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

Abstract

The present invention concerns a method for increasing yield-related traits by modulating expression in a plant of a nucleic acid encoding an AT-hook motif nuclear localized 19/20 (AHL19/20) polypeptide, a Growth Regulating Protein (GRP) polypeptide which is a metallothionein 2a (MT2a) polypeptide, or an alanine aminotransferase (AAT) polypeptide. Also provided are plants having increased yield-related traits relative to control plants thus obtained and constructs useful in the methods of the invention.

1 . A method for increasing yield-related traits in a plant relative to a control plant, comprising increasing expression in a plant of a nucleic acid encoding an AT-hook motif nuclear localized 19/20 (AHL19/20) polypeptide, a Growth Regulating Protein (GRP) polypeptide which is a metallothionein 2a (MT2a) polypeptide, or an alanine aminotransferase (AAT) polypeptide, and optionally selecting for a plant having increased yield-related traits relative to a control plant. 
     
     
         2 . The method of  claim 1 , wherein said nucleic acid encoding a GRP polypeptide is selected from the group consisting of:
 (a) a nucleic acid comprising the nucleotide sequence of SEQ ID NO: 45;   (b) a nucleic acid encoding a polypeptide comprising the amino acid sequence of SEQ ID NO: 46;   (c) a nucleic acid encoding a polypeptide having at least 50% or more sequence identity to the amino acid sequence of SEQ ID NO: 46; and   (d) a nucleic acid which hybridizes to the nucleic acid of (a) or (b) under stringent hybridization conditions.   
     
     
         3 . The method of  claim 1 , wherein said increased expression is effected by introducing and expressing in the plant said nucleic acid. 
     
     
         4 . The method of  claim 1 , further comprising selecting for a plant grown under abiotic stress conditions having increased yield-related traits relative to a control plant. 
     
     
         5 . The method of  claim 4 , wherein said abiotic stress conditions comprise osmotic stress. 
     
     
         6 . The method of  claim 5 , wherein said osmotic stress is water stress, salt stress, oxidative stress, and/or ionic stress. 
     
     
         7 . The method of  claim 6 , wherein said water stress is drought stress. 
     
     
         8 . The method of  claim 6 , wherein said ionic stress is salt stress. 
     
     
         9 . The method of  claim 1 , wherein said increased yield-related traits comprise increased aboveground biomass, increased total seed yield per plant, increased number of filled seeds, increased total number of filled seeds, increased number of primary panicles, and/or increased seed fill rate. 
     
     
         10 . The method of  claim 1 , wherein said nucleic acid is operably linked to a constitutive promoter, a GOS2 promoter, or a GOS2 promoter from rice. 
     
     
         11 . The method of  claim 1 , wherein said nucleic acid encodes a GRP polypeptide, and wherein said nucleic acid is of plant origin, from a dicotyledonous plant, from a plant of the family Brassicaceae, or from an  Arabidopsis thaliana  plant. 
     
     
         12 . A plant obtained from the method of  claim 1 , wherein said plant has increased yield-related traits relative to a control plant. 
     
     
         13 . A plant part, seed or progeny of the plant of  claim 12 , wherein said plant part, seed or progeny comprises a recombinant nucleic acid encoding said GRP polypeptide. 
     
     
         14 . Harvestable parts of the plant of  claim 12 , or products derived from said plant or said harvestable parts, wherein said harvest parts or said products comprise a recombinant nucleic acid encoding said GRP polypeptide. 
     
     
         15 . The plant of  claim 12 , wherein said plant is a crop plant, a monocot or a cereal, or wherein said plant is rice, maize, wheat, barley, millet, rye, triticale, sorghum or oats. 
     
     
         16 . A construct comprising:
 (a) a nucleic acid encoding an AT-hook motif nuclear localized 19/20 (AHL19/20) polypeptide, a Growth Regulating Protein (GRP) polypeptide which is a metallothionein 2a (MT2a) polypeptide, or an alanine aminotransferase (AAT) polypeptide;   (b) one or more control sequences capable of driving expression of the nucleic acid of (a); and optionally   (c) a transcription termination sequence.   
     
     
         17 . The construct of  claim 16 , wherein one of said control sequences is a plant constitutive promoter, a GOS2 promoter, or a GOS2 promoter comprising the nucleotide sequence of SEQ ID NO: 35. 
     
     
         18 . A method for producing a plant having increased seed yield-related traits relative to a control plant, comprising transforming a plant or plant cell the construct of  claim 16 , and selecting for a plant having increased seed yield-related traits relative to a control plant, wherein said increased seed yield-related traits comprise increased number of flowers per panicle, increased total seed weight per plant, increased number of filled seeds, and/or increased harvest index. 
     
     
         19 . A plant, plant part or plant cell comprising the construct of  claim 16 . 
     
     
         20 . A method for the production of a transgenic plant having increased yield-related traits relative to a control plant, comprising:
 (i) introducing and expressing in a plant, plant part, or plant cell, a nucleic acidencoding an AT-hook motif nuclear localized 19/20 (AHL19/20) polypeptide, a Growth Regulating Protein (GRP) polypeptide which is a metallothionein 2a (MT2a) polypeptide, or an alanine aminotransferase (AAT) polypeptide;   (ii) cultivating the plant cell, plant part, or plant under conditions promoting plant growth and development; and   (iii) optionally selecting for a transgenic plant having increased yield-related traits relative to a control plant.