Differential gene expression in desiccation-tolerant and desiccation-sensitive tissue of the resurrection grass, Sporobolus stapfianus

The rare African grass Sporobolus stapfianus is capable of surviving total air-dryness. Little is known about the genetic factors associated with this remarkable trait. Several genes have been isolated from drought-stressed leaf tissue of S. stapfianus, including genes encoding a glycine-rich protein, another with similarity to a yeast glyoxalase I gene and one cDNA which does not show any similarity with known genes. Some of the genes have not previously been linked to desiccation tolerance while some have previously been reported as being upregulated in response to drought stress or expressed throughout all stages of desiccation [Blomstedt, C., et al., Plant Growth Regulation 24, 219-228 (1998)]. To provide insight into changes in gene expression which are important in drought resistance the transcript levels in both desiccation-tolerant and desiccation-sensitive tissues, in response to varying degrees of drought stress, have been analysed. Genes whose expression decreases in leaf tissue in response to desiccation were also characterised, such as those encoding chlorophyll a/b binding protein and catalase. This study indicates the complexity of the drought stress response in the resurrection grass, S. stapfianus, which involves co-ordinated positive and negative regulation of several genes throughout the dehydration process.