DNA encoding a plant deoxyhypusine synthase, a plant eukaryotic initiation factor 5A, transgenic plants and a method for controlling senescence programmed and cell death in plants
Regulation of expression of programmed cell death, including senescence, in plants is achieved by integration of a gene or gene fragment encoding senescence-induced deoxyhypusine synthase, senescence-induced elF-5A or both into the plant genome in antisense orientation. Plant genes encoding senescence-induced deoxyhypusine synthase and senescence-induced elF-5A are identified and the nucleotide sequences of each, alone and in combination are used to modify senescence in transgenic plants.
1. A method for identifying a polynucleotide encoding a deoxyhypusine synthase (DHS) in a plant comprising:
a) exposing a tissue of said plant to injury;
b) isolating RNA from the injured tissue;
c) constructing a cDNA library from the RNA obtained from the injured tissue;
d) screening the library with a known plant DHS polynucleotide to identify a cDNA in the library that hybridizes to the known DHS polynucleotide;
e) sequencing said identified cDNA and aligning said sequence against the sequence of the DHS polynucleotide; and
f) identifying a DHS polynucleotide having at least 73% sequence identity across the entire coding region of the DHS with that of one of said known plant DHS polynucleotide to identify a polynucleotide encoding a DHS in said plant.
2. The method of claim 1 wherein the known DHS polynucleotide is selected from the group consisting of Arabidopsis DHS having the sequence of SEQ ID NO:5, carnation DHS having the sequence of SEQ ID NO:9, and tomato DHS having the sequence of SEQ ID NO:1.
3. The method of claim 1 wherein the injured tissue is injured by chilling or dehydration.
4. The method of claim 1 wherein the injured tissue is a leaf, flower or fruit.