Integration of reproductive meristem fates by a SEPALLATA-like MADS-box gene.
Ontology highlight
ABSTRACT:
SUBMITTER: Uimari A
PROVIDER: S-EPMC524820 | biostudies-literature | 2004 Nov
REPOSITORIES: biostudies-literature
Publications
Integration of reproductive meristem fates by a SEPALLATA-like MADS-box gene.
Uimari Anne A Kotilainen Mika M Elomaa Paula P Yu Deyue D Albert Victor A VA Teeri Teemu H TH
Proceedings of the National Academy of Sciences of the United States of America 20041025 44
Reproductive transition, inflorescence architecture, meristem patterning, and floral organ identity have been studied as distinct research areas in plant science. By using the ornamental plant Gerbera, we demonstrate that all of these keystone aspects of reproductive meristematic fate are integrated genetically by a single SEPALLATA-like MADS-box gene from a functional class designated previously as "floral homeotic" or "organ identity." This extended regulatory network has not been elaborated i ...[more]
Similar Datasets
Project description:In rice panicle development, new meristems are generated sequentially in an organized manner and acquire their identity in a time- and position-dependent manner. In the panicle of the panicle phytomer2-1 (pap2-1) mutant, the pattern of meristem initiation is disorganized and newly formed meristems show reduced competency to become spikelet meristems, resulting in the transformation of early arising spikelets into rachis branches. In addition, rudimentary glumes and sterile lemmas, the outermost organs of the spikelet, elongate into a leafy morphology. We propose that PAP2 is a positive regulator of spikelet meristem identity. Map-based cloning revealed that PAP2 encodes OsMADS34, a member of the SEPALLATA (SEP) subfamily of MADS-box proteins. PAP2/OsMADS34 belongs to the LOFSEP subgroup of MADS-box genes that show grass-specific diversification caused by gene duplication events. All five SEP subfamily genes in rice are expressed exclusively during panicle development, while their spatial and temporal expression patterns vary. PAP2 expression starts the earliest among the five SEP genes, and a low but significant level of PAP2 mRNA was detected in the inflorescence meristem, in branch meristems immediately after the transition, and in glume primordia, consistent with its role in the early development of spikelet formation. Our study provides new evidence supporting the hypothesis that the genes of the LOFSEP subgroup control developmental processes that are unique to grass species.
| S-EPMC2807174 | biostudies-literature
Project description:BackgroundSacred lotus (Nelumbo nucifera) is a vital perennial aquatic ornamental plant. Its flower shape determines the horticultural and ornamental values. However, the mechanisms underlying lotus flower development are still elusive. MADS-box transcription factors are crucial in various features of plant development, especially in floral organogenesis and specification. It is still unknown how the MADS-box transcription factors regulate the floral organogenesis in lotus.ResultsTo obtain a comprehensive insight into the functions of MADS-box genes in sacred lotus flower development, we systematically characterized members of this gene family based on the available genome information. A total of 44 MADS-box genes were identified, of which 16 type I and 28 type II genes were categorized based on the phylogenetic analysis. Furthermore, the structure of MADS-box genes and their expressional patterns were also systematically analyzed. Additionally, subcellular localization analysis showed that they are mainly localized in the nucleus, of which a SEPALLATA3 (SEP3) homolog NnMADS14 was proven to be involved in the floral organogenesis.ConclusionThese results provide some fundamental information about the MADS-box gene family and their functions, which might be helpful in not only understanding the mechanisms of floral organogenesis but also breeding of high ornamental value cultivars in lotus.
