Methods and Compositions for Targeting Sequences of Interest to the Chloroplast

Abstract

Chimeric polynucleotides comprising a nucleotide sequence encoding a chloroplast transit peptide operably linked to a heterologous polynucleotide of interest are provided, wherein the chloroplast transit peptide comprises an amino acid sequence having the chloroplast transit peptide sequence as set forth in SEQ ID NO: 1 or a biologically active variant or fragment thereof or wherein the chloroplast transit peptide comprises the sequence set forth in SEQ ID NO: 58 or an active variant or fragment thereof. Chimeric polypeptides encoding the same, as well as, cells, plant cells, plants and seeds are further provided which comprise the chimeric polynucleotides. Compositions further include HPPD polypeptides and polynucleotides encoding the same as set forth in SEQ ID NOS: 57 and 60 or active variants and fragments thereof. Such sequences comprise the chloroplast transit peptide as set forth in SEQ ID NO: 58 or an active variants or fragments thereof. Cells, plant cells, plants and seeds are further provided which comprise such sequences. Methods of use of the various sequences are also provided.

1 . A chimeric polynucleotide comprising a nucleotide sequence encoding a chloroplast transit peptide operably linked to a heterologous polynucleotide encoding a polypeptide of interest, wherein said chloroplast transit peptide comprises
 a) an amino acid sequence comprising the amino acids of SEQ ID NO:1;   b) an amino acid sequence having at least 90% sequence identity to SEQ ID NO: 1 or   c) an amino acid sequence having at least 17 consecutive amino acids of SEQ ID NO:1.   
     
     
         2 . The chimeric polynucleotide of  claim 1 , wherein said chloroplast transit peptide comprises SEQ ID NO: 2, 3, 4, 5, 6, 7, or 8. 
     
     
         3 . The chimeric polynucleotide of  claim 1 , wherein said polypeptide of interest comprises a 4-hydroxphenylpyruvate dioxygenase (HPPD) polypeptide having HPPD activity. 
     
     
         4 . A nucleic acid construct comprising the chimeric polynucleotide of  claim 1 . 
     
     
         5 . The nucleic acid construct of  claim 4 , further comprising a promoter operably linked to said chimeric polynucleotide. 
     
     
         6 . A cell comprising at least one chimeric polynucleotide of claim I. 
     
     
         7 . The cell of  claim 6 , wherein said cell is a plant cell. 
     
     
         8 . The cell of  claim 7 , wherein said polynucleotide or nucleic acid construct is stably incorporated into the genome of said plant cell. 
     
     
         9 . The cell of  claim 7 , wherein said plant cell is from a monocot. 
     
     
         10 . The cell of  claim 9 , wherein said monocot is maize, wheat, rice, barley, sorghum, or rye. 
     
     
         11 . The cell of  claim 7 , wherein said plant cell is from a dicot. 
     
     
         12 . The cell of  claim 11 , wherein the dicot is soybean,  Brassica , sunflower, cotton, or alfalfa. 
     
     
         13 . A plant comprising at least one plant cell of  claim 7 . 
     
     
         14 . A plant explant comprising at least one plant cell of  claim 7 . 
     
     
         15 . A transgenic seed produced by the plant of  claim 13 . 
     
     
         16 . The plant cell of  claim 7 , wherein the plant cell further comprises at least one polypeptide imparting tolerance to a herbicide. 
     
     
         17 . The plant cell of  claim 16 , wherein said at least one polypeptide imparting tolerance to a herbicide comprises:
 (a) a sulfonylurea-tolerant acetolactate synthase;   (b) an imidazolinone-tolerant acetolactate synthase;   (c) a glyphosate-tolerant 5-enolpyruvylshikimate-3-phosphate   (d) a glyphosate-tolerant glyphosate oxido-reductase;   (e) a glyphosate-N-acetyltransferase;   (f) a phosphinothricin acetyl transferase;   (g) a protoporphyrinogen oxidase;   (h) an auxin enzyme or receptor;   (i) a P450 polypeptide; or,   (j) an acetyl coenzyme A carboxylase (ACCase).   
     
     
         18 . A chimeric polypeptide encoded by the polynucleotide of  claim 1 . 
     
     
         19 . A method of targeting a polypeptide of interest to a chloroplast comprising expressing a chimeric polynucleotide of  claim 1  or the nucleic acid construct of  claim 4  in a plant cell. 
     
     
         20 . A method of targeting a polypeptide of interest to a chloroplast comprising introducing the chimeric polynucleotide of claim I or the nucleic acid construct of  claim 4  in a plant cell and expressing said chimeric polynucleotide in the plant cell. 
     
     
         21 . The method of  claim 19 , wherein said method further comprises regenerating a transgenic plant from said plant cell. 
     
     
         22 . The method of  claim 19 , wherein said plant cell is from a dicot. 
     
     
         23 . The method of  claim 22 , wherein said dicot is selected from the group consisting of soybean,  Brassica , sunflower, cotton, or alfalfa. 
     
     
         24 . The method of  claim 19 , wherein said plant cell is from a monocot. 
     
     
         25 . The method of  claim 24 , wherein said dicot is selected from the group consisting of maize, wheat, rice, barley, sorghum, or rye. 
     
     
         26 . The method of  claim 19 , wherein the plant cell further comprises at least one polypeptide imparting tolerance to a herbicide. 
     
     
         27 . The method of  claim 26 , wherein said at least one polypeptide imparting tolerance to a herbicide comprises:
 (a) a sulfonylurea-tolerant acetolactate synthase;   (b) an imidazolinone-tolerant acetolactate synthase;   (c) a glyphosate-tolerant 5-enolpyruvylshikimate-3-phosphate synthase;   (d) a glyphosate-tolerant glyphosate oxido-reductase;   (e) a glyphosate-N-acetyltransferase;   (f) a phosphinothricin acetyl transferase;   (g) a protoporphyrinogen oxidase;   (h) an auxin enzyme or receptor;   (i) a P450 polypeptide; or,   (j) an acetyl coenzyme A carboxylase (ACCase).   
     
     
         28 - 39 . (canceled)