Final Report Summary - ROMA (To the root of organ growth: the control of root meristem activity in Arabidopsis.)
The maintenance of boundaries between neighboring groups of distinct cells types is vital during development of multicellular organisms, as groups of cells with distinct functions must be kept physically separated to guarantee correct organ and body growth and function. In the Arabidopsis root, the transition zone is a developmental boundary in the meristem that separates dividing from differentiating cells. With this project we show that a well-defined and tightly controlled minimum of the plant hormone auxin acts as a signal to establish the position of the transition zone by controlling the developmental transition from cell division to cell differentiation. We also provide mechanistic evidence of how cell differentiation at the transition zone is coordinated with cell division in the stem cell niche to guarantee coherent root growth. Our results allow proposing a model where the protein encoded by the gene SCR presides over this spatial coordination. By suppressing cytokinin signalling in the stem cell niche organizer thus controlling auxin distribution, SCR controls simultaneously division of the surrounding stem cells and differentiation of distal meristematic cells.
The results of this proposal will have an impact well beyond the organ being studied: most likely, in fact, analogous hormonal interactions control growth and development of all organs of the plant.
Furthermore the control of stem cell activity and of the balance between cell differentiation and cell division is a crucial issue also in animal development: apart from the differences in growth factors and other molecular components specifically acting in plants and animals, our results may shed light on general principles of the logic of this control common to the two kingdoms. To understand basic principles, fundamental strategies of development in plants and animals should in fact be compared.
The results of this proposal will have an impact well beyond the organ being studied: most likely, in fact, analogous hormonal interactions control growth and development of all organs of the plant.
Furthermore the control of stem cell activity and of the balance between cell differentiation and cell division is a crucial issue also in animal development: apart from the differences in growth factors and other molecular components specifically acting in plants and animals, our results may shed light on general principles of the logic of this control common to the two kingdoms. To understand basic principles, fundamental strategies of development in plants and animals should in fact be compared.