Plants Having Improved Growth Characteristics and Methods for Making the Same

Abstract

The present invention relates generally to the field of molecular biology and concerns a method for improving various plant growth characteristics by modulating expression in a plant of a nucleic acid encoding a GRP (Growth-Related Protein). The present invention also concerns plants having modulated expression of a nucleic acid encoding a GRP, which plants have improved growth characteristics relative to corresponding wild type plants or other control plants. The invention also provides constructs useful in the methods of the invention. The GRP may be one of the following: Seed Yield Regulator (SYR), FG-GAP, CYP90B, CDC27, AT-hook transcription factors, DOF transcription factors and Cyclin Dependent Kinase Inhibitors (CKIs).

1 . A method for improving growth characteristics and/or yield in a plant relative to a corresponding control plant, comprising:
 a) modulating expression in a plant of a nucleic acid encoding a Growth-Related Protein (GRP) polypeptide, and   b) optionally selecting for a plant having improved growth characteristics and/or yield relative to a corresponding control plant,   wherein said nucleic acid encoding a GRP polypeptide is:   i) a nucleic acid encodes a SYR polypeptide or a homologue thereof which is not the protein of SEQ ID NO: 26, and wherein the plant has increased seed yield and/or increased growth rate relative to a corresponding control plant;   ii) a nucleic acid encodes a cytochrome P450 (CYP) monooxygenase CYP90B polypeptide or a homologue thereof comprising (a) CYP domains A to D; (b) an N-terminal hydrophobic anchor domain; (c) a transition domain; and (d) within the A domain, the consensus sequence Phe-Ala-Gly-His-Glu-Thr-Ser-Ser (SEQ ID NO: 290), allowing for one amino acid change at any position, wherein the modulated expression is increased non-constitutive expression, and wherein the plant has increased yield relative to a corresponding control plant;   iii) a nucleic acid encodes a CDC27 polypeptide having at least one inactive TPR domain in the NH 2  terminal region of the polypeptide, wherein the modulated expression is preferentially increased in shoot apical meristem tissue of the plant, and wherein the plant has increased seed number relative to a corresponding control plant;   iv) a nucleic acid encodes a polypeptide comprising an AT-hook domain and a DUF296 domain, wherein said plant is a monocotyledonous plant, wherein the modulated expression is preferentially increased in endosperm tissue of the plant, and wherein the plant has increased seed yield relative to a corresponding control plant;   v) a nucleic acid encodes a DOF (DNA-binding with one finger) domain transcription factor polypeptide comprising feature (1) as follows, and additionally either feature (2) or (3) as follow:
 (1) at least 60% sequence identity to either the DOF domain of SEQ ID NO: 200 or SEQ ID NO: 228; and 
 (2) at least 70% sequence identity to the DOF domain of SEQ ID NO: 200; or 
 (3) Motif I: KALKKPDKILP (SEQ ID NO: 229) with no changes, or with one or more conservative change at any position, or with one, two or three non-conservative change(s) at any position; and/or Motif II: DDPGIKLFGKTIPF (SEQ ID NO: 230) with no changes, or with one or more conservative change at any position, or with one, two or three non-conservative change(s) at any position, 
   wherein the modulated expression is increased expression, and wherein the plant has increased yield relative to a corresponding control plant;   or   vi) an endogenous CKI gene, wherein the modulated expression is reduced expression of said endogenous CKI gene in endosperm tissue of the plant, and wherein the plant has increased seed yield relative to a corresponding control plant.   
     
