Maize stress-responsive NAC transcription factors and methods of use

Abstract

Methods and compositions for modulating plant development are provided. Polynucleotide sequences encoding ZmSNAC polypeptides are provided, as are the amino acid sequences of the encoded polypeptides. The sequences can be used in a variety of methods including modulating root development, modulating floral development, modulating leaf and/or shoot development, modulating senescence, modulating seed size and/or weight, and modulating tolerance of plants to abiotic stress. Transformed plants, plant cells, tissues, and seed are also provided. A stress-inducible ZmSNAC1 promoter is also provided.

That which is claimed: 
     
         1 . A method of improving stress tolerance in a plant, relative to a control plant, comprising transforming said plant with an expression cassette comprising a polynucleotide operably linked to a heterologous promoter, wherein the polynucleotide is selected from the group consisting of:
 a. a polynucleotide encoding an amino acid sequence at least 95% identical to SEQ ID NO: 2, 4, 6, 8, or 10;   b. a polynucleotide comprising a nucleotide sequence at least 95% identical to SEQ ID NO: 1, 3, 5, 7, or 9, or the complement thereof; and   c. a polynucleotide comprising a nucleotide sequence of SEQ ID NO: 1, 3, 5, 7, or 9.   
     
     
         2 . The method of  claim 1  wherein said promoter is a tissue-preferred or inducible promoter, or is both tissue-preferred and inducible. 
     
     
         3 . The method of  claim 2 , wherein said promoter is stress-inducible. 
     
     
         4 . The method of  claim 2 , wherein said promoter is root-preferred. 
     
     
         5 . The method of  claim 1 , wherein senescence is delayed, relative to a control. 
     
     
         6 . The method of  claim 1 , wherein root development of the plant is increased, relative to a control. 
     
     
         7 . The method of  claim 1 , wherein the stress tolerance is drought tolerance. 
     
     
         8 . The method of  claim 1 , wherein the plant is maize, wheat, rice, barley, sorghum, rye, soybean,  brassica , or sunflower. 
     
     
         9 . The method of  claim 1 , further comprising the steps of
 a. Producing seed from the transformed plant, wherein said seed comprises the expression cassette; and   b. Propagating the seed to produce progeny, wherein the progeny comprise the expression cassette.   
     
     
         10 . An expression cassette comprising a polynucleotide operably linked to a heterologous promoter, wherein the polynucleotide is selected from the group consisting of:
 a. a polynucleotide encoding an amino acid sequence at least 95% identical to SEQ ID NO: 2, 4, 6, 8, or 10;   b. polynucleotide comprising a nucleotide sequence at least 95% identical to SEQ ID NO: 1, 3, 5, 7, or 9, or the complement thereof; and   c. a polynucleotide comprising the nucleotide sequence of SEQ ID NO: 1, 3, 5, 7, or 9.   
     
     
         11 . A transgenic plant comprising an expression cassette of  claim 10 . 
     
     
         12 . The plant of  claim 11 , wherein said promoter is a tissue-preferred promoter, a constitutive promoter, or an inducible promoter. 
     
     
         13 . The plant of  claim 12 , wherein said tissue-preferred promoter is a root-preferred promoter, a leaf-preferred promoter, a shoot-preferred promoter or an inflorescence-preferred promoter. 
     
     
         14 . The plant of  claim 11 , wherein root development is increased, relative to a control. 
     
     
         15 . The plant of  claim 11 , wherein the drought tolerance of said plant is increased, relative to a control. 
     
     
         16 . The plant of  claim 11 , wherein said plant is maize, wheat, rice, barley, sorghum, rye, soybean,  brassica  or sunflower. 
     
     
         17 . A plant in which the level of expression of a native genomic locus is modified, said genomic locus comprising:
 a. a polynucleotide encoding an amino acid sequence at least 95% identical to SEQ ID NO: 2, 4, 6, 8, or 10;   b. a polynucleotide comprising a nucleotide sequence at least 95% identical to SEQ ID NO: 1, 3, 5, 7, or 9, or the complement thereof; or   c. a polynucleotide comprising a nucleotide sequence of SEQ ID NO: 1, 3, 5, 7, or 9.   
     
     
         18 . The plant of  claim 17 , wherein said plant is maize, wheat, rice, barley, sorghum, rye, soybean,  brassica  or sunflower.