Fig. 1: Temporal resolution of transcriptome changes during synergid degeneration in maize.
From: Fertilization-induced synergid cell death by RALF12-triggered ROS production and ethylene signaling
a–d Tracing synergid cell degeneration using pZmES4::ZmES4-GFP as a marker at indicated times before and after pollination. ZmES4 is expressed in synergid cells and weakly in the egg cell and zygote, respectively. At 28 HAP the synergid signal disappeared. e–h Scheme showing the timing of the double fertilization process and elimination of the two synergid cells. i–l Manually isolated synergid cells at indicated stages. At 26 HAP the persistent synergid cell is no longer visible and the zygote is tightly attached to the degenerated receptive synergid cell (l). Black arrows and arrowheads indicate pollen tube entrance and sperm cell release regions of the receptive synergid cell, respectively. m Expression pattern of known synergid-expressed genes at indicated synergid stages. Transcript levels are shown as FPKM (Fragments Per Kilobase of exon model per Million mapped fragments) values (means ± SD) of three biological replicates. For statistical analysis, count data at the gene level were analyzed with DESeq264. Stage-to-stage comparisons were performed and corrected for multiple testing over all genes and cell stage comparisons using false discovery rate (FDR). Letters above bars indicate significant differences (adjusted P < 0.05). Source data are provided in the source data file. n Volcano plots depict transcriptional dynamics of differentially expressed genes (DEGs) between indicated stages. Observation of GFP signals in pZmES4::ZmES4-GFP (a–d) and synergid cell isolation/observation at sequential stages (i–l) were repeated three times with similar results. CC central cell, dSC degenerated receptive synergid cell, EC egg cell, EN endosperm, mNU micropylar nucellus, pSC persistent synergid cell, SC Synergid cell, ZY zygote. Scale bars, 50 μm.