     
         2 . The method of  claim 1 , wherein said modulated expression is effected by:
 a) introducing and expressing in the plant a nucleic acid encoding a SYR polypeptide or a homologue thereof which is not the protein of SEQ ID NO: 26;   b) introducing and expressing non-constitutively in the plant a nucleic acid encoding a CYP90B polypeptide or a homologue thereof;   c) introducing and expressing in shoot apical meristem tissue of the plant a nucleic acid encoding a CDC27 polypeptide having at least one inactive TPR domain in the NH 2  terminal region of the polypeptide;   d) introducing and expressing in endosperm tissue of the plant a nucleic acid encoding a polypeptide comprising an AT-hook domain and a DUF296 domain;   e) introducing and expressing in the plant a nucleic acid encoding a DOF transcription factor polypeptide; or   f) RNA-mediated downregulation of the endogenous CKI gene expression, preferably, said RNA-mediated downregulation is effected by co-suppression, use of antisense CKI nucleic acid sequences, use of an inverted repeat of a CKI gene or fragment thereof, preferably capable of forming a hairpin structure, use of ribozymes with specificity for a CKI nucleic acid, or by insertion mutagenesis.   
     
     
         3 . The method of  claim 2 , wherein:
 a) said nucleic acid encoding a SYR polypeptide encodes a homologue of the SYR polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or an orthologue or paralogue thereof;   b) said nucleic acid encoding a CYP90B polypeptide encodes a CYP90B polypeptide comprising the amino acid sequence of SEQ ID NO: 78 or an orthologue or paralogue thereof;   c) said nucleic acid encoding a CDC27 polypeptide encodes a CDC27 polypeptide comprising the amino acid sequence of SEQ ID NO: 130 or SEQ ID NO: 132, or an orthologue or paralogue thereof;   d) said nucleic acid encoding a polypeptide comprising an AT-hook domain and a DUF296 domain encodes a polypeptide comprising the amino acid sequence of SEQ ID NO: 153, or an orthologue or paralogue thereof;   e) said nucleic acid encoding a DOF transcription factor polypeptide encodes a polypeptide comprising the amino acid sequence of SEQ ID NO: 199 or SEQ ID NO: 227, or an orthologue or paralogue thereof; or   f) said CKI nucleic acid sequence is from rice and comprises a sufficient length of substantially contiguous nucleotides of SEQ ID NO: 267 (OsCKI4) or a sufficient length of substantially contiguous nucleotides of a nucleic acid sequence encoding an orthologue or paralogue of OsCKI4 (SEQ ID NO: 267).   
     
