POLYNUCLEOTIDES, DNA CONSTRUCTS AND METHODS FOR THE ALTERATION OF PLANT CELLULOSE CONTENT
Polynucleotide, DNA constructs and methods are disclosed for the modification of cellulose content in plant tissues. Plants are transformed with constructs encoding either an active Anabaena sp. sucrose synthase gene or a soybean nodule sucrose synthase gene, which leads to increased cellulose content when over-expressed under the control of a cambium/xylem preferred promoter. Plant transformants harboring an Anabaena sp. or a soybean nodule sucrose synthase gene demonstrated increased content of cellulose, a trait that is thought to improve woody trees for cellulose extraction during pulping and papermaking.
1 . A transgenic plant comprising a nucleic acid molecule encoding a cyanobacterial sucrose synthase lacking an N-terminal phosphorylation domain, wherein said plant is selected for increased cellulose content and decreased lignin content compared with a non-transgenic plant lacking said molecule.
2 . The transgenic plant of claim 1 , obtained by transforming a plant with an expression vector comprising said non-plant sucrose synthase nucleic acid molecule, under the control of a promoter capable of functioning in a plant.
3 . The transgenic plant of claim 1 , wherein said nucleic acid molecule is:
(a) a nucleotide sequence comprising SEQ ID Nos.: 1 or 2; or
(b) a nucleotide sequence of (a) with one or more bases deleted, substituted, inserted, or added that encodes a polypeptide with sucrose synthase enzyme activity.
4 . The transgenic plant of claim 1 , wherein said sucrose synthase molecule is less subject to negative feedback inhibition than a plant sucrose synthase.
5 . The transgenic plant of claim 1 , wherein said plant has sucrose synthase molecule is and Anabaena sp. sucrose synthase.
6 . The transgenic plant of claim 1 , wherein said plant is a dicotyledon.
7 . The transgenic plant of claim wherein said plant is a monocotyledon.
8 . The transgenic plant of claim 1 , wherein said plant is a gymnosperm.
9 . The transgenic plant of claim 1 , wherein said plant is a woody tree.
10 . The transgenic plant of claim 9 , wherein said woody tree is a Eucalyptus plant.
11 . The transgenic plant of claim 9 , wherein said woody tree is a Populus plant.
12 . The transgenic plant of claim 9 , wherein said woody tree is a Pinus plant.
13 . A part of the transgenic plant of claim 1 , selected from the group consisting of a leaf, a stem, a flower, an ovary, a fruit, a seed, and a callus, wherein said plant part comprises a cyanobacterial sucrose synthase nucleic acid molecule lacking an N-terminal phosphorylation domain.
14 . A method for producing a transgenic plant with increased cellulose content and decreased lignin content as compared to a non-transgenic plant, comprising (i) transforming a plant cell with a sequence encoding a cyanobacterial sucrose synthase lacking an N-terminal phosphorylation domain under the control of a promoter capable of functioning in a plant, (ii) culturing said transformed plant cell under conditions that promote growth of a plant, and (iii) selecting a transgenic plant that exhibits increased cellulose content and decreased lignin content.
15 . The method of claim 14 , wherein the nucleotide sequence is a sucrose synthase gene comprising:
(a) a nucleotide sequence comprising SEQ ID Nos.: 1 or 2; or
(b) a nucleotide sequence of (a) with one or more bases deleted, substituted, inserted, or added that encodes a polypeptide with sucrose synthase enzyme activity.
16 . The method of claim 15 , wherein said transgenic plant is a dicotyledon.
17 . The method of claim 15 , wherein said transgenic plant is a monocotyledon.
18 . The method of claim 15 , wherein said transgenic plant is a gymnosperm.
19 . An isolated polynucleotide sequence comprising a nucleic acid sequence of SEQ ID NO:2 encoding a polypeptide that is capable of increasing sucrose synthase and cellulose levels in a plant.