scholarly journals RH17 restricts reproductive fate and represses autonomous seed coat development in sexual Arabidopsis

Development ◽  
2021 ◽  
Vol 148 (19) ◽  
Author(s):  
Ron Eric Stein ◽  
Berit Helge Nauerth ◽  
Laura Binmöller ◽  
Luise Zühl ◽  
Anna Loreth ◽  
...  
Keyword(s):  
Seed Coat ◽  
Reproductive Development ◽  
Female Flower ◽  
Endosperm Development ◽  
Regulatory Control ◽  
Single Mutation ◽  
Rna Helicases ◽  
Germline Development ◽  
Sexual And Asexual Reproduction ◽  
Agricultural Applications

ABSTRACT Plant sexual and asexual reproduction through seeds (apomixis) is tightly controlled by complex gene regulatory programs, which are not yet fully understood. Recent findings suggest that RNA helicases are required for plant germline development. This resembles their crucial roles in animals, where they are involved in controlling gene activity and the maintenance of genome integrity. Here, we identified previously unknown roles of Arabidopsis RH17 during reproductive development. Interestingly, RH17 is involved in repression of reproductive fate and of elements of seed development in the absence of fertilization. In lines carrying a mutant rh17 allele, development of supernumerary reproductive cell lineages in the female flower tissues (ovules) was observed, occasionally leading to formation of two embryos per seed. Furthermore, seed coat, and putatively also endosperm development, frequently initiated autonomously. Such induction of several features phenocopying distinct elements of apomixis by a single mutation is unusual and suggests that RH17 acts in regulatory control of plant reproductive development. Furthermore, an in-depth understanding of its action might be of use for agricultural applications.

scholarly journals Gene Function Rather than Reproductive Mode Drives the Evolution of RNA Helicases in Sexual and Apomictic Boechera

2020 ◽  
Vol 12 (5) ◽  
pp. 656-673 ◽  
Author(s):  
Markus Kiefer ◽  
Berit H Nauerth ◽  
Christopher Volkert ◽  
David Ibberson ◽  
Anna Loreth ◽  
...  
Keyword(s):  
Gene Function ◽  
Higher Plants ◽  
Reproductive Mode ◽  
Deleterious Mutations ◽  
Rna Helicases ◽  
Germline Development ◽  
Allelic Variants ◽  
High Sequence Conservation ◽  
C And N ◽  
Mutant Lines

Abstract In higher plants, sexual and asexual reproductions through seeds (apomixis) have evolved as alternative strategies. Evolutionary advantages leading to coexistence of both reproductive modes are currently not well understood. It is expected that accumulation of deleterious mutations leads to a rapid elimination of apomictic lineages from populations. In this line, apomixis originated repeatedly, likely from deregulation of the sexual pathway, leading to alterations in the development of reproductive lineages (germlines) in apomicts as compared with sexual plants. This potentially involves mutations in genes controlling reproduction. Increasing evidence suggests that RNA helicases are crucial regulators of germline development. To gain insights into the evolution of 58 members of this diverse gene family in sexual and apomictic plants, we applied target enrichment combined with next-generation sequencing to identify allelic variants from 24 accessions of the genus Boechera, comprising sexual, facultative, and obligate apomicts. Interestingly, allelic variants from apomicts did not show consistently increased mutation frequency. Either sequences were highly conserved in any accession, or allelic variants preferentially harbored mutations in evolutionary less conserved C- and N-terminal domains, or presented high mutation load independent of the reproductive mode. Only for a few genes allelic variants harboring deleterious mutations were only identified in apomicts. To test if high sequence conservation correlates with roles in fundamental cellular or developmental processes, we analyzed Arabidopsis thaliana mutant lines in VASA-LIKE (VASL), and identified pleiotropic defects during ovule and reproductive development. This indicates that also in apomicts mechanisms of selection are in place based on gene function.

scholarly journals Seed development in Paeonia ostii (Paeoniaceae), with particular reference to embryogeny

