Molecular networks regulating Arabidopsis seed maturation, after-ripening, dormancy and germination.
The transition between dormancy and germination represents a critical stage in the life cycle of higher plants and is an important ecological and commercial trait. In this review we present current knowledge of the molecular control of this trait in Arabidopsis thaliana, focussing on important components functioning during the developmental phases of seed maturation, after-ripening and imbibition. Establishment of dormancy during seed maturation is regulated by networks of transcription factors with overlapping and discrete functions. Following desiccation, after-ripening determines germination potential and, surprisingly, recent observations suggest that transcriptional and post-transcriptional processes occur in the dry seed. The single-cell endosperm layer that surrounds the embryo plays a crucial role in the maintenance of dormancy, and transcriptomics approaches are beginning to uncover endosperm-specific genes and processes. Molecular genetic approaches have provided many new components of hormone signalling pathways, but also indicate the importance of hormone-independent pathways and of natural variation in key regulatory loci. The influence of environmental signals (particularly light) following after-ripening, and the effect of moist chilling (stratification) are increasingly being understood at the molecular level. Combined postgenomics, physiology and molecular genetics approaches are beginning to provide an unparalleled understanding of the molecular processes underlying dormancy and germination.
Holdsworth
Michael J
MJ
Department of Agricultural and Environmental Sciences, School of BioSciences, University of Nottingham, Nottingham LE12 5RD, UK.
Bentsink
Leónie
L
Department of Molecular Plant Physiology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Soppe
Wim J J
WJJ
Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829, Cologne, Germany.
D000040:Abscisic Acid / Q000096:biosynthesis / Q000502:physiology; D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D018745:Genome, Plant; D018525:Germination / Q000235:genetics*; D005875:Gibberellins / Q000096:biosynthesis / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D029681:Arabidopsis Proteins; D005875:Gibberellins; D007210:Indoleacetic Acids; D014157:Transcription Factors; D000040:Abscisic Acid; C007842:gibberellic acid