|Budget Amount *help
¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 2002: ¥4,800,000 (Direct Cost: ¥4,800,000)
Seedling of dicotyledonous plant has two cotyledons, hypocotyl and embryonic root arranging from the apical to basal. There is a shoot and root apical meristems at the end of hypocotyl root, respectively. Cells in these tissues continue to divide and some of them in the shoot apical meristem are differentiated into lateral organs and stem in turn and root meristem produces root continuously after germination. The purpose of this project is to make clear molecular mechanisms of shoot apical meristem formation during embryogenesis and of lateral root meristem formation using Arabidopsis. We can succeed to get next two interesting results.
1, SAM formation ; CUC 1, 2 (CUP SHAPED COTYLEDONS 1, 2) genes, which are redundantly essential for SAM formation during embryogenesis, are functioned as transcription activators. Ectopic expression of CUC1 caused adventitious shoot induction on cotyledons and leaves. In these processes, CUC1 induced STM (SHOOT MELISTEMLESS) gene expression ectopically. Both CUC1 and CUC2 genes an excel late adventitious shoot induction from callus.
2, RAM formation ; A new root meristem was developed before induction of a lateral root. Phytohormone auxin is important in this process. The novel transcription regulator SLR (SOLITARY ROOT) mediates auxin signal to induce the lateral root meristem from pericycle cells, which re-start cell division. The dominant mutant of this gene (slr) completely lost the ability to induce the lateral root. Suppressors of slr were isolated and one of them was analyzed genetically, which encodes one of the putative chromatin remodeling factors.