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

Embryological studies in the compositae, I. Sporogenesis, Gametogenesis, and Embryogeny in Cotula australis (Less.) Hook. F

1962 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
GL Davis
Keyword(s):  
Mother Cell ◽  
Megaspore Mother Cell ◽  
Embryo Sac ◽  
Subsequent Development ◽  
Pollen Grains ◽  
Archesporial Cell ◽  
Polygonum Type ◽  
Wall Formation ◽  
Chalazal Megaspore

Cotula australis has a discoid heterogamous capitulum in which the outermost three whorls of florets are female and naked. The bisexual disk florets are fully fertile and have a four-lobed corolla with four shortly epipetalous stamens. The anthers contain only two microsporangia. Wall formation and microsporogenesis are described and the pollen grains are shed at the three-celled condition. The ovule is teguinucellate and the hypodermal archesporial cell develops directly as the megaspore mother cell. Megasporogenesis is normal and the monosporio embryo sac develops from the chalazal megaspore. Breakdown of the nucellar epidermis takes place when the embryo sac is binucleate and its subsequent development follows the Polygonum type. The synergids extend deeply into the micropyle and one persists until late in embryogeny as a haustorium. The development of the embryo is of the Asterad type, and the endosperm is cellular. C. coronopifolia agrees with C. australis in the presence of only two microsporangia in each anther and the development of a synergid haustorium.

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 Arabidopsis ICK/KRP cyclin-dependent kinase inhibitors function to ensure the formation of one megaspore mother cell and one functional megaspore per ovule

PLoS Genetics ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. e1007230 ◽  
Author(s):  
Ling Cao ◽  
Sheng Wang ◽  
Prakash Venglat ◽  
Lihua Zhao ◽  
Yan Cheng ◽  
...  
Keyword(s):  
Mother Cell ◽  
Megaspore Mother Cell ◽  
Kinase Inhibitors ◽  
Cyclin Dependent Kinase ◽  
Functional Megaspore

Female gametophyte and embryo development in western hemlock (Tsuga heterophylla)

1974 ◽  
Vol 52 (4) ◽  
pp. 885-893 ◽  
Author(s):  
Elizabeth A. Stanlake ◽  
John N. Owens
Keyword(s):  
Embryo Development ◽  
Mother Cell ◽  
Megaspore Mother Cell ◽  
Morphological Study ◽  
Female Gametophyte ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Seed Fall

A morphological study of the female gametophyte and embryo development was made for western hemlock (Tsuga heterophylla (Raf.) Sarg.) growing in the Victoria, B.C., area. Western hemlock follows a pattern of development similar to other members of the Pinaceae. A comparison was also made between development in western hemlock and other gymnosperm families. Meiosis of the megaspore mother cell in western hemlock begins in early February and is completed at the end of the first week in March. This is 3 weeks before pollination. Fertilization occurs 6 weeks after pollination, in the middle of May. Embryo development takes place throughout June and July and the embryo is mature by the middle of August. Seed fall occurs throughout September, 5 months after pollination.

Megagametogenesis, fertilization, and embryo development in Larixdecidua

1986 ◽  
Vol 16 (6) ◽  
pp. 1301-1309 ◽  
Author(s):  
Grzegorz Kosiński
Keyword(s):  
Cell Wall ◽  
Sexual Reproduction ◽  
Mother Cell ◽  
Megaspore Mother Cell ◽  
Female Gametophyte ◽  
Nuclear Stage ◽  
Empty Seed ◽  
Development Failure ◽  
Major Factors ◽  
Female Gametophyte Development

The phenology of sexual reproduction in Larixdecidua Mill, varies from year to year, and some intra- and inter-clonal differences were also found. Megaspore mother cell meiosis occurred at the time of pollination, during the second half of April, resulting in three or four megaspores. The free nuclear stage and cell wall and archegonia formation were completed in late May and the first half of June. An average of four archegonia was observed in each ovule, but the number ranged from two to six. Fertilization occurred during the first 20 days of June, about 7 weeks after pollination. A four-tiered, 16-celled proembryo formed. Meristematic regions formed in the embryo from the end of June to mid-July. Fully developed embryos were observed in mid-August. Simple polyembryony and delayed cleavage polyembryony were observed. Lack of pollination, disturbances during megasporogenesis and female gametophyte development, failure of fertilization, and embryo degeneration are the major factors resulting in empty seed.

scholarly journals The TRAF Mediated Gametogenesis Progression (TRAMGaP) Gene Is Required for Megaspore Mother Cell Specification and Gametophyte Development

2017 ◽  
Vol 175 (3) ◽  
pp. 1220-1237 ◽  
Author(s):  
Sunil Kumar Singh ◽  
Vajinder Kumar ◽  
Ramamurthy Srinivasan ◽  
Paramvir Singh Ahuja ◽  
Shripad Ramchandra Bhat ◽  
...  
Keyword(s):  
Mother Cell ◽  
Megaspore Mother Cell ◽  
Cell Specification ◽  
Gametophyte Development

ULTRASTRUCTURE OF THE DEVELOPING MEGASPORE MOTHER CELL OF GINKGO BILOBA

1967 ◽  
Vol 54 (3) ◽  
pp. 375-383 ◽  
Author(s):  
K. D. Stewart ◽  
E. M. Gifford
Keyword(s):  
Ginkgo Biloba ◽  
Mother Cell ◽  
Megaspore Mother Cell
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