Compositions and methods for increasing cellulose production

1. An isolated polynucleotide encoding a polypeptide lacking all or a fragment of the extracellular domain of an SRF-6 polypeptide, wherein the SRF-6 lacking all or a fragment of the extracellular domain is resistant to inhibition by isoxaben, and wherein the truncated polypeptide induces increased CesA4 expression relative to the full length endogenous SRF-6 polypeptide, wherein the SRF-6 polypeptide comprises at least 95% identity to SEQ ID NO: 2.

2. The isolated polynucleotide of claim 1 , wherein the polynucleotide comprises at least 95% sequence identity to SEQ ID NO: 53.

3. An isolated polynucleotide encoding a polypeptide lacking all or a fragment of the extracellular domain of an SRF-7 polypeptide, wherein the SRF-7 lacking all or a fragment of the extracellular domain is resistant to inhibition by isoxaben and wherein the truncated polypeptide induces increased CesA4 expression relative to the full length endogenous SRF-7 polypeptide, wherein the SRF 7 comprises at least 95% identity to SEQ ID NO: 4.

4. The polynucleotide of claim 1 , lacking all or a fragment of the C-terminal domain of the SRF-6 polypeptide.

5. The polynucleotide of claim 3 , lacking all or a fragment of the C-terminal domain of the SRF-7 polypeptide.

6. A polypeptide encoded by the polynucleotides of any one of claims 1 - 3 .

7. A vector comprising the polynucleotide of any one of claims 1 - 3 .

8. A host cell transformed with the polynucleotide of any one of claims 1 - 3 .

9. A host cell transformed with a vector of claim 7 .

10. The host cell of claim 8 , wherein the host cell is a plant cell.

11. The host cell of claim 9 , wherein the host cell is a plant cell.

12. A transgenic plant comprising homozygous expression of the polynucleotide of any one of claims 1 - 3 , wherein the transgenic plant comprises increased cellulose production compared to a wild-type plant.