Linked Life Data

15657716

Source:http://linkedlifedata.com/resource/pubmed/id/15657716

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2005-6-14
pubmed:abstractText
The aim of this work was to examine the role of sucrose-6-phosphate phosphatase (SPP; EC 3.1.3.24) in photosynthetic carbon partitioning. SPP catalyzes the final step in the pathway of sucrose synthesis; however, until now the importance of this enzyme in plants has not been studied by reversed-genetics approaches. With the intention of conducting such a study, transgenic tobacco plants with reduced SPP levels were produced using an RNA interference (RNAi) strategy. Transformants with less than 10% of wild-type SPP activity displayed a range of phenotypes, including those that showed inhibition of photosynthesis, chlorosis, and reduced growth rates. These plants had strongly reduced levels of sucrose and hexoses but contained 3-5 times more starch than the control specimens. The leaves were unable to export transient starch during extended periods of darkness and as consequence showed a starch- and maltose-excess phenotype. This indicates that no alternative mechanism for carbon export was activated. Inhibition of SPP resulted in an approximately 1,000-fold higher accumulation of sucrose-6-phosphate (Suc6P) compared to wild-type leaves, whereas the content of hexose-phosphates was reduced. Although the massive accumulation of Suc6P in the cytosol of transgenic leaves was assumed to impair phosphate-recycling into the chloroplast, no obvious signs of phosphate-limitation of photosynthesis became apparent. 3-Phosphoglycerate (3-PGA) levels dropped slightly and the ATP/ADP ratio was not reduced in the transgenic lines under investigation. It is proposed that in SPP-deficient plants, long-term compensatory responses give rise to the observed acceleration of starch synthesis, increase in total cellular Pi content, decrease in protein content, and related reduction in photosynthetic activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0032-0935
pubmed:author
pubmed:issnType
Print
pubmed:volume
221
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
479-92
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Decreased sucrose-6-phosphate phosphatase level in transgenic tobacco inhibits photosynthesis, alters carbohydrate partitioning, and reduces growth.
pubmed:affiliation
Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstrasse 3, 06466 Gatersleben, Germany.
pubmed:publicationType
Journal Article