Most of the cells within one's body are in one of the following states: they either keep dividing to generate more cells, which is called the undifferentiated state; or they assume their final fate as specific types of cells, such as a skin cell or a bone cell, and they are called differentiated. For a body to function properly, all the cells need to be kept in their respective mode. If undifferentiated cells differentiate at the wrong time, there would be too many or too few cells to carry out the function of the specific organ. On the other hand, if differentiated cells randomly become undifferentiated and start dividing again, they can grow into cancers. Therefore, it is important to learn how cells are kept in one state, or how they switch between the two states, when the undifferentiated cells are allowed to grow in numbers. The goal of this research is to answer these questions in plants. This is because nearly all organs in higher plants are derived from the structures called meristems, within which the continuous presence of stem cells serves as the source of development, after germination. In addition, differentiated plant cells can dedifferentiate and form meristems. For example, one can use plant cuttings to grow new plants. And most importantly, it has been shown that many basic mechanisms controlling cell division and differentiation are similar in most organisms. Recent studies show that for stem cells and undifferentiated cells to divide, the organism needs to have sufficient nutrients, including simple sugars. This project investigates how metabolic sugars control the decision by plant stem cells to divide. The successful completion of this work will elucidate new components in plant meristem regulation, and lead to subsequent studies that will be aimed at linking developmental signals and nutrient sensing with the final cell cycle decisions in the meristematic tissues.
Broader Impacts: The work proposed in this study answers one of the most fundamental questions in tissue proliferation in plants, and the results from this study can potentially lead to better understanding of mechanisms controlling tissue proliferation in all multicellular organisms. Thus, this project has enormous potential to address a number of priority national needs. The results from this study will be published in scientific journals and presented at research conferences, and the plant materials generated from this study will be made available for the research community. During the course of the described project, broad and systemic training will be provided to both graduate and undergraduate students, with an emphasis on involving minority students. Additional efforts will be made to foster high school students for their interest in science and research during the summer months.