Document Detail


Amino acid pattern and glutamate metabolism during dehydration stress in the 'resurrection' plant Sporobolus stapfianus: a comparison between desiccation-sensitive and desiccation-tolerant leaves.
MedLine Citation:
PMID:  17901195     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The present study analyses changes in nitrogen compounds, amino acid composition, and glutamate metabolism in the resurrection plant Sporobolus stapfianus during dehydration stress. Results showed that older leaves (OL) were desiccation-sensitive whereas younger leaves (YL) were desiccation-tolerant. OL lost their soluble protein more rapidly, and to a larger extent than YL. Enzymes of primary nitrogen assimilation were affected by desiccation and the decrease in the glutamine synthetase (GS, EC 6.3.1.2) and ferredoxin-dependent GOGAT (Fd-GOGAT, EC 1.4.7.1) activities was higher in OL than in YL, thus suggesting higher sensibility to dehydration. Moreover, YL showed higher total GS enzyme activity at the end of the dehydration stress and was shown to maintain high chloroplastic GS protein content during the entire stress period. Free amino acid content increased in both YL and OL between 88% and 6% relative water content. Interestingly, OL and YL did not accumulate the same amino acids. OL accumulated large amounts of proline and gamma-aminobutyrate whereas YL preferentially accumulated asparagine and arginine. It is concluded (i) that modifications in the nitrogen and amino acid metabolism during dehydration stress were different depending on leaf development and (ii) that proline and gamma-aminobutyrate accumulation in S. stapfianus leaves were not essential for the acquisition of desiccation tolerance. On the contrary, the accumulation of large amounts of asparagine and arginine in the YL during dehydration could be important and serve as essential nitrogen and carbon reservoirs useful during rehydration. In this context, the role of GS for asparagine accumulation in YL is discussed.
Authors:
Tommaso Martinelli; Anne Whittaker; Adriana Bochicchio; Concetta Vazzana; Akira Suzuki; Céline Masclaux-Daubresse
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of experimental botany     Volume:  58     ISSN:  0022-0957     ISO Abbreviation:  J. Exp. Bot.     Publication Date:  2007  
Date Detail:
Created Date:  2007-09-28     Completed Date:  2008-01-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9882906     Medline TA:  J Exp Bot     Country:  England    
Other Details:
Languages:  eng     Pagination:  3037-46     Citation Subset:  IM    
Affiliation:
Dipartimento di Scienze Agronomiche e Gestione del Territorio Agroforestale, Facoltà di Agraria, Università degli Studi di Firenze, I-50144 Firenze, Italia. tommaso.martinelli@unifi.it
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MeSH Terms
Descriptor/Qualifier:
Amino Acids / metabolism*
Chlorophyll / metabolism
Glutamic Acid / metabolism*
Nitrogen Compounds / metabolism
Plant Leaves / enzymology,  metabolism,  physiology
Plant Proteins / metabolism
Poaceae / enzymology,  metabolism*,  physiology
Water / metabolism*
Chemical
Reg. No./Substance:
0/Amino Acids; 0/Nitrogen Compounds; 0/Plant Proteins; 1406-65-1/Chlorophyll; 56-86-0/Glutamic Acid; 7732-18-5/Water

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


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