further validated that LcMADS-box genes can exhibit different responses to various stresses using quantitative real-time PCR (qRT-PCR). Moreover, physicochemical properties, subcellular localization, collinearity, and cis-acting elements were also analyzed. The findings of this study provide valuable insights into the MADS-box gene family in litchi, specifically in relation to stress response. The identification of hormone-related and stress-responsive cis-acting elements in the MADS-box gene promoters suggests their involvement in stress signaling pathways. This study contributes to the understanding of stress tolerance mechanisms in litchi and highlights potential regulatory mechanisms underlying stress responses.

Genome-wide identification of the MADS-box gene family in Avena sativa and its role in photoperiod-insensitive oat

Background

Traditional spring-summer sown oat is a typical long-day crop that cannot head under short-day conditions. The creation of photoperiod-insensitive oats overcomes this limitation. MADS-box genes are a class of transcription factors involved in plant flowering signal transduction regulation. Previous transcriptome studies have shown that MADS-box genes may be related to the oat photoperiod.

Methods

Putative MADS-box genes were identified in the whole genome of oat. Bioinformatics methods were used to analyze their classification, conserved motifs, gene structure, evolution, chromosome localization, collinearity and cis-elements. Ten representative genes were further screened via qRT‒PCR analysis under short days.

Results

In total, sixteen AsMADS genes were identified and grouped into nine subfamilies. The domains, conserved motifs and gene structures of all AsMADS genes were conserved. All members contained light-responsive elements. Using the photoperiod-insensitive oat MENGSIYAN4HAO (MSY4) and spring-summer sown oat HongQi2hao (HQ2) as materials, qRT‒PCR analysis was used to analyze the AsMADS gene at different panicle differentiation stages under short-day conditions. Compared with HQ2, AsMADS3, AsMADS8, AsMADS11, AsMADS13, and AsMADS16 were upregulated from the initial stage to the branch differentiation stage in MSY4, while AsMADS12 was downregulated. qRT‒PCR analysis was also performed on the whole panicle differentiation stages in MSY4 under short-day conditions, the result showed that the expression levels of AsMADS9 and AsMADS11 gradually decreased. Based on the subfamily to which these genes belong, the above results indicated that AsMADS genes, especially SVP, SQUA and Mα subfamily members, regulated panicle development in MSY4 by responding to short-days. This work provides a foundation for revealing the function of the AsMADS gene family in the oat photoperiod pathway.

Genome-Wide Analysis of the MADS-Box Gene Family in Hibiscus syriacus and Their Role in Floral Organ Development

Hibiscus syriacus belongs to the Malvaceae family, and is a plant with medicinal, edible, and greening values. MADS-box transcription factor is a large family of regulatory factors involved in a variety of biological processes in plants. Here, we performed a genome-wide characterization of MADS-box proteins in H. syriacus and investigated gene structure, phylogenetics, cis-acting elements, three-dimensional structure, gene expression, and protein interaction to identify candidate MADS-box genes that mediate petal developmental regulation in H. syriacus. A total of 163 candidate MADS-box genes were found and classified into type I (Mα, Mβ, and Mγ) and type II (MIKC and Mδ). Analysis of cis-acting elements in the promoter region showed that most elements were correlated to plant hormones. The analysis of nine HsMADS expressions of two different H. syriacus cultivars showed that they were differentially expressed between two type flowers. The analysis of protein interaction networks also indicated that MADS proteins played a crucial role in floral organ identification, inflorescence and fruit development, and flowering time. This research is the first to analyze the MADS-box family of H. syriacus and provides an important reference for further study of the biological functions of the MADS-box, especially in flower organ development.

Dynamic transcriptome landscape of developing maize ear

Seed number and harvesting ability in maize (Zea mays L.) are primarily determined by the architecture of female inflorescence, namely the ear. Therefore, ear morphogenesis contributes to grain yield and as such is one of the key target traits during maize breeding. However, the molecular networks of this highly dynamic and complex grain-bearing inflorescence remain largely unclear. As a first step toward characterizing these networks, we performed a high-spatio-temporal-resolution investigation of transcriptomes using 130 ear samples collected from developing ears with length from 0.1 mm to 19.0 cm. Comparisons of these mRNA populations indicated that these spatio-temporal transcriptomes were clearly separated into four distinct stages stages I, II, III, and IV. A total of 23 793 genes including 1513 transcription factors (TFs) were identified in the investigated developing ears. During the stage I of ear morphogenesis, 425 genes were predicted to be involved in a co-expression network established by eight hub TFs. Moreover, 9714 ear-specific genes were identified in the seven kinds of meristems. Additionally, 527 genes including 59 TFs were identified as especially expressed in ear and displayed high temporal specificity. These results provide a high-resolution atlas of gene activity during ear development and help to unravel the regulatory modules associated with the differentiation of the ear in maize.

