BARTELS, Dorothea*; RAMANJULU, Ramtin; M�LLER, Kai; FISCHER, Eberhard; BORSCH, Thomas; University of Bonn: The evolution of desiccation tolerance: genomic aspects

The Scrophulariaceae are one of the most diverse paklnt families and has been shown to be polyphyletic. Several Scrophulariaceae which belong to the genera Craterostigma, Lindernia and its allies are poikilohydric and are therefore of particular interest. Craterostigma plantagineum has been used extensively to identify molecular mechanisms, which are involved in the acquisition of desiccation tolerance. These studies revealed a large number of genes which are up-regulated in response to dehydration. The genes can approximately be divided into two groups. One group encodes proteins which are directly involved in protection of cellular structures. The other group of genes encodes genes which are involved in regulating the response to dehydration. C. plantagineum belongs to the Linderniae which comprises desiccation tolerant and non-desiccation tolerant plants. Using molecular markers a phylogenetic tree was constructed to determine the molecular relationships of the different plant species. It appears that desiccation tolerant plants cluster together and are thus closely related. Comparative studies of these plant species are undertaken to identify genes essential in the acquisition of desiccation tolerance.