Class B Gene Expression and the Modified ABC Model in Nongrass Monocots

Kanno, Akira; Nakada, Mutsumi; Akita, Yusuke; Hirai, Masayo

doi:10.1100/tsw.2007.86

Cited by 61 publications

(37 citation statements)

References 33 publications

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“…An evolutionary interpretation of the data presented here suggests that genes in clades 1 and 2 follow an ancestral pattern of expression, because these genes are expressed in all perianth organs like DEF-like genes from other petaloid monocots (e.g. Tulipa gesneriana and Crocus sativus, reviewed in Kanno et al, 2007). Conversely, the pattern of expression of clade-3 and -4 genes represents a derived state associated with the development of labellum and inner lateral tepals.…”

Section: Evolution Of Orchid Def-like Genesmentioning

confidence: 95%

Conserved differential expression of paralogous DEFICIENS‐ and GLOBOSA‐like MADS‐box genes in the flowers of Orchidaceae: refining the ‘orchid code’

2011

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SUMMARYIn flowering plants, class-B floral homeotic genes encode MADS-domain transcription factors, which are key in the specification of petal and stamen identity, and have two ancient clades: DEF-like and GLO-like genes. Many species have one gene of each clade, but orchids have typically four DEF-like genes, representing ancient gene clades 1, 2, 3 and 4. We tested the 'orchid code', a combinatorial genetic model suggesting that differences between the organs of the orchid perianth (outer tepals, inner lateral tepals and labellum) are generated by the combinatorial differential expression of four DEF-like genes. Our experimental test involves highly sensitive and specific measurements, with qRT-PCR of the expression of DEF-and GLO-like genes from the distantly related Vanilla planifolia and Phragmipedium longifolium, as well as from wild-type and peloric Phalaenopsis hybrid flowers. Our findings support the first 'orchid code' hypothesis, in that absence of clade-3 and -4 gene expression distinguishes the outer tepals from the inner tepals. In contrast to the original hypothesis, however, mRNA of both clade-3 and -4 genes accumulates in wild-type inner lateral tepals and the labellum, and in labellum-like inner lateral tepals of peloric flowers, albeit in different quantities. Our data suggest a revised hypothesis where high levels of clade-1 and -2, and low levels of clade-3 and -4, gene expression specify inner lateral tepals, whereas labellum development requires low levels of clade-1 and -2 expression and high levels of clade-3 and -4 expression.

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Section: Evolution Of Orchid Def-like Genesmentioning

confidence: 95%

Conserved differential expression of paralogous DEFICIENS‐ and GLOBOSA‐like MADS‐box genes in the flowers of Orchidaceae: refining the ‘orchid code’

2011

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“…Both types of paleoAP3/TM6-and PI-lineage gene from C. sativus (CsatAP3 and CsatPIa/b/c) and M. armeniacum (MaDEF1/2 and MaGLOA1/A2/B), respectively, were expressed in whorls 1-3 ( Fig. 3D, E; Kalivas et al, 2007;Kanno et al, 2007;Nakada and Kanno, unpublished data;Nakada et al, 2006;Tsaftaris et al, 2006), similar to that in tulip and lily. However, CsatAP3 and CsatPIa/b/c and MaDEF2 and MaGLOA1/A2/B were also expressed in whorl 4.…”

Section: -2) Lily-type Flowers-a Perianth With Two Petaloid Whorlsmentioning

confidence: 99%

“…On the other hand, the petals of other plant groups, such as monocots, lower eudicots, and basal angiosperms, may not be homologous to those of higher eudicots. To examine the molecular mechanism of petal development in these plant groups, many floral organ identity genes have been characterized in monocots (Kanno, 2006;Kanno et al, 2007), lower eudicots (Kramer, 2009;Kramer and Hodges, 2010), and basal angiosperms (Liu et al, 2013;Soltis et al, 2009). Among these, monocots are very important groups for horticulture because many important floricultural species, such as lilies, tulips, and orchids, are included in them.…”

Section: Introductionmentioning

confidence: 99%

Molecular Mechanism Regulating Floral Architecture in Monocotyledonous Ornamental Plants

