scholarly journals Maize YABBY drooping leaf genes regulate floret development and floral meristem determinacy

2018 ◽  
Author(s):  
Josh Strable ◽  
Erik Vollbrecht
Keyword(s):  
Natural Variation ◽  
Genetic Interaction ◽  
Expression Patterns ◽  
Floral Organ ◽  
Floral Meristem

AbstractFloret units in cereals produce grain, directly impacting yield. Here we report mutations in the maize CRABS CLAW (CRC) co-orthologs drooping leaf1 (drl1) and drl2 alter the development of ear and tassel florets. Pistillate florets of drl1 ears appear sterile and display ectopic unfused carpels that fail to enclose an expanded nucellus. Staminate florets of drl1 tassels have extra stamens and retain fertile anthers. Natural variation and transposon alleles of drl2 enhance drl1 floret phenotypes by reducing floral meristem (FM) determinacy. The drl paralogs are co-expressed in lateral floral organ primordia, but not within the FM. Together, the expression patterns and indeterminate mutant FMs suggest that the drl genes regulate FM activity and impose meristem determinacy by a non-cell autonomous signal. Genetic interaction analyses of drl mutants with maize floral mutants indicate that the drl genes are required throughout floret development, illustrating their importance for proper floret patterning in maize.

scholarly journals Genetic architecture underlying variation in floral meristem termination in Aquilegia

2021 ◽  
Author(s):  
Ya Min ◽  
Evangeline S. Ballerini ◽  
Molly B. Edwards ◽  
Scott A. Hodges ◽  
Elena M. Kramer
Keyword(s):  
Candidate Genes ◽  
Genetic Architecture ◽  
Expression Patterns ◽  
Cell Activity ◽  
Morphological Diversity ◽  
Floral Organ ◽  
Floral Meristem ◽  
Potential Candidate ◽  
Evolutionary Level ◽  
Trait Locus

Floral organs are produced by floral meristems (FMs), which harbor stem cells in their centers. Since each flower only has a finite number of organs, the stem cell activity of a FM will always terminate at a specific time point, a process termed floral meristem termination (FMT). Variation in the timing of FMT can give rise to floral morphological diversity, but how this process is fine-tuned at a developmental and evolutionary level is poorly understood. Flowers from the genus Aquilegia share identical floral organ arrangement except for stamen whorl numbers (SWN), making Aquilegia a well-suited system for investigation of this process: differences in SWN between species represent differences in the timing of FMT. By crossing A. canadensis and A. brevistyla, quantitative trait locus (QTL) mapping has revealed a complex genetic architecture with seven QTL. We identified potential candidate genes under each QTL and characterized novel expression patterns of select candidate genes using in situ hybridization. To our knowledge, this is the first attempt to dissect the genetic basis of how natural variation in the timing of FMT is regulated and our results provide insight into how floral morphological diversity can be generated at the meristematic level.

scholarly journals Sim2 Mutants Have Developmental Defects Not Overlapping with Those of Sim1 Mutants

2002 ◽  
Vol 22 (12) ◽  
pp. 4147-4157 ◽  
Author(s):  
Eleni Goshu ◽  
Hui Jin ◽  
Rachel Fasnacht ◽  
Mike Sepenski ◽  
Jacques L. Michaud ◽  
...  
Keyword(s):  
Genetic Interaction ◽  
Expression Patterns ◽  
Gene Mutations ◽  
Congenital Scoliosis ◽  
Developmental Defects ◽  
Lung Inflation ◽  
Left And Right ◽  
Temporal And Spatial ◽  
Cns Midline ◽  
Midline Cells

ABSTRACT The mouse genome contains two Sim genes, Sim1 and Sim2. They are presumed to be important for central nervous system (CNS) development because they are homologous to the Drosophila single-minded (sim) gene, mutations in which cause a complete loss of CNS midline cells. In the mammalian CNS, Sim2 and Sim1 are coexpressed in the paraventricular nucleus (PVN). While Sim1 is essential for the development of the PVN (J. L. Michaud, T. Rosenquist, N. R. May, and C.-M. Fan, Genes Dev. 12:3264-3275, 1998), we report here that Sim2 mutant has a normal PVN. Analyses of the Sim1 and Sim2 compound mutants did not reveal obvious genetic interaction between them in PVN histogenesis. However, Sim2 mutant mice die within 3 days of birth due to lung atelectasis and breathing failure. We attribute the diminished efficacy of lung inflation to the compromised structural components surrounding the pleural cavity, which include rib protrusions, abnormal intercostal muscle attachments, diaphragm hypoplasia, and pleural mesothelium tearing. Although each of these structures is minimally affected, we propose that their combined effects lead to the mechanical failure of lung inflation and death. Sim2 mutants also develop congenital scoliosis, reflected by the unequal sizes of the left and right vertebrae and ribs. The temporal and spatial expression patterns of Sim2 in these skeletal elements suggest that Sim2 regulates their growth and/or integrity.

