Förslaget inkom 2005-09-07
Characterization of cell wall beta-glucosidae from rye (Secale cereale)
OBS! ANSÖKNINGSTIDEN FÖR DETTA EXJOBB HAR LÖPT UT.
Plants have evolved many different mechanisms for defence against pathogens and herbivores and for the competition with other plants. An increased knowledge of these mechanisms might help in finding resistant varieties and result in the decreased use of synthetic chemicals in agriculture. We are studying aphid-induced responses in barley and a constitutive chemical defence in rye. The defence system in rye consists of secondary metabolites that are glucosylated in the intact plant and become activated by beta-glucosides upon wounding or herbivore attack. This results in the release of toxic compounds that inhibit fungi and insects. The beta-glucosidases are separated from the glucosides in the intact plant. In rye we have found two different beta-glucosidases, one that is localized in the plastid and one that is found in the cell wall. The proposed project concerns the cell wall beta-glucosidase. Preliminary results indicate that this enzyme is unique in that it acts both on cell wall structures and on secondary metabolites involved in defence. The full length cDNA of this protein has been cloned into a plasmid and sequenced. The project involves the expression of this gene sequence in E.coli and purification of the recombinant protein. The protein will then be characterized biochemically, to confirm preliminary results regarding the substrate specificity. The regulation of expression of the gene will also be studied.
The project involves the purification of the recombinant protein using affinity-chromatography, SDS- gel electrophoresis and Western blotting for confirmation of purity, enzyme assays and evaluation using databased kinetic programs, isolation of mRNA and Northern blotting for studies of gene expression.
A suitable background is a biology, biotechnology or molecular cell biology program with training in molecular biology and biochemistry. Some knowledge of plant biology is an advantage.
The department of chemistry, biology, geography and environmental science at Södertörn University College has about 150 members, of which about 50 are post-graduate students. The department has an active research focused on life sciences, and is located in new buildings with modern equipment suitable for molecular research.