Proteomic analysis of nuclear proteins during dehydration of the resurrection plant Xerophyta viscosa

Xerophyta viscosa (family Velloziaceae) is a monocotyledonous poikilochlorophyllous desiccation tolerant plant capable of surviving drying its leaf tissue to 5% relative water content (RWC) for prolonged periods and resuming full physiological activity upon rehydration. X. viscosa and other resurrection plants are excellent model systems for the study of desiccation tolerance mechanisms. In this work, the X. viscosa nuclear protein profile was investigated in response to dehydration stress using 2D gel electrophoresis, protein map analysis and mass spectrometry identification. From an average of 438 protein spots detected on the gels, 18 spots were significantly shown to increase in abundance upon dehydration at 35% RWC. Analysis of the 18 dehydration-induced nuclear protein spots resulted in the identification of proteins associated with gene transcription and regulation, cell signalling, molecular chaperone and proteolysis type activities, protein translation, energy metabolism, and novel proteins. This study revealed that X. viscosa nucleus responded to dehydration stress and that desiccation tolerance was controlled by multiple genes within the plant nucleus. This study indicated that adjusting gene regulation and expression of appropriate stress response proteins in the nucleus was sufficient to protect the cellular structures during dehydration and in the dried state.