Linked Life Data

16506064

Source:http://linkedlifedata.com/resource/pubmed/id/16506064

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2006-8-9
pubmed:abstractText
Cytokinin promotes morphological and physiological processes including the tetrapyrrole biosynthetic pathway during plant development. Only a few steps of chlorophyll (Chl) biosynthesis, exerting the phytohormonal influence, have been individually examined. We performed a comprehensive survey of cytokinin action on the regulation of tetrapyrrole biosynthesis with etiolated and greening barley seedlings. Protein contents, enzyme activities and tetrapyrrole metabolites were analyzed for highly regulated metabolic steps including those of 5-aminolevulinic acid (ALA) biosynthesis and enzymes at the branch point for protoporphyrin IX distribution to Chl and heme. Although levels of the two enzymes of ALA synthesis, glutamyl-tRNA reductase and glutamate 1-semialdehyde aminotransferase, were elevated in dark grown kinetin-treated barley seedlings, the ALA synthesis rate was only significantly enhanced when plant were exposed to light. While cytokinin do not stimulatorily affect Fe-chelatase activity and heme content, it promotes activities of the first enzymes in the Mg branch, Mg protoporphyrin IX chelatase and Mg protoporphyrin IX methyltransferase, in etiolated seedlings up to the first 5 h of light exposure in comparison to control. This elevated activities result in stimulated Chl biosynthesis, which again parallels with enhanced photosynthetic activities indicated by the photosynthetic parameters F(V)/F(M), J (CO2max) and J (CO2) in the kinetin-treated greening seedlings during the first hours of illumination. Thus, cytokinin-driven acceleration of the tetrapyrrole metabolism supports functioning and assembly of the photosynthetic complexes in developing chloroplasts.
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
224
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
700-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Cytokinin effects on tetrapyrrole biosynthesis and photosynthetic activity in barley seedlings.
pubmed:affiliation
Institute of biophysics and cell engineering, National academy of sciences of Belarus, Akademicheskaya 27, 220072 Minsk, Belarus.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't