Molecular Genetic Analysis of Shoot Apical Meristem Development in Arabidopsis thaliana

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

0080853 Barton The Earth's primary producers, plants and algae, capture sunlight and use it to make the biomass that all other organisms on the planet use to survive. Much of plant growth occurs at the tips of branches, where regions of undifferentiated, dividing cells, called meristems, are located. The shoot meristems produce new leaves, stems and flowers. Dr. Kathryn Barton's lab studies how shoot meristems work. Using the small weed Arabidopsis as a model system, her lab studies the genes and proteins that direct meristem function. The work in this proposal focuses on regulation of the SHOOT MERISTEMLESS (STM) gene product of Arabidopsis. When the STM protein is lacking, the plant is not able to make a meristem, and conversely, when the STM protein is supplied in excess, the plant produces a mass of meristems that covers the leaves and results in a highly deformed plant. From these observations it follows that the STM gene must be carefully regulated. The BOBBER gene is required to prevent the expression of STM in the seed leaves; in bobber mutants, the seed leaves inappropriately express STM. bobber mutants also arrest growth during embryogenesis. To understand the mechanism of STM regulation by BOBBER, the BOBBER gene will be molecularly cloned and characterized. bobber mutant embryos will be carefully analyzed to determine the extent to which they are defective in the development of cotyledons and shoot apical meristem. The role of BOBBER in repressing STM in leaves will also be determined and the cis-acting sequences through which BOBBER acts will be defined. These, and other experiments, are leading to improvements in our understanding of basic plant biology, information that will ultimately improve the way in which we manage our crops, woodlands and other natural resources.