     
         4 . The method of  claim 2 , wherein:
 a) said nucleic acid encoding a SYR polypeptide comprises a portion of a SYR nucleic acid or a sequence capable of hybridizing to a SYR nucleic acid, wherein said portion or hybridizing sequence encodes a polypeptide of about 65 to about 200 amino acids and comprising a leucine rich domain preceded by the conserved tripeptide motif 1 of SEQ ID NO: 6, 7, 8 or 9, followed by the conserved motif 2 of SEQ ID NO: 10, and optionally followed by the conserved motif 3 of SEQ ID NO: 11;   b) said nucleic acid encoding a CYP90B polypeptide comprises a portion of a CYP90B nucleic acid or a sequence capable of hybridizing to a CYP90B nucleic acid, wherein said portion or hybridizing sequence encodes a polypeptide comprising (a) CYP domains A to D; (b) an N-terminal hydrophobic anchor domain; (c) a transition domain; and (d) within the A domain, the consensus sequence Phe-Ala-Gly-His-Glu-Thr-Ser-Ser (SEQ ID NO: 290), allowing for one amino acid change at any position;   c) said nucleic acid encoding a CDC27 polypeptide is a splice variant or an allelic variant of a nucleic acid comprising the nucleotide sequence of SEQ ID NO: 129 or SEQ ID NO: 131, or a sequence capable of hybridizing to a nucleic acid comprising the nucleotide sequence of SEQ ID NO: 129 or SEQ ID NO: 131, or a splice variant or allelic variant thereof, wherein said splice variant, allelic variant or hybridizing sequence encodes a CDC27 polypeptide having at least one inactive TPR domain in the NH 2  terminal region of the polypeptide;   d) said nucleic acid encoding a polypeptide comprising an AT-hook domain and a DUF296 domain is a portion, a splice variant or an allelic variant of a nucleic acid comprising the nucleotide sequence of SEQ ID NO: 152, SEQ ID NO: 153, SEQ ID NO: 154, SEQ ID NO: 156, SEQ ID NO: 158, SEQ ID NO: 160, SEQ ID NO: 162, SEQ ID NO: 164, SEQ ID NO: 166, SEQ ID NO: 168 or SEQ ID NO: 170, or a sequence capable of hybridizing thereto, wherein said portion, allelic variant, splice variant or hybridizing sequence encodes a polypeptide comprising an AT-hook domain and a DUF296 domain; or   e) said nucleic acid encoding a DOF transcription factor polypeptide encodes:
 i) a homologue of the DOF transcription factor protein of SEQ ID NO: 199 comprising the amino acid sequence of SEQ ID NO: 202, SEQ ID NO: 204, SEQ ID NO: 206, SEQ ID NO: 208, SEQ ID NO: 210, SEQ ID NO: 212, SEQ ID NO: 214, SEQ ID NO: 216, SEQ ID NO: 218, SEQ ID NO: 220 or SEQ ID NO: 222; or 
 ii) a homologue of the DOF transcription factor protein of SEQ ID NO: 227 comprising the amino acid sequence of SEQ ID NO: 235, SEQ ID NO: 237, SEQ ID NO: 239, SEQ ID NO: 241, SEQ ID NO: 243, SEQ ID NO: 245, SEQ ID NO: 247, SEQ ID NO: 249, SEQ ID NO: 251, SEQ ID NO: 253 or SEQ ID NO: 255; 
   f) said CKI nucleic acid sequence is an orthologue or paralogue of OsCKI4 comprising the amino acid sequence of SEQ ID NO: 270, SEQ ID NO: 272, SEQ ID NO: 274, SEQ ID NO: 276, SEQ ID NO: 278 or SEQ ID NO: 280, or comprises a sufficient length of substantially contiguous nucleotides from the nucleotide sequence of SEQ ID NO: 269, SEQ ID NO: 271, SEQ ID NO: 273, SEQ ID NO: 275, SEQ ID NO: 277 or SEQ ID NO: 279.   
     
     
         5 . The method of  claim 2 , wherein:
 a) said nucleic acid encoding a SYR polypeptide comprises the nucleotide sequence of SEQ ID NO: 1 or encodes a polypeptide comprising the conserved motifs of SEQ ID NO: 6, SEQ ID NO: 10 and SEQ ID NO: 11, wherein the motif of SEQ ID NO: 10 is VLAFMPT and wherein the motif of SEQ ID NO: 11 is PYL;   b) said nucleic acid encoding a CYP90B polypeptide encodes a polypeptide comprising a sequence having more than 50% sequence identity to SEQ ID NO: 78 and having steroid 22-alpha hydroxylase enzymatic activity;   c) said nucleic acid encoding a polypeptide comprising an AT-hook domain and a DUF296 domain encodes a polypeptide further comprising one of the following motifs: Motif 1: QGQ V/I GG (SEQ ID NO: 190); Motif 2: ILSLSGSFLPPPAPP (SEQ ID NO: 191); Motif 3: NATYERLP (SEQ ID NO: 192); Motif 4: SFTNVAYERLPL (SEQ ID NO: 193) with zero or one amino acid change at any position; or Motif 5: GRFEILSLTGSFLPGPAPPGSTGLTIYLAGGQGQVVGGSVVG (SEQ ID NO: 194) with zero, one or two amino acid changes at any position; or   d) said nucleic acid encoding a DOF (DNA-binding with one finger) domain transcription factor polypeptide encodes a polypeptide comprising:
 (i) feature (1) and feature (3) with both Motifs I and II, or 
 (ii) feature (1) and feature (3), and further comprising any one, two or all three of the following motifs:
 Motif III: SPTLGKHSRDE (SEQ ID NO: 231) with no changes, or with one or more conservative change at any position, or with one, two or three non-conservative change(s) at any position; and/or 
 Motif IV: LQANPAALSRSQNFQE (SEQ ID NO: 232) with no changes, or with one or more conservative change at any position, or with one, two or three non-conservative change(s) at any position; and/or 
 Motif V: KGEGCLWVPKTLRIDDPDEAAKSSIWTTLGIK (SEQ ID NO: 233) with no changes, or with one or more conservative change at any position, or with one, two, three, four or five non-conservative change(s) at any position. 
 