| S-EPMC7599106 | biostudies-literature
Project description:Members of the SEPALLATA (SEP) MADS-box subfamily are required for specifying the "floral state" by contributing to floral organ and meristem identity. SEP genes have not been detected in gymnosperms and seem to have originated since the lineage leading to extant angiosperms diverged from extant gymnosperms. Therefore, both functional and evolutionary studies suggest that SEP genes may have been critical for the origin of the flower. To gain insights into the evolution of SEP genes, we isolated nine genes from plants that occupy phylogenetically important positions. Phylogenetic analyses of SEP sequences show that several gene duplications occurred during the evolution of this subfamily, providing potential opportunities for functional divergence. The first duplication occurred prior to the origin of the extant angiosperms, resulting in the AGL2/3/4 and AGL9 clades. Subsequent duplications occurred within these clades in the eudicots and monocots. The timing of the first SEP duplication approximately coincides with duplications in the DEFICIENS/GLOBOSA and AGAMOUS MADS-box subfamilies, which may have resulted from either a proposed genome-wide duplication in the ancestor of extant angiosperms or multiple independent duplication events. Regardless of the mechanism of gene duplication, these pairs of duplicate transcription factors provided new possibilities of genetic interactions that may have been important in the origin of the flower.
| S-EPMC1449606 | biostudies-literature
Project description:AP1/FUL, SEP, AGL6, and FLC subfamily genes play important roles in flower development. The phylogenetic relationships among them, however, have been controversial, which impedes our understanding of the origin and functional divergence of these genes. One possible reason for the controversy may be the problems caused by changes in the exon-intron structure of genes, which, according to recent studies, may generate non-homologous sites and hamper the homology-based sequence alignment. In this study, we first performed exon-by-exon alignments of these and three outgroup subfamilies (SOC1, AG, and STK). Phylogenetic trees reconstructed based on these matrices show improved resolution and better congruence with species phylogeny. In the context of these phylogenies, we traced evolutionary changes of exon-intron structures in each subfamily. We found that structural changes have occurred frequently following gene duplication and speciation events. Notably, exons 7 and 8 (if present) suffered more structural changes than others. With the knowledge of exon-intron structural changes, we generated more reasonable alignments containing all the focal subfamilies. The resulting trees showed that the SEP subfamily is sister to the monophyletic group formed by AP1/FUL and FLC subfamily genes and that the AGL6 subfamily forms a sister group to the three abovementioned subfamilies. Based on this topology, we inferred the evolutionary history of exon-intron structural changes among different subfamilies. Particularly, we found that the eighth exon originated before the divergence of AP1/FUL, FLC, SEP, and AGL6 subfamilies and degenerated in the ancestral FLC-like gene. These results provide new insights into the origin and evolution of the AP1/FUL, FLC, SEP, and AGL6 subfamilies.
| S-EPMC4852290 | biostudies-literature
Project description:Inflorescence architecture is an important determinant of crop productivity. The number of spikelets produced by the wheat inflorescence meristem (IM) before its transition to a terminal spikelet (TS) influences the maximum number of grains per spike. Wheat MADS-box genes VERNALIZATION 1 (VRN1) and FRUITFULL 2 (FUL2) (in the SQUAMOSA-clade) are essential to promote the transition from IM to TS and for spikelet development. Here we show that SQUAMOSA genes contribute to spikelet identity by repressing MADS-box genes VEGETATIVE TO REPRODUCTIVE TRANSITION 2 (VRT2), SHORT VEGETATIVE PHASE 1 (SVP1), and SVP3 in the SVP clade. Constitutive expression of VRT2 resulted in leafy glumes and lemmas, reversion of spikelets to spikes, and downregulation of MADS-box genes involved in floret development, whereas the vrt2 mutant reduced vegetative characteristics in spikelets of squamosa mutants. Interestingly, the vrt2 svp1 mutant showed similar phenotypes to squamosa mutants regarding heading time, plant height, and spikelets per spike, but it exhibited unusual axillary inflorescences in the elongating stem. We propose that SQUAMOSA-SVP interactions are important to promote heading, formation of the TS, and stem elongation during the early reproductive phase, and that downregulation of SVP genes is then necessary for normal spikelet and floral development. Manipulating SVP and SQUAMOSA genes can contribute to engineering spike architectures with improved productivity.
