Control of flower development in Arabidopsis thaliana by APETALA1 and interacting genes

Mutations in the APETALA1 gene disturb two phases of flower development, flower meristem specification and floral organ specification. These effects become manifest as a partial conversion of flowers into inflorescence shoots and a disruption of sepal and petal development. We describe the changes in an allelic series of nine apetala1 mutants and show that the two functions of APETALA1 are separable. We have also studied the interaction between APETALA1 and other floral genes by examining the phenotypes of multiply mutant plants and by in situ hybridization using probes for several floral control genes. The results suggest that the products of APETALA1 and another gene, LEAFY, are required to ensure that primordia arising on the flanks of the inflorescence apex adopt a floral fate, as opposed to becoming an inflorescence shoot. APETALA1 and LEAFY have distinct as well as overlapping functions and they appear to reinforce each other's action. CAULIFLOWER is a newly discovered gene which positively regulates both APETALA1 and LEAFY expression. All functions of CAULIFLOWER are redundant with those of APETALA1. APETALA2 also has an early function in reinforcing the action of APETALA1 and LEAFY, especially if the activity of either is compromised by mutation. After the identity of a flower primordium is specified, APETALA1 interacts with APETALA2 in controlling the development of the outer two whorls of floral organs.

Download Full-text

Transcriptome-Wide Analyses Provide Insights into Development of the Hedychium Coronarium Flower, Revealing Potential Roles of PTL

10.21203/rs.3.rs-75413/v1 ◽

2020 ◽

Author(s):

Tong Zhao ◽

Alma Piñeyro-Nelson ◽

Qianxia Yu ◽

Xiaoying Hu ◽

Huanfang Liu ◽

...

Keyword(s):

In Situ Hybridization ◽

Flower Development ◽

Molecular Mechanisms ◽

Expression Patterns ◽

Floral Organ ◽

Mrna In Situ Hybridization ◽

Hedychium Coronarium ◽

Organ Identity

Abstract Background:The flower of Hedychium coronarium possesses highly specialized floral organs: a synsepalous calyx, petaloid staminodes and a labellum. The formation of these organs is controlled by two gene categories: floral organ identity genes and organ boundary genes, which may function individually or jointly during flower development. Although the floral organogenesis of H. coronarium has been studied at the morphological level, the underlying molecular mechanisms involved in its floral development still remain poorly understood. In addition, previous works analyzing the role of MADS-box genes in controlling floral organ specification in some Zingiberaceae did not address the molecular mechanisms involved in the formation of particular organ morphologies that emerge later in flower development, such as the synsepalous calyx formed through intercalary growth of adjacent sepals. Results:Here, we used comparative transcriptomics combined with Real-time quantitative PCR and mRNA in situ hybridization to investigate gene expression patterns of ABC-class genes in H. coronarium flowers, as well as the homolog of the organ boundary gene PETAL LOSS (HcPTL). qRT-PCR detection showed that HcAP3 and HcAG were expressed in both the petaloid staminode and the fertile stamen. mRNA in situ hybridization showed that HcPTL was expressed in developing meristems, including cincinnus primordia, floral primordia, common primordia and almost all new initiating floral organ primordia.Conclusions:Our studies found that stamen/petal identity or stamen fertility in H. coronarium was not necessarily correlated with the differential expression of HcAP3 and HcAG. We also found a novel spatio-temporal expression pattern for HcPTL mRNA, suggesting it may have evolved a lineage-specific role in the morphogenesis of the Hedychium flower. Our study provides a new transcriptome reference and a functional hypothesis regarding the role of a boundary gene in organ fusion that should be further addressed through phylogenetic analyzes of this gene, as well as functional studies.

