JXB Advance Access originally published online on November 2, 2008
Journal of Experimental Botany 2008 59(15):4205-4217; doi:10.1093/jxb/ern262
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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.
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RESEARCH PAPER |
Sucrose helps regulate cold acclimation of Arabidopsis thaliana
School of Biology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
$ To whom correspondence should be addressed. E-mail: r.s.pearce{at}ncl.ac.uk
A test was carried out to see if sucrose could regulate cold-acclimation-associated gene expression in Arabidopsis. In plants and excised leaves, sucrose caused an increase in GUS activity, as a reporter for the activity of the cold-responsive COR78 promoter. This increase was transient at 21 °C but lasted for at least 4 d at 4 °C in continuous darkness. However, at 4 °C with a 16 h photoperiod, GUS activity was similarly high with solutions lacking sucrose or with different concentrations of sucrose. In peeled lower epidermis in the cold dark environment, 40 mM sucrose increased COR78 transcript abundance to substantially above that in the controls, but sorbitol had no effect. Similarly to the cold and dark conditions, sucrose increased COR78 transcript abundance in the epidermis in the warm light and warm dark environments, but not in a cold light environment. Sucrose had much less effect on COR78 transcript abundance in leaves without the lower epidermis. Thus sucrose regulates expression of COR78, possibly mainly in the epidermis, at the level of transcription. Furthermore, 40 mM sucrose at 4 °C for 24 h in constant darkness was sufficient to give the same GUS activity as in fully acclimated plants of the same age in a 16 h photoperiod, although by 48 h, GUS activity had become intermediate between control and fully cold-acclimated plants. Thus sucrose has a regulatory role in the acclimation of whole plants to cold and this may be important during diurnal dark periods.
Key words: Acclimation, Arabidopsis, cold, COR78, freezing, gene expression, soluble carbohydrates, sucrose
* Present address: Biotek–Maderas, Lasao poligonoa, Anardi Area 5, E-20730, Azpeitia, Gipuzkoa, Spain.
Present address: Nasser University, College of Science, Department of Biology, Al Khomus, Libya.
Present address: Al-Jabal Elgharbi University, Faculty of Science, Libya.
Received 1 April 2008; Revised 23 September 2008 Accepted 6 October 2008