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.

Contrasting Evolutionary Forces in theArabidopsis thalianaFloral Developmental Pathway

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1641-1650 ◽  
Author(s):  
Kenneth M Olsen ◽  
Andrew Womack ◽  
Ashley R Garrett ◽  
Jane I Suddith ◽  
Michael D Purugganan
Keyword(s):  
Floral Organ ◽  
Regulatory Genes ◽  
Coding Region ◽  
Developmental Pathway ◽  
Evolutionary Forces ◽  
Coding Regions ◽  
Organ Identity ◽  
Meristem Identity ◽  
Floral Organ Identity Genes ◽  
Population Genetic Analyses

AbstractThe floral developmental pathway in Arabidopsis thaliana is composed of several interacting regulatory genes, including the inflorescence architecture gene TERMINAL FLOWER1 (TFL1), the floral meristem identity genes LEAFY (LFY), APETALA1 (AP1), and CAULIFLOWER (CAL), and the floral organ identity genes APETALA3 (AP3) and PISTILLATA (PI). Molecular population genetic analyses of these different genes indicate that the coding regions of AP3 and PI, as well as AP1 and CAL, share similar levels and patterns of nucleotide diversity. In contrast, the coding regions of TFL1 and LFY display a significant reduction in nucleotide variation, suggesting that these sequences have been subjected to a recent adaptive sweep. Moreover, the promoter of TFL1, unlike its coding region, displays high levels of diversity organized into two distinct haplogroups that appear to be maintained by selection. These results suggest that patterns of molecular evoution differ among regulatory genes in this developmental pathway, with the earlier acting genes exhibiting evidence of adaptive evolution.

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.

Induction of "filamentous structures" in wild type Antirrhinum majus flowers by benzylaminopurine

1998 ◽  
Vol 76 (11) ◽  
pp. 1828-1834
Author(s):  
Laureen M Blahut-Beatty ◽  
Peta C Bonham-Smith ◽  
Vipen K Sawhney
Keyword(s):  
Floral Organ ◽  
Distal Portion ◽  
Antirrhinum Majus ◽  
Basal Region ◽  
Wild Type ◽  
Dorsal Region ◽  
Organ Identity ◽  
Specific Factors ◽  
Or Genes ◽  
Floral Organ Identity Genes

The cytokinin, N6-benzylaminopurine (BAP), when applied to young inflorescences of wild-type Antirrhinum majus L., resulted in the formation of chimeric "filamentous structures" in the dorsal region of the third whorl, the position where a stamen primordium is suppressed in wild-type flowers. In addition, BAP induced similar filamentous structures in between the first and second whorls, and this response was concentration dependent. The basal region of the filamentous structures was similar to the filament of a stamen, while the distal portion resembled a petal. These observations suggest that cytokinins may be site-specific factors involved in the regulation of floral organ identity genes or genes that control floral symmetry, i.e., the CYCLOIDEA gene.Key words: Antirrhinum, benzylaminopurine, cytokinin, filament, floral genes, staminode.

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.

The WUSCHEL gene is required for shoot and floral meristem integrity in Arabidopsis

Development ◽  
1996 ◽  
Vol 122 (1) ◽  
pp. 87-96 ◽  
Author(s):  
T. Laux ◽  
K.F. Mayer ◽  
J. Berger ◽  
G. Jurgens
Keyword(s):  
Developmental Stages ◽  
Shoot Meristem ◽  
Wild Type ◽  
Recessive Mutations ◽  
Organ Identity ◽  
Flat Structures ◽  
Meristem Identity ◽  
Wus Gene ◽  
Floral Meristems ◽  
Shoot Meristems

Self perpetuation of the shoot meristem is essential for the repetitive initiation of shoot structures during plant development. In Arabidopsis shoot meristem maintenance is disrupted by recessive mutations in the WUSCHEL (WUS) gene. The defect is evident at all developmental stages and is restricted to shoot and floral meristems, whereas the root meristem is not affected. wus mutants fail to properly organize a shoot meristem in the embryo. Postembryonically, defective shoot meristems are initiated repetitively but terminate prematurely in aberrant flat structures. In contrast to wild-type shoot meristems, primordia initiation occurs ectopically across mutant apices, including the center, and often new shoot meristems instead of organs are initiated. The cells of wus shoot apices are larger and more vacuolated than wild-type shoot meristem cells. wus floral meristems terminate prematurely in a central stamen. Double mutant studies indicate that the number of organ primordia in the center of wus flowers is limited, irrespective of organ identity and we propose that meristem cells are allocated into floral whorl domains in a sequential manner. WUS activity also appears to be required for the formation of supernumerary organs in the center of agamous, superman or clavata1 flowers, suggesting that the WUS gene acts upstream of the corresponding genes. Our results suggest that the WUS gene is specifically required for central meristem identity of shoot and floral meristems to maintain their structural and functional integrity.

scholarly journals Phytoplasma-Induced Floral Abnormalities in Catharanthus roseus Are Associated with Phytoplasma Accumulation and Transcript Repression of Floral Organ Identity Genes