The PINHEAD/ZWILLE gene acts pleiotropically in Arabidopsis development and has overlapping functions with the ARGONAUTE1 gene

Development ◽  
1999 ◽  
Vol 126 (3) ◽  
pp. 469-481 ◽  
Author(s):  
K. Lynn ◽  
A. Fernandez ◽  
M. Aida ◽  
J. Sedbrook ◽  
M. Tasaka ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Bilateral Symmetry ◽  
Floral Organ ◽  
Axillary Shoot ◽  
Apical Meristems ◽  
Shoot Apical Meristems ◽  
Positional Identity ◽  
Competence Factor ◽  
High Level

Several lines of evidence indicate that the adaxial leaf domain possesses a unique competence to form shoot apical meristems. Factors required for this competence are expected to cause a defect in shoot apical meristem formation when inactivated and to be expressed or active preferentially in the adaxial leaf domain. PINHEAD, a member of a family of proteins that includes the translation factor eIF2C, is required for reliable formation of primary and axillary shoot apical meristems. In addition to high-level expression in the vasculature, we find that low-level PINHEAD expression defines a novel domain of positional identity in the plant. This domain consists of adaxial leaf primordia and the meristem. These findings suggest that the PINHEAD gene product may be a component of a hypothetical meristem forming competence factor. We also describe defects in floral organ number and shape, as well as aberrant embryo and ovule development associated with pinhead mutants, thus elaborating on the role of PINHEAD in Arabidopsis development. In addition, we find that embryos doubly mutant for PINHEAD and ARGONAUTE1, a related, ubiquitously expressed family member, fail to progress to bilateral symmetry and do not accumulate the SHOOT MERISTEMLESS protein. Therefore PINHEAD and ARGONAUTE1 together act to allow wild-type growth and gene expression patterns during embryogenesis.

scholarly journals SlGT11 Controls Floral Organ Patterning and Floral Determinacy in Tomato

2020 ◽  
Author(s):  
Liling Yang ◽  
Shilian Qi ◽  
Arfa touqeer ◽  
Haiyang Li ◽  
Xiaolan Zhang ◽  
...  
Keyword(s):  
Floral Development ◽  
Bulked Segregant Analysis ◽  
Floral Organ ◽  
Fruit Production ◽  
Floral Meristem ◽  
Rnai Silencing ◽  
The Third ◽  
Spatiotemporal Expression ◽  
Higher Temperature ◽  
Floral Determinacy

Abstract Background: Flower development directly affects fruit production in tomato. Despite the framework mediated by ABC genes have been established in Arabidopsis, the spatiotemporal precision of floral development in tomato has not been well examined.Results: Here, we analyzed a novel tomato stamenless like flower (slf) mutant in which the development of stamens and carpels is disturbed, with carpelloid structure formed in the third whorl and ectopic formation of floral and shoot apical meristem in the fourth whorl. Using bulked segregant analysis (BSA), we assigned the causal mutation to the gene Solanum lycopersicum GT11 (SlGT11) that encodes a transcription factor belonging to Trihelix gene family. SlGT11 is expressed in the early stages of the flower and the expression becomes more specific to the primordium position corresponding to stamens and carpels in later stages of the floral development. Further RNAi silencing of SlGT11 verifies the defective phenotypes of the slf mutant. The carpelloid stamen in slf mutant indicates that SlGT11 is required for B-function activity in the third whorl. The failed termination of floral meristem and the occurrence of floral reversion in slf indicate that part of the C-function requires SlGT11 activity in the fourth whorl. Furthermore, we find that at higher temperature, the defects of slf mutant are substantially enhanced, with petals transformed into sepals, all stamens disappeared, and the frequency of ectopic shoot/floral meristem in fourth whorl increased, indicating that SlGT11 functions in the development of the three inner floral whorls. Consistent with the observed phenotypes, it was found that B, C and an E-type MADS-box genes were in part down regulated in slf mutants.Conclusions: Together with the spatiotemporal expression pattern, we suggest that SlGT11 functions in floral organ patterning and maintenance of floral determinacy in tomato.

scholarly journals Polycomb Requires Chaperonin Containing TCP-1 Subunit 7 for Maintaining Gene Silencing in Drosophila

2021 ◽  
Vol 9 ◽  
Author(s):  
Najma Shaheen ◽  
Jawad Akhtar ◽  
Zain Umer ◽  
Muhammad Haider Farooq Khan ◽  
Mahnoor Hussain Bakhtiari ◽  
...  
Keyword(s):  
Genetic Interaction ◽  
Expression Patterns ◽  
Cell Types ◽  
Polycomb Group ◽  
Specific Gene ◽  
Cellular Memory ◽  
Trithorax Group ◽  
T Complex ◽  
Ring Complex ◽  
Active Expression