Download Full-text

Spatio-temporal Dynamics of the Patterning of Arabidopsis Flower Meristem

10.1101/2020.12.02.375790 ◽

2020 ◽

Author(s):

José Díaz ◽

Elena R. Álvarez-Buylla

Keyword(s):

Flower Development ◽

Apical Meristem ◽

Temporal Dynamics ◽

Positional Information ◽

Floral Organ ◽

Necessary Condition ◽

Sufficient Condition ◽

Abc Model ◽

Flower Meristem ◽

Spatio Temporal

AbstractThe qualitative model presented in this work recovers the onset of the four fields that correspond to those of each floral organ whorl of Arabidopsis flower, suggesting a mechanism for the generation of the positional information required for the differential expression of the A, B and C identity genes according to the ABC model for organ determination during early stages of flower development. Our model integrates a previous model for the emergence of WUS pattern in the apical meristem, and shows that this pre-pattern is a necessary but not sufficient condition for the posterior information of the four fields predicted by the ABC model. Furthermore, our model predicts that LFY diffusion along the L1 layer of cells is not a necessary condition for the patterning of the floral meristem.

Download Full-text

Floral transcriptomes reveal gene networks in pineapple floral growth and fruit development

Communications Biology ◽

10.1038/s42003-020-01235-2 ◽

2020 ◽

Vol 3 (1) ◽

Cited By ~ 1

Author(s):

Lulu Wang ◽

Yi Li ◽

Xingyue Jin ◽

Liping Liu ◽

Xiaozhuan Dai ◽

...

Keyword(s):

Fruit Development ◽

Gene Networks ◽

Floral Organ ◽

Reproductive Organ ◽

Molecular Networks ◽

Organ Growth ◽

Petal Development ◽

Genomic Resource

AbstractProper flower development is essential for sexual reproductive success and the setting of fruits and seeds. The availability of a high quality genome sequence for pineapple makes it an excellent model for studying fruit and floral organ development. In this study, we sequenced 27 different pineapple floral samples and integrated nine published RNA-seq datasets to generate tissue- and stage-specific transcriptomic profiles. Pairwise comparisons and weighted gene co-expression network analysis successfully identified ovule-, stamen-, petal- and fruit-specific modules as well as hub genes involved in ovule, fruit and petal development. In situ hybridization confirmed the enriched expression of six genes in developing ovules and stamens. Mutant characterization and complementation analysis revealed the important role of the subtilase gene AcSBT1.8 in petal development. This work provides an important genomic resource for functional analysis of pineapple floral organ growth and fruit development and sheds light on molecular networks underlying pineapple reproductive organ growth.

Download Full-text

Procedure for whole mount fluorescence in situ hybridization of interphase nuclei on Arabidopsis thaliana

The Plant Journal ◽

10.1046/j.1365-313x.1994.6010123.x ◽

1994 ◽

Vol 6 (1) ◽

pp. 123-131 ◽

Cited By ~ 17

Author(s):

Serge Bauwens ◽

Katerina Katsanis ◽

Marc Van Montagu ◽

Patrick Van Oostveldt ◽

Gilbert Engler

Keyword(s):

Arabidopsis Thaliana ◽

In Situ Hybridization ◽

Fluorescence In Situ Hybridization ◽

Interphase Nuclei ◽

Whole Mount

Download Full-text

Fibronectin mRNA in the developing glomerular crescent in rabbit antiglomerular basement membrane disease.

Journal of the American Society of Nephrology ◽

10.1681/asn.v5122087 ◽

1995 ◽

Vol 5 (12) ◽

pp. 2087-2090

Author(s):

S P Sady ◽

M Goyal ◽

P E Thomas ◽

B L Wharram ◽

R C Wiggins

Keyword(s):

