Gene Details:

Functional Descriptions:

  • OsMADS1 is not expressed during panicle branching; earliest expression is in spikelet meristems where it is excluded from the outer rudimentary/sterile glumes.
  • OsMADS1 knockdown perturbs the differentiation of specific cell types in the lemma and palea, creating glume-like features, with severe derangements in lemma differentiation.
  • We thus demonstrate the differential contribution of OsMADS1 for lemma versus palea development and provide evidence for its regulatory function in patterning inner whorl organs.
  • OsMADS1, a rice MADS-box factor, controls differentiation of specific cell types in the lemma and palea and is an early-acting regulator of inner floral organs.
  • Auxin-responsive OsMGH3, a common downstream target of OsMADS1 and OsMADS6, controls rice floret fertility.
  • Simultaneous knockdown of the four rice SEP-like genes OsMADS1, OsMADS5, OsMADS7 and OsMADS8, leads to homeotic transformation of all floral organs except the lemma into leaf-like organs.
  • Collectively, our study suggests that the origin and diversification of OsMADS34 and OsMADS1 contribute to the origin of distinct grass inflorescences and spikelets.
  • The overexpression of OsMGH3 during the vegetative phase affects the overall plant architecture, whereas its inflorescence-specific overexpression creates short panicles with reduced branching, resembling in part the effects of OsMADS1 overexpression.
  • During organogenesis, OsMADS1 expression is confined to the lemma and palea, with weak expression in the carpel.
  • Together, these data suggest a distinct role for OsMADS1 and its monocot relatives in assigning lemma/palea identity.
  • Ectopic expression of rice OsMADS1 reveals a role in specifying the lemma and palea, grass floral organs analogous to sepals.
  • RT-PCR analyses of the OsMADS50 KO and ubiquitin (ubi):OsMADS50 plants showed that OsMADS50 is an upstream regulator of OsMADS1, OsMADS14, OsMADS15, OsMADS18, and Hd (Heading date)3a, but works either parallel with or downstream of Hd1 and O.
  • OsMGH3/OsGH3-8 is expressed abundantly in rice florets and is regulated by two related and redundant transcription factors, OsMADS1 and OsMADS6, but its contribution to flower development is not known.
  • These characteristics are very similar to those of leafy hull sterile1 (LHS1).
  • And molecular analysis indicated that nsr was a novel homeotic mutation in OsMADS1, suggesting that OsMADS1 played a distinct role in regulating the differentiation pattern of floral primordium and in conferring the determination of flower meristem.
  • The multiple effects of OsMADS1 in promoting auxin transport, signaling, and auxin-dependent expression and its direct repression of three cytokinin A-type response regulators show its role in balancing meristem growth, lateral organ differentiation, and determinacy.
  • leafy hull sterile1/OsMADS1, from a grass-specific subgroup of LOFSEP genes, is required for specifying a single floret on the spikelet meristem and for floret organ development, but its downstream mechanisms are unknown.
  • Severe loss-of-function mutations of OsMADS1cause complete homeotic conversion of organs (lodicules, stamens, and carpels) of three inner whorls into lemma- and palea-like structures.
  • The gain-of-function of OsMADS1 transgenic lines presented the transformation of outer glumes to lemma-/palea-like organs and no changes in length of lemma and palea, but loss-of-function of OsMADS1 transgenic lines displayed the overdeveloped lemma and palea.
  • Both findings revealed that OsMADS1 played a role in specifying lemma and palea and acted as a repressor of overdevelopment of lemma and palea.
  • Ectopic OsMADS1 expression results in stunted panicles with irregularly positioned branches and spikelets.
  • Strikingly, mutation of a SEPALLATA (SEP)-like gene, OsMADS1 (LHS1), enhanced the defect of osmads6 flowers, and no inner floral organs or glume-like structures were observed in whorls 2 and 3 of OsMADS1-z osmads6-1 flowers.
  • Furthermore, the OsMADS1-z osmads6-1 double mutants developed severely indeterminate floral meristems.
  • Our finding, therefore, suggests that the ancient OsMADS6 gene is able to specify floral state by determining floral organ and meristem identities in monocot crop rice together with OsMADS1.
  • In this work, we found three naturally occurring mutants in rice, namely, phoenix (pho), degenerative palea (dep), and abnormal floral organs (AFO).
  • 9-kb 5’ upstream promoter region, are required for the GUS expression pattern that coincides with flower-preferential expression of OsMADS1.
  • Notably, incorporation of the intragenic region into the CaMV35S promoter directed the GUS expression pattern similar to that of the endogenous spatial expression of OsMADS1 in flowers.
