title: NYC4, the rice ortholog of Arabidopsis THF1, is involved in the degradation of chlorophyll - protein complexes during leaf senescence.
abstract: Yellowing/chlorophyll breakdown is a prominent phenomenon in leaf senescence, and is associated with the degradation of chlorophyll - protein complexes. From a rice mutant population generated by ionizing radiation, we isolated nyc4-1, a stay-green mutant with a defect in chlorophyll breakdown during leaf senescence. Using gene mapping, nyc4-1 was found to be linked to two chromosomal regions. We extracted Os07g0558500 as a candidate for NYC4 via gene expression microarray analysis, and concluded from further evidence that disruption of the gene by a translocation-related event causes the nyc4 phenotype. Os07g0558500 is thought to be the ortholog of THF1 in Arabidopsis thaliana. The thf1 mutant leaves show variegation in a light intensity-dependent manner. Surprisingly, the Fv /Fm value remained high in nyc4-1 during the dark incubation, suggesting that photosystem II retained its function. Western blot analysis revealed that, in nyc4-1, the PSII core subunits D1 and D2 were significantly retained during leaf senescence in comparison with wild-type and other non-functional stay-green mutants, including sgr-2, a mutant of the key regulator of chlorophyll degradation SGR. The role of NYC4 in degradation of chlorophyll and chlorophyll - protein complexes during leaf senescence is discussed.
authors: Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors: Hiroshi
authors: H
authors: Yamatani
authors: Yutaka
authors: Y
authors: Sato
authors: Yu
authors: Y
authors: Masuda
authors: Yusuke
authors: Y
authors: Kato
authors: Ryouhei
authors: R
authors: Morita
authors: Kenji
authors: K
authors: Fukunaga
authors: Yoshiaki
authors: Y
authors: Nagamura
authors: Minoru
authors: M
authors: Nishimura
authors: Wataru
authors: W
authors: Sakamoto
authors: Ayumi
authors: A
authors: Tanaka
authors: Makoto
authors: M
authors: Kusaba
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D016922:Cellular Senescence; D002734:Chlorophyll / Q000378:metabolism; D061146:Chlorophyll Binding Proteins / Q000378:metabolism*; D002874:Chromosome Mapping; D003624:Darkness; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D008027:Light; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D010641:Phenotype; D045332:Photosystem II Protein Complex / Q000378:metabolism; D010860:Pigments, Biological / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis; D017382:Reactive Oxygen Species / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D014178:Translocation, Genetic
chemical_list: D029681:Arabidopsis Proteins; D061146:Chlorophyll Binding Proteins; D008565:Membrane Proteins; D045332:Photosystem II Protein Complex; D010860:Pigments, Biological; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; C512069:THF1 protein, Arabidopsis; D002734:Chlorophyll