title: Induction of dormancy in Arabidopsis summer annuals requires parallel regulation of DOG1 and hormone metabolism by low temperature and CBF transcription factors.
abstract: Summer annuals overwinter as seeds in the soil seed bank. This is facilitated by a cold-induced increase in dormancy during seed maturation followed by a switch to a state during seed imbibition in which cold instead promotes germination. Here, we show that the seed maturation transcriptome in Arabidopsis thaliana is highly temperature sensitive and reveal that low temperature during seed maturation induces several genes associated with dormancy, including DELAY OF GERMINATION1 (DOG1), and influences gibberellin and abscisic acid levels in mature seeds. Mutants lacking DOG1, or with altered gibberellin or abscisic acid synthesis or signaling, in turn show reduced ability to enter the deeply dormant states in response to low seed maturation temperatures. In addition, we find that DOG1 promotes gibberellin catabolism during maturation. We show that C-REPEAT BINDING FACTORS (CBFs) are necessary for regulation of dormancy and of GA2OX6 and DOG1 expression caused by low temperatures. However, the temperature sensitivity of CBF transcription is markedly reduced in seeds and is absent in imbibed seeds. Our data demonstrate that inhibition of CBF expression is likely a critical feature allowing cold to promote rather than inhibit germination and support a model in which CBFs act in parallel to a low-temperature signaling pathway in the regulation of dormancy.
authors.affiliation: Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Kendall
authors.forename: Anja
authors.initials: A
authors.lastname: Hellwege
authors.forename: Poppy
authors.initials: P
authors.lastname: Marriot
authors.forename: Celina
authors.initials: C
authors.lastname: Whalley
authors.forename: Ian A
authors.initials: IA
authors.lastname: Graham
authors.forename: Steven
authors.initials: S
authors.lastname: Penfield
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D050660:Core Binding Factors / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000378:metabolism*; D046228:Microarray Analysis; D008954:Models, Biological; D057445:Plant Dormancy / Q000235:genetics*; D012621:Seasons; D015398:Signal Transduction / Q000235:genetics; D014158:Transcription, Genetic; D059467:Transcriptome
chemical_list: D029681:Arabidopsis Proteins; D050660:Core Binding Factors; C532384:DOG1 protein, Arabidopsis; D005875:Gibberellins; D000040:Abscisic Acid