Linked Life Data

17114182

Source:http://linkedlifedata.com/resource/pubmed/id/17114182

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2007-1-8
pubmed:abstractText
The cytochrome-b6f complex, a key component of the photosynthetic electron transport chain, contains a number of very small protein subunits whose functions are not well defined. Here we have investigated the function of the 31-amino acid PetL subunit encoded in the chloroplast genome in all higher plants. Chloroplast-transformed petL knock-out tobacco plants display no obvious phenotype, suggesting that PetL is not essential for cytochrome b6f complex biogenesis and function (Fiebig, A., Stegemann, S., and Bock, R. (2004) Nucleic Acids Res. 32, 3615-3622). We show here that, whereas young mutant leaves accumulate comparable amounts of cytochrome b6f complex and have an identical assimilation capacity as wild type leaves, both cytochrome b6f complex contents and assimilation capacities of mature and old leaves are strongly reduced in the mutant, indicating that the cytochrome b6f complex is less stable than in the wild type. Reduced complex stability was also confirmed by in vitro treatments of isolated thylakoids with chaotropic reagents. Adaptive responses observed in the knockout mutants, such as delayed down-regulation of plastocyanin contents, indicate that plants can sense the restricted electron flux to photosystem I yet cannot compensate the reduced stability of the cytochrome b6f complex by adaptive up-regulation of complex synthesis. We propose that efficient cytochrome b6f complex biogenesis occurs only in young leaves and that the capacity for de novo synthesis of the complex is very low in mature and aging leaves. Gene expression analysis indicates that the ontogenetic down-regulation of cytochrome b6f complex biogenesis occurs at the post-transcriptional level.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
282
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
976-85
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Knock-out of the plastid-encoded PetL subunit results in reduced stability and accelerated leaf age-dependent loss of the cytochrome b6f complex.
pubmed:affiliation
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany. schoettler@mpimp-golm.mpg.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't