Maize metallothionein gene and promoter

Abstract

The present invention provides compositions and methods for regulating expression of heterologous nucleotide sequences in a plant. Compositions include a novel nucleotide sequence for a root-preferred promoter for the gene encoding, a metallothionein gene and sequences isolated therefrom. A method for expressing a heterologous nucleotide sequence in a plant using the promoter sequences disclosed herein is provided. The method comprises transforming a plant cell with a nucleotide sequence operably linked to one of the root-preferred promoters of the present invention and regenerating a stably transformed plant that expresses the nucleotide sequence in a root-preferred manner from the transformed plant cell. Compositions and methods for expressing metallothionein genes in plants, plant cells and tissues are also provided. The compositions comprise nucleotide sequences encoding plant metallothionein. The sequences are useful in transforming plants for tissue-preferred or constitutive expression of metallothionein. Such sequences find use in modulating levels of metal ions in plants and plant tissues.

What is claimed is:  
     
         1 . An isolated nucleotide sequence selected from the group consisting of: 
 a) a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:3;    b) a nucleotide sequence set forth in SEQ ID NO:2; and    c) a complement of a) or b).    
     
     
         2 . A DNA construct comprising a nucleotide sequence of  claim 1 , wherein said nucleotide sequence is operably linked to a promoter that drives expression in a plant cell.  
     
     
         3 . The construct of  claim 2 , wherein said promoter is a tissue specific promoter.  
     
     
         4 . The construct of  claim 3 , wherein said promoter is selected from the group consisting of promoters driving expression in root, seed, embryo, and green tissue.  
     
     
         5 . The construct of  claim 3 , wherein said promoter is a constitutive promoter.  
     
     
         6 . Host cells containing or capable of expressing the construct of  claim 2 .  
     
     
         7 . A method for modulating levels of metal ions in a plant cell, said method comprising transforming a plant with at least one nucleotide sequence of  claim 1 , said nucleotide sequence operably linked to a heterologous promoter that drives expression in a plant cell.  
     
     
         8 . The method of  claim 7 , wherein said metal ion is a divalent cation.  
     
     
         9 . The method of  claim 8 , wherein said divalent cation is Cu ++ .  
     
     
         10 . A transformed plant cell having stably incorporated into its genome at least one nucleotide sequence of  claim 1 , said nucleotide sequence operably linked to a heterologous promoter that drives expression in a plant cell.  
     
     
         11 . A transformed plant having stably incorporated into its genome at least one nucleotide sequence of  claim 1 , said nucleotide sequence operably linked to a heterologous promoter that drives expression in a plant cell.  
     
     
         12 . The plant of  claim 11 , wherein said promoter is a tissue-preferred or promoter.  
     
     
         13 . The plant of  claim 2 , wherein said promoter is an root-preferred promoter.  
     
     
         14 . The plant of  claim 11 , wherein said promoter is a constitutive promoter.  
     
     
         15 . The plant of  claim 11 , wherein said plant is a monocot.  
     
     
         16 . The plant of  claim 15 , wherein said monocot is maize, wheat, rice, barley, sorghum, or rye.  
     
     
         17 . The plant of  claim 11 , wherein said plant is a dicot.  
     
     
         18 . The plant of  claim 17 , wherein said dicot is selected from the group consisting of soybean, canola, sunflower, alfalfa, or safflower.  
     
     
         19 . Seed of the plant of  claim 11 .  
     
     
         20 . An isolated nucleotide sequence having 70% sequence identity to SEQ ID NO:2 wherein said sequence encodes a polypeptide having metal binding activity.  
     
     
         21 . The nucleotide sequence of  claim 20  wherein said sequence has 80% sequence identity to SEQ ID NO:2.  
     
     
         22 . The nucleotide sequence of  claim 20  wherein said sequence has 90% sequence identity to SEQ ID NO:2.  
     
     
         23 . The nucleotide sequence of  claim 20  wherein said sequence has 95% sequence identity to SEQ ID NO:2.