Transgenic barley grain overexpressing thioredoxin shows evidence that the starchy endosperm communicates with the embryo and the aleurone
| Autor: | Bob B. Buchanan, Yong-Bum Kim, Peter Hedden, Myeong-Je Cho, Nick Cai, Peggy G. Lemaux, Joshua H. Wong, Pei-Hsien Ren |
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| Rok vydání: | 2002 |
| Předmět: |
Glutens
Recombinant Fusion Proteins Thioredoxin h Germination Protein Sorting Signals Biology Endosperm chemistry.chemical_compound Thioredoxins Aleurone Transgenes Desiccation Promoter Regions Genetic Gibberellic acid Triticum Plant Proteins Multidisciplinary Homozygote food and beverages Hordeum Starch Biological Sciences Plants Genetically Modified Gibberellins Biochemistry chemistry Hordein Protein body Enzyme Induction Seeds Gibberellin alpha-Amylases Thioredoxin Oxidation-Reduction |
| Zdroj: | Proceedings of the National Academy of Sciences. 99:16325-16330 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.212641999 |
| Popis: | Homozygous lines of barley overexpressing a wheat thioredoxin h transgene (up to 30-fold) were generated earlier by using a B 1 -hordein promoter with a signal peptide sequence for targeting to the protein body and found to be enriched in starch debranching enzyme (pullulanase). Here, we describe the effect of biochemically active, overexpressed thioredoxin h on germination and the onset of α-amylase activity. Relative to null segregant controls lacking the transgene, homozygotes overexpressing thioredoxin h effected ( i ) an acceleration in the rate of germination and appearance of α-amylase activity with a 1.6- to 2.8-fold increase in gibberellin A 1 (GA 1 ) content; ( ii ) a similar acceleration in the appearance of the α-amylase activity in deembryonated transgenic grain incubated with gibberellic acid; ( iii ) a 35% increase in the ratio of relative reduction (abundance of SH) of the propanol soluble proteins (hordein I fraction); and ( iv ) an increase in extractable and soluble protein of 5–12% and 11–35%, respectively. Thioredoxin h , which was highly reduced in the dry grain, was degraded in both the null segregant and homozygote after imbibition. The increase in α-amylase activity and protein reduction status was accompanied by a shift in the distribution of protein from the insoluble to the soluble fraction. The results provide evidence that thioredoxin h of the starchy endosperm communicates with adjoining tissues, thereby regulating their activities, notably by accelerating germination of the embryo and the appearance of α-amylase released by the aleurone. |
| Databáze: | OpenAIRE |
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