GSE29134
Epigenetic Regulation of the Transition from Seed Maturation to Germination in Soybean
How epigenetics is involved in the transition from seed maturation to seed germination largely remains elusive. To uncover the possible role of epigenetics in gene expression during the transition from seed maturation to seed germination in soybean, the transcriptome of cotyledons from four stages of soybean seed maturation and germination, including mid-late maturation, late maturation, seed dormancy and seed germination, were profiled by Illumina sequencing. For the genes that are quantitatively regulated at the four stages, two antagonistic epigenetic marks, H3K4me3 and H3K27me3, together with the binding of RNA polymerase II, were investigated at the four stages by chromatin immunoprecipitation (ChIP). For 10 out of 16 genes examined, the relative enrichment of histone modification marks (H3K4me3 and H3K27me3) and RNA polymerase II binding on their promoter regions correlates well with their relative expression levels at four stages, suggesting the involvement of epigenetics in transcriptional regulation. A striking finding is that seed germination-specific genes start to show open chromatin (H3K4me3) during late seed maturation although their transcripts do not accumulate, which is further supported by RNA polymerase II binding. Together, our results provide the first evidence that seed germination genes can be primed for transcription (open chromatin and RNA polymerase II binding) during seed maturation, highlighting that the transition from seed maturation to seed germination starts at late seed maturation stages at both the genetic and epigenetic levels. Overall design: Illumina sequencing of transcripts from cotyledons of mid-maturation (B1 stage) and late maturation (AA1 stage) seeds, whole dry seeds, and cotyledons of seedlings six days after imbibition.