Figure 5.

HDG11/12 act as maternal parent-of-origin factors in zygote asymmetry. (A) Elongation and the A/B ratio of one-cell stage embryos of the indicated genotypes. Crosses are denoted as female × male. (hdg11/12) hdg11-1 hdg12-2. (B) Expression of the indicated reporter genes in pollen grains. Arrowheads point to the sperm cell nuclei. (C) Relative intensity of pHDG11:YFP signals in the zygote and the egg cell. Egg cell is set as 1. (D) Model of the regulation of zygote asymmetry. Sperm-derived SSP triggers the YDA–MPK3/6 cascade in the zygote to phosphorylate WRKY2. WRKY2 and maternally derived HDG11/12 directly bind to the WOX8 intron and activate its transcription to regulate elongation and asymmetry of the zygote and embryo patterning. Bar, 10 µm. Error bars represent SD. n ≥ 80 (A); n ≥ 19 (C). The characters on columns indicate the significantly associated categories. P < 0.05 by the Tukey-Kramer test. (n.s) Not significant (Student's t-test).