Linked Life Data

11556795

Source:http://linkedlifedata.com/resource/pubmed/id/11556795

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2001-9-14
pubmed:abstractText
The enzyme geranylgeranyl reductase (CHL P) catalyses the reduction of geranylgeranyl diphosphate to phytyl diphosphate in higher-plant chloroplasts and provides phytol for both chlorophyll (Chl) and tocopherol synthesis. The reduction in CHL P activity in transgenic tobacco (Nicotiana tabacum L.) plants is accompanied by the reduction in total Chl and tocopherol content and the accumulation of geranylgeranylated Chl (ChlGG). The photosynthetic performance and the susceptibility to photo-oxidative stress have been investigated in these transgenic plants. The reduced total Chl content in Chl P antisense plants resulted in the reduction of electron transport chains per leaf area without a concomitant effect on the stoichiometry, composition and activity of both photosystems. However, Chl P antisense plants were much more sensitive to light stress. Analyses of Chl fluorescence quenching indicated an increased photoinhibitory quenching at the expense of the pH-dependent fluorescence quenching after short illumination (15 min) at moderate light intensities. Prolonged illumination (up to 1 h) at saturating light intensities induced an increased photoinactivation from which the Chl P antisense plants could not recover or could only partially recover during a subsequent low light phase. Our data imply that the presence of ChlGG has no influence on harvesting and transfer of light energy in either photosystem. However, the reduced tocopherol content of the thylakoid membrane is a limiting factor for defensive reactions to photo-oxidative stress.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0032-0935
pubmed:author
pubmed:issnType
Print
pubmed:volume
213
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
620-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Loss of alpha-tocopherol in tobacco plants with decreased geranylgeranyl reductase activity does not modify photosynthesis in optimal growth conditions but increases sensitivity to high-light stress.
pubmed:affiliation
Heinrich-Heine-Universität Düsseldorf, Institut für Biochemie der Pflanzen, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't