| S-EPMC8643710 | biostudies-literature
Project description:BackgroundMADS-box transcription factors, besides being involved in floral organ specification, have also been implicated in several aspects of plant growth and development. In recent years, there have been reports on genomic localization, protein motif structure, phylogenetic relationships, gene structure and expression of the entire MADS-box family in the model plant system, Arabidopsis. Though there have been some studies in rice as well, an analysis of the complete MADS-box family along with a comprehensive expression profiling was still awaited after the completion of rice genome sequencing. Furthermore, owing to the role of MADS-box family in flower development, an analysis involving structure, expression and functional aspects of MADS-box genes in rice and Arabidopsis was required to understand the role of this gene family in reproductive development.ResultsA genome-wide molecular characterization and microarray-based expression profiling of the genes encoding MADS-box transcription factor family in rice is presented. Using a thorough annotation exercise, 75 MADS-box genes have been identified in rice and categorized into MIKCc, MIKC*, Malpha, Mbeta and Mgamma groups based on phylogeny. Chromosomal localization of these genes reveals that 16 MADS-box genes, mostly MIKCc-type, are located within the duplicated segments of the rice genome, whereas most of the M-type genes, 20 in all, seem to have resulted from tandem duplications. Nine members belonging to the Mbeta group, which was considered absent in monocots, have also been identified. The expression profiles of all the MADS-box genes have been analyzed under 11 temporal stages of panicle and seed development, three abiotic stress conditions, along with three stages of vegetative development. Transcripts for 31 genes accumulate preferentially in the reproductive phase, of which, 12 genes are specifically expressed in seeds, and six genes show expression specific to panicle development. Differential expression of seven genes under stress conditions is also evident. An attempt has been made to gain insight into plausible functions of rice MADS-box genes by collating the expression data of functionally validated genes in rice and Arabidopsis.ConclusionOnly a limited number of MADS genes have been functionally validated in rice. A comprehensive annotation and transcriptome profiling undertaken in this investigation adds to our understanding of the involvement of MADS-box family genes during reproductive development and stress in rice and also provides the basis for selection of candidate genes for functional validation studies.
| S-EPMC1947970 | biostudies-literature
Project description:The AGAMOUS-LIKE6 (AGL6)-like genes are ancient MADS-box genes and are functionally studied in a few model plants. The knowledge of these genes in wheat remains limited. Here, by studying a 'double homoeolog mutant' of the AGL6 gene in tetraploid wheat, we showed that AGL6 was required for the development of all four whorls of floral organs with dosage-dependent effect on floret fertility. Yeast two-hybrid analyses detected interactions of AGL6 with all classes of MADS-box proteins in the ABCDE model for floral organ development. AGL6 was found to interact with several additional proteins, including the G protein β and γ (DEP1) subunits. Analysis of the DEP1-B mutant showed a significant reduction in spikelet number per spike in tetraploid wheat, while overexpression of AGL6 in common wheat increased the spikelet number per spike and hence the grain number per spike. RNA-seq analysis identified the regulation of several meristem activity genes by AGL6, such as FUL2 and TaMADS55. Our work therefore extensively updated the wheat ABCDE model and proposed an alternative approach to improve wheat grain yield by manipulating the AGL6 gene.
| S-EPMC8710900 | biostudies-literature
Project description:In Arabidopsis thaliana, the E-class SEPALLATA (SEP) genes are generally expressed across all floral whorls. These genes play fundamental roles in floral organ fate determination during development by interacting with other MADS-box gene products, such as those from A-, B-, and C-class genes. However, the function of SEP genes in orchid remains obscure. Here, we analyzed a mutant orchid cultivar with greenish flowers in Habenaria radiata and found that this phenotype is caused by the absence of SEP function. Wild type H. radiata flowers contain a column and two perianth whorls consisting of three greenish sepals, two white petals, and a lip (labellum). By contrast, the flowers of H. radiata cultivar 'Ryokusei' appear greenish, with three normal sepals in whorl 1, two greenish petals and a lip in whorl 2, and several sepaloid organs and a ventral column in whorls 3 and 4. We isolated two SEP-like genes (HrSEP-1 and HrSEP-2) and two AGAMOUS-like genes (HrAG-1 and HrAG-2) from wild type H. radiata and compared their expression in the wild type vs. the mutant cultivar. HrAG-1 and HrAG-2 were expressed in the column in the wild type, whereas these genes were expressed in the ventral column and in sepaloid organs that had been converted from a column in 'Ryokusei.' HrSEP-1 and HrSEP-2 were expressed in all floral organs in the wild type. However, in the mutant cultivar, HrSEP-2 was expressed in all floral organs, while HrSEP-1 expression was not detected. Thus, we analyzed the genomic structures of HrSEP-1 in the wild type and 'Ryokusei' and identified a retrotransposon-like element in its first exon in 'Ryokusei.' Yeast two-hybrid assays demonstrated that HrSEP-1 interacts with HrDEF, HrAG-1, and HrAG-2. These results indicate that the mutant phenotype of 'Ryokusei' flowers is caused by the loss of function of HrSEP-1. Therefore, this gene plays an important role in column, lip, and petal development in H. radiata flowers.
