title: ABA-mediated inhibition of seed germination is associated with ribosomal DNA chromatin condensation, decreased transcription, and ribosomal RNA gene hypoacetylation.
abstract: Seed germination is a highly organized biological process accompanied by many cellular and metabolic changes. The ribosomal RNA (rRNA) gene, which forms the  nucleolus at interphase and is transcribed for ribosome production and protein synthesis, has an important role during seed germination. In this study, we report that there is a decondensation of ribosomal DNA (rDNA) chromatin during seed germination accompanied with increased rRNA gene expression and overall genomic hyperacetylation. Analysis of the rRNA gene promoter region by using chromatin immunoprecipitation (ChIP) shows that there is an increase in acetylation levels at the rRNA gene promoter region. Application of seed germination inhibitor abscisic acid (ABA) suppresses rDNA chromatin decondensation, the expression of rRNA genes and global genomic acetylation. The further ChIP experiments show that ABA treatment hinders the elevation of acetylation levels in the promoter region of the rRNA gene. The data together indicate that ABA treatment inhibits seed germination, which is associated with rDNA chromatin condensation, decreased transcription and rRNA gene hypoacetylation.
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Hu
authors.forename: Shihan
authors.initials: S
authors.lastname: Yan
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Shibin
authors.initials: S
authors.lastname: He
authors.forename: Min
authors.initials: M
authors.lastname: Huang
authors.forename: Lijia
authors.initials: L
authors.lastname: Li
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000107:Acetylation / Q000187:drug effects; D002843:Chromatin / Q000235:genetics* / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D004275:DNA, Ribosomal / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D018525:Germination / Q000187:drug effects* / Q000235:genetics; D012639:Seeds / Q000187:drug effects* / Q000378:metabolism*
chemical_list: D002843:Chromatin; D004275:DNA, Ribosomal; D000040:Abscisic Acid