  • Conversely, ectopic OsMADS1 expression suffices to direct lemma-like differentiation in the glume.
  • Moreover, analysis of the double mutant osmads34 OsMADS1 suggests that OsMADS34 specifies the identities of floral organs, including the lemma/palea, lodicules, stamens, and carpel, in combination with another rice SEP-like gene, OsMADS1.
  • We also found that the floral meristem and organ identity gene OsLHS1 showed altered expression with respect to both pattern and levels in the eg1 mutant, and is probably responsible for the pleiotropic floral defects in eg1.
  • Rice LHS1/OsMADS1 controls floret meristem specification by coordinated regulation of transcription factors and hormone signaling pathways.
  • Thus, OsMADS1 and OsMADS15 are both required to ensure sexual reproduction in rice and mutations of them lead to the switch of reproductive habit from sexual to asexual in rice.
  • These results suggest that the OsMADS1 gene is involved in flower induction and that it may be used for genetic manipulation of certain plant species.
  • Furthermore, the expression of two regulators of flowering, Hd3a and OsMADS1, was also affected in the nl1 mutant.
  • These phenotypes resemble the phenotypes caused by mutations of the dicot E-class genes, such as the Arabidopsis SEP123(SEPALLATA1/2/3) and the petunia FBP2(Floral Binding Protein 2), suggesting that OsMADS1play a very similar role in rice to that of defined E-class genes in dicot plants.
  • Conservation of the E-function for floral organ identity in rice revealed by the analysis of tissue culture-induced loss-of-function mutants of the OsMADS1 gene.
  • OsMADS1 is a rice MADS box gene necessary for floral development.
  • Through a screen for OsMADS1 targets we identify a flower-specific Nt-gh3 type gene, OsMGH3, as a downstream gene.
  • It has been demonstrated previously that one of these genes, OsMADS1 (for Oryza sativa MADS box gene1), is expressed preferentially in flowers and causes early flowering when ectopically expressed in tobacco plants.
  • In this study, we demonstrated that ectopic expression of OsMADS1 in rice also results in early flowering.
  • To further investigate the role of OsMADS1 during rice flower development, we generated transgenic rice plants expressing altered OsMADS1 genes that contain missense mutations in the MADS domain.
  • DEP and AFO regulate reproductive habit in rice.
  • Morphogenesis and molecular basis on naked seed rice, a novel homeotic mutation of OsMADS1 regulating transcript level of AP3 homologue in rice.
  • OsJAZ1 also interacts with OsMYC2, a transcription factor in the JA signalling pathway, and represses OsMYC2’s role in activating OsMADS1, an E-class gene crucial to the spikelet development.
  • Interactions of OsMADS1 with Floral Homeotic Genes in Rice Flower Development.
  • However, molecular mechanisms underlying interactions of OsMADS1 with other floral homeotic genes in regulating flower development remains largely elusive.
  • The physical and genetic interaction of OsMADS1 and OsMADS3 is essential for floral meristem activity maintenance and organ identity specification; while OsMADS1 physically and genetically interacts with OsMADS58 in regulating floral meristem determinacy and suppressing spikelet meristem reversion.
  • Gene expression profiling further identified that OsMADS1 regulates expression of OsMADS17, and affects other genes involved in floral identity and hormone signaling.
  • In brief, this work provides new insights about the physical and regulatory interaction network of OsMADS1 with other floral homeotic genes in rice floral organ identity specification and meristem determinacy.
  • In this work, we studied the genetic interactions of OsMADS1 with B-, C-, and D-class genes along with physical interactions among their proteins, and provided some important evidence to further support the neofunctionalization of two rice C-class genes.
  • OsMADS1 controls rice (Oryza sativa) floral fate and organ development.
  • Overall, OsMADS1 binds to several regulatory genes and, probably in combination with other factors, controls a gene regulatory network that ensures rice floret development.
  • Genome-wide targets regulated by the OsMADS1 transcription factor reveals its DNA recognition properties.
  • Combining expression data from OsMADS1 knockdown florets with these DNA binding data, a snapshot of a gene regulatory network was deduced where targets, such as AP2/ERF and bHLH transcription factors and chromatin remodelers form nodes.
  • OsMADS1 specifies the determinacy of spikelet meristem and lemma/palea identity in rice.
  • OsMADS1 Represses microRNA172 in Elongation of Palea/Lemma Development in Rice.
  • However, the pathway through which OsMADS1 regulates floral organs remains elusive; here, we identified the microRNA172 (miR172) family as possible regulators downstream of OsMADS1.
  • Our results suggested that in rice, OsMADS1 and miR172s/AP2s formed a regulatory network involved in floral organ development, particularly the elongation of the lemma and the palea.
