HUA ENHANCER2, a putative DExH-box RNA helicase, maintains homeotic B and C gene expression inArabidopsis

Development ◽  
2002 ◽  
Vol 129 (7) ◽  
pp. 1569-1581 ◽  
Author(s):  
Tamara L. Western ◽  
Yulan Cheng ◽  
Jun Liu ◽  
Xuemei Chen
Keyword(s):  
Gene Expression ◽  
Floral Organ ◽  
Rna Helicase ◽  
Reproductive Organ ◽  
Recessive Mutation ◽  
Homeotic Genes ◽  
Organ Identity ◽  
Quadruple Mutant ◽  
Normal Spacing ◽  
Floral Homeotic

Reproductive organ identity in Arabidopsis is controlled by the B, C and SEPALLATA classes of floral homeotic genes. We have identified a recessive mutation in a novel gene, HUA ENHANCER2, which, when combined with mutations in two weak class C genes, HUA1 and HUA2, leads to the production of third whorl sepal-petal-stamens and fourth whorl sepal-carpels. Quadruple mutant analysis and in situ localization of A, B, C and SEPALLATA floral homeotic RNAs suggest that HUA ENHANCER2 is required for the maintenance of B and C gene expression in the reproductive whorls. In addition to its role in floral homeotic gene expression, HUA ENHANCER2 is required for normal spacing and number of perianth organ primordia. We show that HUA ENHANCER2 encodes a putative DExH-box RNA helicase that is expressed in specific patterns in the inflorescence meristem and developing flowers. As a possible ortholog of the yeast exosome-associated protein, Dob1p (Mtr4p), HUA ENHANCER2 may affect floral organ spacing and identity through the regulation of protein synthesis or mRNA degradation. Therefore, our studies on HUA ENHANCER2 not only demonstrate that B and C gene expression is established and maintained separately, but also implicate the existence of post-transcriptional mechanisms in the maintenance of B and C gene expression.

scholarly journals AINTEGUMENTA and AINTEGUMENTA-LIKE6 directly regulate floral homeotic and growth genes in young flowers

2020 ◽  
Author(s):  
Beth A. Krizek ◽  
Alexis T. Bantle ◽  
Jorman M. Heflin ◽  
Han Han ◽  
Nowlan H. Freese ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Binding Sites ◽  
Floral Organ ◽  
Homeotic Genes ◽  
Flower Primordia ◽  
Floral Organ Identity ◽  
Floral Organogenesis ◽  
Floral Homeotic Genes ◽  
Organ Identity ◽  
Floral Homeotic

AbstractArabidopsis flower primordia give rise to floral organ primordia in stereotypical positions within four concentric whorls. Floral organ primordia in each whorl undergo distinct developmental programs to become one of four organ types (sepals, petals, stamens, and carpels). The Arabidopsis transcription factors AINTEGUMENTA (ANT) and AINTEGUMENTA-LIKE6 (AIL6) play critical and partially overlapping roles during floral organogenesis. They are required for correct positioning of floral organ initiation, contribute to the specification of floral organ identity, and regulate the growth and morphogenesis of developing floral organs. To gain insight into the molecular means by which ANT and AIL6 contribute to floral organogenesis, we identified the genome-wide binding sites of both ANT and AIL6 in stage 3 flower primordia, the developmental stage at which sepal primordia become visible and class B and C floral homeotic genes are first expressed. AIL6 binds to a subset of ANT sites, suggesting that AIL6 regulates some but not all of the same target genes as ANT. ANT and AIL6 binding sites are associated with genes involved in many biological processes related to meristem and flower organ development. Comparison of genes associated with both ANT and AIL6 ChIP-Seq peaks and those differentially expressed after perturbation of ANT or AIL6 activity identified likely direct targets of ANT and AIL6 regulation. These include the floral homeotic genes APETALA3 (AP3) and AGAMOUS (AG) and four growth regulatory genes: BIG BROTHER (BB), ROTUNDIFOLIA3 (ROT3), ANGUSTIFOLIA3/GRF INTERACTING FACTOR (AN3/GIF1), and XYLOGLUCAN ENDOTRANSGLUCOLSYLASE/HYDROLASE9 (XTH9).One Sentence SummaryThe transcription factors ANT and AIL6 directly regulate genes involved in different aspects of flower development including genes that specify floral organ identity and those that regulate growth.

