The resurrection plant Craterostigma plantagineum is able to withstand desiccation of its vegetative tissues and is found in areas with variable water availability. The closely related species Lindernia brevidens and Lindernia subracemosa are both endemic to montane rainforests of coastal Africa, but remarkably L. brevidens is tolerant to desiccation. We studied the regulation of the desiccation-related LEA-like 11-24 gene at multiple levels in closely related species in order to investigate the conservation of mechanisms involved in desiccation tolerance. The dehydration-responsive transcription of the LEA-like 11-24 gene is differentially regulated in these plants. Comparison of the LEA-like 11-24 core promoter regions revealed that promoters have different activities, but some functional cis-acting elements are conserved between species. Upon dehydration, LEA-like 11-24 proteins are phosphorylated at different levels and phosphorylation sites are not conserved among the three LEA-like 11-24 proteins. Differences in the regulation of the LEA-like 11-24 gene in the studied plant species appear to be the result of mutations that occurred during evolution. We postulate that L. brevidens will eventually lose the ability to survive vegetative desiccation, given that this trait appears not to be essential for survival.
Keywords: LEA-like 11-24 gene; Linderniaceae; desiccation tolerance; gene regulation; promoters; protein phosphorylation; resurrection plants.
© 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.