tailieunhanh - báo cáo khoa học: " BYPASS1: synthesis of the mobile root-derived signal requires active root growth and arrests early leaf development"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: BYPASS1: synthesis of the mobile root-derived signal requires active root growth and arrests early leaf development | Van Norman et al. BMC Plant Biology 2011 11 28 http 1471-2229 11 28 BMC Plant Biology RESEARCH ARTICLE Open Access BYPASS1 synthesis of the mobile root-derived signal requires active root growth and arrests early leaf development Jaimie M Van Norman2 Caroline Murphy1 Leslie E Sieburth1 Abstract Background The Arabidopsis bypass bps mutant root produces a biologically active mobile compound that induces shoot growth arrest. However it is unknown whether the root retains the capacity to synthesize the mobile compound or if only shoots of young seedlings are sensitive. It is also unknown how this compound induces arrest of shoot growth. This study investigated both of these questions using genetic inhibitor reporter gene and morphological approaches. Results Production of the bps root-synthesized mobile compound was found to require active root growth. Inhibition of postembryonic root growth by depleting glutathione either genetically or chemically allowed seedlings to escape shoot arrest. However the treatments were not completely effective as the first leaf pair remained radialized but elongated. This result indicated that the embryonic root transiently synthesized a small amount of the mobile substance. In addition providing glutathione later in vegetative development caused shoot growth arrest to be reinstated revealing that these late-arising roots were still capable of producing the mobile substance and that the older vegetative leaves were still responsive. To gain insight into how leaf development responds to the mobile signal leaf development was followed morphologically and using the CYCB1 1 GUS marker for G2 M phase cells. We found that arrest of leaf growth is a fully penetrant phenotype and a dramatic decrease in G2 M phase cells was coincident with arrest. Analyses of stress phenotypes found that late in development bps cotyledons produced necrotic lesions however neither hydrogen peroxide nor superoxide were abundant as leaves .