Methods and Compositions for Modulating Flowering and Maturity in Plants

Abstract

The present invention provides compositions and methods for modulating flowering time in plants. Maize RAP2.7 nucleotide sequences are disclosed which upon overexpression cause later flowering and when inhibited cause earlier flowering. Also disclosed is a DNA sequence which acts as a regulator/enhancer of RAP2.7, termed VGT1. This sequence does not code for any known protein, but acts as either a RNAi element or a regulatory DNA or RNA element that either directly regulates expression of flowering genes such as Rap2.7 or specifically targets expression of other genes which control flowering genes such as Rap2.7. This element this can be used as a sequence—based marker to identify inbred and hybrids which have altered maturity. Methods for expressing these nucleotide sequences in a plant for modifying maturity and flowering in plants are provided as well as expression constructs, vectors, transformed cells and plants.

1 . An isolated nucleic acid molecule that encodes a polypeptide having RAP2.7-like activity, said nucleic acid molecule being selected from the group consisting of:
 (a) a nucleic acid molecule comprising the sequence set forth in SEQ ID NOS: 1, 3, or 4;   (b) a nucleic acid molecule comprising a sequence encoding the amino acid sequence set forth in SEQ ID NOS: 2;   (c) a nucleic acid molecule comprising a sequence having at least 80% sequence identity to the nucleotide sequence set forth in SEQ ID NOS: 1, 3, or 4; and
 (d) a nucleic acid molecule comprising a sequence of at least 50 consecutive nucleic acids of any of (a) through (d). 
   
     
     
         2 . A vector comprising the nucleic acid molecule of  claim 1 . 
     
     
         3 . A plant cell having stably incorporated in its genome the nucleic acid molecule of  claim 1 . 
     
     
         4 . The plant cell of  claim 3 , wherein said plant cell is from a monocot plant. 
     
     
         5 . The plant cell of  claim 4 , wherein said monocot plant is maize. 
     
     
         6 . A plant having stably incorporated into its genome the nucleic acid molecule of  claims 1 . 
     
     
         7 . A method for altering flowering time in a plant comprising:
 transforming a plant cell with a nucleic acid molecule operably linked to a promoter that regulates transcription of said sequence in a plant cell;
 wherein said nucleic acid molecule comprises a nucleotide sequence selected from the group consisting of: 
 (a) a nucleotide sequence comprising the sequence set forth in SEQ ID NOS: 1, 3, or 4; 
 (b) a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:2; 
 (c) a nucleotide sequence having at least 80% sequence identity to the sequence of SEQ ID NOS: 1, 3, or 4, wherein said nucleotide sequence encodes a protein which regulates flowering in plants. 
   
     
     
         8 . The method of  claim 6 , wherein said plant is a monocot. 
     
     
         9 . The method of  claim 7 , wherein said monocot is maize. 
     
     
         10 . The method of  claim 7  wherein said nucleic acid molecule is a vector for over-expression of RAP2.7. 
     
     
         11 . The method of  claim 7  wherein said plant flowers later than a plant which does not have the overexpression vector incorporated therein. 
     
     
         12 . The method of  claim 7  wherein said nucleic acid moleculare is a vector for inhibiting expression of RAP2.7. 
     
     
         13 . The method of  claim 12  wherein said vector is an RNA interference vector. 
     
     
         14 . The method of  claim 13  wherein said plant flowers earlier than a plant which does not have an RNA interference vector incorporated therein. 
     
     
         15 . A method for altering maturity of a plant, said method comprising:
 transforming said plant with a nucleic acid molecule comprising a heterologous sequence operably linked to a promoter that induces transcription of said heterologous sequence in a plant cell; and   regenerating stably transformed plants, wherein said heterologous sequence comprises a nucleotide sequence selected from the group consisting of:
 (a) a nucleotide sequence comprising the sequence set forth in SEQ ID NOS: 1, 3 or 4; 
 (b) a nucleotide sequence comprising at least 50 contiguous nucleotides of the sequence of SEQ ID NOS: 1, 3, or 4, wherein said nucleotide sequence encodes a protein flowering regulatory activity; and 
 (c) a nucleotide sequence having at least 80% sequence identity to the sequence of SEQ ID NOS: 1, 3, or 4. 
   
     
     
         16 . The plant of  claim 18 , wherein said promoter is a constitutive promoter. 
     