Kanno

2016

The Hortic J

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Molecular and genetic analyses of flower development have been conducted primarily in dicot model plants such as Arabidopsis thaliana and Antirrhinum majus. The obtained data are the basis for the ABC model, which was extended to the ABCE model of floral development. This model has been validated in many dicot species using genetic transformation studies and mutant analyses. Many dicot flowers have two distinctive perianth whorls, which include greenish sepals and showy petals. By contrast, the monocot lily flower has two almost identical petaloid whorls, the inner and outer tepals. To explain this type of floral morphology, a modified ABC model, the further extended modified ABCE model, was proposed. According to this model, B-class genes are expressed in whorls 1-3, and whorls 1 and 2 form petaloid structures. This review describes the molecular mechanisms regulating flower development in monocots. Since the showy perianth is one of the most important traits in floricultural crops, we focused on the B-and C-class genes, which are related to the development and modification of the perianth. The review describes the expression patterns of floral organ identity genes, and presents functional studies using double-flowered and viridiflora cultivars in some monocot species. Besides lily-type flowers, there are several types of monocot flower, such as commelina type with two whorls of distinctive perianth, orchid and grass flowers. The review also describes the molecular analyses of these types of monocot flower.

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“…The function of B group genes, such as APETALA3 (AP3) and PISTILLATA (PI), has been thought to have a major role in specifying petal and stamen development (Jack et al, 1992;Goto and Meyerowitz, 1994;Krizek and Meyerowitz, 1996;Kramer et al, 1998;Hernandez-Hernandez et al, 2007;Kanno et al, 2007;Whipple et al, 2007;Irish, 2009). In Arabidopsis (Arabidopsis thaliana), mutation in AP3 or PI caused identical phenotypes of second whorl petal conversion into a sepal structure and third flower whorl stamen into a carpel structure (Bowman et al, 1989;Jack et al, 1992;Goto and Meyerowitz, 1994).…”

mentioning

confidence: 99%

Characterization of the Possible Roles for B Class MADS Box Genes in Regulation of Perianth Formation in Orchid

Chang

Kao

et al. 2009

Plant Physiol.

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To investigate sepal/petal/lip formation in Oncidium Gower Ramsey, three paleoAPETALA3 genes, O. Gower Ramsey MADS box gene5 (OMADS5; clade 1), OMADS3 (clade 2), and OMADS9 (clade 3), and one PISTILLATA gene, OMADS8, were characterized. The OMADS8 and OMADS3 mRNAs were expressed in all four floral organs as well as in vegetative leaves. The OMADS9 mRNA was only strongly detected in petals and lips. The mRNA for OMADS5 was only strongly detected in sepals and petals and was significantly down-regulated in lip-like petals and lip-like sepals of peloric mutant flowers. This result revealed a possible negative role for OMADS5 in regulating lip formation. Yeast two-hybrid analysis indicated that OMADS5 formed homodimers and heterodimers with OMADS3 and OMADS9. OMADS8 only formed heterodimers with OMADS3, whereas OMADS3 and OMADS9 formed homodimers and heterodimers with each other. We proposed that sepal/petal/lip formation needs the presence of OMADS3/8 and/or OMADS9. The determination of the final organ identity for the sepal/ petal/lip likely depended on the presence or absence of OMADS5. The presence of OMADS5 caused short sepal/petal formation. When OMADS5 was absent, cells could proliferate, resulting in the possible formation of large lips and the conversion of the sepal/petal into lips in peloric mutants. Further analysis indicated that only ectopic expression of OMADS8 but not OMADS5/9 caused the conversion of the sepal into an expanded petal-like structure in transgenic Arabidopsis (Arabidopsis thaliana) plants.The ABCDE model predicts the formation of any flower organ by the interaction of five classes of homeotic genes in plants (Yanofsky et al

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Class B Gene Expression and the Modified ABC Model in Nongrass Monocots

Cited by 61 publications

References 33 publications

Conserved differential expression of paralogous DEFICIENS‐ and GLOBOSA‐like MADS‐box genes in the flowers of Orchidaceae: refining the ‘orchid code’

Conserved differential expression of paralogous DEFICIENS‐ and GLOBOSA‐like MADS‐box genes in the flowers of Orchidaceae: refining the ‘orchid code’

Molecular Mechanism Regulating Floral Architecture in Monocotyledonous Ornamental Plants

Characterization of the Possible Roles for B Class MADS Box Genes in Regulation of Perianth Formation in Orchid

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