  • Quantitative PCR analysis indicated that OsLG3b expression was higher during the panicle and seed development stages.
  • Alternative<U+00A0>splicing of OsLG3b controls grain length and yield in japonica rice.
  • Six SNPs in the OsLG3b region led to alternative splicing, which were associated with grain length in an association analysis of candidate region.
  • Phylogenetic analysis and pedigree records showed that OsLG3b had been employed by breeders, but the gene still has much breeding potential for increasing grain length in indica.
  • Analysis of haplotypes and introgression regions revealed that the long-grain allele of OsLG3b might have arisen after domestication of tropical japonica and spread to subspecies indica or temperate japonica by natural crossing and artificial selection.
  • OsLG3b is therefore a target of human selection for adaptation to tropical regions during domestication and/or improvement of rice.
  • The G subunits GS3 and DEP1 interact directly with the conserved keratin-like domain of MADS transcription factors, function as cofactors to enhance OsMADS1 transcriptional activity and promote the co-operative transactivation of common target genes, thereby regulating grain size and shape.
  • Yet, several evidences suggest the evolution of distinctive functions for some of these rice floral regulators, the occurrence of other grass species-specific factors and regulatory pathways - for example LOFSEP ‘E’ class genes OsMADS1 and OsMAD34 and ramosa genes.
  • Further linkage analysis indicated that the point mutation in the OsMADS1Olr is associated with Oat-like rice phenotype, and expression analysis of the OsMADS1 by qRT-PCR and GUS staining also indicated that it is highly expressed in flower organs as well as in the early stages of grain development.
  • Finally, compared with Oat-like rice, OsMADS1Olr-overexpressing and OsMADS1-RNAi plants, mild phenotype of seed-specific OsMADS1-RNAi transgenic plants indicated that OsMADS1 may has has a direct regulation role in grain development and the grain phenotypes of Oat-like rice, OsMADS1Olr-overexpressing and OsMADS1-RNAi plants are majorly caused by the abnormal lemma and palea development.
  • Characterization of the ‘Oat-Like Rice’ Caused by a Novel Allele OsMADS1 Olr Reveals Vital Importance of OsMADS1 in Regulating Grain Shape in Oryza sativa L.
  • Furthermore, our findings suggested that OsMADS1 mediates grain shape possibly by affecting the expression of representative genes related to grain shape regulation.
  • Thus, this study not only revealed that OsMADS1 plays a vital role in regulating grain shape of rice but also highlighted the importance and value of OsMADS1 to improve the quality and yield of rice by molecular breeding.
  • By map-based cloning, we discovered that Oat-like rice harbors a novel allele of OsMADS1 gene (OsMADS1Olr), which has a spontaneous point mutation that causes the substitution of an amino acid that is highly conserved in the MADS-box domain of the MADS-box family.
  • A new, stable, null mutant of OsMADS1 generated by homologous recombination-based gene targeting in an indica rice confirms its regulatory role for floral meristem identity, its determinate development and floral organ differentiation.
  • Our data suggest, OsMADS1 commits and maintains determinate floret development by regulating floral meristem termination, carpel and ovule differentiation genes (OsMADS58, OsMADS13) while its modulation of genes such as OsMADS15, OsIG1 and OsMADS32 could be relevant in the differentiation and development of palea.
  • We also noticed striking instances of floral reversion to inflorescence and vegetative states which has not been reported for other mutant alleles of OsMADS1 and further reinforces the role of OsMADS1 in controlling floral meristem determinacy.
  • Characterization of a new rice OsMADS1 null mutant generated by homologous recombination-mediated gene targeting.
  • In this study, we generated an OsMADS1 null mutant by homologous recombination-mediated gene targeting by inserting a selectable marker gene (hpt) in OsMADS1 and replacing parts of its cis-regulatory and coding sequences.