Evolution of cereal floral architecture and threshability

Hulled grains, while providing natural protection for seeds, pose a challenge to manual threshing due to the pair of glumes tightly encasing them. Based on natural evolution and artificial domestication, gramineous crops evolved various hull-like floral organs. Recently, progress has been made in uncovering novel domesticated genes associated with cereal threshability and deciphering common regulatory modules pertinent to the specification of hull-like floral organs. Here we review morphological similarities, principal regulators, and common mechanisms implicated in the easy-threshing traits of crops. Understanding the shared and unique features in the developmental process of cereal threshability may not only shed light on the convergent evolution of cereals but also facilitate the de novo domestication of wild cereal germplasm resources through genome-editing technologies.

Genome-Wide Identification and Expression Analysis of the MADS Gene Family in Tulips (Tulipa gesneriana)

To investigate the cold response mechanism and low temperature regulation of flowering in tulips, this study identified 32 MADS-box transcription factor family members in tulips based on full-length transcriptome sequencing, named TgMADS1-TgMADS32. Phylogenetic analysis revealed that these genes can be divided into two classes: type I and type II. Structural analysis showed that TgMADS genes from different subfamilies have a similar distribution of conserved motifs. Quantitative real-time PCR results demonstrated that some TgMADS genes (e.g., TgMADS3, TgMADS15, TgMADS16, and TgMADS19) were significantly upregulated in buds and stems under cold conditions, implying their potential involvement in the cold response of tulips. In summary, this study systematically identified MADS family members in tulips and elucidated their evolutionary relationships, gene structures, and cold-responsive expression patterns, laying the foundation for further elucidating the roles of these transcription factors in flowering and the cold adaptability of tulips.

Genome-Wide Analysis of the MADS-box Gene Family and Expression Analysis during Anther Development in Salvia miltiorrhiza

MADS-box genes constitute a large family of transcription factors that play important roles in plant growth and development. However, our understanding of MADS-box genes involved in anther development and male sterility in Salvia miltiorrhiza is still limited. In this study, 63 MADS-box genes were identified from the genome of the male sterility ecotype Sichuan S. miltiorrhiza (S. miltiorrhiza_SC) unevenly distributed among eight chromosomes. Phylogenetic analysis classified them into two types and 17 subfamilies. They contained 1 to 12 exons and 10 conserved motifs. Evolution analysis showed that segmental duplication was the main force for the expansion of the SmMADS gene family, and duplication gene pairs were under purifying selection. Cis-acting elements analysis demonstrated that the promoter of SmMADS genes contain numerous elements associated with plant growth and development, plant hormones, and stress response. RNA-seq showed that the expression levels of B-class and C-class SmMADS genes were highly expressed during anther development, with SmMADS11 likely playing an important role in regulating anther development and male fertility in S. miltiorrhiza_SC. Overall, this study provides a comprehensive analysis of the MADS-box gene family in S. miltiorrhiza, shedding light on their potential role in anther development and male sterility.

Comparative transcriptomic analysis reveals differences in MADS-box genes of different hypericum in Changbai Mountains

To explore the differences between the hypericum in the Changbai Mountains, we carried out a transcriptome analysis of two common hypericums in the area, which was Hypericum attenuatum Choisy and Hypericum longistylum Oliv. We screened the MADS-box genes to analyze divergence time and evolutionary selection expression, and determine their expression levels. The results showed that we detected 9287 differentially expressed genes in the two species, of which shared 6044 genes by the two species. Analysis of the selected MADS genes revealed that the species was in an environment adapted to its natural evolution. The divergence time estimation showed that the segregation of these genes in the two species was related to the changes of external environment and genome replication events. The results of relative expression showed that the later flowering period of Hypericum attenuatum Choisy was related to the higher expression of the SVP (SHORT VEGETATIVE PHASE) and the AGL12 (AGAMOUS LIKE 12), while the lower expression of the FUL (FRUITFULL).