scholarly journals SUPERMAN, a regulator of floral homeotic genes in Arabidopsis

Development ◽  
1992 ◽  
Vol 114 (3) ◽  
pp. 599-615 ◽  
Author(s):  
J.L. Bowman ◽  
H. Sakai ◽  
T. Jack ◽  
D. Weigel ◽  
U. Mayer ◽  
...  
Keyword(s):  
Gene Product ◽  
Expression Patterns ◽  
Floral Organ ◽  
Homeotic Genes ◽  
Wild Type ◽  
Floral Homeotic Genes ◽  
Mature Flower ◽  
Organ Identity ◽  
Superman Gene ◽  
Floral Homeotic

We describe a locus, SUPERMAN, mutations in which result in extra stamens developing at the expense of the central carpels in the Arabidopsis thaliana flower. The development of superman flowers, from initial primordium to mature flower, is described by scanning electron microscopy. The development of doubly and triply mutant strains, constructed with superman alleles and previously identified homeotic mutations that cause alterations in floral organ identity, is also described. Essentially additive phenotypes are observed in superman agamous and superman apetala2 double mutants. The epistatic relationships observed between either apetala3 or pistillata and superman alleles suggest that the SUPERMAN gene product could be a regulator of these floral homeotic genes. To test this, the expression patterns of AGAMOUS and APETALA3 were examined in superman flowers. In wild-type flowers, APETALA3 expression is restricted to the second and third whorls where it is required for the specification of petals and stamens. In contrast, in superman flowers, APETALA3 expression expands to include most of the cells that would normally constitute the fourth whorl. This ectopic APETALA3 expression is proposed to be one of the causes of the development of the extra stamens in superman flowers. The spatial pattern of AGAMOUS expression remains unaltered in superman flowers as compared to wild-type flowers. Taken together these data indicate that one of the functions of the wild-type SUPERMAN gene product is to negatively regulate APETALA3 in the fourth whorl of the flower. In addition, superman mutants exhibit a loss of determinacy of the floral meristem, an effect that appears to be mediated by the APETALA3 and PISTILLATA gene products.

OsMADS32 Regulates Rice Floral Patterning through Interactions with Multiple Floral Homeotic Genes

2020 ◽  
Author(s):  
Yun Hu ◽  
Li Wang ◽  
Ru Jia ◽  
Wanqi Liang ◽  
Xuelian Zhang ◽  
...  
Keyword(s):  
Flower Development ◽  
Floral Organ ◽  
Floral Meristem ◽  
Homeotic Genes ◽  
Dependent Manner ◽  
Floral Meristem Identity ◽  
Floral Homeotic Genes ◽  
Organ Identity ◽  
Meristem Identity ◽  
Floral Homeotic

Abstract Floral patterning is regulated by intricate networks of floral identity genes. The peculiar MADS32 subfamily genes, absent in eudicots but prevalent in monocots, regulate floral organ identity. However, how the MADS32 family genes interact with other floral homeotic genes during flower development is mostly unknown. 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. Furthermore, our results indicate important roles of OsMADS32 in defining stamen, pistil and ovule development through physical and genetic interactions with OsMADS1, OsMADS58 and OsMADS13, and in specifying floral meristem identity with OsMADS6, OsMADS3 and OsMADS58 respectively. Our findings suggest that OsMADS32 is an important factor for floral meristem identity maintenance and that it integrates the action of other MADS-box homeotic proteins to sustain floral organ specification and development in rice. Given that OsMADS32 is an orphan gene and absent in eudicots, our data substantially expand our understanding of flower development in plants.

scholarly journals Pitfall Flower Development and Organ Identity of Ceropegia sandersonii (Apocynaceae-Asclepiadoideae)

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1767
Author(s):  
Annemarie Heiduk ◽  
Dewi Pramanik ◽  
Marlies Spaans ◽  
Loes Gast ◽  
Nemi Dorst ◽  
...  
Keyword(s):  
Gene Expression ◽  
Floral Anatomy ◽  
Floral Organ ◽  
Mads Box ◽  
Floral Organs ◽  
Abcde Model ◽  
Organ Identity ◽  
Mads Box Gene ◽  
Flower Evolution ◽  
Developmental Phases

