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Accumulation of the NON ‐ YELLOW COLORING 1 protein of the chlorophyll cycle requires chlorophyll b in A rabidopsis thaliana
Author(s) -
Jia Ting,
Ito Hisashi,
Hu Xueyun,
Tanaka Ayumi
Publication year - 2015
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12753
Subject(s) - chlorophyll , chlorophyll b , chlorophyll a , chloroplast , chemistry , biochemistry , biology , botany , gene
Summary Chlorophyll a and chlorophyll b are interconverted in the chlorophyll cycle. The initial step in the conversion of chlorophyll b to chlorophyll a is catalyzed by the chlorophyll b reductases NON ‐ YELLOW COLORING 1 ( NYC 1) and NYC 1‐like ( NOL ), which convert chlorophyll b to 7‐hydroxymethyl chlorophyll a . This step is also the first stage in the degradation of the light‐harvesting chlorophyll a / b protein complex ( LHC ). In this study, we examined the effect of chlorophyll b on the level of NYC 1. NYC 1 mRNA and NYC 1 protein were in low abundance in green leaves, but their levels increased in response to dark‐induced senescence. When the level of chlorophyll b was enhanced by the introduction of a truncated chlorophyllide a oxygenase gene and the leaves were incubated in the dark, the amount of NYC 1 was greatly increased compared with that of the wild type; however, the amount of NYC 1 mRNA was the same as in the wild type. In contrast, NYC 1 did not accumulate in the mutant without chlorophyll b , even though the NYC 1 mRNA level was high after incubation in the dark. Quantification of the LHC protein showed no strong correlation between the levels of NYC 1 and LHC proteins. However, the level of chlorophyll fluorescence of the dark adapted plant ( F o ) was closely related to the accumulation of NYC 1, suggesting that the NYC 1 level is related to the energetically uncoupled LHC . These results and previous reports on the degradation of chlorophyllide a oxygenase suggest that the a feedforward and feedback network is included in chlorophyll cycle.