Browsing by Author "Thomson, Jennifer"

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    Molecular characterization of XVT8, a stress-responsive gene from the resurrection plant Xerophyta viscosa Baker.
    (Springer, 2001) Ndima, Tozama; Farrant, Jill; Thomson, Jennifer; Mundree, Sagadevan
    Xerophyta viscosa (Baker) is a monocotyledonous resurrection plant that is capable of tolerating extremes of desiccation. Upon rewatering, it rehydrates completely, assuming its full physiological activities. Studies on changes in gene expression associated with dehydration stress tolerance were conducted. A cDNA library was constructed from mRNA isolated from dehydrated X. viscosa leaves [85%, 37% and 5% relative water content (RWC)]. XVT8 represents one of 30 randomly selected clones that were differentially expressed when X. viscosa was dehydrated. Sequence analysis of XVT8 revealed that XVT8 exhibited 45% and 43% identity to dehydrin proteins from Arabidopsis thaliana and Pisum sativum respectively, at the amino acid level. XVT8 encodes a glycine -rich protein (27 kDa) which is largely hydrophilic and contains a hydrophobic segment at the C-terminus. Southern blot analysis confirmed the presence of XVT8 in the X. viscosa genome. XVT8 transcripts accumulated in X. viscosa plants that were exposed to heat, low temperature and dehydration stresses, and to exogenous abscisic acid and ethylene. These results provide direct evidence for the heat, low temperature, dehydration, abscisic acid and ethylene -dependent regulation of the XVT8 gene in X. viscosa.
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    The characterization of XVSAP1: a gene isolated from the resurrection plant Xerophyta viscosa Baker, and its expression in transgenic plants
    (2003) Garwe, Dahlia; Thomson, Jennifer; Mundree, Sagadevan
    The strategy of "complementation by functional sufficiency" was used to isolate a cDNA, designated XVSAP1, from a cDNA library constructed from dehydrated Xerophyta viscosa Baker leaves. Analysis of the cDNA sequence indicated a highly hydrophobic protein with six transmembrane regions. Southern blot analysis revealed that there are at least two copies of XVSAP1 in X. viscosa. The deduced amino acid sequence showed 49% identity to WCOR413, a low temperature-regulated protein from wheat. The protein also showed between 25% to 56% identity to WCOR413-like proteins from Arabidopsis thaliana.