Plants with enhanced tolerance to multiple abiotic stresses

Abstract

The present disclosure describes genetically-modified plants having enhanced tolerance to multiple abiotic stressors, such as extreme temperatures (heat or cold) and/or drought. Abiotic stress tolerance is enhanced by ectopic expression of a heterologous glutaredoxin. Abiotic stress tolerance (particularly drought) is also enhanced by inhibited function, activity, or expression of an endogenous glutaredoxin. Methods of producing such genetically-modified plants are also disclosed.

1 . A genetically-modified plant having enhanced tolerance to an abiotic stressor as compared to a control plant, said genetically-modified plant having ectopic expression of a heterologous, abiotic stress tolerance gene, said gene encoding for a glutaredoxin. 
     
     
         2 . The genetically-modified plant of  claim 1 , wherein said glutaredoxin is GRXS17. 
     
     
         3 . The genetically-modified plant of  claim 1 , wherein said gene comprises a sequence selected from the group consisting of: (a) a nucleotide sequence comprising SEQ ID NO:1; (b) a nucleotide sequence comprising an antisense sequence corresponding to SEQ ID NO:1; (c) a nucleotide sequence having at least about 70% sequence identity to SEQ ID NO:1; (d) a nucleotide sequence encoding a glutaredoxin protein comprising SEQ ID NO:2; (e) a nucleotide sequence encoding a glutaredoxin protein having at least about 50% amino acid identity to SEQ ID NO:2 and retaining the functional characteristics thereof; (f) a nucleotide sequence comprising SEQ ID NO:3; (g) a nucleotide sequence comprising an antisense sequence corresponding to SEQ ID NO:3; (h) a nucleotide sequence having at least about 70% sequence identity to SEQ ID NO:3; (i) a nucleotide sequence encoding a glutaredoxin fusion protein comprising SEQ ID NO:4; and (j) a nucleotide sequence encoding a glutaredoxin fusion protein having at least about 50% amino acid identity to SEQ ID NO:4 and retaining the functional characteristics thereof. 
     
     
         4 . The genetically-modified plant of  claim 1 , wherein said genetically-modified plant is a monocot or a dicot. 
     
     
         5 . The genetically-modified plant of  claim 4 , wherein said plant is selected from the group consisting of grains, tubers, nightshades, and cash crops. 
     
     
         6 . The genetically-modified plant of  claim 5 , wherein said genetically-modified plant is selected from the group consisting of wheat, oat, barley, rice, maize, millet, rye, sorghum, triticale, buckwheat, quinoa, soybeans, beans, peas, alfalfa, potatoes, sweet potatoes, cassava, yam, tomatoes, peppers, tobacco, and cotton. 
     
     
         7 . The genetically-modified plant of  claim 1 , wherein said gene is stably incorporated into the genome of said genetically-modified plant. 
     
     
         8 . The genetically-modified plant of  claim 1 , wherein said genetically-modified plant comprises a phenotype that is substantially similar to the phenotype of said control plant when said plants are grown under non-stress conditions. 
     
     
         9 . The genetically-modified plant of  claim 1 , wherein said genetically-modified plant comprises an improved phenotype as compared to said control plant, when said plants are grown under abiotic stress. 
     
     
         10 . The genetically-modified plant of  claim 1 , wherein said genetically-modified plant further comprises inhibited expression, activity, or function of an endogenous glutaredoxin gene. 
     
     
         11 . The genetically-modified plant of  claim 1 , wherein said abiotic stressor is selected from the group consisting of: heat, cold, drought, salinity, and combinations thereof. 
     
     
         12 .- 30 . (canceled) 
     
     
         31 . A fusion protein for enhancing the abiotic stress tolerance of a plant, said fusion protein comprising a glutaredoxin amino acid sequence linked to a reporter amino acid sequence by one or more peptide bonds. 
     
     
         32 . The fusion protein of  claim 31 , wherein said reporter is a fluorescent protein. 
     
     
         33 . The fusion protein of  claim 31 , wherein said reporter is green fluorescent protein, beta-glucuronidase, luciferase, or dsRed. 
     
     
         34 . The fusion protein of  claim 31 , wherein said glutaredoxin amino acid sequence comprises a sequence selected from the group consisting of (a) SEQ ID NO:2, 6, or 31; and (b) an amino acid sequence having at least about 50% amino acid identity to SEQ ID NO: 2, 6, or 31 and retaining the functional characteristics thereof. 
     
     
         35 . The fusion protein of  claim 31 , wherein said fusion protein comprises SEQ ID NO:4, or a sequence having at least about 50% sequence identify to SEQ ID NO:4 and retaining the functional characteristics thereof. 
     
     
         36 . A genetically-modified plant having enhanced resistance to an abiotic stressor, as compared to a control plant, said genetically-modified plant having inhibited expression, activity, or function of an endogenous glutaredoxin gene. 
     
     
         37 . The genetically-modified plant of  claim 36 , wherein said resistant plant comprises a nucleic acid construct that inhibits expression, activity, or function of said glutaredoxin gene. 
     
     
         38 . The genetically-modified plant of  claim 37 , wherein said nucleic acid construct comprises a sense sequence operably linked to its complementary antisense sequence and encoding double stranded RNA that inhibits expression, activity, or function of said glutaredoxin gene. 
     
     
         39 . The genetically-modified plant of  claim 36 , wherein said expression, activity, or function in said resistant plant is inhibited by mutation of said glutaredoxin gene. 
     
     
         40 . The genetically-modified plant of  claims 36 , wherein said plant does not express a glutaredoxin protein comprising SEQ ID NO:6 or 31, or an amino acid sequence comprising at least about 50% amino acid identity with SEQ ID NO:6 or 31.