2011 ◽  
Vol 24 (12) ◽  
pp. 1502-1512 ◽  
Author(s):  
Yi-Ting Su ◽  
Jen-Chih Chen ◽  
Chan-Pin Lin
Keyword(s):  
Plant Pathogens ◽  
Chalcone Synthase ◽  
Floral Development ◽  
Transcript Abundance ◽  
Floral Organ ◽  
Organ Identity ◽  
Leaf Yellowing ◽  
Or Gene ◽  
Highly Correlated ◽  
Floral Organ Identity Genes

Floral symptoms caused by phytoplasma largely resemble floral reversion in other plants. Periwinkle leaf yellowing (PLY) phytoplasma and peanut witches'-broom (PnWB) phytoplasma caused different degrees of floral abnormalities on infected periwinkle plants. The PLY phytoplasma-infected plants exhibited floral discoloration, virescence, small flowers, and only occasionally full floral reversion. In contrast, PnWB phytoplasma frequently induced complete floral reversion and resulted in a witches'-broom symptom from the floral reversion. Although different degrees of floral symptoms were induced by these two phytoplasmas, the morphological disorders were similar to those of other plants carrying SEPALLATA mutations or gene silencing. Here, we compared expression levels of organ-identity-related genes and pigmentation genes during floral symptom development. Accumulation of phytoplasmas in malformed flowers and their closely surrounding leaves was also compared. In infected plants, transcript abundance of all examined organ identity genes and pigmentation genes was suppressed. Indeed, CrSEP3, a SEPALLALA3 ortholog, showed the greatest suppression among genes examined. Of the pigmentation genes, transcript reduction of chalcone synthase was most highly correlated with the loss in floral pigmentation. Floral symptom severities were associated with the accumulation of either phytoplasmas. Interestingly, both phytoplasmas accumulated to higher levels in malformed flowers than in their surrounding leaves. Many plant pathogens manipulate host plant development to their advantage. It is intriguing to see whether phytoplasmas alter floral development to increase their population.

Floral organ initiation and development in wild-type Arabidopsis thaliana (Brassicaceae) and in the organ identity mutants apetala2-1 and agamous-1

1994 ◽  
Vol 72 (3) ◽  
pp. 384-401 ◽  
Author(s):  
Wilson Crone ◽  
Elizabeth M. Lord
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Division ◽  
Key Words ◽  
Floral Organ ◽  
Tissue Differentiation ◽  
Main Stem ◽  
Wild Type ◽  
Cell Numbers ◽  
Organ Identity ◽  
Component Cell

The flowers of Arabidopsis thaliana (Brassicaceae) were examined for histological events during organ initiation and later development. An inflorescence floral plastochron of the main stem raceme was used as a basis for the timing and staging of developmental events. Sepals, petals, stamens, and carpels in wild-type Landsberg erecta Arabidopsis are distinguishable as primordia in terms of cell division events associated with initiation, size, and component cell numbers. Flower organogenesis in the organ identity (homeotic) mutants apetala2-1 and agamous-1 was compared with that of the wild type. In both mutants, each whorl of floral organs initiates much like the wild type and only subsequently produces visibly altered organs with mosaic features. The flower organ identity mutants achieve their mature phenotypes by alterations in tissue differentiation that occur after initiation and early primordial development. Key words: Arabidopsis, apetala2-1, agamous-1, plastochron, homeosis, flower.

scholarly journals DEGENERATED LEMMA (DEL) Is a New Allele of OsRDR6 That Regulates Lemma Development and Affects Rice Grain Yield

2022 ◽  
Author(s):  
Jing You ◽  
Qiannan Duan ◽  
Jun Zhang ◽  
Wenqiang Shen ◽  
Yue Zhou ◽  
...  
Keyword(s):  
Grain Yield ◽  
Nucleotide Substitution ◽  
Floral Organ ◽  
Rice Grain ◽  
Amino Acid Mutation ◽  
Single Nucleotide ◽  
Organ Identity ◽  
Floral Organ Identity Genes ◽  
Seed Setting Rate ◽  
1000 Grain Weight

Abstract The lemma and palea are floral organ structures unique to grasses, and their development affects grain size. However, information on the molecular mechanism of lemma development is limited. In this study, we investigated a rice spikelet mutant, degenerated lemma (del), which developed florets with a slightly degenerated or rod-like lemma. The results indicate that the mutation of the DEL gene interfered with lemma development. In addition, del also showed a significant reduction in grain length and width, seed setting rate, and 1000-grain weight, which led to a reduction in yield. The results indicate that the mutation of the DEL gene further affects rice grain yield. Map-based cloning shows a single-nucleotide substitution from T to A within Os01g0527600/DEL, causing an amino acid mutation of Leu-34 to His-34 in the del mutant. DEL is an allele of OsRDR6, encoding the RNA-dependent RNA polymerase 6, and is highly expressed in the spikelet. RT-qPCR results show that the expression of some floral organ identity genes was changed, which indicates that the DEL gene regulates lemma development by modulating the expression of these genes. The present results suggest that DEL plays an important role in lemma development and rice grain yield.

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