Research article summary (published 29 Nov 2005):

RNA interference of Arabidopsis beta-amylase8 prevents maltose accumulation upon cold shock and increases sensitivity of PSII photochemical efficiency to freezing stress.

Full Abstract

It has been suggested that beta-amylase (BMY) induction during temperature stress in Arabidopsis could lead to starch-dependent maltose accumulation, and that maltose may contribute to protection of the electron transport chain and proteins in the chloroplast stroma during acute stress. A time-course transcript profiling analysis for cold shock at 4 degrees C revealed that BMY8 (At4g17090) was induced specifically in response to cold shock, while major induction was not observed for any of the other eight beta-amylases. A parallel metabolite-profiling analysis revealed a robust transient maltose accumulation during cold shock. BMY8 RNAi lines with lower BMY8 expression exhibited a starch-excess phenotype, and a dramatic decrease in maltose accumulation during a 6-h cold shock at 4 degrees C. The decreased maltose content was also accompanied by decreased glucose, fructose and sucrose content in the BMY8 RNAi plants, consistent with the roles of beta-amylase and maltose in transitory starch metabolism. BMY8 RNAi lines with reduced soluble sugar content exhibited diminished chlorophyll fluorescence as F(v)/F(m) ratio compared with wild type, suggesting that PSII photochemical efficiency was more sensitive to freezing stress. Together, carbohydrate analysis and freezing stress results of BMY8 RNAi lines indicate that increased maltose content, by itself or together through a maltose-dependent increase in other soluble sugars, contributes to the protection of the photosynthetic electron transport chain during freezing stress.

Author information

Author/s: Kaplan, Fatma (F); Guy, Charles L (CL);

Affiliation: Plant Molecular and Cellular Biology Program, Department of Environmental Horticulture, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611-0675, USA.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.

Journal: The Plant journal : for cell and molecular biology (Plant J), published in England. (Language: eng)

Reference: 2005-Dec; vol 44 (issue 5) : pp 730-43

Dates: Created 2005/11/21; Completed 2006/02/14; Revised 2008/11/21;

PMID: 16297066, status: MEDLINE (last retrieved date: 2/18/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MeSH Headings (categories) shown below.

Arabidopsis - enzymology; genetics Cold Temperature Freezing Gene Expression Regulation, Enzymologic Gene Expression Regulation, Plant Maltose - metabolism

Mutagenesis, Insertional Phenotype Photosynthesis Photosystem II Protein Complex - metabolism RNA Interference beta-Amylase - chemistry; genetics; metabolism

Note: Bold headings indicate primary MeSH headings or qualifiers.

Associated Chemicals: Photosystem II Protein Complex (0) ; Maltose (69-79-4) ; beta-Amylase (EC 3.2.1.2) ; beta-amylase8, Arabidopsis (EC 3.2.1.2)

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