Almost every organism on earth depends on plants as their primary source of food energy. Many of the plants on which humans depend for sustenance are flowering plants. By understanding how flowers develop, we may be able to enhance flower development and increase crop yield. One area of flower development of particular interest is that of the stamen, the male reproductive part and source of the pollen necessary for fertilization in flowers. Multicellular organs, such as stamens, develop via specific stepwise pathways. If there is a malfunction in one of the steps, then the entire process stops and the structure and/or function of the organ is impaired. Each step in such a pathway is governed by the expression of the organism’s genes. Mutations in the cbl10 gene in Arabidopsis thaliana prevent the production of a calcineurin-B-like protein (CBL10) and cause a breakdown in the stamen development pathway, resulting in stamens that cannot produce normal pollen and are too short to support fertilization. We can determine where CBL10 acts in the developmental pathway by performing RT-PCR, a common technique used to track gene expression, on normal plants and cbl10 mutants. If there is equal expression of a particular gene between these plants, then CBL10 must act in a subsequent step of the pathway. If there is unequal expression between the two plant types, then CBL10 must act in a previous step. Initially, we looked at gene expression in leaves of each plant in order to optimize reaction conditions because leaves are larger and more abundant than flowers. Once optimized, we looked at expression in the open flowers of wild type and cbl10 plants. Preliminary data show that three of the genes studied are expressed equally in the open flowers of each plant, indicating that CBL10 acts in a subsequent step in the pathway. In the future, optimization assays will be performed on several more genes in the pathway and then their expression will be studied in various stages of flower development in both wild type and cbl10 plants.
Faculty Mentor: Margaret Dietrich, Cell & Molecular Biology