A green-revertible albino mutant-Qiufeng M was found from the japonica rice （Oryza sativa L. ssp. japonica） Qiufeng in the field. The first three leaves of the mutant were albino with some green. The leaf color beca...A green-revertible albino mutant-Qiufeng M was found from the japonica rice （Oryza sativa L. ssp. japonica） Qiufeng in the field. The first three leaves of the mutant were albino with some green. The leaf color became pale green since the fourth leaf and the glume had the same phenomenon as the first three leaves. The measuring data of the pigment content confirmed the visually observed results. It truly had a remarkable changing process in the leaf color in Qiufeng M. Comparison of the main agronomic characters between Qiufeng and Qiufeng M indicated that the neck length and grain weight showed significant difference at the 1% level, and other characters were not different. Genetic analysis showed that the green-revertible albino trait was controlled by a single recessive nucleic gene. Using 209 recessive mutant individuals in the F2 population derived from the cross Pei＇ai 64S × Qiufeng M, a gene, tentatively named gra（t）, was located between the SSR markers of RM475 and RM2-22 on the long arm of chromosome 2. The genetic distance were 17.3 cM and 2.9 cM respectively.展开更多
Albino mutants are useful genetic resource for studying chlorophyll biosynthesis and chloroplast development and cloning genes involved in these processes in plants. Here we report a novel rice mutant low temperature ...Albino mutants are useful genetic resource for studying chlorophyll biosynthesis and chloroplast development and cloning genes involved in these processes in plants. Here we report a novel rice mutant low temperature albino I （ltal） that showed albino leaves before 4-leaf stage when grown under temperature lower than 20℃, but developed normal green leaves under temperature higher than 24℃ or similar morphological phenotypes in dark as did the wild-type （WT）. Our analysis showed that the contents of chlorophylls and chlo- rophyll precursors were remarkably decreased in the Ital mutant under low temperature compared to WT. Transmission electron microscope observation revealed that chloroplasts were defectively developed in the albino ltal leaves, which lacked of well-stacked granum and contained less stroma lamellae. These results suggested that the ltal mutation may delay the light-induced thylakoid assembly under low temperature. Genetic analysis indicated that the albino phenotype was controlled by a single recessive locus. Through map-based approach, we finally located the Ltal gene to a region of 40.3 kb on the short arm of chromosome 11. There are 8 predicted open reading frames （ORFs） in this region and two of them were deleted in ltal genome compared with the WT genome. The further characterization of the Ltal gene would provide a good approach to uncover the novel molecular mechanisms involved in chloroplast development under low temperature stress.展开更多
The cytochrome b_(6f)(Cyt b_(6f))complex is a multisubunit protein complex in chloroplast thylakoid membranes required for photosynthetic electron transport.Here we report the isolation and characterization of the new...The cytochrome b_(6f)(Cyt b_(6f))complex is a multisubunit protein complex in chloroplast thylakoid membranes required for photosynthetic electron transport.Here we report the isolation and characterization of the new tiny albino 1(nta1)mutant in Arabidopsis,which has severe defects in Cyt b_(6f) accumulation and chloroplast development.Gene cloning revealed that the nta1 phenotype was caused by disruption of a single nuclear gene,NTA1,which encodes an integral thylakoid membrane protein conserved across green algae and plants.Overexpression of NTA1 completely rescued the nta1 phenotype,and knockout of NTA1 in wild-type plants recapitulated the mutant phenotype.Loss of NTA1 function severely impaired the accumulation of multiprotein complexes related to photosynthesis in thylakoid membranes,particularly the components of Cyt b_(6f).NTA1 was shown to directly interact with four subunits(Cyt b6/PetB,PetD,PetG,and PetN)of Cyt b_(6f) through the DUF1279 domain and C-terminal sequence to mediate their assembly.Taken together,our results identify NTA1 as a new and key regulator of chloroplast development that plays essential roles in assembly of the Cyt b_(6f) complex by interacting with multiple Cyt b_(6f) subunits.展开更多
基金This work was supported by the Major Research Program on Technology of Agricultural Structure Adjustment (No. 05-01-05B)Jiangsu High Technology Program (No. BG2004301, BG2004304, and BG2005301).
