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Defect in non‐yellow coloring 3, an α/β hydrolase‐fold family protein, causes a stay‐green phenotype during leaf senescence in rice
Author(s) -
Morita Ryouhei,
Sato Yutaka,
Masuda Yu,
Nishimura Minoru,
Kusaba Makoto
Publication year - 2009
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/j.1365-313x.2009.03919.x
Subject(s) - chlorophyll , mutant , senescence , biology , pheophytin , chlorophyll b , tetrapyrrole , wild type , chlorophyllin , chlorophyll a , biochemistry , botany , microbiology and biotechnology , gene , enzyme , photosystem ii , photosynthesis
Summary Chlorophyll degradation is an important phenomenon in the senescence process. It is necessary for the degradation of certain chlorophyll–protein complexes and thylakoid membranes during leaf senescence. Mutants retaining greenness during leaf senescence are known as ‘stay‐green’ mutants. Non‐functional type stay‐green mutants, which possess defects in chlorophyll degradation, retain greenness but not leaf functionality during senescence. Here, we report a new stay‐green mutant in rice, nyc3 . nyc3 retained a higher chlorophyll a and chlorophyll b content than the wild‐type but showed a decrease in other senescence parameters during dark incubation, suggesting that it is a non‐functional stay‐green mutant. In addition, a small amount of pheophytin a , a chlorophyll a ‐derivative without Mg 2+ ions in its tetrapyrrole ring, accumulated in the senescent leaves of nyc3 . nyc3 shows a similar but weaker phenotype to stay green ( sgr ), another non‐functional stay‐green mutant in rice. The chlorophyll content of nyc3 sgr double mutants at the late stage of leaf senescence was also similar to that of sgr . Linkage analysis revealed that NYC3 is located near the centromere region of chromosome 6. Map‐based cloning of genes near the centromere is very difficult because of the low recombination rate; however, we overcame this problem by using ionizing radiation‐induced mutant alleles harboring deletions of hundreds of kilobases. Thus, it was revealed that NYC3 encodes a plastid‐localizing α/β hydrolase‐fold family protein with an esterase/lipase motif. The possible function of NYC3 in the regulation of chlorophyll degradation is discussed.