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Thioredoxin h overexpressed in barley seeds enhances selenite resistance and uptake during germination and early seedling development
Yong-Bum Kim, Carlos Garbisu, Ingrid J. Pickering, Roger C. Prince, Graham N. George, Myeong-Je Cho, Joshua H. Wong and Bob B. Buchanan
Vol. 218, No. 2 (December 2003), pp. 186-191
Published by: Springer
Stable URL: http://www.jstor.org/stable/23388302
Page Count: 6
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The uptake, distribution and metabolism of selenite were examined in germinating homozygous barley (Hordeum vulgare L.) grain with thioredoxin h overexpressed in starchy endosperm. Results were related to the null segregant in which the transgene had segregated out during crossing. Compared with the null segregant, the homozygote showed enhanced germination and root and shoot growth in the presence of 1 and 2 mM sodium selenite. The rate of incorporation of selenite by the homozygote was approximately twice that of the null segregant. Based on X-ray absorption spectroscopy, the major products in both cases were selenomethionine-like species and the red, monoclinic form of elemental selenium, a derivative not previously reported in green plants. Selenite and selenate made up the balance. The distribution of the products formed differed as to the tissue — root, shoot, aleurone, endosperm — but the ratios were similar in the homozygote and null segregant. The results provide evidence that, in addition to the accelerated germination observed previously in water, barley grain overexpressing thioredoxin h are resistant to the inhibitory effects of selenite. These properties raise the possibility that plants overexpressing thioredoxin h could find application in the remediation of polluted environments.
Planta © 2003 Springer