Document Detail

Nonsymbiotic hemoglobin-2 leads to an elevated energy state and to a combined increase in polyunsaturated fatty acids and total oil content when overexpressed in developing seeds of transgenic Arabidopsis plants.
MedLine Citation:
PMID:  21205621     Owner:  NLM     Status:  MEDLINE    
Nonsymbiotic hemoglobins are ubiquitously expressed in plants and divided into two different classes based on gene expression pattern and oxygen-binding properties. Most of the published research has been on the function of class 1 hemoglobins. To investigate the role of class 2 hemoglobins, transgenic Arabidopsis (Arabidopsis thaliana) plants were generated overexpressing Arabidopsis hemoglobin-2 (AHb2) under the control of a seed-specific promoter. Overexpression of AHb2 led to a 40% increase in the total fatty acid content of developing and mature seeds in three subsequent generations. This was mainly due to an increase in the polyunsaturated C18:2 (ω-6) linoleic and C18:3 (ω-3) α-linolenic acids. Moreover, AHb2 overexpression led to an increase in the C18:2/C18:1 and C18:3/C18:2 ratios as well as in the C18:3 content in mol % of total fatty acids and in the unsaturation/saturation index of total seed lipids. The increase in fatty acid content was mainly due to a stimulation of the rate of triacylglycerol synthesis, which was attributable to a 3-fold higher energy state and a 2-fold higher sucrose content of the seeds. Under low external oxygen, AHb2 overexpression maintained an up to 5-fold higher energy state and prevented fermentation. This is consistent with AHb2 overexpression results in improved oxygen availability within developing seeds. In contrast to this, overexpression of class 1 hemoglobin did not lead to any significant increase in the metabolic performance of the seeds. These results provide evidence for a specific function of class 2 hemoglobin in seed oil production and in promoting the accumulation of polyunsaturated fatty acids by facilitating oxygen supply in developing seeds.
Helene Vigeolas; Daniela Hühn; Peter Geigenberger
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-01-03
Journal Detail:
Title:  Plant physiology     Volume:  155     ISSN:  1532-2548     ISO Abbreviation:  Plant Physiol.     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-03-02     Completed Date:  2011-05-31     Revised Date:  2013-07-03    
Medline Journal Info:
Nlm Unique ID:  0401224     Medline TA:  Plant Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1435-44     Citation Subset:  IM    
Genetics of Microorganisms, Department of Life Sciences, Institute of Botany, University of Liege, 4000 Liege, Belgium.
Data Bank Information
Bank Name/Acc. No.:
RefSeq/NM_111887;  NM_127165
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MeSH Terms
Arabidopsis / drug effects,  embryology*,  genetics,  metabolism
Arabidopsis Proteins / metabolism*
Energy Metabolism* / drug effects
Fatty Acids, Unsaturated / metabolism*
Fermentation / drug effects
Hemoglobins / metabolism*
Organ Specificity / drug effects,  genetics
Oxygen / pharmacology
Plant Oils / metabolism*
Plants, Genetically Modified
Promoter Regions, Genetic / genetics
Seeds / drug effects,  embryology,  genetics,  metabolism*
Sucrose / metabolism
Symbiosis* / drug effects
Triglycerides / metabolism
alpha-Linolenic Acid / metabolism
Reg. No./Substance:
0/AHB1 protein, Arabidopsis; 0/AHB2 protein, Arabidopsis; 0/Arabidopsis Proteins; 0/Fatty Acids, Unsaturated; 0/Hemoglobins; 0/Plant Oils; 0/Triglycerides; 463-40-1/alpha-Linolenic Acid; 57-50-1/Sucrose; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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