     
         17 . The plant of  claim 18 , wherein said promoter is a tissue-preferred promoter. 
     
     
         18 . The plant of  claim 18 , wherein said promoter is an inducible promoter. 
     
     
         19 . The method of  15 , wherein said plant is a monocot. 
     
     
         20 . The method of  16 , wherein said monocot is maize. 
     
     
         21 . The method of  claim 15  wherein said nucleic acid molecule is a vector for over-expression of RAP2.7. 
     
     
         22 . The method of  claim 18  wherein said plant matures earlier than a plant which does not have the overexpression vector incorporated therein. 
     
     
         23 . The method of  claim 15  wherein said nucleic acid molecule is a vector for inhibiting expression of RAP2.7. 
     
     
         24 . The method of  claim 20  wherein said vector is an RNA interference vector. 
     
     
         25 . The method of  claim 13  wherein said plant matures later than a plant which does not have an RNA interference vector incorporated therein. 
     
     
         26 . An isolated polypeptide having flowering regulatory activity and selected from the group consisting of:
 (a) a polypeptide comprising the amino acid sequence set forth in SEQ ID NOS: 2;   (b) a polypeptide encoded by a nucleotide sequence comprising the sequence set forth in SEQ ID NOS: 1, 3, or 4;   (c) a polypeptide encoded by a nucleotide sequence that has at least 80% sequence identity to the sequence set forth in SEQ ID NOS: 1, 3, or 4.   (d) a polypeptide comprising an amino acid sequence having at least 90% sequence identity to the sequence set forth in SEQ ID NO:2; and   (e) a polypeptide comprising an amino acid sequence of at least 30 consecutive amino acids of any of (a) through (d).   
     
     
         27 . A nucleotide construct comprising:
 a nucleic acid molecule encoding an amino acid of  claim 23 , wherein said nucleic acid molecule is operably linked to a promoter that drives expression in a host cell.   
     
     
         28 . An isolated nucleic acid molecule that encodes a regulatory element having regulatory activity for flowering time, said nucleic acid molecule being selected from the group consisting of:
 (a) a nucleic acid molecule comprising the sequence set forth in SEQ ID NOS: 5, 6, 7, or 8;   (b) a nucleic acid molecule comprising a sequence having at least 80% sequence identity to the nucleotide sequence set forth in SEQ ID NOS: 5, 6, 7, or 8; and
 (c) a nucleic acid molecule comprising a sequence of at least 50 consecutive nucleic acids of any of (a) through (c). 
   
     
     
         29 . A vector comprising the nucleic acid molecule of  claim 28 . 
     
     
         30 . A plant cell having stably incorporated in its genome the nucleic acid molecule of  claim 27 . 
     
     
         31 . The plant cell of  claim 30 , wherein said plant cell is from a monocot plant. 
     
     
         32 . The plant cell of  claim 31 , wherein said monocot plant is maize. 
     
     
         33 . A plant having stably incorporated in its genome the nucleic acid molecule of  claim 27 . 
     
     
         34 . A method for changing maturity of a plant, said method comprising:
 stably introducing into the genome of a plant, at least one nucleotide construct comprising a nucleic acid molecule operably linked to a heterologous promoter that drives transcription in a plant cell, wherein said nucleic acid molecule encodes a regulatory element having regulatory activity on flowering time and is selected from the group consisting of:
 (a) a nucleic acid molecule comprising the sequence set forth in SEQ ID NOS: 5, 6, 7, or 8; 
 (b) a nucleic acid molecule comprising a sequence having at least 80% sequence identity to the nucleotide sequence set forth in SEQ ID NOS: 5, 6, 7, or 8; and
 (c) a nucleic acid molecule comprising a sequence of at least consecutive nucleic acids of any of (a) through (c). 
 
   
     
     
         35 . A method of changing the maturity of a plant comprising, introducing to a plant cell, a VGT1 expression construct, comprising, a VGT1 regulatory element which regulates RAP2.7 expression, operably linked to a promoter. 
     
     
         36 . A method of identifying a plant with altered maturity time, comprising: assaying said plant for a VGT1 polymorphism, wherein said polymorphism is identified in  FIG. 8  wherein said VGT1 polymorphism is associated with a earlier maturity in said plant than the maturity of a plant without said VGT1 polymorphism.