| S-EPMC6018480 | biostudies-literature
Project description:BACKGROUND: The identity of flower organs is specified by various MIKC MADS-box transcription factors which act in a combinatorial manner. TM8 is a MADS-box gene that was isolated from the floral meristem of a tomato mutant more than twenty years ago, but is still poorly known from a functional point of view in spite of being present in both Angiosperms and Gymnosperms, with some species harbouring more than one copy of the gene. This study reports a characterization of TM8 that was carried out in transgenic tomato plants with altered expression of the gene. RESULTS: Tomato plants over-expressing either TM8 or a chimeric repressor form of the gene (TM8:SRDX) were prepared. In the TM8 up-regulated plants it was possible to observe anomalous stamens with poorly viable pollen and altered expression of several floral identity genes, among them B-, C- and E-function ones, while no apparent morphological modifications were visible in the other whorls. Oblong ovaries and fruits, that were also parthenocarpic, were obtained in the plants expressing the TM8:SRDX repressor gene. Such ovaries showed modified expression of various carpel-related genes. No apparent modifications could be seen in the other flower whorls. The latter plants had also epinastic leaves and malformed flower abscission zones. By using yeast two hybrid assays it was possible to show that TM8 was able to interact in yeast with MACROCALIX. CONCLUSIONS: The impact of the ectopically altered TM8 expression on the reproductive structures suggests that this gene plays some role in the development of the tomato flower. MACROCALYX, a putative A-function MADS-box gene, was expressed in all the four whorls of fully developed flowers, and showed quantitative variations that were opposite to those of TM8 in the anomalous stamens and ovaries. Since the TM8 protein interacted in vitro only with the A-function MADS-box protein MACROCALYX, it seems that for the correct differentiation of the tomato reproductive structures possible interactions between TM8 and MACROCALYX proteins might be important.
| S-EPMC4258831 | biostudies-literature
Project description:BackgroundThe MADS-box transcription factors are an ancient family of genes that regulate numerous physiological and biochemical processes in plants and facilitate the development of floral organs. However, the functions of most of these transcription factors in soybean remain unknown.ResultsIn this work, a MADS-box gene, GmAGL1, was overexpressed in soybean. Phenotypic analysis showed that GmAGL1 overexpression not only resulted in early maturation but also promoted flowering and affected petal development. Furthermore, the GmAGL1 was much more effective at promoting flowering under long-day conditions than under short-day conditions. Transcriptome sequencing analysis showed that before flowering, the photoperiod pathway photoreceptor CRY2 and several circadian rhythm genes, such as SPA1, were significantly down-regulated, while some other flowering-promoting circadian genes, such as GI and LHY, and downstream genes related to flower development, such as FT, LEAFY, SEP1, SEP3, FUL, and AP1, were up-regulated compared with the control. Other genes related to the flowering pathway were not noticeably affected.ConclusionsThe findings reported herein indicate that GmAGL1 may promote flowering mainly through the photoperiod pathway. Interestingly, while overexpression of GmAGL1 promoted plant maturity, no reduction in seed production or oil and protein contents was observed.
| S-EPMC5769455 | biostudies-literature