scholarly journals Distribution of Arabinogalactan Proteins During Microsporogenesis in the Anther of Bellis Perennis (Asteraceae) L.

2015 ◽  
Vol 56 (2) ◽  
pp. 49-60
Author(s):  
Barbara Chudzik ◽  
Ewa Szczuka ◽  
Barbara Zarzyka ◽  
Agata Leszczuk
Keyword(s):  
Developmental Stages ◽  
Pollen Grains ◽  
Arabinogalactan Proteins ◽  
Arabinogalactan Protein ◽  
Flower Bud ◽  
Somatic Tissues ◽  
Tapetal Cells ◽  
Temporal And Spatial ◽  
Asymmetric Mitosis

Abstract Using monoclonal antibodies (mAbs) JIM13, JIM15 and MAC207, we investigated the temporal and spatial dis-tribution of some arabinogalactan protein (AGP) epitopes in cells of the Bellis perennis L. anther at different developmental stages. AGP epitopes recognized by JIM13 were detected in the protoplasts of tapetal cells, dividing microsporocytes, and microspores; AGP epitopes recognized by JIM15 were present in the cytoplasm of tapetal cells only at the stage with tetrads of microspores in the anther loculus. AGP epitopes recognized by MAC207 were present in the cells of different somatic tissues of the flower bud, but after asymmetric mitosis in the microspore they appeared abundantly in the protoplasts of immature pollen and were still present in mature pollen grains. Callose, revealed by mAb, appeared at the same stage of microsporocyte division as AGPs labelled with JIM13 and JIM15. We discuss the differences in callose and AGP localization and the possible role of the latter during anther development.

scholarly journals GPI-anchoring is required for the proper transport and glycosylation of arabinogalactan protein precursor

2020 ◽  
Author(s):  
Daiki Nagasato ◽  
Yuto Sugita ◽  
Yuhei Tsuno ◽  
Rutsuko Tanaka ◽  
Ken Matsuoka
Keyword(s):  
Fusion Protein ◽  
Culture Medium ◽  
Fluorescent Protein ◽  
Microscopic Analysis ◽  
Arabinogalactan Proteins ◽  
Arabinogalactan Protein ◽  
Coding Region ◽  
Protein Precursor ◽  
Green Fluorescent

AbstractArabinogalactan proteins (AGPs) are extracellular proteoglycans with many O-linked glycan chains. Precursors to many AGPs contain a C-terminal signal for the addition of a GPI-anchor, yet the role of this modification has not been elucidated. NtAGP1, a tobacco precursor to AGP, comprises a signal peptide, an AGP-coding region and a GPI-anchoring signal, and classified as a member of classical AGP. Using green fluorescent protein (GFP) and sweet potato sporamin (SPO) as tags and tobacco BY-2 cells as the host, we analyzed the transport and modification of NtAGP1. The fusion protein of GFP or SPO and NtAGP1 expressed in BY-2 cells migrated as a large smear on SDS-polyacrylamide gel. Confocal microscopic analysis indicated that the GFP and NtAGP1 fusion protein localized to the plasma membrane (PM), and fractionation studies of microsomes indicated that the majority of the fusion protein of SPO and NtAGP1 (SPO-AGP) localized to the PM. In contrast, the expression of mutants without a GPI-anchoring signal yielded several forms, and the largest forms migrating as large smears on the gel were secreted into the culture medium, whereas other forms were recovered in the endomembrane organelles. Comparison of the glycan structures of the SPO-AGP recovered in microsomes and the secreted mutant SPO-AGP without a GPI-anchoring signal using antibodies against AGP glycan epitopes indicated that the glycan structures of these proteins are different. These observations indicated that a GPI-anchoring signal is required for both the proper transport and glycosylation of the AGP precursor.

Analytical Techniques for Determining the Role of Domain of Unknown Function 579 Proteins in the Synthesis of O-Methylated Plant Polysaccharides

2020 ◽  
Vol 25 (4) ◽  
pp. 345-355 ◽  
Author(s):  
Peter J. Smith ◽  
Malcolm A. O’Neill ◽  
Jason Backe ◽  
William S. York ◽  
Maria J Peña ◽  
...  
Keyword(s):  
Unknown Function ◽  
Developmental Stages ◽  
Family Members ◽  
Analytical Techniques ◽  
Arabinogalactan Protein ◽  
Loss Of Function ◽  
Domain Of Unknown Function ◽  
Matrix Glycans

