Os01g0726400
Please input one-sentence summary here.
Annotated Information
1) CFO1 Is an Important Regulator of Floral Organ Identity in Rice
The rice floret consists of one lemma, one palea, two lodicules, six stamens, and one central pistil that contains one ovule. The lemma, palea, and lodicule are monocot-specific organs, whereas the stamen, pistil, and ovule are highly conserved across all angiosperms (Kellogg, 2001). In this study, map-based cloning and functional characterization demonstrated that CFO1, a monocot-specific MIKCC-type gene, is a key regulator in the specification of palea and lodicule identities in rice. Several important genes for floral organ identity have been characterized in rice. The SEP-like gene OsMADS1 is required for determination of the identities of the lemma and palea (Jeon et al., 2000; Agrawal et al., 2005; Prasad et al., 2005; Chen et al., 2006). The B-class geneOsMADS16, C-class genes OsMADS3 and OsMADS58, and D-class gene OsMADS13 play critical roles in the specification of stamen and pistil/ovule identities (Nagasawa et al., 2003; Yamaguchi et al., 2006; Dreni et al., 2007). Recently, the AGL6-like gene OsMADS6/MOSAIC FLORAL ORGANS1 was shown to specify palea, lodicule, and stamen identities (Ohmori et al., 2009; Li et al., 2010). All of these genes are MIKCC-type members of the MADS box gene family. The B-, C-, and D-class genes mainly specify conserved organs, whereas theOsMADS1, OsMADS6, and CFO1 genes determine grass-specific organs.
2) CFO1 Is Required for mrp Identity
In grass flowers, the palea and lemma are thought to have different origins(Kellogg, 2001). However, some evidence indicates that the rice palea might be derived from fusion of the mrp and bop. This finding suggests that only the mrp, and not the whole palea, is equivalent to the sepal.The mrp of cfo1 developed a lemma- or bop-like identity, and CFO1 was expressed abundantly in the wild-type mrp. Recent studies have shown that OsMADS6 is also expressed predominantly in the mrp, and mutations in OsMADS6 lead to conversion of the mrp into lemma- or bop-like structures(Ohmori et al., 2009; Li et al., 2010). These results suggest that CFO1 and OsMADS6 confer important functions in the regulation of mrp identity but not bop identity.
3) Role of CFO1 in Lodicule Development
Lodicules are grass-specific organs that are considered to be homologous to dicot petals (Bommert et al., 2005;Whipple et al., 2007). The rice B-class genes OsMADS2, OsMADS4, and OsMADS16 determine lodicule identity (Nagasawa et al., 2003; Prasad and Vijayraghavan, 2003; Xiao et al., 2003; Yadav et al., 2007; Yao et al., 2008).In this paper, CFO1 was shown to maintain proper lodicule identity by prevention of the establishment of hull- and pistil-like identities in lodicules, whereas OsMADS6 prevented hull-like tissue formation, and B-class genes prevented mrp-like tissue formation, in whorl 2.
4) CFO1 Regulates Asymmetrical Development in Whorl 2
Rice flowers might have evolved from an ancestral species with flowers that possessed three lodicules (Clifford, 1987; Grass Phylogeny Working Group, 2001; Yamaguchi et al., 2006). Grasses comprise the basal grasses and BEP and PACMAD clades (Grass Phylogeny Working Group II, 2012). Flowers with three lodicules occur among the basal grasses and many species of Bambusoideae, a subfamily in the BEP clade, whereas other species in the BEP and PACMAD clades develop flowers with two lodicules. Therefore, it is hypothesized that flowers with two lodicules evolved near the base of the BEP+PACMAD clade. It is possible that CFO1-like,OsMADS6-like, OsMADS3-like, and OsMADS58-like genes evolved new functions involved in the regulation of the asymmetrical development of lodicules near the base of the BEP+PACMAD clade, with a subsequent reversal in Bambusoideae species. However, it remains unclear whether the four MADS box genes function in the same regulatory pathway. In addition, it would be interesting to determine the correlation between the asymmetrical arrangement of lodicules and the functions of related genes such as CFO1-like, AGL6-like, and C-class genes in additional grass species.
5) CFO1 Negatively Regulates DL
The DL gene, which is expressed in whorl 4 and specifies pistil identity, antagonizes OsMADS16 gene function between whorls 3 and 4 (Nagasawa et al., 2003; Yamaguchi et al., 2004).The DL gene is also expressed in the peripheral domain of the medial vascular bundle of the lemma, but it is not clear whether DL controls lemma development (Fig. 6J; Yamaguchi et al., 2004). It is possible that CFO1 plays a pivotal role in the maintenance of floral organ identity through repression of DL transcription in the mrp, lodicule, and stamen (Fig. 11A). When CFO1 is dysfunctional, DL expression is extended, which results in a lemma-like mrp and chimeric organs in whorls 2 and 3 (Fig. 11B). We also observed that overexpression of CFO1 did not result in dl phenotypes in the leaf, lemma, and pistil. Moreover, CFO1 is expressed not only in the mrp in whorls 2 and 3 but also in the lemma and pistil. These results suggest that CFO1 restriction of DL expression should depend on interaction with other factors in the mrp in whorls 2 and 3. Therefore, characterization of these factors will improve our understanding of the regulation of floral organ identity in rice.
