Root specific expression conferred by chimeric gene regulatory elements

1. A chimeric polynucleotide sequence comprising SEQ ID NO:1, and wherein the chimeric polynucleotide sequence promotes root-specific expression of a transgene.

2. The chimeric polynucleotide sequence of claim 1 , wherein the polynucleotide consists of SEQ ID NO:1.

3. The chimeric polynucleotide sequence of claim 1 , wherein the chimeric polynucleotide sequence is operably linked to a transgene.

4. The chimeric polynucleotide sequence of claim 3 , wherein the transgene is tcdA.

5. The chimeric polynucleotide sequence of claim 1 , wherein the operably linked transgene encodes a polypeptide or small RNA.

6. A transgenic cell comprising a synthetic polynucleotide comprising SEQ ID NO:1, wherein the synthetic polynucleotide is a root-specific promoter.

7. The transgenic cell of claim 6 , wherein the synthetic polynucleotide consists of SEQ ID NO:1.

8. The transgenic cell of claim 6 , wherein the transgenic cell is produced by a plant transformation method.

9. The transgenic cell of claim 8 , wherein the plant transformation method is selected from the group consisting of an Agrobacterium -mediated transformation method, a biolistics transformation method, a silicon carbide transformation method, a protoplast transformation method, and a liposome transformation method.

10. A transgenic plant comprising the transgenic cell of claim 6 .

11. The transgenic plant of claim 10 , wherein the transgenic plant is a monocotyledonous or a dicotyledonous plant.

12. The transgenic plant of claim 11 , wherein the monocotyledonous plant is selected from the group consisting of a maize plant, a rice plant, and a wheat plant.

13. A transgenic seed from the transgenic plant of claim 10 , wherein the seed comprises said chimeric polynucleotide.