Abstract
The inability of many higher eukaryotes to convert 5-fluorocytosine to cytotoxic 5-fluorouracil presents the possibility of using the bacterial cytosine deaminase codA gene for negative selection. In transformed plant callus, expression of codA results in cell death on 5-fluorocytosine. In transgenic tobacco and Lotus japonicus plants the substrate-dependent negative marker segregates as a single dominant gene, and on 5-fluorocytosine CodA+ seedlings stop growing at the early seedling stage. Positive selection of CodA+ tobacco on the pyrimidine biosynthetic inhibitor N-(phosphonacetyl)-L-aspartate was obtained, by pyrimidine salvage from external cytosine. Activity of cytosine deaminase was determined by conversion of labelled cytosine to uracil followed by separation in thin layer chromatography. The codA marker therefore provides substrate-dependent negative and positive selection, together with cytosine deaminase reporter activity.
| Original language | English |
|---|---|
| Journal | Plant Journal |
| Volume | 3 |
| Issue | 5 |
| Pages (from-to) | 755-761 |
| Number of pages | 7 |
| ISSN | 0960-7412 |
| Publication status | Published - 1993 |