Genome-Wide Identification and Analysis of the MADS-Box Transcription Factor Genes in Blueberry (Vaccinium spp.) and Their Expression Pattern during Fruit Ripening

MADS-box is a class of transcriptional regulators that are ubiquitous in plants and plays important roles in the process of plant growth and development. Identification and analysis of blueberry MADS-box genes can lay a foundation for their function investigations. In the present study, 249 putative MADS-box genes were identified in the blueberry genome. Those MADS-box genes were distributed on 47 out of 48 chromosomes. The phylogenetic and evolutionary analyses showed that blueberry MADS-box genes were divided into 131 type I members and 118 type II members. The type I genes contained an average of 1.89 exons and the type II genes contained an average of 7.83 exons. Motif analysis identified 15 conserved motifs, of which 4 were related to the MADS domain and 3 were related to the K-box domain. A variety of cis-acting elements were found in the promoter region of the blueberry MADS-box gene, indicating that the MADS-box gene responded to various hormones and environmental alterations. A total of 243 collinear gene pairs were identified, most of which had a Ka/Ks value of less than 1. Nine genes belonging to SEP, AP3/PI, and AGL6 subfamilies were screened based on transcriptomic data. The expression patterns of those nine genes were also verified using quantitative PCR, suggesting that VcMADS6, VcMADS35, VcMADS44, VcMADS58, VcMADS125, VcMADS188, and VcMADS212 had potential functions in blueberry fruit ripening. The results of this study provide references for an in-depth understanding of the biological function of the blueberry MADS-box genes and the mechanism of blueberry fruit ripening.

Systematic analysis of MADS-box gene family in the U's triangle species and targeted mutagenesis of BnaAG homologs to explore its role in floral organ identity in Brassica napus

MADS-box transcription factors play an important role in regulating floral organ development and participate in environmental responses. To date, the MADS-box gene family has been widely identified in Brassica rapa (B. rapa), Brassica oleracea (B. oleracea), and Brassica napus (B. napus); however, there are no analogous reports in Brassica nigra (B. nigra), Brassica juncea (B. juncea), and Brassica carinata (B. carinata). In this study, a whole-genome survey of the MADS-box gene family was performed for the first time in the triangle of U species, and a total of 1430 MADS-box genes were identified. Based on the phylogenetic relationship and classification of MADS-box genes in Arabidopsis thaliana (A. thaliana), 1430 MADS-box genes were categorized as M-type subfamily (627 genes), further divided into Mα, Mβ, Mγ, and Mδ subclades, and MIKC-type subfamily (803 genes), further classified into 35 subclades. Gene structure and conserved protein motifs of MIKC-type MADS-box exhibit diversity and specificity among different subclades. Comparative analysis of gene duplication events and syngenic gene pairs among different species indicated that polyploidy is beneficial for MIKC-type gene expansion. Analysis of transcriptome data within diverse tissues and stresses in B. napus showed tissue-specific expression of MIKC-type genes and a broad response to various abiotic stresses, particularly dehydration stress. In addition, four representative floral organ mutants (wtl, feml, aglf-2, and aglf-1) in the T0 generation were generated by editing four AGAMOUS (BnaAG) homoeologs in B. napus that enriched the floral organ variant phenotype. In brief, this study provides useful information for investigating the function of MADS-box genes and contributes to revealing the regulatory mechanisms of floral organ development in the genetic improvement of new varieties.

Genome-wide analysis of MADS-box gene family in kiwifruit (Actinidia chinensis var. chinensis) and their potential role in floral sex differentiation

Kiwifruit (Actinidia chinensis Planch.) is a functionally dioecious plant, which displays diverse morphology in male and female flowers. MADS-box is an ancient and huge gene family that plays a key role in plant floral organ differentiation. In this study, we have identified 89 MADS-box genes from A. chinensis Red 5 genome. These genes are distributed on 26 chromosomes and are classified into type I (21 genes) and type II (68 genes). Overall, type II AcMADS-box genes have more complex structures than type I with more exons, protein domains, and motifs, indicating that type II genes may have more diverse functions. Gene duplication analysis showed that most collinearity occurred in type II AcMADS-box genes, which was consistent with a large number of type II genes. Analysis of cis-acting elements in promoters showed that AcMADS-box genes are mainly associated with light and phytohormone responsiveness. The expression profile of AcMADS-box genes in different tissues showed that most genes were highly expressed in flowers. Further, the qRT-PCR analysis of the floral organ ABCDE model-related genes in male and female flowers revealed that AcMADS4, AcMADS56, and AcMADS70 were significantly expressed in female flowers. It indicated that those genes may play an important role in the sex differentiation of kiwifruit. This work provided a comprehensive analysis of the AcMADS-box genes and may help facilitate our understanding of the sex differentiation regulatory mechanism in kiwifruit.