Matrix polysaccharides are a diverse group of structurally complex carbohydrates and account for a large portion of the biomass consumed as food or used to produce fuels and materials. Glucuronoxylan and arabinogalactan protein are matrix glycans that have sidechains decorated with 4- O-methyl glucuronosyl residues. Methylation is a key determinant of the physical properties of these wall glycopolymers and consequently affects both their biological function and ability to interact with other wall polymers. Indeed, there is increasing interest in determining the distribution and abundance of methyl-etherified polysaccharides in different plant species, tissues, and developmental stages. There is also a need to understand the mechanisms involved in their biosynthesis. Members of the Domain of Unknown Function (DUF) 579 family have been demonstrated to have a role in the biosynthesis of methyl-etherified glycans. Here we describe methods for the analysis of the 4- O-methyl glucuronic acid moieties that are present in sidechains of arabinogalactan proteins. These methods are then applied toward the analysis of loss-of-function mutants of two DUF579 family members that lack this modification in muro. We also present a procedure to assay DUF579 family members for enzymatic activity in vitro using acceptor oligosaccharides prepared from xylan of loss-of-function mutants. Our approach facilitates the characterization of enzymes that modify glycosyl residues during cell wall synthesis and the structures that they generate.

scholarly journals Comprehensive Analysis of Arabinogalactan Protein-Encoding Genes Reveals the Involvement of Three BrFLA Genes in Pollen Germination in Brassica rapa

2021 ◽  
Vol 22 (23) ◽  
pp. 13142
Author(s):  
Huiting Huang ◽  
Yingjing Miao ◽  
Yuting Zhang ◽  
Li Huang ◽  
Jiashu Cao ◽  
...  
Keyword(s):  
Brassica Rapa ◽  
Pollen Germination ◽  
Protein Structures ◽  
Pollen Grains ◽  
Comprehensive Analysis ◽  
Arabinogalactan Protein ◽  
Sequencing Data ◽  
Protein Encoding ◽  
Encoding Genes

Arabinogalactan proteins (AGPs) are a superfamily of hydroxyproline-rich glycoproteins that are massively glycosylated, widely implicated in plant growth and development. No comprehensive analysis of the AGP gene family has been performed in Chinese cabbage (Brassica rapa ssp. chinensis). Here, we identified a total of 293 putative AGP-encoding genes in B. rapa, including 25 classical AGPs, three lysine-rich AGPs, 30 AG-peptides, 36 fasciclin-like AGPs (FLAs), 59 phytocyanin-like AGPs, 33 xylogen-like AGPs, 102 other chimeric AGPs, two non-classical AGPs and three AGP/extensin hybrids. Their protein structures, phylogenetic relationships, chromosomal location and gene duplication status were comprehensively analyzed. Based on RNA sequencing data, we found that 73 AGP genes were differentially expressed in the floral buds of the sterile and fertile plants at least at one developmental stage in B. rapa, suggesting a potential role of AGPs in male reproductive development. We further characterized BrFLA2, BrFLA28 and BrFLA32, three FLA members especially expressed in anthers, pollen grains and pollen tubes. BrFLA2, BrFLA28 and BrFLA32 are indispensable for the proper timing of pollen germination under high relative humidity. Our study greatly extends the repertoire of AGPs in B. rapa and reveals a role for three members of the FLA subfamily in pollen germination.

Giscience in the Mountain Geography

2010 ◽  
Vol 27 (1-2) ◽  
pp. 81-90
Author(s):  
Krishna Poudel
Keyword(s):  
Spatial Data ◽  
Environmental Data ◽  
Temporal Data ◽  
Observation Systems ◽  
Research Findings ◽  
Temporal And Spatial ◽  
Temporal And Spatial Characteristics ◽  
Mountain Geography ◽  
Different Sources

Mountains have distinct geography and are dynamic in nature compared to the plains. 'Verticality' and 'variation' are two fundamental specificities of the mountain geography. They possess distinct temporal and spatial characteristics in a unique socio-cultural setting. There is an ever increasing need for spatial and temporal data for planning and management activities; and Geo Information (GI) Science (including Geographic Information and Earth Observation Systems). This is being recognized more and more as a common platform for integrating spatial data with social, economic and environmental data and information from different sources. This paper investigates the applicability and challenges of GISscience in the context of mountain geography with ample evidences and observations from the mountain specific publications, empirical research findings and reports. The contextual explanation of mountain geography, mountain specific problems, scientific concerns about the mountain geography, advances in GIScience, the role of GIScience for sustainable development, challenges on application of GIScience in the contexts of mountains are the points of discussion. Finally, conclusion has been made with some specific action oriented recommendations.

