Because of the high prevalence and associated suffering, disability and economic burden of painful DPN, it is important that diabetic patients are periodically screened, using a simple instrument such as the DN4, and receive appropriate treatment if symptoms develop.

Main conclusionProvides a first comprehensive review of integrated physiological and molecular aspects of desiccation toleranceXerophyta viscosa. A synopsis of biotechnological studies being undertaken to improve drought tolerance in maize is given.Xerophyta viscosa (Baker) is a monocotyledonous resurrection plant from the family Vellociacea that occurs in summer-rainfall areas of South Africa, Lesotho and Swaziland. It inhabits rocky terrain in exposed grasslands and frequently experiences periods of water deficit. Being a resurrection plant it tolerates the loss of 95 % of total cellular water, regaining full metabolic competency within 3 days of rehydration. In this paper, we review some of the molecular and physiological adaptations that occur during various stages of dehydration of X. viscosa, these being functionally grouped into early and late responses, which might be relevant to the attainment of desiccation tolerance. During early drying (to 55 % RWC) photosynthesis is shut down, there is increased presence and activity of housekeeping antioxidants and a redirection of metabolism to the increased formation of sucrose and raffinose family oligosaccharides. Other metabolic shifts suggest water replacement in vacuoles proposed to facilitate mechanical stabilization. Some regulatory processes observed include increased presence of a linker histone H1 variant, a Type 2C protein phosphatase, a calmodulin- and an ERD15-like protein. During the late stages of drying (to 10 % RWC) there was increased expression of several proteins involved in signal transduction, and retroelements speculated to be instrumental in gene silencing. There was induction of antioxidants not typically found in desiccation-sensitive systems, classical stress-associated proteins (HSP and LEAs), proteins involved in structural stabilization and those associated with changes in various metabolite pools during drying. Metabolites accumulated in this stage are proposed, inter alia, to facilitate subcellular stabilization by vitrification process which can include glass- and ionic liquid formation.

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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.