   
     
     
         6 . The method of  claim 2 , wherein:
 a) said nucleic acid encoding a SYR polypeptide is of plant origin, from a monocotyledonous plant, from the family Poaceae, or from  Oryza sativa;      b) said nucleic acid encoding a CYP90B polypeptide is of plant origin, from a monocotyledon plant, from the family Poaceae, from the genus  Oryza , or from  Oryza sativa;      c) said nucleic acid encoding a CDC27 polypeptide is of plant origin, from a dicotyledonous plant, from the family Brassicaceae, or from  Arabidopsis thaliana;      d) said nucleic acid encoding a polypeptide comprising an AT-hook domain and a DUF296 domain is of plant origin, from a monocotyledonous plant, from the family Poaceae, from the genus  Oryza , or from  Oryza sativa;      e) said nucleic acid encoding a DOF transcription factor polypeptide is of plant origin, from a dicotyledonous plant, from the family Brassicaceae, or from  Arabidopsis thaliana ; or   f) said endogenous CKI gene is a CKI gene found in the plant in its natural form or is an isolated CKI gene subsequently introduced into said plant, and wherein said isolated CKI gene is from a plant source or artificial source.   
     
     
         7 . The method of  claim 2 , wherein:
 a) said nucleic acid encoding a SYR polypeptide is operably linked to a constitutive promoter, a GOS2 promoter or a high mobility group protein promoter;   b) said nucleic acid encoding a CYP90B polypeptide is operably linked to a non-constitutive promoter, a seed-specific promoter, an endosperm-specific promoter, a prolamin promoter, a rice RP6 prolamin promoter, an endosperm-specific promoter comprising the nucleotide sequence of SEQ ID NO: 109 or a nucleic acid sequence substantially similar to SEQ ID NO: 109, an embryo/aleurone-specific promoter, an oleosin promoter, a rice oleosin 18 kDa promoter, an embryo/aleurone-specific promoter comprising the nucleotide sequence of SEQ ID NO: 110 or a nucleic acid sequence substantially similar to SEQ ID NO: 110;   c) said nucleic acid encoding a CDC27 polypeptide having at least one inactive TPR domain in the NH 2  terminal region of the polypeptide is operably linked to a shoot apical meristem promoter, an early shoot apical meristem promoter or an OSH1 promoter;   d) said nucleic acid encoding a polypeptide comprising an AT-hook domain and a DUF296 domain is operably linked to an endosperm-specific promoter or a prolamin promoter;   e) said nucleic acid encoding a DOF transcription factor polypeptide is operably linked to a constitutive promoter, a GOS2 promoter, a GOS2 promoter from rice, a seed-specific promoter, an endosperm-specific promoter, or a prolamin promoter; or   f) said reduced expression of the endogenous CKI gene in the endosperm tissue of the plant is effected by an endosperm-specific promoter or a prolamin promoter.   
     
