Defects in a proteolytic step of light-harvesting complex II in anArabidopsis stay-green mutant,ore10, during dark-induced leaf senescence

During dark-induced leaf senescence (DIS), the non-functional stay-green mutantore10 showed delayed chlorophyll (Chl) degradation and increased stability in its light-harvesting complex II (LHCII). These phenomena were closely related to the formation of aggregates that mainly consisted of terminal-...

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Bibliographic Details
Published in:Journal of plant biology = Singmul Hakhoe chi 2004-12, Vol.47 (4), p.330-337
Main Authors: Oh, Min-Hyuk, Kim, Jin-Hong, Moon, Yong-Hwan, Lee, Choon-Hwan
Format: Article
Language:English
Subjects:
Chlorophyll
Defects
Degradation
Leaves
Light-harvesting complex
Mutants
Polypeptides
Protease
Proteinase
Proteolysis
Senescence
Stability
Stroma
Thylakoids
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Summary:During dark-induced leaf senescence (DIS), the non-functional stay-green mutantore10 showed delayed chlorophyll (Chl) degradation and increased stability in its light-harvesting complex II (LHCII). These phenomena were closely related to the formation of aggregates that mainly consisted of terminal-truncated LHCII (Oh et al., 2003). Theore10 mutant apparently lacks the protease needed to degrade the truncated LHCII. In wild-type (WT) plants, protease was found in the thylakoid fraction, but not the soluble fraction. A similar experiment using dansylated LHCII revealed that the protease degraded both WT andore10 LHCII, indicating that its stability inore10 perhaps did not result from a defect in the LHCII polypeptides themselves. Although protease activity was not present in non-senesced WT leaves, it was induced during DIS. It also was possible to diminish the high level of protease present in the thylakoids through high-salt washing, suggesting that this enzyme is extrinsically bound to the outer surface of the stroma-exposed thylakoid regions.
ISSN:1226-9239
1867-0725
DOI:10.1007/BF03030548