Development of a Ti plasmid vector for plant genetic engineering. Progress report, April 15, 1981-April 14, 1984
The Agrobacterium Ti plasmids have the natural ability to insert a specific portion of their DNA, called T-DNA, into the nuclear genome of host plant cells, where it is maintained, replicated and transcribed into mRNA that is translated into foreign protein products. These pathogenic Ti plasmids in nature are acting as gene vectors, for they insert genes that benefit Agrobacterium in several ways. They encode novel enzymes that divert host plant metabolites into storage forms (compounds called opines) that are inaccessible to the plant and to other organisms, but that are specifically catabolized by Agrobacterium. Other genes in the transferred DNA (T-DNA) bring about elevated auxin and cytokinin biosynthesis, causing the tumorous cells to grow autonomously (increasing the size of the opine factory). The present project, begun three years ago, had as its objective the domestication of the Ti plasmid pTi T37 as a gene vector for introduction of desirable genes into higher plants. Three obstacles had to be overcome to this end: (1) insertion of foreign DNA precisely into T-DNA (technically challenging because of the enormous size of the Ti plasmid); (2) developing a disarmed form of the T-DNA that would not cause cells to grow as tumors (a problem because tumor cells could not regenerate into complete plants); and (3) developing new selectable or screenable markers to allow facile isolation of the transformed cells containing genetically engineered T-DNA necessary because the tumorous trait is not usable in the disarmed vector. All of these objectives have been accomplished in the course of the last three years.
- Research Organization:
- Washington Univ., St. Louis, MO (USA). Dept. of Biology
- DOE Contract Number:
- AC02-81ER10889
- OSTI ID:
- 5335819
- Report Number(s):
- DOE/ER/10889-T1; ON: DE84007943
- Country of Publication:
- United States
- Language:
- English
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