401. Live Imaging of embryogenic structures in Brassica napus microspore embryo cultures highlights the developmental plasticity of induced totipotent cells
- Author
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Patricia Corral-Martínez, Gerco C. Angenent, Norbert C.A. de Ruijter, Anneke Horstman, Charlotte Siemons, and Kim Boutilier
- Subjects
0106 biological sciences ,Wageningen Electron Microscopy Centre ,animal structures ,LEAFY COTYLEDON1 ,Cell Plasticity ,Plant Science ,Haploidy ,Biology ,Cell fate determination ,01 natural sciences ,03 medical and health sciences ,Microspore ,Totipotency ,Laboratorium voor Moleculaire Biologie ,BIOS Plant Development Systems ,030304 developmental biology ,Gametophyte ,0303 health sciences ,Zygote ,Microspore embryogenesis ,Time-lapse imaging ,Embryogenesis ,Brassica napus ,food and beverages ,Embryo ,Laboratorium voor Celbiologie ,Cell Biology ,Cell biology ,Laboratory of Cell Biology ,Seeds ,embryonic structures ,Pollen ,Original Article ,Laboratory of Molecular Biology ,EPS ,Totipotent Stem Cells ,Suspensor ,Pollen wall ,010606 plant biology & botany - Abstract
Key message In vitro embryo development is highly plastic; embryo cell fate can be re-established in tissue culture through different pathways. Abstract In most angiosperms, embryo development from the single-celled zygote follows a defined pattern of cell divisions in which apical (embryo proper) and basal (root and suspensor) cell fates are established within the first cell divisions. By contrast, embryos that are induced in vitro in the absence of fertilization show a less regular initial cell division pattern yet develop into histodifferentiated embryos that can be converted into seedlings. We used the Brassica napus microspore embryogenesis system, in which the male gametophyte is reprogrammed in vitro to form haploid embryos, to identify the developmental fates of the different types of embryogenic structures found in culture. Using time-lapse imaging of LEAFY COTYLEDON1-expressing cells, we show that embryogenic cell clusters with very different morphologies are able to form haploid embryos. The timing of surrounding pollen wall (exine) rupture is a major determinant of cell fate in these clusters, with early exine rupture leading to the formation of suspensor-bearing embryos and late rupture to suspensorless embryos. In addition, we show that embryogenic callus, which develops into suspensor-bearing embryos, initially expresses transcripts associated with both basal- and apical-embryo cell fates, suggesting that these two cell fates are fixed later in development. This study reveals the inherent plasticity of in vitro embryo development and identifies new pathways by which embryo cell fate can be established.
- Published
- 2020
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