Author
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Zhang, Xing Hai |
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WIDHOLM, JACK - CROP SCIENCES UOFI URBANA |
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PORTIS JR, ARCHIE |
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Submitted to: Soybean Research World Conference Proceedings
Publication Type: Proceedings Publication Acceptance Date: 8/7/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Soybean yield largely depends on the solar energy utilization by the plants through photosynthesis in chloroplasts. A key CO2-fixing enzyme is ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). Improving the Rubisco's functionality could increase soybean productivity. One way of doing it is to replace the soybean Rubisco with a "better" enzyme from another species. We are trying to genetically modify soybeans by chloroplast transformation, introducing Rubisco genes from the alga, Chlamydomonas reinhardtii, into the soybean plastid genome. Thus, the photosynthesis in soybeans would be catalyzed by the more efficient Chlamydomonas Rubisco. The successful transformation of the soybean chloroplasts could potentially increase the photosynthesis rate by 7 percent under the present CO2 level and by 95 percent when the atmospheric CO2 level doubles as projected for the mid-21ST century, thus resulting in a significant increase in soybean yield and cost efficiency. We have designed several transgene constructs containing a selectable marker gene conferring resistance to spectinomycin, and the Chlamydomonas rbcL and rbcS fused with soybean rbcL or 16S rDNA promoters. Soybean (Glycine max L. cv. Jack) embryogenic tissues were bombarded with gold particles coated with the DNA of these transgene constructs. These tissues were cultivated in a medium containing spectinomycin, and several lines of resistant embryos were selected. Preliminary PCR analysis showed the presence of Chlamydomonas Rubico coding sequences in these embryos. We are now in the process of regenerating plants from the putative transformants for further laboratory analysis and field trial. |
