Separation of AG function in floral meristem determinacy from that in reproductive organ identity by expressing antisense AG RNA

1995 ◽  
Vol 28 (5) ◽  
pp. 767-784 ◽  
Author(s):  
Yukiko Mizukami ◽  
Hong Ma
Keyword(s):  
Reproductive Organ ◽  
Floral Meristem ◽  
Organ Identity

scholarly journals Mutations in the PERIANTHIA gene of Arabidopsis specifically alter floral organ number and initiation pattern

Development ◽  
1996 ◽  
Vol 122 (4) ◽  
pp. 1261-1269 ◽  
Author(s):  
M.P. Running ◽  
E.M. Meyerowitz
Keyword(s):  
Floral Organ ◽  
Floral Meristem ◽  
Wild Type ◽  
Organ Identity ◽  
The Family ◽  
Dividing Cells ◽  
Meristem Identity ◽  
Plant Families ◽  
Open Question ◽  
Floral Organ Identity Genes

An open question in developmental biology is how groups of dividing cells can generate specific numbers of segments or organs. We describe the phenotypic effects of mutations in PERIANTHIA, a gene specifically required for floral organ patterning in Arabidopsis thaliana. Most wild-type Arabidopsis flowers have 4 sepals, 4 petals, 6 stamens, and 2 carpels. Flowers of perianthia mutant plants most commonly show a pentamerous pattern of 5 sepals, 5 petals 5 stamens, and 2 carpels. This pattern is characteristic of flowers in a number of plant families, but not in the family Brassicaceae, which includes Arabidopsis. Unlike previously described mutations affecting floral organ number, perianthia does not appear to affect apical or floral meristem sizes, nor is any other aspect of vegetative or floral development severely affected. Floral organs in perianthia arise in a regular, stereotypical pattern similar to that in distantly related species with pentamerous flowers. Genetic analysis shows that PERIANTHIA acts downstream of the floral meristem identity genes and independently of the floral meristem size and floral organ identity genes in establishing floral organ initiation patterns. Thus PERIANTHIA acts in a previously unidentified process required for organ patterning in Arabidopsis flowers.

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.

PpAG1, a homolog of AGAMOUS, expressed in developing peach flowers and fruit

2006 ◽  
Vol 84 (5) ◽  
pp. 767-776 ◽  
Author(s):  
Teresa Martin ◽  
Ming Hu ◽  
Hélène Labbé ◽  
Sylvia McHugh ◽  
Antonet Svircev ◽  
...  
Keyword(s):  
Prunus Persica ◽  
Single Gene ◽  
Floral Organ ◽  
Floral Meristem ◽  
35S Promoter ◽  
Mads Box ◽  
Specific Expression ◽  
Organ Identity ◽  
Constitutive Overexpression ◽  
Mads Box Gene

MADS-box transcription factors are known to play a central role in floral organ identity and floral meristem determinacy in many gymnosperms and angiosperms. Studies of this nature are limited in fruit tree species despite the economic importance of this group. A peach ( Prunus persica (L.) Batsch) gene, PpAG1, was isolated and shown to be homologous to the Arabidopsis thaliana (L.) Heynh. MADS-box gene AGAMOUS (AG). It is a single gene in peach and codes for a type II or MIKC-type MADS-box protein. The features of the deduced protein sequence indicate that it is similar to other AG homologs from woody plant species. The spatial and developmental patterns of expression parallel those of AG and homologs from other angiosperms with similar floral structures but with some minor differences. In the floral meristem, where AG is responsible for conversion of the vegetative meristem into the floral meristem, the differentiation of the whorls that generate the carpels and stamens coincides with the tissue-specific expression of PpAG1. It continues to be expressed in the ovules, developing fruit and seeds that subsequently develop from the carpels. Constitutive overexpression of PpAG1 in Arabidopsis, using the 35S promoter, caused the homeotic conversion of sepals to carpelloid tissues and altered petal development. This is consistent with C-function genes according to the ABC model of flower development. The data support the conclusion that PpAG1 is the peach homolog of Arabidopsis AG.

scholarly journals Functional Analysis of All AGAMOUS Subfamily Members in Rice Reveals Their Roles in Reproductive Organ Identity Determination and Meristem Determinacy