Deceptive Ceropegia pitfall flowers are an outstanding example of synorganized morphological complexity. Floral organs functionally synergise to trap fly-pollinators inside the fused corolla. Successful pollination requires precise positioning of flies headfirst into cavities at the gynostegium. These cavities are formed by the corona, a specialized organ of corolline and/or staminal origin. The interplay of floral organs to achieve pollination is well studied but their evolutionary origin is still unclear. We aimed to obtain more insight in the homology of the corona and therefore investigated floral anatomy, ontogeny, vascularization, and differential MADS-box gene expression in Ceropegia sandersonii using X-ray microtomography, Light and Scanning Electronic Microscopy, and RT-PCR. During 10 defined developmental phases, the corona appears in phase 7 at the base of the stamens and was not found to be vascularized. A floral reference transcriptome was generated and 14 MADS-box gene homologs, representing all major MADS-box gene classes, were identified. B- and C-class gene expression was found in mature coronas. Our results indicate staminal origin of the corona, and we propose a first ABCDE-model for floral organ identity in Ceropegia to lay the foundation for a better understanding of the molecular background of pitfall flower evolution in Apocynaceae.

scholarly journals Rice MADS6 Interacts with the Floral Homeotic Genes SUPERWOMAN1, MADS3, MADS58, MADS13, and DROOPING LEAF in Specifying Floral Organ Identities and Meristem Fate

2011 ◽  
Vol 23 (7) ◽  
pp. 2536-2552 ◽  
Author(s):  
Haifeng Li ◽  
Wanqi Liang ◽  
Yun Hu ◽  
Lu Zhu ◽  
Changsong Yin ◽  
...  
Keyword(s):  
Floral Organ ◽  
Homeotic Genes ◽  
Floral Homeotic Genes ◽  
Floral Homeotic

scholarly journals Interactions between FLORAL ORGAN NUMBER4 and floral homeotic genes in regulating rice flower development

2017 ◽  
Vol 68 (3) ◽  
pp. 483-498 ◽  
Author(s):  
Wei Xu ◽  
Juhong Tao ◽  
Mingjiao Chen ◽  
Ludovico Dreni ◽  
Zhijing Luo ◽  
...  
Keyword(s):  
Flower Development ◽  
Floral Organ ◽  
Homeotic Genes ◽  
Floral Homeotic Genes ◽  
Floral Homeotic

scholarly journals Epidermal control of floral organ identity by class B homeotic genes in Antirrhinum and Arabidopsis

Development ◽  
2001 ◽  
Vol 128 (14) ◽  
pp. 2661-2671
Author(s):  
Nadia Efremova ◽  
Marie-Christine Perbal ◽  
Alexander Yephremov ◽  
Winfried A. Hofmann ◽  
Heinz Saedler ◽  
...  
Keyword(s):  
Transgene Expression ◽  
Transgenic Arabidopsis ◽  
Cell Communication ◽  
Cell Types ◽  
Floral Organ ◽  
Epidermal Differentiation ◽  
Homeotic Genes ◽  
Organ Identity ◽  
Class B ◽  
Functional Homologues

To assess the contribution of the epidermis to the control of petal and stamen organ identity, we have used transgenic Antirrhinum and Arabidopsis plants that expressed the Antirrhinum class B homeotic transcription factors DEFICIENS (DEF) and GLOBOSA (GLO) in the epidermis. Transgene expression was controlled by the ANTIRRHINUM FIDDLEHEAD (AFI) promoter, which directs gene expression to the L1 meristematic layer and, later, to the epidermis of differentiating organs. Transgenic epidermal DEF and GLO chimeras display similar phenotypes, suggesting similar epidermal contributions by the two class B genes in Antirrhinum. Epidermal B function autonomously controls the differentiation of Antirrhinum petal epidermal cell types, but cannot fully control the pattern of cell divisions and the specification of sub-epidermal petal cell-identity by epidermal signalling. This non-autonomous control is enhanced if the endogenous class B genes can be activated from the epidermis. The developmental influence of epidermal B function in Antirrhinum stamen development is very limited. In contrast, epidermal B function in Arabidopsis can control most if not all epidermal and sub-epidermal differentiation events in petals and stamens, without any contribution from the endogenous class B genes. Possible reasons for differences in the efficacy of B-function-mediated cell communication between the two species are discussed. Interestingly, our experiments uncovered partial incompatibility between class B functional homologues. Although the DEFICIENS/PISTILLATA heterodimer is functional in transgenic Arabidopsis plants, the APETALA3/GLOBOSA heterodimer is not.