6) CFO1 Is Also Required for Floral Meristem Development
In cfo1 flowers, the initiation and development of floral organ primordia in whorls 3 and 4 were delayed, and the numbers of stamens and pistils were altered, which indicated that normal floral meristem development was disturbed. However, compared with the above-mentioned mutants, floral meristem determinacy was affected less by mutation of CFO1, because no repeated organs developed and the floral meristem was consumed by the pistils in cfo1 flowers. These results suggest that CFO1 is required for normal floral meristem development but contributes very weakly to the regulation of floral meristem determinacy.
We investigated CFO1 expression in wild-type plants using in situ hybridization. The CFO1 gene was expressed initially in the primary and secondary branch meristems (Fig. 9D).Abundant CFO1 transcripts were detected subsequently in the meristems of spikelets and florets (Fig. 9, E and F). During stages Sp6 and Sp7, when the stamen primordia were initiated, analysis of serial longitudinal and transverse sections indicated that the expression signals of CFO1 were focused on several specific domains and organs (Fig. 9, G–K). First, CFO1 was expressed strongly in organ primordia, such as rudimentary glumes (Fig. 9, G and H), the mrp (lines in Fig. 9, I–K), lodicules (triangles in Fig. 9, G, H, and L), upper and central regions of stamens (asterisks in Fig. 9, I–K), and the upper region of the pistil (Fig. 9, G–K). Second, CFO1 was expressed in vascular bundles of floral organ primordia, such as the rachilla (arrows in Fig. 9G), sterile lemma (arrows in Fig. 6I),
and lemma and palea (arrows in Fig. 9, I–K), which are normal in cfo1 flowers. During stage Sp8, CFO1 was expressed at high levels in the lodicules and rudimentary glumes and at low levels in the stamens and pistils (Fig. 9L).
Genetic analysis demonstrated that the cfo1trait was controlled by a single recessive gene.The cfo1 locus was mapped on the short arm of chromosome 1 within an approximately 645-kb region between the simple sequence repeat markers RM1152 and RM128 (Fig. 7, A and B). Fortunately, a gene that encodes a 196-residue MADS box transcription factor, OsMADS32, occurs in this region. Sequence comparison revealed that OsMADS32 in the cfo1 mutant was missing a single nucleotide (T) at position 214 of the open reading frame, which caused a premature translation stop (Fig. 7, C and D). An RsaI restriction site in the wild-type allele was abolished in the cfo1 mutant allele because of this single-nucleotide deletion (Fig. 7C).
CFO1 Belongs to a Monocot-Specific Class.The MIKC-type genes are classified as a plant-specific subfamily of the MADS box gene family. This subfamily contains a well-conserved MADS (M) domain and three additional plant-specific domains: an intervening (I) domain, a keratin-like coiled-coil (K) domain, and a C-terminal (C) domain. The MIKC-type genes can be further divided into two subgroups, MIKCC and MIKC*, based on the intron-exon structure. (Fig8)
Labs working on this gene
Please input related labs here.
References
Please input cited references here.
Structured Information
| Gene Name |
Os01g0726400 |
|---|---|
| Description |
Transcription factor, MADS-box domain containing protein |
| Version |
NM_001050654.1 GI:115439678 GeneID:4324731 |
| Length |
2179 bp |
| Definition |
Oryza sativa Japonica Group Os01g0726400, complete gene. |
| Source |
Oryza sativa Japonica Group ORGANISM Oryza sativa Japonica Group
Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
Spermatophyta; Magnoliophyta; Liliopsida; Poales; Poaceae; BEP
clade; Ehrhartoideae; Oryzeae; Oryza.
