Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Arabidopsis brassinosteroid biosynthetic mutant dwarf7-1 exhibits slower rates of cell division and shoot induction | Cheon et al. BMC Plant Biology 2010 10 270 http 1471-2229 10 270 BMC Plant Biology RESEARCH ARTICLE Open Access Arabidopsis brassinosteroid biosynthetic mutant dwarf7-1 exhibits slower rates of cell division and shoot induction Jinyeong Cheon 1 So-Young Park2 Burkhard Schulz3 Sunghwa Choe1 4 Abstract Background Plant growth depends on both cell division and cell expansion. Plant hormones including brassinosteroids BRs are central to the control of these two cellular processes. Despite clear evidence that BRs regulate cell elongation their roles in cell division have remained elusive. Results Here we report results emphasizing the importance of BRs in cell division. An Arabidopsis BR biosynthetic mutant dwarf7-1 displayed various characteristics attributable to slower cell division rates. We found that the DWARF4 gene which encodes for an enzyme catalyzing a rate-determining step in the BR biosynthetic pathways is highly expressed in the actively dividing callus suggesting that BR biosynthesis is necessary for dividing cells. Furthermore dwf7-1 showed noticeably slower rates of callus growth and shoot induction relative to wild-type control. Flow cytometric analyses of the nuclei derived from either calli or intact roots revealed that the cell division index which was represented as the ratio of cells at the G2 M vs. G1 phases was smaller in dwf7-1 plants. Finally we found that the expression levels of the genes involved in cell division and shoot induction such as PROLIFERATING CELL NUCLEAR ANTIGEN2 PCNA2 and ENHANCER OF SHOOT REGENERATION2 ESR2 were also lower in dwf7-1 as compared with wild type. Conclusions Taken together results of callus induction shoot regeneration flow cytometry and semi-quantitative RT-PCR analysis suggest that BRs play important roles in both cell division and cell differentiation in Arabidopsis. Background Plant steroidal hormones brassinosteroids BRs are central to supporting the proper growth and development of .
