Defects in a Proteolytic Step of Light-Harvesting Complex 2 in an Arabidopsis Stay-Green Mutant, ore10, during Dark-Induced Leaf Senescence

During dark-induced leaf senescence (DIS), the non-functional stay-green mutant orel0 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-t...

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Bibliographic Details
Published in:Journal of plant biology = Singmul Hakhoe chi 2004-12, Vol.47 (4), p.330
Main Authors: Min Hyuk Oh, Jin Hong Kim, Yong Hwan Moon, Choon Hwan Lee
Format: Article
Language:Korean
Subjects:
Arabidopsis thaliana
leaf senescence
light-harvesting complex 2
proteolysis
stay-green mutant
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Summary:During dark-induced leaf senescence (DIS), the non-functional stay-green mutant orel0 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). The orel0 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 and orel0 LHCⅡ, indicating that its stability in orel0 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 stromaexposed thylakoid regions.
ISSN:1226-9239
1867-0725