Linked Life Data

9351249

Source:http://linkedlifedata.com/resource/pubmed/id/9351249

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1997-12-24
pubmed:abstractText
The structurally related light-dependent protochlorophyllide (Pchlide) oxidoreductases PORA and PORB mediate the only light-requiring step in chlorophyll (Chl) biosynthesis in higher plants. Correlative evidence suggests that some in vivo functions of PORA and PORB may be unique, including a postulated photoprotective role for PORA. For example, wild-type Arabidopsis thaliana seedlings grown in non-photooxidative far-red light (cFR) resemble those grown in white light (WL), but they are yellow and do not green normally thereafter in WL. This defect is accompanied by the absence of detectable PORA and reduced levels of PORB expression. Here, direct evidence is provided that the presence of POR, either as PORA or PORB, can confer photoprotection in plants. In contrast to the wild-type, the plastids of transgenic PORA- or PORB-overexpressing Arabidopsis seedlings grown in cFR possess extensive prolamellar bodies. Upon a subsequent shift to WL, POR-overexpressing seedlings develop thylakoid membranes, accumulate large amounts of Chl and are viable at fluence rates lethal to the wild-type. Intriguingly, the plastid membrane architectures of greening transgenic seedlings seem to depend on whether PORA or PORB has been overproduced. POR-overexpressing seedlings shifted from cFR to WL of fluence rates from 20 to 500 muE m-2 sec-1 accumulate substantially higher amounts of Chl than does the wild-type. Furthermore, the WL fluence rate that permits maximal Chl accumulation increases from 8 muE m-2 sec-1 in the wild-type to 125 muE m-2 sec-1 in transgenic seedlings. POR overexpression during growth in cFR also correlates with a fourfold decrease in the steady-state content of Pchlide, a potentially lethal photosensitizer.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0960-7412
pubmed:author
pubmed:issnType
Print
pubmed:volume
12
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
649-58
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Overexpression of light-dependent PORA or PORB in plants depleted of endogenous POR by far-red light enhances seedling survival in white light and protects against photooxidative damage.
pubmed:affiliation
Institute for Plant Sciences, Plant Genetics, Swiss Federal Institute of Technology (ETH), Zürich, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't