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Keliang Zhang ◽  
Weizhang Cao ◽  
Jerry M. Baskin ◽  
Carol C. Baskin ◽  
Jing Sun ◽  
...  
Keyword(s):  
Seed Development ◽  
Seed Coat ◽  
Soluble Sugars ◽  
Outer Integument ◽  
Dry Mass ◽  
Endosperm Development ◽  
Raw Material ◽  
Lack Of Information ◽  
Two Stages ◽  
Peripheral Cells

Abstract Background Seeds of Paeonia ostii have been proposed as a source of raw material for the production of edible oil; however, lack of information about the developmental biology of the seeds hampers our ability to use them. Our aim was to investigate development of the seed coat, endosperm and embryo of P. ostii in relation to timing of accumulation of nutrient reserves from pollination to seed maturity. Ovules and developing seeds of P. ostii were collected at various stages of development from zygote to maturity. Seed fresh mass, dry mass, germination, moisture, soluble sugars, starch, protein and oil content were determined. Ontogeny of seeds including embryo, endosperm and seed coat were analyzed histologically. Results The ovule of P. ostii is anatropous, crassinucellate and bitegmic. The zygote begins to divide at about 5 days after pollination (DAP), and the division is not accompanied by cell wall formation. By 25 DAP, the proembryo begins to cellularize. Thereafter, several embryo primordia appear at the surface of the cellularized proembryo, but only one matures. Endosperm development follows the typical nuclear type. The seed coat is derived from the outer integument. During seed development, soluble sugars, starch and crude fat content increased and then decreased, with maximum contents at 60, 80 and 100 DAP, respectively. Protein content was relatively low compared with soluble sugars and crude fat, but it increased throughout seed development. Conclusions During seed development in P. ostii, the seed coat acts as a temporary storage tissue. Embryo development of P. ostii can be divided into two stages: a coenocytic proembryo from zygote (n + n) that degenerates and a somatic embryo from peripheral cells of the proembryo (2n → 2n). This pattern of embryogeny differs from that of all other angiosperms, but it is similar to that of gymnosperms.

scholarly journals Embriología de Erythroxylum havanense Jacq. (Erythroxylaceae)

2017 ◽  
pp. 25
Author(s):  
Sonia Vázquez-Santana ◽  
César A. Domínguez ◽  
Judith Márquez-Guzmán
Keyword(s):  
Seed Coat ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Endosperm Development ◽  
Anther Wall ◽  
Starch Grains ◽  
Reproductive Structures ◽  
Exine Sculpturing ◽  
Erythroxylum Havanense ◽  
Mature Anther

We studied the development of reproductive structures in pin and thrum morphs of Erythroxylum havanense. The young anther wall consists of an epidermis, endothecium , 1-3 middle layers anda binucleate secretory tapetum. The mature anther wall has only two layers: epidermis and endothecium. Microspore tetrads are tetrahedral or isobilateral. Mature pollen grains are tricolporate, bicellular and contain starch grains. Exine sculpturing is verrugate in thrum pollen and reticulate in pin pollen. The ovule is sessile, pendulous, anatropous, bitegmic and crassinucellate. The embryo sac is heptacellular. An endothelium is differentiated. The endosperm development is nuclear, and the basal part of the nucellus persists during early endosperm development. Both integuments form the seed coat.

scholarly journals mRNA localization is linked to translation regulation in the Caenorhabditis elegans germ lineage

2020 ◽  
Author(s):  
Dylan M. Parker ◽  
Lindsay P. Winkenbach ◽  
Samuel P. Boyson ◽  
Matthew N. Saxton ◽  
Camryn Daidone ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Regulatory Control ◽  
Translational Repression ◽  
Translation Regulation ◽  
Germline Development ◽  
P Granules ◽  
C Elegans ◽  
Early Embryos