Control of floral homeotic gene expression and organ morphogenesis in Antirrhinum

Development ◽  
1998 ◽  
Vol 125 (13) ◽  
pp. 2359-2369
Author(s):  
P.C. McSteen ◽  
C.A. Vincent ◽  
S. Doyle ◽  
R. Carpenter ◽  
E.S. Coen
Keyword(s):  
Gene Expression ◽  
Floral Organ ◽  
Reproductive Organs ◽  
Floral Meristem ◽  
Homeotic Gene ◽  
Loss Of Function ◽  
Organ Identity ◽  
Underlying Mechanisms ◽  
Reduced Rate ◽  
Homeotic Gene Expression

The development of reproductive organs in Antirrhinum depends on the expression of an organ identity gene, plena, in the central domain of the floral meristem. To investigate the mechanism by which plena is regulated, we have characterised three mutants in which the pattern of plena expression is altered. In polypetala mutants, expression of plena is greatly reduced, resulting in a proliferation of petals in place of reproductive organs. In addition, polypetala mutants exhibit an altered pattern of floral organ initiation, quite unlike that seen in loss-of-function plena mutants. This suggests that polypetala normally has two roles in flower development: regulation of plena and control of organ primordia formation. In fistulata mutants, plena is ectopically expressed in the distal domain of petal primordia, resulting in the production of anther-like tissue in place of petal lobes. Flowers of fistulata mutants also show a reduced rate of petal lobe growth, even in a plena mutant background. This implies that fistulata normally has two roles in the distal domain of petal primordia: inhibition of plena expression and promotion of lobe growth. A weak allele of the floral meristem identity gene, floricaula, greatly enhances the effect of fistulata on plena expression, showing that floricaula also plays a role in repression of plena in outer whorls. Taken together, these results show that genes involved in plena regulation have additional roles in the formation of organs, perhaps reflecting underlying mechanisms for coupling homeotic gene expression to morphogenesis.

scholarly journals Molecular Evolution of Genes Controlling Petal and Stamen Development: Duplication and Divergence Within the APETALA3 and PISTILLATA MADS-Box Gene Lineages

Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 765-783 ◽  
Author(s):  
Elena M Kramer ◽  
Robert L Dorit ◽  
Vivian F Irish
Keyword(s):  
Morphological Evolution ◽  
Floral Organ ◽  
Duplication Event ◽  
Homeotic Genes ◽  
Mads Box ◽  
Floral Organ Identity ◽  
Organ Identity ◽  
Duplication Events ◽  
Mads Box Gene ◽  
Dicot Species

Abstract The specification of floral organ identity in the higher dicots depends on the function of a limited set of homeotic genes, many of them members of the MADS-box gene family. Two such genes, APETALA3 (AP3) and PISTILLATA (PI), are required for petal and stamen identity in Arabidopsis; their orthologs in Antirrhinum exhibit similar functions. To understand how changes in these genes may have influenced the morphological evolution of petals and stamens, we have cloned twenty-six homologs of the AP3 and PI genes from two higher eudicot and eleven lower eudicot and magnolid dicot species. The sequences of these genes reveal the presence of characteristic PI- and AP3-specific motifs. While the PI-specific motif is found in all of the PI genes characterized to date, the lower eudicot and magnolid dicot AP3 homologs contain distinctly different motifs from those seen in the higher eudicots. An analysis of all the available AP3 and PI sequences uncovers multiple duplication events within each of the two gene lineages. A major duplication event in the AP3 lineage coincides with the base of the higher eudicot radiation and may reflect the evolution of a petal-specific AP3 function in the higher eudicot lineage.

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