Jee-Eun Heo

Molecular characterization of a 2-Cys peroxiredoxin induced by abiotic stress in mungbean

A mungbean low temperature-inducible VrPrx1 encoding 2-Cys peroxiredoxin (2-Cys Prx) was cloned by subtractive suppression hybridization. The deduced VrPrx1 amino acid sequence showed highest sequence homology to 2-Cys Prxs of Phaseolus vulgaris (95%), Pisum sativum (89%), and Arabidopsis thaliana (87%). VrPrx1 RNA and protein levels were increased by low temperature, hydrogen peroxide (H2O2), and wounding but decreased by high salinity, drought, and exogenous abscisic acid. Recombinant His-tagged VrPrx1 recombinant protein protected DNA and glutamine synthetase activity from degradation via the thiol/Fe(III) oxygen mixed-function oxidation system, and exhibited peroxidase activity to H2O2 in the presence of the reducing agent dithiothreitol (DTT) in vitro. The oxidized dimers and oligomers of the VrPrx1 recombinant protein were reduced to monomers by DTT or thioredoxin. Subcellular localization studies confirmed that VrPrx1-GFP was targeted to the plastid. To evaluate the function of VrPrx1in planta, the antioxidant activities and photosynthetic efficiency were investigated in VrPrx1-overexpressing Arabidopsis plants. VrPrx1 ectopic expression conferred improved photosynthetic efficiency under oxidative stress conditions. Hence, mungbean VrPrx1 may play an important role in protecting the photosynthetic apparatus against oxidative and abiotic stress conditions.

Analyses of Morphological Characteristics, Antibiotic Effect, and Molecular Cytogenetics in Baegseon (Dictamnus dasycarpus Turcz)

The importance of wild plant resources along with the development of high biotechnology is highlighted for exploitation of new materials which can make the added value. The goal of this study is providing fundamental data bases for developing new materials through the analyses of morphological characteristics, antibiotics and molecular cytogenetics in Baegseon (Dictamnus dasycarpus Turcz.). Baegseon has several characteristics; there are two types of flower color, pink and white, the seed germination starts about February 20th, the maximum flowering season is around May 17th in southern Korea, the growth period is about 60 days. The number of chromosomes are 2n=2x=36, the size of chromosomes in metaphase is 4.2~8.1 μm. The amount of 2C nuclear DNA is 1.93 pg, and there is no variation of genome size amoung varieties. The extraction juice of baegseon young roots has the excellent antibiotic activity against the mold (Botrytis cinerea).