     
         8 . The method of  claim 2 , wherein:
 a) said nucleic acid encodes a SYR polypeptide, and wherein the plant has increased seed yield comprising increased total weight of seeds, increased number of filled seeds, seed fill rate and/or increased harvest index, and/or increased growth rate comprising at least increased seed yield obtained without delay in flowering time relative to a corresponding control plant;   b) said nucleic acid encodes a CYP90B polypeptide, and wherein the plant has increased yield comprising increased total seed yield, increased harvest index (HI), increased thousand kernel weight (TKW), increased seed area and/or increased seed length relative to a corresponding control plant;   c) said nucleic acid encodes a polypeptide comprising an AT-hook domain and a DUF296 domain, and wherein the plant has increased yield comprising increased total seed weight, increased number of filled seeds, increased total number of seeds, increased number of flowers per panicle and/or increased harvest index (HI) relative to a corresponding control plant;   d) said nucleic acid encodes a DOF transcription factor polypeptide, and wherein the plant has increased yield comprising increased number of filled seeds, increased seed weight, increased number of flowers per panicle, increased seed fill rate, increased harvest index (HI), increased thousand kernel weight (TKW), increased root biomass, increased root length and/or increased root diameter relative to a corresponding control plant; or   e) the expression of said endogenous CKI gene is reduced in endosperm tissue of the plant, and wherein the plant has increased seed yield comprising increased seed biomass, increased number of flowers per plant, increased number of (filled) seeds and/or increased harvest index relative to a corresponding control plant.   
     
     
         9 . The method of  claim 2 , wherein:
 a) said nucleic acid encodes a SYR polypeptide, and wherein the plant is grown under non-stress conditions or abiotic stress conditions;   b) said nucleic acid encodes a CYP90B polypeptide, and wherein the plant is a monocotyledonous plant;   c) said nucleic acid encodes a DOF transcription factor polypeptide, and wherein said increased yield occurs under mild drought stress; or   d) the expression of said endogenous CKI gene is reduced in endosperm tissue of the plant, and wherein said increased seed yield occurs under mild stress conditions.   
     
     
         10 . A plant or plant cell obtained by the method of  claim 1 , or a seed or progeny of said plant, wherein said plant or part thereof, or said seed or progeny, comprises:
 a) a recombinant nucleic acid encoding a SYR polypeptide;   b) a recombinant nucleic acid encoding CYP90B polypeptide;   c) a recombinant nucleic acid encoding a CDC27 polypeptide having at least one inactive TPR domain in the NH2 terminal region of the polypeptide;   d) a recombinant nucleic acid encoding a polypeptide comprising an AT-hook domain and a DUF296 domain operably linked to an endosperm-specific promoter;   e) a recombinant nucleic acid encoding a DOF transcription factor polypeptide; or   f) a recombinant nucleic acid reducing the expression of said endogenous CKI gene.   
     
     
         11 . A construct comprising:
 a) a nucleic acid encoding a Growth-Related Protein (GRP) polypeptide;   b) one or more control sequences capable of driving expression of the nucleic acid of a); and optionally   c) a transcription termination sequence   wherein said nucleic acid encoding a GRP polypeptide is:   i) a nucleic acid encoding a SYR polypeptide or a homologue thereof which is not the protein of SEQ ID NO: 26;   ii) a nucleic acid encoding a cytochrome P450 (CYP) monooxygenase CYP90B polypeptide or a homologue thereof comprising (a) CYP domains A to D; (b) an N-terminal hydrophobic anchor domain; (c) a transition domain; and (d) within the A domain, the consensus sequence Phe-Ala-Gly-His-Glu-Thr-Ser-Ser (SEQ ID NO: 290), allowing for one amino acid change at any position;   iii) a nucleic acid encoding a CDC27 polypeptide having at least one inactive TPR domain in the NH2 terminal region of the polypeptide;   iv) a nucleic acid encoding a polypeptide comprising an AT-hook domain and a DUF296 domain; or   v) a nucleic acid encodes a DOF domain transcription factor polypeptide comprising feature (1) as follows, and additionally either feature (2) or (3) as follow:
 (1) at least 60% sequence identity to either the DOF domain of SEQ ID NO: 200 or SEQ ID NO: 228; and 
 (2) at least 70% sequence identity to the DOF domain of SEQ ID NO: 200; or 
 (3) Motif I: KALKKPDKILP (SEQ ID NO: 229) with no changes, or with one or more conservative change at any position, or with one, two or three non-conservative change(s) at any position; and/or Motif II: DDPGIKLFGKTIPF (SEQ ID NO: 230) with no changes, or with one or more conservative change at any position, or with one, two or three non-conservative change(s) at any position. 
   