Wound Healing ◽

In Situ Hybridization ◽

Basement Membrane ◽

Matrix Protein ◽

Crescent Formation ◽

Plasma Phase ◽

Two Phases ◽

Fibronectin Mrna ◽

In Cells

Fibronectin is a multifunctional matrix protein important in wound healing that is markedly increased in glomerular crescents. A previous report established two phases of fibronectin metabolism in crescent formation in an anti-glomerular basement membrane model of crescentic nephritis in the rabbit. Phase I was associated with increased glomerular fibronectin content from plasma. Phase II was associated with increased fibronectin mRNA in glomeruli. To examine the hypothesis that fibronectin is synthesized in the developing crescent, rabbit fibronectin cDNA was cloned, sense and antisense riboprobes were prepared and their specificity under the conditions to be used was validated and in situ hybridization studies were performed in the model. The results showed that the cells in the developing glomerular crescent express an intense fibronectin mRNA signal at Day 7 and that this signal persisted in cells of the crescent at Day 14. This result shows that fibronectin synthesis does indeed take place in cells of the developing crescent in this model and supports the hypothesis that fibronectin may be an important agent regulating crescent formation and fibrosis.

Download Full-text

Genetic analysis of flower development in Arabidopsis thaliana. The ABC model of floral organ identity determination

Key Experiments in Practical Developmental Biology ◽

10.1017/cbo9780511546204.014 ◽

2005 ◽

pp. 143-152

Author(s):

J. L. Riechmann

Keyword(s):

Arabidopsis Thaliana ◽

Genetic Analysis ◽

Flower Development ◽

Floral Organ ◽

Abc Model ◽

Floral Organ Identity ◽

Organ Identity

Download Full-text

Succession of Internal Sulfur Cycles and Sulfur-Oxidizing Bacterial Communities in Microaerophilic Wastewater Biofilms

Applied and Environmental Microbiology ◽

10.1128/aem.71.5.2520-2529.2005 ◽

2005 ◽

Vol 71 (5) ◽

pp. 2520-2529 ◽

Cited By ~ 55

Author(s):

Satoshi Okabe ◽

Tsukasa Ito ◽

Kenichi Sugita ◽

Hisashi Satoh

Keyword(s):

In Situ Hybridization ◽

Sulfur Cycle ◽

Rrna Gene ◽

Second Phase ◽

Sulfate Reducing ◽

Sulfur Oxidizing ◽

Reducing Activity ◽

Two Phases ◽

Microelectrode Measurements

ABSTRACT The succession of sulfur-oxidizing bacterial (SOB) community structure and the complex internal sulfur cycle occurring in wastewater biofilms growing under microaerophilic conditions was analyzed by using a polyphasic approach that employed 16S rRNA gene-cloning analysis combined with fluorescence in situ hybridization, microelectrode measurements, and standard batch and reactor experiments. A complete sulfur cycle was established via S0 accumulation within 80 days in the biofilms in replicate. This development was generally split into two phases, (i) a sulfur-accumulating phase and (ii) a sulfate-producing phase. In the first phase (until about 40 days), since the sulfide production rate (sulfate-reducing activity) exceeded the maximum sulfide-oxidizing capacity of SOB in the biofilms, H2S was only partially oxidized to S0 by mainly Thiomicrospira denitirificans with NO3 − as an electron acceptor, leading to significant accumulation of S0 in the biofilms. In the second phase, the SOB populations developed further and diversified with time. In particular, S0 accumulation promoted the growth of a novel strain, strain SO07, which predominantly carried out the oxidation of S0 to SO4 2− under oxic conditions, and Thiothrix sp. strain CT3. In situ hybridization analysis revealed that the dense populations of Thiothrix (ca. 109 cells cm−3) and strain SO07 (ca. 108 cells cm−3) were found at the sulfur-rich surface (100 μm), while the population of Thiomicrospira denitirificans was distributed throughout the biofilms with a density of ca. 107 to 108 cells cm−3. Microelectrode measurements revealed that active sulfide-oxidizing zones overlapped the spatial distributions of different phylogenetic SOB groups in the biofilms. As a consequence, the sulfide-oxidizing capacities of the biofilms became high enough to completely oxidize all H2S produced by SRB to SO4 2− in the second phase, indicating establishment of the complete sulfur cycle in the biofilms.

