Plants Having Enhanced Yield-Related Traits and a Method for Making the Same

Abstract

The present invention relates generally to the field of molecular biology and concerns a method for enhancing various yield-related traits in plants by modulating expression in a plant of a nucleic acid encoding a TCP1 or a TCP2 transcription factor, an Epsin-like polypeptide, a tRNA delta(2)-isopentenylpyrophosphate transferase (IPPT) polypeptide, or a SHORT-ROOT (SHR) polypeptide. The present invention also concerns plants having modulated expression of a nucleic acid encoding a TCP1 or TCP2 polypeptide, an Epsin-like polypeptide, a tRNA delta(2)-isopentenylpyrophosphate transferase (IPPT) polypeptide, or a SHORT-ROOT (SHR) polypeptide, which plants have enhanced yield-related traits relative to corresponding wild type plants or other control plants. The invention also provides constructs useful in performing the methods of the invention.

1 . A method for enhancing a yield-related trait in a plant relative to a control plant, comprising:
 a) modulating expression of a nucleic acid encoding a TCP2 polypeptide in a plant, and optionally selecting for a plant having an increased yield-related trait relative to a control plant;   b) modulating expression of a nucleic acid encoding an Epsin-like polypeptide in a plant, and optionally selecting for a plant having an increased yield-related trait relative to a control plant, wherein said Epsin-like polypeptide comprises an ENTH domain;   c) modulating expression of a nucleic acid encoding a tRNA delta(2)-isopentenylpyrophosphate transferase (IPPT) polypeptide in a seed of a plant, and optionally selecting for a plant having an increased yield-related trait relative to a control plant, wherein said IPPT polypeptide comprises (i) a tRNA isopentenyltransferase domain with an InterPro accession IPR002627, and (ii) an N-terminal ATP/GTP-binding site motif A (P-loop); or   d) modulating expression of a nucleic acid encoding an SHR polypeptide in a plant, and optionally selecting for a plant having an increased yield-related trait relative to a control plant, wherein said plant is grown under conditions of sub-optimal nutrient availability.   
     
     
         2 . The method of  claim 1 , wherein said increased yield-related trait is obtained by modulating expression of a nucleic acid encoding a TCP2 polypeptide in a plant, wherein said TCP2 polypeptide comprises:
 (i) a TCP domain having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more sequence identity to the TCP domain of any of the sequences indicated in  FIG. 2 ;   (ii) a domain having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more sequence identity to Domain 1 of any of the sequences indicated in  FIG. 2 ;   (iii) a domain having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more sequence identity to Domain 2 of any of the sequences indicated in  FIG. 2 ; and   (iv) a domain having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more sequence identity to Domain 3 of any of the sequences indicated in  FIG. 2 .   
     
     
         3 . The method of  claim 2 , wherein said TCP2 polypeptide further comprises:
 (v) a domain having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more sequence identity to Domain 4 of any of the sequences indicated in  FIG. 2 ; and   (vi) a domain having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more sequence identity to Domain 5 of any of the sequences indicated in  FIG. 2 .   
     
     
         4 . The method of  claim 1 , wherein the nucleic acid encodes an orthologue or paralogue of SEQ ID NO: 4. 
     
     
         5 . The method of  claim 2 , wherein said modulated expression is increased expression of a nucleic acid encoding a TCP2 polypeptide. 
     
     
         6 . The method of  claim 5 , wherein said increased expression is effected by any one or more of T-DNA activation tagging, TILLING, or homologous recombination. 
     
     
         7 . The method of  claim 5 , wherein said increased expression is effected by introducing and expressing in a plant a nucleic acid sequence encoding said TCP2 polypeptide. 
     
     
         8 . The method of  claim 1 , wherein said enhanced yield-related traits comprise increased seed weight relative to a control plant. 
     
     
         9 . The method of  claim 7 , wherein said nucleic acid is operably linked to a constitutive promoter, a HMGP (High Mobility Group Protein) promoter, or a GOS2 promoter. 
     
     
         10 . The method of  claim 7 , wherein said nucleic acid encoding a TCP2 polypeptide is of plant origin, or wherein said nucleic acid is from a plant of the  Medicago  family. 
     
     
         11 . A plant or part thereof including seeds obtained by the method of  claim 1 , or a progeny of said plant, wherein said plant or part thereof, or said progeny, comprises a nucleic acid transgene encoding the TCP2 polypeptide. 
     
     
         12 . A construct comprising:
 (i) a nucleic acid sequence encoding a TCP2 polypeptide as defined in  claim 2 ;   (ii) one or more control sequences capable of driving expression of the nucleic acid of (i); and optionally   (iii) a transcription termination sequence.   
     
     
         13 . The construct of  claim 12 , wherein said one or more control sequences is at least a constitutive promoter, an HMGP, or a GOS2 promoter. 
     
     
         14 . A method for obtaining a plant having increased yield or seed yield relative to a control plant comprising growing a plant which comprises the construct of  claim 12 . 
     
     
         15 . A plant, plant part, or plant cell transformed with the construct of  claim 12 , or a progeny of said plant, wherein said progeny comprises said construct. 
     
     
         16 . A method for the production of a transgenic plant having increased seed yield relative to a control plant, which method comprises:
 (i) introducing and expressing in a plant or plant cell a nucleic acid encoding a TCP2 polypeptide as defined in  claim 2 ;   (ii) cultivating the plant or plant cell under conditions promoting plant growth and development; and   (iii) optionally selecting a plant having increased seed yield relative to a control plant.   
     
     
         17 . A transgenic plant having increased yield or increased seed yield relative to a control plant resulting from increased expression of a nucleic acid encoding a TCP2 polypeptide as defined in  claim 2 , or a transgenic plant cell or progeny derived from said transgenic plant, wherein said transgenic plant cell or progeny comprises the nucleic acid encoding the TCP2 polypeptide. 
     
     
         18 . The transgenic plant of  claim 17 , wherein said increased seed yield is one or more of the following: (i) increased seed weight; (ii) increased harvest index; (iii) increased Thousand Kernel Weight, (iv) increased number of flowers per panicle, (v) increased fill rate, or (vi) increased number of filled seeds. 
     
     
         19 . The transgenic plant of  claim 17 , wherein said plant is a crop plant, a monocot or a cereal, or a transgenic plant cell derived from said plant. 
     
     
         20 . Harvestable parts of the transgenic plant of  claim 17 , wherein said harvestable parts comprise seeds having the nucleic acid transgene encoding the TCP2 polypeptide. 
     
     
         21 . Products derived from the transgenic plant of  claim 17  and/or from harvestable parts of said plant, wherein the products comprise said nucleic acid transgene encoding a TCP2 polypeptide.