Mechanisms Underlying Hormone‐Induced Changes in the Moss Physcomitrella patens – A Genetic Approach

Hormones act as messengers between cells and can cause critical changes during the development of both animals and plants. There is much that is still unknown about how cells perceive and respond to a hormonal signal. The moss, Physcomitrella patens , is well‐suited for the observation of hormone‐induced development because the developmental process is extremely predictable, the cell which is affected by the hormone is easily accessible, the moss is easy to grow in culture, and the genome is being sequenced. When exposed to the hormone cytokinin, P. patens shifts from filamentous growth to the formation of the leafy gametophyte. Mutants have been generated in order to identify components of the cytokinin signaling pathway. One mutant, created by the random insertion of a fragment of foreign DNA into the moss genome, has been identified which is capable of producing initial cells (the target for the hormone cytokinin); however, these cells are unable to respond to cytokinin. Thermal asymmetric interlaced (TAIL) PCR is being used to amplify the sequence disrupted by the insertion. Once the sequence is obtained, we will use it to create a targeted mutation to confirm its role and will also perform in situ hybridization to determine where the mRNA is localized and/or immunolocalization experiments. By determining the function of this sequence, we will further clarify the cytokinin signaling process.