In metazoans, heritable states of cell type-specific gene expression patterns linked with specialization of various cell types constitute transcriptional cellular memory. Evolutionarily conserved Polycomb group (PcG) and trithorax group (trxG) proteins contribute to the transcriptional cellular memory by maintaining heritable patterns of repressed and active expression states, respectively. Although chromatin structure and modifications appear to play a fundamental role in maintenance of repression by PcG, the precise targeting mechanism and the specificity factors that bind PcG complexes to defined regions in chromosomes remain elusive. Here, we report a serendipitous discovery that uncovers an interplay between Polycomb (Pc) and chaperonin containing T-complex protein 1 (TCP-1) subunit 7 (CCT7) of TCP-1 ring complex (TRiC) chaperonin in Drosophila. CCT7 interacts with Pc at chromatin to maintain repressed states of homeotic and non-homeotic targets of PcG, which supports a strong genetic interaction observed between Pc and CCT7 mutants. Depletion of CCT7 results in dissociation of Pc from chromatin and redistribution of an abundant amount of Pc in cytoplasm. We propose that CCT7 is an important modulator of Pc, which helps Pc recruitment at chromatin, and compromising CCT7 can directly influence an evolutionary conserved epigenetic network that supervises the appropriate cellular identities during development and homeostasis of an organism.

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

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.

scholarly journals Quantitative live-imaging of Aquilegia floral meristems reveals distinct patterns of floral organ initiation and cell-level dynamics of floral meristem termination

2021 ◽  
Author(s):  
Ya Min ◽  
Stephanie J. Conway ◽  
Elena M. Kramer
Keyword(s):  
Cell Division ◽  
Floral Organ ◽  
Live Imaging ◽  
Confocal Imaging ◽  
Floral Meristem ◽  
Flowering Plant ◽  
Molecular Networks ◽  
Floral Organs ◽  
Meristem Development ◽  
Floral Meristems

ABSTRACTIn-depth investigation of any developmental process in plants requires knowledge of both the underpinning molecular networks and how they directly determine patterns of cell division and expansion over time. Floral meristems (FM) produce floral organs, after which they undergo floral meristem termination (FMT), and precise control of organ initiation and FMT is crucial to reproductive success of any flowering plant. Using a live confocal imaging, we characterized developmental dynamics during floral organ primordia initiation and FMT in Aquilegia coerulea (Ranunculaceae). Our results have uncovered distinct patterns of primordium initiation between stamens and staminodes compared to carpels, and provided insight into the process of FMT, which is discernable based on cell division dynamics preceding carpel initiation. To our knowledge, this is the first quantitative live imaging of meristem development in a system with numerous whorls of floral organs as well as an apocarpous gynoecium. This study provides crucial information for our understanding of how the spatial-temporal regulation of floral meristem behavior is achieved in both an evolutionary and developmental context.

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.

scholarly journals Evolutionary transition from degenerate to nonredundant cytokine signaling networks supporting intrathymic T cell development

2019 ◽  
Vol 116 (52) ◽  
pp. 26759-26767
Author(s):  
Divine-Fondzenyuy Lawir ◽  
Isabell Hess ◽  
Katarzyna Sikora ◽  
Norimasa Iwanami ◽  
Iliana Siamishi ◽  
...  
Keyword(s):  
T Cell ◽  
Signaling Pathway ◽  
Genetic Interaction ◽  
Expression Patterns ◽  
T Cell Development ◽  
Cell Development ◽  
Cytokine Signaling ◽  
Cytokine Network ◽  
Immune Disorder ◽  
Mild Reduction

In mammals, T cell development critically depends on the IL-7 cytokine signaling pathway. Here we describe the identification of the zebrafish ortholog of mammalian IL-7 based on chromosomal localization, deduced protein sequence, and expression patterns. To examine the biological role ofil7in teleosts, we generated anil7allele lacking most of its coding exons using CRISPR/Cas9-based mutagenesis.il7-deficient animals are viable and exhibit no obvious signs of immune disorder. With respect to intrathymic T cell development,il7deficiency is associated with only a mild reduction of thymocyte numbers, contrasting with a more pronounced impairment of T cell development inil7r-deficient fish. Genetic interaction studies betweenil7andil7rmutants, andil7andcrlf2(tslpr) mutants suggest the contribution of additional, as-yet unidentified cytokines to intrathymic T cell development. Such activities were also ascertained for other cytokines, such as il2 and il15, collectively indicating that in contrast to the situation in mammals, T cell development in the thymus of teleosts is driven by a degenerate multicomponent network of γccytokines; this explains why deficiencies of single components have little detrimental effect. In contrast, the dependence on a single cytokine in the mammalian thymus has catastrophic consequences in cases of congenital deficiencies in genes affecting the IL-7 signaling pathway. We speculate that the transition from a degenerate to a nonredundant cytokine network supporting intrathymic T cell development emerged as a consequence of repurposing evolutionarily ancient constitutive cytokine pathways for regulatory functions in the mammalian peripheral immune system.

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