Linked Life Data

18318659

Source:http://linkedlifedata.com/resource/pubmed/id/18318659

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-5-9
pubmed:abstractText
Photosynthetic light reactions comprise a significant source of hydrogen peroxide (H(2)O(2)) in illuminated leaves. APXs (ascorbate peroxidases) reduce H(2)O(2) to water and play an important role in the antioxidant system of plants. In the present study we addressed the significance of chloroplast APXs in stress tolerance and signalling in Arabidopsis thaliana. To this end, T-DNA (transfer DNA) insertion mutants tapx, sapx and tapx sapx, lacking the tAPX (thylakoid-bound APX), sAPX (stromal APX) or both respectively, were characterized. Photo-oxidative stress during germination led to bleaching of chloroplasts in sapx single-mutant and particularly in the tapx sapx double-mutant plants, whereas the greening process of wild-type and tapx plants was only partially impaired. Mature leaves of tapx sapx double mutants were also susceptible to short-term photo-oxidative stress induced by high light or methyl viologen treatments. After a 2-week acclimation period under high light or under low temperature, none of the mutants exhibited enhanced stress symptoms. Immunoblot analysis revealed that high-light-stress-acclimated tapx sapx double mutants compensated for the absence of tAPX and sAPX by increasing the level of 2-cysteine peroxiredoxin. Furthermore, the absence of tAPX and sAPX induced alterations in the transcriptomic profile of tapx sapx double-mutant plants already under quite optimal growth conditions. We conclude that sAPX is particularly important for photoprotection during the early greening process. In mature leaves, tAPX and sAPX are functionally redundant, and crucial upon sudden onset of oxidative stress. Moreover, chloroplast APXs contribute to chloroplast retrograde signalling pathways upon slight fluctuations in the accumulation of H(2)O(2) in chloroplasts.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1470-8728
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
412
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
275-85
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Diverse roles for chloroplast stromal and thylakoid-bound ascorbate peroxidases in plant stress responses.
pubmed:affiliation
Department of Biology, University of Turku, FI-20014 Turku, Finland.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't