2011 ◽  
Vol 23 (8) ◽  
pp. 2850-2863 ◽  
Author(s):  
Ludovico Dreni ◽  
Alessandro Pilatone ◽  
Dapeng Yun ◽  
Stefano Erreni ◽  
Alice Pajoro ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Reproductive Organ ◽  
Organ Identity

scholarly journals Proliferating Floral Organs (Pfo ), a Lotus japonicus gene required for specifying floral meristem determinacy and organ identity, encodes an F-box protein

2003 ◽  
Vol 33 (4) ◽  
pp. 607-619 ◽  
Author(s):  
Shulu Zhang ◽  
Niels Sandal ◽  
Patricia L. Polowick ◽  
Jiri Stiller ◽  
Jens Stougaard ◽  
...  
Keyword(s):  
Lotus Japonicus ◽  
Floral Meristem ◽  
Floral Organs ◽  
Organ Identity ◽  
F Box Protein

scholarly journals The movement of a leaf-derived mobile AGL24 mRNA specifies floral organ identity in Arabidopsis

2020 ◽  
Author(s):  
Nien-Chen Huang ◽  
Huan-Chi Tien ◽  
Tien-Shin Yu
Keyword(s):  
Plant Development ◽  
Developmental Plasticity ◽  
Protein Translation ◽  
Floral Organ ◽  
Floral Meristem ◽  
Long Distance ◽  
Floral Organ Identity ◽  
Organ Identity ◽  
Meristem Identity

AbstractCell-to-cell and inter-organ communication play pivotal roles in synchronizing and coordinating plant development. In addition to serving as templates for protein translation within cells, many mRNAs can move and exert their function non-cell-autonomously. However, because the proteins encoded by some mobile mRNAs are also mobile, whether the systemic function of mobile mRNAs is attributed to proteins transported distally or translated locally remains controversial. Here, we show that Arabidopsis AGAMOUS-LIKE 24 (AGL24) mRNA acts as a leaf-derived signal to specify meristem identity. AGL24 is expressed in both apex and leaves. Upon floral meristem (FM) transition, apex-expressed AGL24 is transcriptionally inhibited by APETALA1 (AP1) to ensure FM differentiation. The leaf-expressed AGL24 can act as a mobile signal to bypass AP1 inhibition and revert FM differentiation. Although AGL24 mRNA is expressed in leaves, AGL24 protein is rapidly degraded in leaves. In contrast, AGL24 mRNA can move long distance from leaf to apex where the translocated AGL24 mRNAs can be used as templates to translate into proteins. Thus, the movement of AGL24 mRNA can provide the developmental plasticity to fit with environmental dynamics.

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 Expression of KNUCKLES in the Stem Cell Domain Is Required for Its Function in the Control of Floral Meristem Activity in Arabidopsis

2021 ◽  
Vol 12 ◽  
Author(s):  
Kamila Kwaśniewska ◽  
Caoilfhionn Breathnach ◽  
Christina Fitzsimons ◽  
Kevin Goslin ◽  
Bennett Thomson ◽  
...  
Keyword(s):  
Stem Cell ◽  
Regulatory Gene ◽  
Cell Activity ◽  
Floral Organ ◽  
Floral Meristem ◽  
Perturbation Approach ◽  
Expression Domain ◽  
Organ Identity ◽  
Early Expression ◽  
Floral Meristems

In the model plant Arabidopsis thaliana, the zinc-finger transcription factor KNUCKLES (KNU) plays an important role in the termination of floral meristem activity, a process that is crucial for preventing the overgrowth of flowers. The KNU gene is activated in floral meristems by the floral organ identity factor AGAMOUS (AG), and it has been shown that both AG and KNU act in floral meristem control by directly repressing the stem cell regulator WUSCHEL (WUS), which leads to a loss of stem cell activity. When we re-examined the expression pattern of KNU in floral meristems, we found that KNU is expressed throughout the center of floral meristems, which includes, but is considerably broader than the WUS expression domain. We therefore hypothesized that KNU may have additional functions in the control of floral meristem activity. To test this, we employed a gene perturbation approach and knocked down KNU activity at different times and in different domains of the floral meristem. In these experiments we found that early expression in the stem cell domain, which is characterized by the expression of the key meristem regulatory gene CLAVATA3 (CLV3), is crucial for the establishment of KNU expression. The results of additional genetic and molecular analyses suggest that KNU represses floral meristem activity to a large extent by acting on CLV3. Thus, KNU might need to suppress the expression of several meristem regulators to terminate floral meristem activity efficiently.

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