AbstractCaenorhabditis elegans early embryos generate cell-specific transcriptomes despite lacking active transcription. This presents an opportunity to study mechanisms of post-transcriptional regulatory control. In seeking the mechanisms behind this patterning, we discovered that some cell-specific mRNAs accumulate non-homogenously within cells, localizing to membranes, P granules (associated with progenitor germ cells in the P lineage), and P-bodies (associated with RNA processing). Transcripts differed in their dependence on 3’UTRs and RNA Binding Proteins, suggesting diverse regulatory mechanisms. Notably, we found strong but imperfect correlations between low translational status and P granule localization within the progenitor germ lineage. By uncoupling these, we untangled a long-standing question: Are mRNAs directed to P granules for translational repression or do they accumulate there as a downstream step? We found translational repression preceded P granule localization and could occur independent of it. Further, disruption of translation was sufficient to send homogenously distributed mRNAs to P granules. Overall, we show transcripts important for germline development are directed to P granules by translational repression, and this, in turn, directs their accumulation in the progenitor germ lineage where their repression can ultimately be relieved.SummaryMaternally loaded mRNAs localize non-homogeneously within C. elegans early embryos correlating with their translational status and lineage-specific fates.

scholarly journals Structural Analysis of Reproductive Development in Pistillate Flowers of Laurus nobilis L.

2013 ◽  
Vol 41 (2) ◽  
pp. 361
Author(s):  
Özlem AYTÜRK ◽  
Meral ÜNAL
Keyword(s):  
Apical Meristem ◽  
Reproductive Development ◽  
Female Flower ◽  
Floral Meristem ◽  
Vascular Bundles ◽  
Laurus Nobilis ◽  
Transmitting Tissue ◽  
Starch Grains ◽  
Nucellar Tissue ◽  
Fruit Formation

In Laurus nobilis L. (Lauraceae) the development of female flowers (pistillate), between floral meristem differentiation and fruit formation was inspected through histological sections and SEM techniques. The reproductive development of the female flower starts when the apical meristem converts into a floral meristem. Four tepals, four stamens and a carpel are developed from the floral meristem in turn. Filaments emerge however, anther development is arrested, and stamens become nonfunctional staminodes. The stigma is of the dry type. The solid style being short and thick consists of an epidermis, a cortex, a vascular bundle and a core of transmitting tissue composed of elongated cells. In the style a funnel-shaped zone extending from within the stigma to the stylar base is visible. The presence of high amounts of sugars and lipid substances within and around the vascular bundles are identified by histochemical techniques. The ovary contains an anatropous, bitegmic and crassinucellate ovule. Starch grains are present throughout the development of nucellar tissue. The chalazal region of nuclear endosperm forms a short haustorium. Endosperm does not exist in mature seed; the cotyledons are piled with considerably large starch grains. Idioblasts are observed in all stages of development.

scholarly journals Controlling Apomixis: Shared Features and Distinct Characteristics of Gene Regulation

Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 329 ◽  
Author(s):  
Anja Schmidt
Keyword(s):  
Transcriptional Activation ◽  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Higher Plants ◽  
Rna Helicases ◽  
Seed Formation ◽  
Molecular Control ◽  
Sexual And Asexual Reproduction

In higher plants, sexual and asexual reproduction through seeds (apomixis) have evolved as alternative strategies. As apomixis leads to the formation of clonal offspring, its great potential for agricultural applications has long been recognized. However, the genetic basis and the molecular control underlying apomixis and its evolutionary origin are to date not fully understood. Both in sexual and apomictic plants, reproduction is tightly controlled by versatile mechanisms regulating gene expression, translation, and protein abundance and activity. Increasing evidence suggests that interrelated pathways including epigenetic regulation, cell-cycle control, hormonal pathways, and signal transduction processes are relevant for apomixis. Additional molecular mechanisms are being identified that involve the activity of DNA- and RNA-binding proteins, such as RNA helicases which are increasingly recognized as important regulators of reproduction. Together with other factors including non-coding RNAs, their association with ribosomes is likely to be relevant for the formation and specification of the apomictic reproductive lineage. Subsequent seed formation appears to involve an interplay of transcriptional activation and repression of developmental programs by epigenetic regulatory mechanisms. In this review, insights into the genetic basis and molecular control of apomixis are presented, also taking into account potential relations to environmental stress, and considering aspects of evolution.

scholarly journals Characterization of germline development and identification of genes associated with germline specification in pineapple

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Lihua Zhao ◽  
Liping Liu ◽  
Yanhui Liu ◽  
Xianying Dou ◽  
Hanyang Cai ◽  
...  
Keyword(s):  
Plant Species ◽  
Mother Cell ◽  
Expression Patterns ◽  
Germline Development ◽  
Regulatory Pathways ◽  
Male Germline ◽  
Agricultural Applications ◽  
Related Plant ◽  
Female Gametophyte Development ◽  
Female Germline