文摘A green-revertible albino mutant-Qiufeng M was found from the japonica rice （Oryza sativa L. ssp. japonica） Qiufeng in the field. The first three leaves of the mutant were albino with some green. The leaf color became pale green since the fourth leaf and the glume had the same phenomenon as the first three leaves. The measuring data of the pigment content confirmed the visually observed results. It truly had a remarkable changing process in the leaf color in Qiufeng M. Comparison of the main agronomic characters between Qiufeng and Qiufeng M indicated that the neck length and grain weight showed significant difference at the 1% level, and other characters were not different. Genetic analysis showed that the green-revertible albino trait was controlled by a single recessive nucleic gene. Using 209 recessive mutant individuals in the F2 population derived from the cross Pei＇ai 64S × Qiufeng M, a gene, tentatively named gra（t）, was located between the SSR markers of RM475 and RM2-22 on the long arm of chromosome 2. The genetic distance were 17.3 cM and 2.9 cM respectively.
基金supported by the grants from the National Basic Research Program of China(No.2009CB119000)the Ministry of Agriculture of China for Transgenic Research (Nos.2011ZX08009-003,2011ZX08001-005)the National Science Foundation of China(Nos.31000094,30970246, 31100188 and 31161130533)
文摘Albino mutants are useful genetic resource for studying chlorophyll biosynthesis and chloroplast development and cloning genes involved in these processes in plants. Here we report a novel rice mutant low temperature albino I （ltal） that showed albino leaves before 4-leaf stage when grown under temperature lower than 20℃, but developed normal green leaves under temperature higher than 24℃ or similar morphological phenotypes in dark as did the wild-type （WT）. Our analysis showed that the contents of chlorophylls and chlo- rophyll precursors were remarkably decreased in the Ital mutant under low temperature compared to WT. Transmission electron microscope observation revealed that chloroplasts were defectively developed in the albino ltal leaves, which lacked of well-stacked granum and contained less stroma lamellae. These results suggested that the ltal mutation may delay the light-induced thylakoid assembly under low temperature. Genetic analysis indicated that the albino phenotype was controlled by a single recessive locus. Through map-based approach, we finally located the Ltal gene to a region of 40.3 kb on the short arm of chromosome 11. There are 8 predicted open reading frames （ORFs） in this region and two of them were deleted in ltal genome compared with the WT genome. The further characterization of the Ltal gene would provide a good approach to uncover the novel molecular mechanisms involved in chloroplast development under low temperature stress.
基金This work was supported by Program for New Century Excellent Talents in University (No. NCET-04-0907) and Program for In-novative Research Team in University (No.IRT0453).
基金supported by the General Research Fund(CUHK codes 14121915,14148916,and 14104521)the Area of Excellence Scheme(AoE/M-403/16 and AoE/M-05/12)of the Research Grants Council(RGC)of Hong Kong+1 种基金the National Natural Science Foundation of China(NSFC)-RGC Joint Scheme(N_CUHK452/17)direct grants from the Chinese University of Hong Kong(CUHK).
文摘The cytochrome b_(6f)(Cyt b_(6f))complex is a multisubunit protein complex in chloroplast thylakoid membranes required for photosynthetic electron transport.Here we report the isolation and characterization of the new tiny albino 1(nta1)mutant in Arabidopsis,which has severe defects in Cyt b_(6f) accumulation and chloroplast development.Gene cloning revealed that the nta1 phenotype was caused by disruption of a single nuclear gene,NTA1,which encodes an integral thylakoid membrane protein conserved across green algae and plants.Overexpression of NTA1 completely rescued the nta1 phenotype,and knockout of NTA1 in wild-type plants recapitulated the mutant phenotype.Loss of NTA1 function severely impaired the accumulation of multiprotein complexes related to photosynthesis in thylakoid membranes,particularly the components of Cyt b_(6f).NTA1 was shown to directly interact with four subunits(Cyt b6/PetB,PetD,PetG,and PetN)of Cyt b_(6f) through the DUF1279 domain and C-terminal sequence to mediate their assembly.Taken together,our results identify NTA1 as a new and key regulator of chloroplast development that plays essential roles in assembly of the Cyt b_(6f) complex by interacting with multiple Cyt b_(6f) subunits.
