Identification and use of grape genes controlling salt/drought tolerance and fruit sweetness

Abstract

The present invention provides the identification and use of EGTom1 and/or EGTom2, homologs of EGTom1 and/or EGTom2, orthologs of EGTom1 and/or EGTom2, paralogs of EGTom1 and/or EGTom2, and fragments and variations thereof for altering salt tolerance, drought tolerance and/or sugar content of fruit (sweetness) in plants.

1 . A transgenic grape plant, plant part, plant cell, or plant tissue culture comprising a construct comprising a nucleic acid encoding an EGTom polypeptide having 95% sequence identity to SEQ ID NO 14; wherein said transgenic grape plant, or transgenic grape plant produced from said plant part, plant cell, or plant tissue culture, expresses said EGTom polypeptide, and has increased fruit sweetness compared to the fruit of an untransformed control grape plant. 
     
     
         2 . The transgenic grape plant, plant part, plant cell, or plant tissue culture, of  claim 1 , wherein the nucleic acid encodes an EGTom polypeptide having 95% sequence identity to SEQ ID NO 14. 
     
     
         3 . The transgenic grape plant, plant part, plant cell, or plant tissue culture, of  claim 1 , wherein the construct further comprises a gene termination sequence. 
     
     
         4 . The transgenic grape plant, plant part, plant cell, or plant tissue culture, of  claim 1 , wherein the construct further comprises a promoter. 
     
     
         5 . The transgenic grape plant, plant part, plant cell, or plant tissue culture, of  claim 1 , wherein the construct is an overexpression construct. 
     
     
         6 . A genetic construct comprising, in the 5′-3′ direction:
 (i) a promoter sequence; 
 (ii) the nucleic acid sequence of  claim 1 ; and 
 (iii) a gene termination sequence; 
 wherein expression of said genetic construct in a plant causes the plant to bear fruit with increased sweetness compared to the fruit of an untransformed plant. 
 
     
     
         7 . A method for producing a transgenic grape plant with increased fruit sweetness, said method comprising:
 (i) transforming a grape plant cell with a construct comprising a nucleic acid sequence encoding a EGTom polypeptide having at least 95% identity to SEQ ID NO 14; and   (ii) cultivating the transgenic grape cell under conditions conducive to regeneration and mature plant growth;   wherein the transgenic grape plant regenerated from said transgenic plant cell expresses said EGTom polypeptide, and has increased fruit sweetness compared to the fruit of untransformed control grape plants.   
     
     
         8 . The method of  claim 7 , wherein the construct is an overexpression construct. 
     
     
         9 . A method of producing hybrid grape seed, said method comprising: crossing the transgenic grape plant of  claim 1  with another grape plant, and harvesting the resultant seed. 
     
     
         10 . A method of breeding grape plants to produce plants with increased fruit sweetness, said method comprising:
 (i) making a cross between a first transgenic grape plant of  claim 1  with a second plant to produce an F, 1 plant;   (ii) backcrossing the F1 plant to the second plant; and   (iii) repeating the backcrossing step one or more times to generate a near isogenic or isogenic line,   wherein the construct of  claim 1  is integrated into the genome of the second plant and the near isogenic or isogenic line derived from the second plant with the nucleic acid encoding the EGTom polypeptide has increased fruit sweetness compared to the fruit of a second plant without said nucleic acid sequence.   
     
     
         11 . A method of culturing plant tissue, said method comprising culturing at least part of the plant of  claim 1 , wherein said plant is cultured in conditions conducive to plant regeneration, thereby regenerating said plant. 
     
     
         12 . Progeny plants produced by the method of  claim 9 , wherein the progeny plants have increased fruit sweetness as a result of inheriting the polynucleotide when compared to a parent plant without the genetic construct of the present invention and wherein the parent plant is a non-transgenic plant as a wildtype plant or an appropriate check plant. 
     
     
         13 . A transgenic grape plant of  claim 1 , wherein the plant is a cultivated grape plant ( Vitis vinifera ). 
     
     
         14 . The transgenic grape plant, plant part, plant cell, or plant tissue culture of  claim 1 , wherein the nucleic acid sequence encodes an EGTom polypeptide having at least 96% sequence identity to SEQ ID No 14. 
     
     
         15 . The transgenic grape plant, plant part, plant cell, or plant tissue culture of  claim 1 , wherein the nucleic acid sequence encodes an EGTom polypeptide having at least 97% sequence identity to SEQ ID No 14. 
     
     
         16 . The transgenic grape plant, plant part, plant cell, or plant tissue culture of  claim 1 , wherein the nucleic acid sequence encodes an EGTom polypeptide having at least 98% sequence identity to SEQ ID No 14. 
     
     
         17 . The transgenic grape plant, plant part, plant cell, or plant tissue culture of  claim 1 , wherein the nucleic acid sequence encodes an EGTom polypeptide having at least 99% sequence identity to SEQ ID No 14. 
     
     
         18 . A method of growing a plant comprising placing the seeds from the plants produced in  claim 9 , in an environment conducive to plant growth, thereby growing the plant.