RRC ID 608
Author Pruzinská A, Tanner G, Aubry S, Anders I, Moser S, Müller T, Ongania KH, Kräutler B, Youn JY, Liljegren SJ, Hörtensteiner S.
Title Chlorophyll breakdown in senescent Arabidopsis leaves. Characterization of chlorophyll catabolites and of chlorophyll catabolic enzymes involved in the degreening reaction.
Journal Plant Physiol.
Abstract During senescence, chlorophyll (chl) is metabolized to colorless nonfluorescent chl catabolites (NCCs). A central reaction of the breakdown pathway is the ring cleavage of pheophorbide (pheide) a to a primary fluorescent chl catabolite. Two enzymes catalyze this reaction, pheide a oxygenase (PAO) and red chl catabolite reductase. Five NCCs and three fluorescent chl catabolites (FCCs) accumulated during dark-induced chl breakdown in Arabidopsis (Arabidopsis thaliana). Three of these NCCs and one FCC (primary fluorescent chl catabolite-1) were identical to known catabolites from canola (Brassica napus). The presence in Arabidopsis of two modified FCCs supports the hypothesis that modifications, as present in NCCs, occur at the level of FCC. Chl degradation in Arabidopsis correlated with the accumulation of FCCs and NCCs, as well as with an increase in PAO activity. This increase was due to an up-regulation of Pao gene expression. In contrast, red chl catabolite reductase is not regulated during leaf development and senescence. A pao1 knockout mutant was identified and analyzed. The mutant showed an age- and light-dependent cell death phenotype on leaves and in flowers caused by the accumulation of photoreactive pheide a. In the dark, pao1 exhibited a stay-green phenotype. The key role of PAO in chl breakdown is discussed.
Volume 139(1)
Pages 52-63
Published 2005-9
DOI 10.1104/pp.105.065870
PII pp.105.065870
PMID 16113212
PMC PMC1203357
MeSH Apoptosis Regulatory Proteins / metabolism Arabidopsis / enzymology* Arabidopsis / metabolism Arabidopsis Proteins / metabolism Cell Death Chlorophyll / analogs & derivatives* Chlorophyll / chemistry Chlorophyll / metabolism* DNA, Bacterial / genetics Gene Expression Regulation, Enzymologic Gene Expression Regulation, Plant Light Molecular Structure Mutagenesis, Insertional / genetics Oxidoreductases / metabolism Oxygenases / genetics Oxygenases / metabolism Phenotype Plant Leaves / enzymology Plant Leaves / growth & development* Plant Leaves / metabolism* Time Factors
IF 5.949
Times Cited 144
Arabidopsis / Cultured plant cells, genes pda07874