Analysis And Characterization Of RRL In Arabidopsis Thaliana

Beacause of the simplicity of its organization, the Arabidopsis root is one of the most tractable systems for the study of plant organogenesis.At present, rapid progress has been made in the Arabidopsis root morphogenesis and development, but the mechanism has not been elucidated completely.The previous studies show that the plant root development is governed by the inteacted genes and the banlance of hormones. However, the molecular mechanism of the post-embryonic root apical meristem development is not very clear. Especially, The function and regulation of mitochondria in plant root development is relatively scarce.In this study, based on the data on the short root mutant rrg 1(RETARDED ROOT GROWTH 1), which we have obtained.And the RRG gene encoded a unknown function protein, localized in the mitochondrial membrane by subcellular localization analysis and regulated Arabidopsis root apical meristem development in the post-emboynic.In the Arabidopsis genome, there is a homolog gene (At5g13610) of At1g69380,named RRL (RETARDED ROOT GROWTH-LIKE). The main results are as follows:1. We purchased At5g13610 of T-DNA insertion mutant (SALK-022878C) from TAIR, isolated and identificated loss-function T-DNA insertion mutants.And we found that the mutant also displayed a short root phenotype, named rrll, Compared to wild-type, the root meristem size and the meristem cell number is reduced in the rrll,2. Expression profiling analyses by RT-PCR and In situ hybridization indicated that RRL is a constitutively expressed and tissue-specific expressed in root apical meristem gene, which is highly expressed in root.3. The expression pattern of SHR and SCR has not been affected in rrll mutant. And the root ransverse section revealed:the radial structure of the root is normal: epidermi cortex, endodermis and pericycle cell layers remain unchanged. Indicated that RRL gene did not regulate the stem cell activity of RAM and the function of QC in Arabidopsis. 4. The rrll mutant performs normal response to exogenous auxin. The typical expression of DR5::GUS in the incipient root meristem has not been affected, compared with the wild type. And loss of the gene has not affected the expression of PIN family genes, such as PIN1, PIN3, PIN4.5. The rrll mutant is insensitive to exogenous cytokinin. By RT-PCR analysis of cytokinin signal transduction gene expression, we found the expression of CKX4 is decreased.6. CYCB1 is a specific marker cell cycle gene for G2/M. In rrll mutant containing the D-box CYCB1-GFP, the expression of CYCB1;1 was reduced.7. We forecast the protein encoded by RRL genes located in mitochondria by mass spectrometric analysis and biological software.