scholarly journals Analysis of the reproduction mode in Psidium spp. using the pollen:ovule ratio

2020 ◽  
Vol 43 ◽  
pp. e44062
Author(s):  
Maria Lorraine Fonseca Oliveira ◽  
Telma Nair Santana Pereira ◽  
Rodrigo Miranda Barbosa ◽  
Alexandre Pio Viana
Keyword(s):  
Pollen Grains ◽  
Flower Bud ◽  
Reproduction Mode ◽  
Reproductive Characteristics ◽  
Reproduction Strategy ◽  
Pollen:Ovule Ratio ◽  
Floral Bud

This research aimed to explore the reproductive characteristics of three species of Psidium (P. guajava L., P. cattleyanum Sabine, and P. guineense Sw.) and estimate a probable reproduction strategy based on the pollen:ovule (P:O) methodology. The number of pollen grains per floral bud (NGPB), number of pollen grains per anther (NGPA), number of anthers per flower bud (NAB), number of ovules per flower bud (NOB), and the P:O ratio of each species were estimated. All species had a P:O ratio over 2,000 and were classified as xenogamous. P.guajava presented the highest values for all characteristics evaluated, with the NGPB at 3,777,519, the NOB at 584.50 and a P:O ratio of 6,462.82. Similarly, P. cattleyanum had a P:O ratio of 5,649.89 (NGPB 762,736 and NOB 135). However, P. guineense was considered facultative xenogamous, with P:O of 2,085.75, the NGPB at 741,484 and the NOB at 355.50. Thus, it was concluded that the studied species have a preference for allogamy and require many pollen grains to fertilize each ovule, demonstrating that the transfer of pollen to the stigma is not very specialized.

scholarly journals Crayfish hemocytes develop along the granular cell lineage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fang Li ◽  
Zaichao Zheng ◽  
Hongyu Li ◽  
Rongrong Fu ◽  
Limei Xu ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Cell Lineage ◽  
Granular Cell ◽  
Marker Genes ◽  
Hematopoietic Tissue ◽  
Differentiated Cells ◽  
Stage Of Development ◽  
Almost All ◽  
Relationship Of

AbstractDespite the central role of hemocytes in crustacean immunity, the process of hemocyte differentiation and maturation remains unclear. In some decapods, it has been proposed that the two main types of hemocytes, granular cells (GCs) and semigranular cells (SGCs), differentiate along separate lineages. However, our current findings challenge this model. By tracking newly produced hemocytes and transplanted cells, we demonstrate that almost all the circulating hemocytes of crayfish belong to the GC lineage. SGCs and GCs may represent hemocytes of different developmental stages rather than two types of fully differentiated cells. Hemocyte precursors produced by progenitor cells differentiate in the hematopoietic tissue (HPT) for 3 ~ 4 days. Immature hemocytes are released from HPT in the form of SGCs and take 1 ~ 3 months to mature in the circulation. GCs represent the terminal stage of development. They can survive for as long as 2 months. The changes in the expression pattern of marker genes during GC differentiation support our conclusions. Further analysis of hemocyte phagocytosis indicates the existence of functionally different subpopulations. These findings may reshape our understanding of crustacean hematopoiesis and may lead to reconsideration of the roles and relationship of circulating hemocytes.

scholarly journals A Duplicated Copy of the Meiotic Gene ZIP4 Preserves up to 50% Pollen Viability and Grain Number in Polyploid Wheat

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 290
Author(s):  
Abdul Kader Alabdullah ◽  
Graham Moore ◽  
Azahara C. Martín
Keyword(s):  
Pollen Viability ◽  
Pollen Grains ◽  
Wheat Chromosome ◽  
Grain Number ◽  
Meiotic Gene ◽  
Chromosome 5B ◽  
Mutant Pollen ◽  
Female Gametogenesis ◽  
Chromosome 3B