Download Full-text

A nucleostemin-like GTPase required for normal apical and floral meristem development in Arabidopsis

Molecular Biology of the Cell ◽

10.1091/mbc.e11-09-0797 ◽

2012 ◽

Vol 23 (8) ◽

pp. 1446-1456 ◽

Cited By ~ 13

Author(s):

Xiaomin Wang ◽

Daniel K. Gingrich ◽

Yunfei Deng ◽

Zonglie Hong

Keyword(s):

Flower Development ◽

Cell Cycle Progression ◽

Floral Organ ◽

Regulatory Proteins ◽

Cycle Progression ◽

New Class ◽

Meristem Development ◽

Promote Cell Cycle Progression ◽

Floral Primordia ◽

Floral Organ Specification

Mammalian nucleostemin (NS) is preferentially expressed in stem cells and acts to promote cell cycle progression. In plants, stem cell activities have to be terminated during flower development, and this process requires the activation of AGAMOUS (AG) gene expression. Here, a nucleostemin-like 1 gene, NSN1, is shown to be required for flower development in Arabidopsis. The NSN1 mRNA was found in the inflorescence meristem and floral primordia, and its protein was localized to the nucleoli. Both heterozygous and homozygous plants developed defective flowers on inflorescences that were eventually terminated by the formation of carpelloid flowers. Overexpression of NSN1 resulted in loss of apical dominance and formation of defective flowers. Expression of the AG gene was found to be up-regulated in nsn1. The carpelloid flower defect of nsn1 was suppressed by the ag mutation in the nsn1 ag double mutant, whereas double mutants of nsn1 apetala2 (ap2) displayed enhanced defective floral phenotypes. These results suggest that in the delicately balanced regulatory network, NSN1 acts to repress AG and plays an additive role with AP2 in floral organ specification. As a midsize nucleolar GTPase, NSN1 represents a new class of regulatory proteins required for flower development in Arabidopsis.

Download Full-text

Characterization of telomeres in Hordeum vulgare chromosomes by in situ hybridization. II. Healed broken chromosomes in telotrisomic 4L and acrotrisomic 4L4S lines

Genome ◽

10.1139/g92-149 ◽

1992 ◽

Vol 35 (6) ◽

pp. 975-980 ◽

Cited By ~ 11

Author(s):

Shaoke Wang ◽

Nora L. V. Lapitan ◽

Marion Roder ◽

Takumi Tsuchiya

Keyword(s):

Arabidopsis Thaliana ◽

In Situ Hybridization ◽

Hordeum Vulgare ◽

Telomeric Sequences ◽

The Absolute ◽

The Cross ◽

The Stability ◽

Different Parts

The ends of barley chromosomes hybridize in situ to the telomeric sequences of Arabidopsis thaliana. It was confirmed that the cross-hybridizing sequences in barley are found at the absolute ends of the chromosomes by exonuclease Bal31 digestion. The Bal31 experiments also indicated that telomere-like sequences do not occur in high copies at interstitial sites in barley. To determine whether healing of broken chromosomes occurred in aneuploid lines of barley containing extra chromosomes with breakages in different parts, in situ hybridization with the A. thaliana telomere on telotrisomic 4L and acrotrisomic 4L4S lines was conducted. Telosome 4L possesses breaks in the centromere and in an interstitial location in the long arm, while acrosome 4L4S possesses interstitial breaks in both long and short arms. In situ hybridization revealed the presence of telomere sequences on both broken ends of telosome 4L and acrosome 4L4S. In telosome 4L, telomere sequences were present even at the broken site of the centromere. These results show that broken ends of barley chromosomes were healed. Such healing may explain the stability of these chromosomes through many generations.Key words: telomere, centromere, telosome, acrosome, acrotrisomic, telotrisomic.

Download Full-text