Literature:

Gene Resources:

Sequences:

cDNA Sequence
  • >LOC_Os03g11614.1
    ATACGATCAGGTAGCCAAACCACACCACCATAAAGCTAGCTTGCAAAGGGGATAGAGTAGTAGAGAGAGAGAGAGAGGAGAGGAGGAGGAAGAAGATGGGGAGGGGGAAGGTGGAGCTGAAGCGGATCGAGAACAAGATCAGCCGGCAGGTGACGTTCGCCAAGCGCAGGAACGGCCTGCTCAAGAAGGCCTACGAGCTCTCCCTCCTCTGCGACGCCGAGGTCGCCCTCATCATCTTCTCCGGCCGCGGCCGCCTCTTCGAGTTCTCCAGCTCATCATGCATGTACAAAACCTTGGAGAGGTACCGCAGCTGCAACTACAACTCACAGGATGCAGCAGCTCCAGAAAACGAAATTAATTACCAAGAATACCTGAAGCTGAAAACAAGAGTTGAATTTCTTCAAACCACACAGAGAAATATTCTTGGTGAGGATTTGGGCCCACTAAGCATGAAGGAGCTGGAGCAGCTTGAGAACCAGATAGAAGTATCCCTCAAACAAATCAGGTCAAGAAAGAACCAAGCACTGCTTGATCAGCTGTTTGATCTGAAGAGCAAGGAGCAACAGCTGCAAGATCTCAACAAAGACTTGAGGAAAAAGTTACAGGAAACCAGTGCAGAGAATGTGCTCCATATGTCCTGGCAAGATGGTGGTGGGCACAGCGGTTCTAGCACTGTTCTTGCTGATCAGCCTCATCACCATCAGGGTCTTCTCCACCCTCACCCAGATCAGGGTGACCATTCCCTGCAGATTGGGTATCATCACCCTCATGCTCACCATCACCAGGCCTACATGGACCATCTGAGCAATGAAGCAGCAGACATGGTTGCTCATCACCCCAATGAACACATCCCATCCGGCTGGATATGATGTGTGTGTTCAGTTCAGGCTTCAGGCTTCAGAGAAGCCAATGCAAACAGTGTCCTGTAATCCAGTAATTACAGGGCATATGTAATGTAATGTAATGTAATCCCTGATCTATATTTTGCTAAGTACGTGCGTGCTCTCTTACGACCTTCTCCCCCAAACAGTTAATCAGGGGAATAATAATTTCGTTTGATGCACGTACTGTATGTCTGTATCTGTCACTGTATCGTAGGACCGTCCATGTATAACAATTTCCGTTTTGGATGTGGTAACAAGTTAATTGGCACTTAAATTTATATTTGTGATGATCTGGGAGAGTACCTAATCTCAAAAACTTGTGGAGATTATGTTAGGGAGTAGTGCAAGAAATGTTTTAAGACGGCAGCTGTTATCTCATGAGATATTGATAATGATGTTGTCTCTGCTGCTGTCGCGATCGCC
CDS Sequence
  • >LOC_Os03g11614.1
    ATGGGGAGGGGGAAGGTGGAGCTGAAGCGGATCGAGAACAAGATCAGCCGGCAGGTGACGTTCGCCAAGCGCAGGAACGGCCTGCTCAAGAAGGCCTACGAGCTCTCCCTCCTCTGCGACGCCGAGGTCGCCCTCATCATCTTCTCCGGCCGCGGCCGCCTCTTCGAGTTCTCCAGCTCATCATGCATGTACAAAACCTTGGAGAGGTACCGCAGCTGCAACTACAACTCACAGGATGCAGCAGCTCCAGAAAACGAAATTAATTACCAAGAATACCTGAAGCTGAAAACAAGAGTTGAATTTCTTCAAACCACACAGAGAAATATTCTTGGTGAGGATTTGGGCCCACTAAGCATGAAGGAGCTGGAGCAGCTTGAGAACCAGATAGAAGTATCCCTCAAACAAATCAGGTCAAGAAAGAACCAAGCACTGCTTGATCAGCTGTTTGATCTGAAGAGCAAGGAGCAACAGCTGCAAGATCTCAACAAAGACTTGAGGAAAAAGTTACAGGAAACCAGTGCAGAGAATGTGCTCCATATGTCCTGGCAAGATGGTGGTGGGCACAGCGGTTCTAGCACTGTTCTTGCTGATCAGCCTCATCACCATCAGGGTCTTCTCCACCCTCACCCAGATCAGGGTGACCATTCCCTGCAGATTGGGTATCATCACCCTCATGCTCACCATCACCAGGCCTACATGGACCATCTGAGCAATGAAGCAGCAGACATGGTTGCTCATCACCCCAATGAACACATCCCATCCGGCTGGATATGA
Protein Sequence
  • >LOC_Os03g11614.1
    MGRGKVELKRIENKISRQVTFAKRRNGLLKKAYELSLLCDAEVALIIFSGRGRLFEFSSSSCMYKTLERYRSCNYNSQDAAAPENEINYQEYLKLKTRVEFLQTTQRNILGEDLGPLSMKELEQLENQIEVSLKQIRSRKNQALLDQLFDLKSKEQQLQDLNKDLRKKLQETSAENVLHMSWQDGGGHSGSSTVLADQPHHHQGLLHPHPDQGDHSLQIGYHHPHAHHHQAYMDHLSNEAADMVAHHPNEHIPSGWI*