Although most flowering plants are polyploid, little is known of how the meiotic process evolves after polyploidisation to stabilise and preserve fertility. On wheat polyploidisation, the major meiotic gene ZIP4 on chromosome 3B duplicated onto 5B and diverged (TaZIP4-B2). TaZIP4-B2 was recently shown to promote homologous pairing, synapsis and crossover, and suppress homoeologous crossover. We therefore suspected that these meiotic stabilising effects could be important for preserving wheat fertility. A CRISPR Tazip4-B2 mutant was exploited to assess the contribution of the 5B duplicated ZIP4 copy in maintaining pollen viability and grain setting. Analysis demonstrated abnormalities in 56% of meiocytes in the Tazip4-B2 mutant, with micronuclei in 50% of tetrads, reduced size in 48% of pollen grains and a near 50% reduction in grain number. Further studies showed that most of the reduced grain number occurred when Tazip4-B2 mutant plants were pollinated with the less viable Tazip4-B2 mutant pollen rather than with wild type pollen, suggesting that the stabilising effect of TaZIP4-B2 on meiosis has a greater consequence in subsequent male, rather than female gametogenesis. These studies reveal the extraordinary value of the wheat chromosome 5B TaZIP4-B2 duplication to agriculture and human nutrition. Future studies should further investigate the role of TaZIP4-B2 on female fertility and assess whether different TaZIP4-B2 alleles exhibit variable effects on meiotic stabilisation and/or resistance to temperature change.

scholarly journals Transcriptomic Analysis of the Anthocyanin Biosynthetic Pathway Reveals the Molecular Mechanism Associated with Purple Color Formation in Dendrobium Nestor

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 113
Author(s):  
Xueqiang Cui ◽  
Jieling Deng ◽  
Changyan Huang ◽  
Xuan Tang ◽  
Xianmin Li ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Developmental Stages ◽  
Anthocyanin Biosynthesis ◽  
Transcriptome Profiling ◽  
Flower Color ◽  
Flower Bud ◽  
Color Formation ◽  
Color Development ◽  
Purple Coloration ◽  
Purple Color

Dendrobium nestor is a famous orchid species in the Orchidaceae family. There is a diversity of flower colorations in the Dendrobium species, but knowledge of the genes involved and molecular mechanism underlying the flower color formation in D. nestor is less studied. Therefore, we performed transcriptome profiling using Illumina sequencing to facilitate thorough studies of the purple color formation in petal samples collected at three developmental stages, namely—flower bud stage (F), half bloom stage (H), and full bloom stage (B) in D. nestor. In addition, we identified key genes and their biosynthetic pathways as well as the transcription factors (TFs) associated with purple flower color formation. We found that the phenylpropanoid–flavonoid–anthocyanin biosynthesis genes such as phenylalanine ammonia lyase, chalcone synthase, anthocyanidin synthase, and UDP-flavonoid glucosyl transferase, were largely up-regulated in the H and B samples as compared to the F samples. This upregulation might partly account for the accumulation of anthocyanins, which confer the purple coloration in these samples. We further identified several differentially expressed genes related to phytohormones such as auxin, ethylene, cytokinins, salicylic acid, brassinosteroid, and abscisic acid, as well as TFs such as MYB and bHLH, which might play important roles in color formation in D. nestor flower. Sturdy upregulation of anthocyanin biosynthetic structural genes might be a potential regulatory mechanism in purple color formation in D. nestor flowers. Several TFs were predicted to regulate the anthocyanin genes through a K-mean clustering analysis. Our study provides valuable resource for future studies to expand our understanding of flower color development mechanisms in D. nestor.

scholarly journals Epigenetic transgenerational inheritance, Gametogenesis and Germline Development

2021 ◽  
Author(s):  
Millissia Ben Maamar ◽  
Eric E Nilsson ◽  
Michael K Skinner
Keyword(s):  
Developmental Biology ◽  
Environmental Factors ◽  
Biological System ◽  
Developmental Stages ◽  
Primordial Germ Cell ◽  
Cell Types ◽  
Transgenerational Inheritance ◽  
Germline Development ◽  
Current Review

Abstract One of the most important developing cell types in any biological system is the gamete (sperm and egg). The transmission of phenotypes and optimally adapted physiology to subsequent generations is in large part controlled by gametogenesis. In contrast to genetics, the environment actively regulates epigenetics to impact the physiology and phenotype of cellular and biological systems. The integration of epigenetics and genetics is critical for all developmental biology systems at the cellular and organism level. The current review is focused on the role of epigenetics during gametogenesis for both the spermatogenesis system in the male and oogenesis system in the female. The developmental stages from the initial primordial germ cell through gametogenesis to the mature sperm and egg are presented. How environmental factors can influence the epigenetics of gametogenesis to impact the epigenetic transgenerational inheritance of phenotypic and physiological change in subsequent generations is reviewed.

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