JXB Advance Access originally published online on October 17, 2008
Journal of Experimental Botany 2008 59(14):3869-3884; doi:10.1093/jxb/ern227
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© 2008 The Author(s).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details)
RESEARCH PAPER |
An Arabidopsis mutant able to green after extended dark periods shows decreased transcripts of seed protein genes and altered sensitivity to abscisic acid


1Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
2Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
To whom correspondence should be addressed. E-mail: jcg2{at}mole.bio.cam.ac.uk.
An Arabidopsis mutant showing an altered ability to green on illumination after extended periods of darkness has been isolated in a screen for genomes uncoupled (gun) mutants. Following illumination for 24 h, 10-day-old dark-grown mutant seedlings accumulated five times more chlorophyll than wild-type seedlings and this was correlated with differences in plastid morphology observed by transmission electron microscopy. The mutant has been named greening after extended darkness 1 (ged1). Microarray analysis showed much lower amounts of transcripts of genes encoding seed storage proteins, oleosins, and late embryogenesis abundant (LEA) proteins in 7-day-old seedlings of ged1 compared with the wild type. RNA gel-blot analyses confirmed very low levels of transcripts of seed protein genes in ged1 seedlings grown for 2–10 d in the dark, and showed higher amounts of transcripts of photosynthesis-related genes in illuminated 10-day-old dark-grown ged1 seedlings compared with the wild type. Consensus elements similar to abscisic acid (ABA) response elements (ABREs) were detected in the upstream regions of all genes highly affected in ged1. Germination of ged1 seeds was hypersensitive to ABA, although no differences in ABA content were detected in 7-day-old seedlings. This suggests the mutant may have an altered responsiveness to ABA, affecting expression of ABA-responsive genes and plastid development during extended darkness.
Key words: abscisic acid, Arabidopsis, greening, photosynthesis genes, seed protein genes
* Present address: Division of Cardiovascular Medicine, University of Cambridge, Box 110, ACCI, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK.
Present address: School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
Received 12 June 2008; Revised 10 August 2008 Accepted 11 August 2008