title: Epigenetics in plants-vernalisation and hybrid vigour.
abstract: In this review we have analysed two major biological systems involving epigenetic control of gene activity. In the first system we demonstrate the interplay between genetic and epigenetic controls over the transcriptional activity of FLC, a major repressor of flowering in Arabidopsis. FLC is down-regulated by low temperature treatment (vernalisation) releasing the repressor effect on flowering. We discuss the mechanisms of the reduced transcription and the memory of the vernalisation treatment through vegetative development. We also discuss the resetting of the repressed activity level of the FLC gene, following vernalisation, to the default high activity level and show it occurs during both male and female gametogenesis but with different timing in each. In the second part of the review discussed the complex multigenic system which is responsible for the patterns of gene activity which bring about hybrid vigour in crosses between genetically similar but epigenetically distinct parents. The epigenetic systems that we have identified as contributing to the heterotic phenotype are the 24nt siRNAs and their effects on RNA dependent DNA methylation (RdDM) at the target loci leading to changed expression levels. We conclude that it is likely that epigenetic controls are involved in expression systems in many aspects of plant development and plant function.
authors: Commonwealth Scientific and Industrial Research Organisation, Plant Industry, Canberra ACT 2601, Australia.
authors: Michael
authors: M
authors: Groszmann
authors: Ian K
authors: IK
authors: Greaves
authors: Nicolas
authors: N
authors: Albert
authors: Ryo
authors: R
authors: Fujimoto
authors: Chris A
authors: CA
authors: Helliwell
authors: Elizabeth S
authors: ES
authors: Dennis
authors: W James
authors: WJ
authors: Peacock
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics; D002843:Chromatin / Q000235:genetics; D019175:DNA Methylation; D002523:Edible Grain / Q000235:genetics / Q000254:growth & development; D044127:Epigenesis, Genetic; D035264:Flowers / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D018745:Genome, Plant; D006823:Hybrid Vigor / Q000235:genetics; D026161:MADS Domain Proteins / Q000235:genetics; D008957:Models, Genetic; D063245:Plant Development; D010944:Plants / Q000235:genetics* / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D022661:RNA, Untranslated / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D002843:Chromatin; C418902:At5g10140 protein, Arabidopsis; D026161:MADS Domain Proteins; D018749:RNA, Plant; D034741:RNA, Small Interfering; D022661:RNA, Untranslated