Gene Details:

Functional Descriptions:

  • OsMADS6 was initially named as MFO1 for mosaic floral organs based on its moderate mutant phenotypes.
  • Here, we report a null allele of OsMADS6 (OsMADS6-5), which exhibited a strong mutant phenotype in spikelet without affecting vegetative traits, causing all floral organs except lemma homeotically transformed into lemma-like organs (LLOs) as well as an indeterminate floral meristem, thus resulting in a mutant floret consisting of reiterating whorls of lemma and LLOs.
  • Here, we describe an AGL6-like gene in rice (Oryza sativa), MOSAIC FLORAL ORGANS1 (MFO1/MADS6), that regulates floral organ identity and floral meristem determinacy.
  • Furthermore, the determinacy of the floral meristem was lost, and extra carpels or spikelets developed in MFO1 florets.
  • So far, four moderate or weak mutant alleles of OsMADS6 have been described, providing valuable insights into its role in flower development.
  • Taken together, our results revealed that OsMADS6 acts as a critical regulator for early flower development in rice and provide novel insights into the molecular mechanism of OsMADS6.
  • Characterization of OsMADS6-5, a null allele, reveals that OsMADS6 is a critical regulator for early flower development in rice (Oryza sativa L.).
  • OsMADS17 has been shown to play a minor role in floral development and appears to result from a duplication of OsMADS6.
  • Here, we show the biological role of the AGL6-like gene, OsMADS6, in specifying floral organ and meristem identities in rice (Oryza sativa L.
  • OsMADS6 was strongly expressed in the floral meristem at early stages.
  • Compared to wild type plants, OsMADS6 mutants displayed altered palea identity, extra glume-like or mosaic organs, abnormal carpel development and loss of floral meristem determinacy.
  • 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.
  • The AGL6-like gene OsMADS6 regulates floral organ and meristem identities in rice.
  • Subsequently, OsMADS6 transcripts were mainly detectable in paleas, lodicules, carpels and the integument of ovule, as well as in the receptacle.
  • Further investigation shows that ADP-glucose pyrophosphorylase genes, encoding the rate-limiting step enzyme in the starch synthesis pathway, are subject to the regulation of OsMADS6.
  • Auxin-responsive OsMGH3, a common downstream target of OsMADS1 and OsMADS6, controls rice floret fertility.
  • In the flower of MFO1 mutants, the identities of palea and lodicule are disturbed, and mosaic organs were observed.
  • Whereas single mutants in either MFO1 or the SEPALLATA-like gene LHS1 showed moderate phenotypes, the MFO1 lhs1 double mutant showed a severe phenotype, including the loss of spikelet meristem determinacy.
  • 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.
  • In consistently, over-expression of OsMADS6 led to additional lodicule-, stamen- and carpel-like organs.
  • Expression analysis showed that OsMADS6 controls the formation of the incipient primordia of lodicule, stamen and carpel via regulating the expression of class B, C and SEP-like MADS-box genes.
  • Here, we report that OsMADS6 is highly expressed in flower and endosperm in Oryza sativa (rice).
  • OsMADS6 plays an essential role in endosperm nutrient accumulation and is subject to epigenetic regulation in rice (Oryza sativa).
  • However, in contrast to other OsMADS6 alleles, the afg1 mutant showed altered grain size and grain quality, with decreased total starch and amylose contents, and increased protein and soluble sugar contents.
  • The analysis of transcriptional activity suggested that AFG1 is a transcriptional activator and may affect grain size by regulating the expression levels of several genes related to cell expansion and proliferation in the AFG1 mutant.
  • These results revealed that AFG1 plays an important role in determining palea identity and affecting grain yield and quality in rice.
  • Similar to previously characterized OsMADS6 alleles, in the afg1 floret, the palea lost its marginal region and acquired the lemma identity.
  • We show here that the rice homeotic transcription factor OsMADS32 regulates floral patterning by interacting synergistically with E class protein OsMADS6 in a dosage-dependent manner.

Literature:

Gene Resources:

