Cloning And Functional Analysis Of Rice Plastid Development Regulation Of Gene(OsFLN2)

Chloroplast is an important part in green plants for photosynthesis, but also the carrier of photosynthetic pigment, widely distributed in the leaf green tissue cells. Chloroplast development of higher plants is a very complicated regulation process, needs a nuclear gene encoding protein and chloroplast gene encoding protein coordination to complete, and the leaf color mutation is the important materials to study of plastid and chloroplast development, and relevant regulatory mechanism results play a very important role in basic research and production practice. Rice albino panicles mutant ap(t)1 was screened from Nipponbare(Oryza sativa L. ssp. japonica) variety by EMS mutagenesis. Before 3 leaf stage,the mutant characterized by complete white. With the growth of plants, the new leaves begined to turn green after 3 leaf stage extraction, and the chloroplast development of old leaves was slow recovery, showing the white stripes and albino panicles in heading stage. Map-based cloning found that AP (t)1(LOC_Os03g405500) gene located in no.3 chromosome,and the mutant gene showed a single-base substitution,base G to base A, and caused the 537th amino acid tryptophan (Trp) mutant to termination codon which led to early termination of protein coding.After complementary vector mutant, mutation phenotype was restored to normal, confirmed that theAP(t)lgsne mutation was the internal cause of rice whitening.Bio informatics analysis indicates that the AP(t)land arabidopsis AtFLN2 was homologous genes. Real-time PCR Experiments showed that the OsFLN2 gene have expresseds in all tissue of rice, but the main expression was in the blade. OsFLN2 gene expression in Ap(t)1 mutant was significantly decreased, and the expression in complementary transgenic plants and wild type was Basically the same.After OsFLN2 gene mutation, p las mid encoding RNA polymerase (PEP) participate in the genes encoding was enormous implications, andgene expression depending on the PEP polymerization enzymes in the mutant decreased significantly which compared with wild type.However, the change of the gene depending on nuclear encoded RNA polymerase (NEP) is not big. Subcellular localization experiment found OsFLN2 located on rice protoplast of chloroplast.Use the CRISPR-Cas9 technology according to the purpose gene sequence to fixed-point knockout of wild type, the phenotype of plants knockouted positive transgenic plants similar to mutant, and transgenic plants fixed point mutation late doesn’t turn green after bleaching, OsFLN2 function in fixed point mutations that could have done more serious damage.The understanding of the FLN2 function that lay a foundation for further revealing the plastid and chloroplast development mechanism and clarifying molecular mechanism of plant photosynthetic complexes.