Linked Life Data

21205028

Source:http://linkedlifedata.com/resource/pubmed/id/21205028

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2011-3-22
pubmed:abstractText
Ferredoxins are the main electron shuttles in chloroplasts, accepting electrons from photosystem I and delivering them to essential oxido-reductive pathways in the stroma. Ferredoxin levels decrease under adverse environmental conditions in both plants and photosynthetic micro-organisms. In cyanobacteria and some algae, this decrease is compensated for by induction of flavodoxin, an isofunctional flavoprotein that can replace ferredoxin in many reactions. Flavodoxin is not present in plants, but tobacco lines expressing a plastid-targeted cyanobacterial flavodoxin developed increased tolerance to environmental stress. Chloroplast-located flavodoxin interacts productively with endogenous ferredoxin-dependent pathways, suggesting that its protective role results from replacement of stress-labile ferredoxin. We tested this hypothesis by using RNA antisense and interference techniques to decrease ferredoxin levels in transgenic tobacco. Ferredoxin-deficient lines showed growth arrest, leaf chlorosis and decreased CO(2) assimilation. Chlorophyll fluorescence measurements indicated impaired photochemistry, over-reduction of the photosynthetic electron transport chain and enhanced non-photochemical quenching. Expression of flavodoxin from the nuclear or plastid genome restored growth, pigment contents and photosynthetic capacity, and relieved the electron pressure on the electron transport chain. Tolerance to oxidative stress also recovered. In the absence of flavodoxin, ferredoxin could not be decreased below 45% of physiological content without fatally compromising plant survival, but in its presence, lines with only 12% remaining ferredoxin could grow autotrophically, with almost wild-type phenotypes. The results indicate that the stress tolerance conferred by flavodoxin expression in plants stems largely from functional complementation of endogenous ferredoxin by the cyanobacterial flavoprotein.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1365-313X
pubmed:author
pubmed:copyrightInfo
© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.
pubmed:issnType
Electronic
pubmed:volume
65
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
922-35
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Cyanobacterial flavodoxin complements ferredoxin deficiency in knocked-down transgenic tobacco plants.
pubmed:affiliation
División Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Universidad Nacional de Rosario, S2002LRK Rosario, Argentina.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't