Functional Analysis Of MTERFs Family Proteins In Chloroplast Localization Of Arabidopsis Thaliana

Organellar gene expression(OGE) is crucial for plant photosynthesis,respiration and development, but the mechanisms that regulate it are still unclear. In mammals, The mitochondrial transcription termination factor(m TERF) family plays important roles in the process of organellar gene expression, but information relating to their roles in photosynthetic organisms remains scarce. In this study, we obtained the 14 T-DNA insertion lines of genes encoding plastid-localized mTERF members in Arabidopsis thaliana. T-DNA insertion sites of mTERF3 and mTERF12 gene are located in the promoter regions, T-DNA of mTERF4 gene is located in the 3’UTR region, T-DNA of mTERF16 gene is located in the intron, T-DNAs of the remaining 10 mTERF genes are located in the exon regions. By isolation of these 14 homozygous T-DNA insertion lines, we found that mterf3, 4, 7, 8, 10, 11, 12, 27 have no visible mutant phenotypes. We treated them with various abiotic stress and found that mterf10, 11, 12 plants are sensitive to strong light. The mterf1, 2, 16 mutants exhibit embryo-lethal phenotypes. Embryo-defective phenotypes were analyzed in seeds produced by selfed mterf10, 11, 12 heterozygotes by differential interference contrast microscope. Homozygous mutant mterf1, 2, 16 embryos morphologically arrested at the late heart-shaped embryo stage. We collect mterf2, 16 embryos and separate RNA to analyze chloroplast gene expression by QRT-PCR and RT-PCR experiment. The result showed that the read through transcript ion of the chloroplast gene psbA occurs, and the splicing of petB intron is impaired in mterf2. In mterf16 mutant, the read through transcript level of the chloroplast gene psbA increases and the splicing of the petB and trnL introns is defecitve. These results showed that plastid-localized mTERF protein s are involved in stress responses, plastid gene transcription and post-transcriptional processing in Arabidopsis thaliana.