The Arabidopsis Spontaneous Cell Death1 gene, encoding a ζ-carotene desaturase essential for carotenoid biosynthesis, is involved in chloroplast development, photoprotection and retrograde signalling  

作　　者：Haili Dong Yan Deng Jinye Mu Qingtao Lu Yiqin Wang Yunyuan Xu Chengcai Chu Kang Chong Congming Lu Jianru Zuo 

机构地区：[1]State Key Laboratory of Plant Genomics and National Plant Gene Research Center (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China, [2]Graduate School Chinese Academy of Sciences, Beijing 100039, China [3]Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China

出　　处：《Cell Research》2007年第5期458-470,共13页细胞研究（英文版）

基　　金：grants from National Natural Science Foundation of China （Grant Nos. 30330360, 30125025 , 30221002）; Chinese Academy of Sciences （Grant No. KSCX2- YW-N-015）

摘　　要：Carotenoids, a class of natural pigments found in all photosynthetic organisms, are involved in a variety of physiological processes, including coloration, photoprotection, biosynthesis of abscisic acid （ABA） and chloroplast biogenesis. Although carotenoid biosynthesis has been well studied biochemically, the genetic basis of the pathway is not well understood. Here, we report the characterization of two allelic Arabidopsis mutants, spontaneous cell death1-1 （spcl-1） and spc1-2. The weak allele spc1-1 mutant showed characteristics of bleached leaves, accumulation of superoxide and mosaic cell death. The strong mutant allele spc1-2 caused a complete arrest of plant growth and development shortly after germination, leading to a seedling-lethal phenotype. Genetic and molecular analyses indicated that SPC1 encodes a putative ζ-carotene desaturase （ZDS） in the carotenoid biosynthesis pathway. Analysis of carotenoids revealed that several major carotenoid compounds downstream of SPC 1/ZDS were substantially reduced in spc1-1, suggesting that SPC 1 is a functional ZDS. Consistent with the downregulated expression of CAO and PORB, the chlorophyll content was decreased in spc1-1 plants. In addition, expression of Lhcb1. 1, Lhcbl. 4 and RbcS was absent in spc1-2, suggesting the possible involvement of carotenoids in the plastid-to-nucleus retrograde signaling. The spc1-1 mutant also displays an ABA-deficient phenotype that can be partially rescued by the externally supplied phytohormone. These results suggest that SPC1/ZDS is essential for biosynthesis of carotenoids and plays a crucial role in plant growth and development.

关 键 词：carotenoid biosynthesis cell death chloroplast development PHOTOPROTECTION Arabidopsis SPC1/ZDS 

分 类 号：Q943[生物学—植物学]