FREEZE TOLERANT EUCALYPTUS
The present disclosure relates to freeze-tolerant transgenic Eucalyptus, including methodology for making and products produced there from. Following exposure to cold temperature, and compared to a control plant, the freeze-tolerant Eucalyptus displays a freeze-tolerant phenotype characterized by at least one of increased height, less leaf damage, less dieback of main stem, less crown defoliation, and/or improved tree stem form.
1 . A transgenic Eucalyptus displaying a freeze-tolerant phenotype.
2 . The transgenic Eucalyptus of claim 1 , wherein said plant is a hybrid.
3 . The transgenic hybrid of claim 2 , wherein said hybrid has a genotype of E. grandis×E. urophylla.
4 . The transgenic Eucalyptus of claim 1 , wherein said freeze-tolerant phenotype is any one or combination of increased height, less leaf damage, less dieback of main stem, less crown defoliation, and/or improved tree stem form (single dominant leader stem), relative to a control plant.
5 . Wood or wood fiber produced from transgenic Eucalyptus of claim 1 .
6 . Pulp produced from the transgenic Eucalyptus of claim 1 .
7 . Paper produced from the transgenic Eucalyptus of claim 1 .
8 . Oil produced from the transgenic Eucalyptus of claim 1 .
9 . A method of conferring freezing tolerance in Eucalyptus, comprising
(a) introducing into a Eucalyptus cell a construct comprising an isolated polynucleotide sequence operably linked to a promoter, wherein said isolated polynucleotide encodes a CBF polypeptide and wherein the promoter drives the expression of the CBF polypeptide Eucalyptus upon exposure to cold for a period of time;
(b) culturing the transformed Eucalyptus cell under conditions promoting growth of a transgenic Eucalyptus tree, thereby producing a transgenic tree;
(c) subjecting the transgenic Eucalyptus tree to cold acclimation;
(d) exposing the transgenic tree to a freezing temperature for a period of time; and
(e) allowing the transgenic tree to recover under conditions that promote growth of the transgenic tree.
10 . The method of claim 9 , wherein said promoter is Arabidopsis thaliana rd29A promoter.
11 . The method of claim 9 , wherein said freezing temperature is from about 0° C. to about −30° C.
12 . The method of claim 9 , wherein said period of time is from about 2 hours to about 72 hours.
13 . The method of claim 9 , wherein said isolated polynucleotide sequence is selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5 and SEQ ID NO: 7, or a fragment or variant thereof having at least 70% sequence identity to SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7.