Sequences:

cDNA Sequence
  • >LOC_Os02g45770.1
    ATATTCTCGTCATCATTGGAGGCTTTAGCAAGCAAGAAGAGAGGCAGTGGTGGTGGTGGTGGAGGAGGAGCTAGCTAGCCTGTGCTTGCTGATCGGTGCTGAGCTGAGGAATCGTTCGATCGATCGGGCGAGATGGGGAGGGGAAGAGTTGAGCTGAAGCGCATCGAGAACAAGATCAACAGGCAGGTCACCTTCTCCAAGCGCCGCAACGGCCTCCTCAAGAAGGCCTACGAGCTGTCCGTTCTCTGCGACGCCGAGGTCGCGCTCATCATCTTCTCCAGCCGCGGCAAGCTCTACGAGTTCGGCAGCGCCGGCATAACAAAGACTTTAGAAAGGTACCAACATTGTTGCTACAATGCTCAAGATTCCAACAATGCACTTTCTGAAACCCAGAGTTGGTACCATGAAATGTCAAAGTTGAAAGCAAAATTTGAAGCTTTGCAGCGCACTCAAAGGCACTTGCTTGGGGAGGATCTTGGACCACTCAGCGTCAAAGAATTGCAGCAGCTGGAGAAACAGCTTGAATGTGCACTATCACAGGCGAGACAGAGAAAGACGCAACTGATGATGGAACAAGTGGAGGAACTTCGCAGAAAGGAGCGTCAGCTGGGTGAAATTAATAGGCAACTCAAGCACAAGCTCGAGGTTGAAGGTTCCACCAGCAACTACAGAGCCATGCAGCAAGCCTCCTGGGCTCAGGGCGCCGTGGTGGAGAATGGCGCCGCATACGTGCAGCCGCCGCCACACTCCGCGGCCATGGACTCTGAACCCACCTTGCAAATTGGGTATCCTCATCAATTTGTGCCTGCTGAAGCAAACACTATTCAGAGGAGCACTGCCCCTGCAGGTGCAGAGAACAACTTCATGCTGGGATGGGTTCTTTGAGCTAAGCAGCCATCGATCAGCTGTCAGAAGTTGGAGCTAATAATAAAAGGGATGTGGAGTGGGCTACATGTATCTCGGATCTCTCTGCGAGCCACCTAATGGTCTTGCGTGGCCCTTTAATCTGTATGTTTTTGTGTGTAAGCTACTGCTAGCTGTTTGCACCTTCTGCGTCCGTGGTTGTGTTTCCGTGCTACCTTTTTATGTTTTGATTTGGATCTTGTTTGAAAATAATCTTACCAGCTTTGGGTAAACTGTTTATTACGTACTCTATATAGCATATGTGACCGACGACAACGGTTTCATTTTAGATGATGTGTATGGATGATTTCTTTCCAAAATCACATCTTTAGTATAAGAGCAATTTTACCATCCAATACCAAA
CDS Sequence
  • >LOC_Os02g45770.1
    ATGGGGAGGGGAAGAGTTGAGCTGAAGCGCATCGAGAACAAGATCAACAGGCAGGTCACCTTCTCCAAGCGCCGCAACGGCCTCCTCAAGAAGGCCTACGAGCTGTCCGTTCTCTGCGACGCCGAGGTCGCGCTCATCATCTTCTCCAGCCGCGGCAAGCTCTACGAGTTCGGCAGCGCCGGCATAACAAAGACTTTAGAAAGGTACCAACATTGTTGCTACAATGCTCAAGATTCCAACAATGCACTTTCTGAAACCCAGAGTTGGTACCATGAAATGTCAAAGTTGAAAGCAAAATTTGAAGCTTTGCAGCGCACTCAAAGGCACTTGCTTGGGGAGGATCTTGGACCACTCAGCGTCAAAGAATTGCAGCAGCTGGAGAAACAGCTTGAATGTGCACTATCACAGGCGAGACAGAGAAAGACGCAACTGATGATGGAACAAGTGGAGGAACTTCGCAGAAAGGAGCGTCAGCTGGGTGAAATTAATAGGCAACTCAAGCACAAGCTCGAGGTTGAAGGTTCCACCAGCAACTACAGAGCCATGCAGCAAGCCTCCTGGGCTCAGGGCGCCGTGGTGGAGAATGGCGCCGCATACGTGCAGCCGCCGCCACACTCCGCGGCCATGGACTCTGAACCCACCTTGCAAATTGGGTATCCTCATCAATTTGTGCCTGCTGAAGCAAACACTATTCAGAGGAGCACTGCCCCTGCAGGTGCAGAGAACAACTTCATGCTGGGATGGGTTCTTTGA
Protein Sequence
  • >LOC_Os02g45770.1
    MGRGRVELKRIENKINRQVTFSKRRNGLLKKAYELSVLCDAEVALIIFSSRGKLYEFGSAGITKTLERYQHCCYNAQDSNNALSETQSWYHEMSKLKAKFEALQRTQRHLLGEDLGPLSVKELQQLEKQLECALSQARQRKTQLMMEQVEELRRKERQLGEINRQLKHKLEVEGSTSNYRAMQQASWAQGAVVENGAAYVQPPPHSAAMDSEPTLQIGYPHQFVPAEANTIQRSTAPAGAENNFMLGWVL*