AbstractUnderstanding germline specification in plants could be advantageous for agricultural applications. In recent decades, substantial efforts have been made to understand germline specification in several plant species, including Arabidopsis, rice, and maize. However, our knowledge of germline specification in many agronomically important plant species remains obscure. Here, we characterized the female germline specification and subsequent female gametophyte development in pineapple using callose staining, cytological, and whole-mount immunolocalization analyses. We also determined the male germline specification and gametophyte developmental timeline and observed male meiotic behavior using chromosome spreading assays. Furthermore, we identified 229 genes that are preferentially expressed at the megaspore mother cell (MMC) stage during ovule development and 478 genes that are preferentially expressed at the pollen mother cell (PMC) stage of anther development using comparative transcriptomic analysis. The biological functions, associated regulatory pathways and expression patterns of these genes were also analyzed. Our study provides a convenient cytological reference for exploring pineapple germline development and a molecular basis for the future functional analysis of germline specification in related plant species.

scholarly journals Transcriptome Analysis of the Arabidopsis Megaspore Mother Cell Uncovers the Importance of RNA Helicases for Plant Germline Development

PLoS Biology ◽  
2011 ◽  
Vol 9 (9) ◽  
pp. e1001155 ◽  
Author(s):  
Anja Schmidt ◽  
Samuel E. Wuest ◽  
Kitty Vijverberg ◽  
Célia Baroux ◽  
Daniela Kleen ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Mother Cell ◽  
Megaspore Mother Cell ◽  
Rna Helicases ◽  
Germline Development ◽  
Plant Germline

The co-expression of genes involved in seed coat and endosperm development promotes seed abortion in grapevine

Planta ◽  
2021 ◽  
Vol 254 (5) ◽  
Author(s):  
Shasha Li ◽  
Xiangyu Geng ◽  
Shuo Chen ◽  
Keke Liu ◽  
Saisai Yu ◽  
...  
Keyword(s):  
Seed Coat ◽  
Endosperm Development ◽  
Seed Abortion ◽  
Expression Of Genes

Combinatorial RNA interference indicates GLH-4 can compensate for GLH-1; these two P granule components are critical for fertility in C. elegans

Development ◽  
2000 ◽  
Vol 127 (13) ◽  
pp. 2907-2916 ◽  
Author(s):  
K.A. Kuznicki ◽  
P.A. Smith ◽  
W.M. Leung-Chiu ◽  
A.O. Estevez ◽  
H.C. Scott ◽  
...  
Keyword(s):  
Rna Interference ◽  
Caenorhabditis Elegans ◽  
Pattern Formation ◽  
Zinc Fingers ◽  
Polar Granule ◽  
Rna Helicases ◽  
Germline Development ◽  
P Granules ◽  
C Elegans ◽  
Embryonic Pattern Formation

We report that four putative germline RNA helicases, GLHs, are components of the germline-specific P granules in Caenorhabditis elegans. GLH-3 and GLH-4, newly discovered, belong to a multi-gene glh family. Although GLHs are homologous to Drosophila VASA, a polar granule component necessary for oogenesis and embryonic pattern formation, the GLHs are distinguished by containing multiple CCHC zinc fingers. RNA-mediated interference (RNAi) reveals the GLHs are critical for oogenesis. By RNAi at 20 degrees C, when either loss of GLH-1 or GLH-4 alone has no effect, loss of both GLH-1 and GLH-4 results in 97% sterility in the glh-1/4(RNAi) offspring of injected hermaphrodites. glh-1/4(RNAi) germlines are under-proliferated and are without oocytes. glh-1/4(RNAi) animals produce sperm; however, spermatogenesis is delayed and the sperm are defective. P granules are still present in glh-1/4(RNAi) sterile worms as revealed with antibodies against the remaining GLH-2 and GLH-3 proteins, indicating the GLHs function independently in P granule assembly. These studies reveal that C.elegans can use GLH-1 or GLH-4 to promote germline development.

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