Map-based Cloning And Founctional Analysis Of Chlorophyll Fluorescence Mutant E1991 In Arabidopsis Thaliana

Photosynthesis, which plays a key role in maintaining ecological balance, is the material fundamental of the food chain. As an organelle for assimilation in most photosynthetic autotrophs,the morphological structure of chloroplast varies with the species. Chloroplast is a semiautonomous organelle with complex signaling pathway, and its development was regulated by nuclear genome and chloroplast genes. Because of its complexity, the molecular mechanism is not yet clear. A comprehensive research could not only enrich our knowledge, but also improve agriculture character of crops.In this research, Arabidopsis thaliana wildtype Columbia-0 was used for establishing a mutant libary. We treated its seeds with chemical mutagenesis agent sulfonic acid ethylester?EMS?and screened and separated mutant E1991 from Col-0 background by chlorophyll fluorescence imaging. The chlorophyll fluorescence characters of the mutant and the wildtype showed that E1991 is a mutant with higher parameter of F₀ and F_m, what's more, the F_v/F_m parameter is lower than Col-0. Further study on phenotype showed that E1991 is insensitive to ABA during germination stage with slow-grouth. The contant of chlorophyll a, chlorophyll b and carotene of the mutant are higher than Col-0. Genetic analysis showed that unusual parameter in E1991 was caused by a single recessive gene mutation. We crossed E1991 and Landsburg eracta to construct a collection of F₂ for mapping, and the gene was resided near BAC?Bacteria Artificial Chromosome? F3F19. Finally, the gene CFNY was detected by sequencing. The 95 th basis of CFNY changed from G to A, and the corresponding amino acid turned form Arg to Cys. Thegenome strusture consists 7 introns and 8 extrons. It encodes an unknown protein. In order to a further study of its founction, tissue expression localization and subcellular localization, we constructed complementation vector, over expressing vector, 1391 vecter, and transient expression vector etc.Results indicated that CFNY is a gene that possibly involved in Arabidopsis thaliana chlorophlast development, plant senescence and photosythetic physiology. The results of subcellular localization show that CFNY localized near intracellular membranes and chloroplasts.RT-PCR results revealed that there is an down-regulation of CAB and up-regulation of RBCS in E1991 and overexpress plants. The further work on its signaling pathway is awaited.