|
| Chromosome | |
| Location |
Chromosome 1:32034244..32036422 |
| Sequence Coding Region |
32034337..32034347,32034435..32034510,32035466..32035507,32035653..32035794,32035866..32035927 |
| Expression | |
| Genome Context |
<gbrowseImage1> name=NC_008394:32034244..32036422 source=RiceChromosome01 preset=GeneLocation </gbrowseImage1> |
| Gene Structure |
<gbrowseImage2> name=NC_008394:32034244..32036422 source=RiceChromosome01 preset=GeneLocation </gbrowseImage2> |
| Coding Sequence |
<cdnaseq>atggggagggggcgcagcgagataaagaggatagagaaccccacgcagcggcagtccaccttctacaagcgcagggacggcctgttcaagaaggccagggagctcgccgtcctctgcgacgccgacctcctcctcctcctcttctccgcctccggcaagctctaccacttcctctcccccaccgtcccctccgtgagggagtttgtcgagaggtacgaggccaccacgcacaccaaggtttgggcagatatcaggcaggagaggcgcgccgagctggagaaggtgggcagcatgtgcgacctcctggagaaacagctgaggttcatgacggtggacgacggcgaggagtacacggtgccgtcgctggaggcgctggagcacaatctggaggccgccatgcgcaaggtgcgctccgagaaggaccgcaagatcggaggcgagatctgctacctccagaacattattagggggcgacaagaggagcggtacgggctgtgcgacaagattgctcatgcacagactctgaaggatgtggaatgtggatccacctcactaagcaatggcttggaccttaaactggggttcaactag</cdnaseq> |
| Protein Sequence |
<aaseq>MGRGRSEIKRIENPTQRQSTFYKRRDGLFKKARELAVLCDADLL LLLFSASGKLYHFLSPTVPSVREFVERYEATTHTKVWADIRQERRAELEKVGSMCDLL EKQLRFMTVDDGEEYTVPSLEALEHNLEAAMRKVRSEKDRKIGGEICYLQNIIRGRQE ERYGLCDKIAHAQTLKDVECGSTSLSNGLDLKLGFN</aaseq> |
| Gene Sequence |
<dnaseqindica>2076..2086#1913..1988#916..957#629..770#496..557#309..375#1..191#atggggagggggcgcagcgagataaagaggatagagaaccccacgcagcggcagtccaccttctacaagcgcagggacggcctgttcaagaaggccagggagctcgccgtcctctgcgacgccgacctcctcctcctcctcttctccgcctccggcaagctctaccacttcctctcccccaccgtcccctcgtaagctgccctgccacacatccgcttgtcgatccgtcacgtatgtatatgcgcgcgcgctgtctcctgacattgttggttaatccacgtttcgttgctgcttctttcttggcgcagcgtgagggagtttgtcgagaggtacgaggccaccacgcacaccaaggtttgggcagatatcaggcaggtacgtagcacgtagtacaacgcaacgcgcgtagtaatcagttgtttgagcgttttctcaccagtaaataaacgtgcgccgttttttttttctcttccttggcaccgcgcatgcatgtaggagaggcgcgccgagctggagaaggtgggcagcatgtgcgacctcctggagaaacagctgaggtaagcaactcgatgcgagctgatcgatgtcactcgtcatgatatcgtgtgtgcttttgtgtttttggcaggttcatgacggtggacgacggcgaggagtacacggtgccgtcgctggaggcgctggagcacaatctggaggccgccatgcgcaaggtgcgctccgagaaggaccgcaagatcggaggcgagatctgctacctccagaacattgtacgtctttcgtaaacacggcccacttctgatacgattcatacctgtgccgtcaggacacttgtacagatttacagattgcgttgtgaaccgagaccaaacatcactagtaatatacatgtgtttttcgattatctgcgtgcagattagggggcgacaagaggagcggtacgggctgtgcgacaaggtaaagaatataatcattctggctatttatcaagttgtactatcttcgtttgttagtcagttcattatcatcgtcatcatcaattttccctttcaaatggtcaaaaagaaatcttgtgtaaatgttcttcataggcaaatgttgacagatgataggcaaacactcgtgagaaacatagcacttggcagcaatttcatataagtattgaacccacaagtgcaaagaaagacattgatccaaacaggtagctaagttctttggtgttcttggtcctgtagttttgccttcagatcttaattcatctctaaattagagataaataagcaaatactagcctataagaatggttagctgagaaatcattggtttattttagttgacggatcaagatacatagctttccctccaaaaataaaaataagacagaaaatagatcgaaaaaccatggtagatttgttttaaatttattccccttttgttgctgtgcctggatatttggttctttttttcagactataggatacagtataaagatagacgcaagtataggactatagaagcaccattcagaggaagcgtgcatgccctactcatggtactacatacacaggcacagtagaccgatgctagacaagagcaatgctccattacaaggcataaagagacacaaagtatactaacctagaacatatagaccctttcatggaacccctttaccatggaagtggaatagctttcagttcgtgaaagcaactgcatcaacctacatgaaactatgcagggtagctcatgaagcctacctacagtggccgctagtagcttactattgggttacgtgggtagagaaagtgaccaaaactttttgtttgatttctcaaaccctcctttttgtttctttctgagattttgaaatgcttcagtattttagatgttgctctgtaattttcctgcacagattgctcatgcacagactctgaaggatgtggaatgtggatccacctcactaagcaatggcttggaccttaaactgggttagtcatacgactgaatcatgtaccttatgtatgaattgggtgatccgattgtatttgtaccttacaaacctcggtattatgcagggttcaactagaaacagatggacgcttgacgttcagatttcctttattgctgcttagagccagtgttctattatgaaagattatgctgaacttttccggggtta</dnaseqindica> |
| External Link(s) |
