ISHS Acta Horticulturae 521: XXV International Horticultural Congress, Part 11: Application of Biotechnology and Molecular Biology and Breeding - Gene Expression and Molecular Breeding, Genome Analysis.
IRON ACCUMULATION IN TRANSGENIC PLANTS EXPRESSING THE SOYBEAN FERRITIN GENE |
| Authors: | F. Goto, T. Yoshihara, H. Saiki, F. Takaiwa, N. Shigemoto |
| Keywords: | ferritin, iron, lettuce, rice, soyabean, tobacco, transgenic |
| Abstract:
The cDNA of soybean ferritin was transferred into tobacco, rice and lettuce via an - Agrobacterium--mediated transformation. In transformants of tobacco and lettuce, the ferritin gene was under the control of the Cauliflower mosaic virus 35S promoter. In rice transformants, the ferritin gene was under the control of GluB-1, the promoter for the rice seed-storage protein glutelin. Expression of the introduced gene was confirmed in all transformants by Western blot analysis. A peptide of the size predicted from soybean ferritin cDNA was not detected in protein extracts from transformants, however 2 kinds of smaller subunits, of similar size to the native soybean mature subunit, were detected. These results show that ferritin protein assembly in transgenic plants occurs in a fashion similar to assembly in soybean. The iron content of transgenic plants was higher than that of control plants. The highest iron content of leaves from transformed tobacco and lettuce, in which the exogenous ferritin gene was expressed constitutively, was approximately 30% and 70% higher than leaves from control plant, respectively. The iron content of transformed rice seeds increased significantly to a maximum of 3 times that of controls. Furthermore, an enhanced growth of transgenic tobacco and lettuce was observed at early developmental stages. Taken together, these results demonstrate that ferritin derived from an exogenous gene functions as iron accumulator in both monocots (including graminaceous plants) and dicots. Therefore, it seems probable to breed for high iron content crops by introduction of the ferritin gene. | |
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