The 30th International Conference on Arabidopsis Research (ICAR 2019)

556 / 2019-03-15 21:52:43

Zygotic genome activation and early embryogenesis in flowering plants

ZGA, RNA-Seq, Sumoylation, Asymmetric zygote division

Plenary track > Development

The formation of a zygote via the fusion of an egg and sperm cell and its subsequent asymmetric division herald the start of the plant’s life cycle. Zygotic genome activation (ZGA) is thought to occur gradually, with the initial steps of zygote and embryo development being primarily maternally controlled, and subsequent steps being governed by the zygotic genome. Here, using maize (Zea mays) as a model plant system, we generated RNA-Seq transcriptome profiles of gametes, zygotes, apical and basal daughter cells and found that ZGA (zygotic genome activation) occurs shortly after fertilization and involves ~10% of the genome being activated in a highly dynamic pattern (1). We reported the function of the ubiquitin-like modifier diSUMO-LIKE (DSUL) for early embryo development in maize. Introducing a DSUL-RNAi construct by sperm cell inhibits completion of cytokinesis generating non-separated zygotic daughter nuclei or multinucleate embryonic cells lacking cell plates. Identification of DSUL targets by Co-IP suggests its predominant roles in regulation of translation machinery and in cell plate formation. A comparison of DSUL and SUMO1 localization during the cell cycle and of their substrates reveals the complementary role of the monomeric (SUMO1) and the dimeric (DSUL) modifiers (2).

(1) Chen et al. (2017) The Plant Cell, 29, 2106-2125.
(2) Chen et al. (2018) Current Biology, 28, 1-13.