Enhanced Floral Sink Strength and Increased Stability of Seed Set in Plants

Abstract

The invention discloses a transgenic method for enhancing sink strength in female reproductive organs. It involves the temporal and spatial expression of genes affecting the starch and sucrose metabolic pathways in a plant organ or plant tissue. The invention also includes expression constructs, and methods for the production of crop plants with heritable phenotypes which are useful in breeding programs designed to increase yield potential over a range of environmental conditions.

1 . An expression construct for production of transgenic plants that will enhance yield potential comprising: 
 a recombinant sink strength enhancing nucleotide sequence; and    a promoter operably linked to said sequence, said promoter being one which provides temporal and spatial expression during anthesis development.    
   
   
       2 . The expression construct of  claim 1  where said promoter provides expression during the exponential growth phase of the ear.  
   
   
       3 . The expression construct of  claim 1  wherein said promoter provides expression during the lag phase of development of the kernel.  
   
   
       4 . The expression construct of  claim 1  wherein said promoter provides expression from about 14 days prior to about 14 days after flowering.  
   
   
       5 . An expression construct for production of transgenic plants that will enhance yield potential comprising: 
 a sink strength enhancing nucleotide sequence and a promoter operably linked to said sequence, said promoter being one which gives temporal and spatial expression of said construct during anthesis development, said sink strength enhancing nucleotide sequence being one which encodes upon expression a protein which increases starch reserves in female reproductive organs.    
   
   
       6 . The expression construct of  claim 5  where said promoter provides expression during the exponential growth phase of the ear.  
   
   
       7 . The expression construct of  claim 5  wherein said promoter provides expression during the lag phase of development of the kernel.  
   
   
       8 . The expression construct of  claim 5  wherein said promoter provides expression from about 14 days prior to about 14 days after flowering.  
   
   
       9 . The expression construct of  claim 5  wherein said nucleotide sequence includes: 
 a first DNA sequence encoding a gene product useful for affecting the sucrose content of a plant or plant tissue; and a second DNA sequence encoding a gene product useful for affecting the starch content of a plant or plant tissue.    
   
   
       10 . The expression construct of  claim 5 , said combination of genes comprising: 
 a DNA sequence encoding an acid invertase; and    a DNA sequence encoding ADPglucose pyrophosphorylase.    
   
   
       11 . The expression construct of  claim 5  wherein said nucleotide sequence includes natural variants of genes enhancing reproductive sink strength.  
   
   
       12 . The expression construct of  claim 5  wherein said promoter is a maternal tissue promoter.  
   
   
       13 . The expression construct of  claim 5  wherein said promoter is selected from a group comprising: zag2, cim1, nuclc, mze40-2, b22e, 1tp2, end1, and bet11.  
   
   
       14 . The expression construct of  claim 5  wherein said promoter is an inducible promoter.  
   
   
       15 . An expression construct useful for the production of a transgenic plant with improved yield potential, the genetic construct comprising: 
 a recombinant gene or combination of genes which encode upon expression a protein which causes an increase in starch reserves in female reproductive organs; and    a promoter operably linked to said gene or genes, said promoter being one which gives temporal and spatial expression of said gene products during anthesis.    
   
   
       16 . The expression construct of  claim 15  where said promoter provides expression during the exponential growth phase of the ear.  
   
   
       17 . The expression construct of  claim 15  wherein said promoter provides expression during the lag phase of development of the kernel.  
   
   
       18 . The expression construct of  claim 15  wherein said promoter provides expression from about 14 days prior to about 14 days after flowering.  
   
   
       19 . The expression construct of  claim 15  wherein said combination of genes includes: 
 a first DNA sequence encoding a gene product useful for affecting the sucrose content of a plant or plant tissue; and a second DNA sequence encoding a gene product useful for affecting the starch content of a plant or plant tissue.    
   
   
       20 . The expression construct of  claim 15  wherein said genes include: 
 acid invertase and ADPglucose pyrophosphorylase.    
   
   
       21 . The expression construct of  claim 15  wherein said genes include natural variants of genes enhancing sink strength.  
   
   
       22 . The expression construct of  claim 15  wherein said gene construct includes a maternal tissue promoter.  
   
   
       23 . The expression construct of  claim 15  wherein said promoter is selected from a group comprising: zag2, cim1, nuclc, mze40-2, b22e, 1tp2, end1, and bet11.  
   
   
       24 . The expression construct of  claim 15  wherein said promoter is an inducible promoter.  
   
   
       25 . The expression construct of  claim 15  wherein said plant is selected from the group consisting of maize, barley, sorghum, soybeans, wheat, rice, and  Arabidopsis.    
   
   
       26 . A transgenic plant comprising a plant cell or ancestor thereof which has been transformed with the expression construct of  claim 1 .  
   
   
       27 . A method of increasing yield potential in a plant comprising: 
 introducing to a plant cell a genetic construct, said genetic construct comprising a recombinant nucleotide sequence which encodes upon expression a protein which is associated with an increase in starch or sucrose reserves in the female reproductive organ of said plant, and;    a promoter operably linked to said nucleotide sequence, said promoter being one which gives temporal and spatial expression of said sequence during anthesis development; and,    said gene construct is integrated in said seed.    
   
   
       28 . The expression construct of  claim 27  where said promoter provides expression during the exponential growth phase of the ear.  
   
   
       29 . The expression construct of  claim 27  wherein said promoter provides expression during the lag phase of development of the kernel.  
   
   
       30 . The expression construct of  claim 27  wherein said promoter provides expression from about 14 days prior to about 14 days after flowering.  
   
   
       31 . The expression construct of  claim 27  wherein said nucleotide sequence further comprises: 
 a first DNA sequence encoding a gene product useful for affecting the sucrose content of a plant or plant tissue; and a second DNA sequence encoding a gene product useful for affecting the starch content of a plant or plant tissue.    
   
   
       32 . The method of  claim 27  wherein said genes include: 
 acid invertase and ADPglucose pyrophosphorylase.    
   
   
       33 . The method of  claim 27  wherein said genes include natural variants of genes enhancing sink strength.  
   
   
       34 . The method of  claim 27  wherein said gene construct includes a maternal tissue promoter.  
   
   
       35 . The method of  claim 27  wherein said promoter is selected from a group comprising: zag2, cim1, nuclc, mze40-2, b22e, 1tp2, end1, and bet11.  
   
   
       36 . The method of  claim 27  wherein said promoter is an inducible promoter.  
   
   
       37 . The method of  claim 27  wherein said plant is selected from the group consisting of corn, barley, sorghum, soybeans, wheat, rice, and  Arabidopsis.