     
     
         12 . The construct of  claim 11 , wherein:
 a) said nucleic acid encodes a SYR polypeptide or a homologue thereof, and wherein said control sequence is a constitutive promoter, a GOS2 promoter, a High Mobility Group Protein (HMGP) promoter, or a promoter comprising the nucleotide sequence of SEQ ID NO: 5 or 33;   b) said nucleic acid encodes a CYP90B polypeptide or a homologue thereof, and wherein said control sequence is a non-constitutive promoter, a seed-specific promoter, an endosperm-specific promoter, a prolamin promoter, a rice RP6 prolamin promoter, an endosperm-specific promoter comprising the nucleotide sequence of SEQ ID NO: 109 or a nucleic acid sequence substantially similar to SEQ ID NO: 109, an embryo/aleurone-specific promoter, an oleosin promoter, a rice oleosin 18 kDa promoter, an embryo/aleurone-specific promoter comprising the nucleotide sequence of SEQ ID NO: 110 or a nucleic acid sequence substantially similar to SEQ ID NO: 110;   c) said nucleic acid encodes a CDC27 polypeptide having at least one inactive TPR domain in the NH2 terminal region of the polypeptide, and wherein said control sequence is an OSH1 promoter;   d) said nucleic acid encodes a polypeptide comprising an AT-hook domain and a DUF296 domain, and wherein said control sequence is a prolamin promoter; or   e) said nucleic acid encodes a DOF domain transcription factor polypeptide, and wherein said control sequence is a constitutive promoter or a seed-specific promoter.   
     
     
         13 . A plant, plant part or plant cell transformed with the construct of  claim 11 . 
     
     
         14 . A plant, plant part or plant cell comprising the construct of  claim 11 . 
     
     
         15 . A method for the production of a transgenic plant having improved growth characteristics and/or yield relative to a corresponding control plant, comprising:
 a) introducing and expressing in a plant a nucleic acid encoding a Growth-Related Protein (GRP) polypeptide as defined in  claim 11 , or introducing and expressing in a plant, plant part or plant cell a gene construct comprising one or more control sequences capable of preferentially driving expression of a sense and/or antisense CKI nucleic acid sequence in plant endosperm tissue so as to silence an endogenous CKI gene in endosperm tissue of a plant;   b) cultivating the plant under conditions promoting plant growth and development; and   c) selecting for a plant having an improved growth characteristics and/or yield relative to a corresponding control plant,   wherein said nucleic acid encoding a GRP polypeptide is:   i) a nucleic acid encoding a SYR polypeptide or a homologue thereof which is not the protein of SEQ ID NO: 26, and wherein the plant has increased yield relative to a corresponding control plant;   ii) a nucleic acid encoding a CYP90B polypeptide or a homologue thereof, wherein said nucleic acid is expressed non-constitutively in said plant, and wherein said plant has increased yield relative to a corresponding control plant;   iii) a nucleic acid encoding a CDC27 polypeptide having at least one inactive TPR domain in the NH2 terminal region of the polypeptide, wherein said nucleic acid is operably linked to an shoot apical meristem-specific promoter, and wherein said plant has increased seed number relative to a corresponding control plant;   iv) a nucleic acid encoding a polypeptide comprising an AT-hook domain and a DUF296 domain, wherein said nucleic acid is preferentially expressed in endosperm tissue of said plant, wherein said plant is a monocotyledonous plant, and wherein said plant has increased seed yield relative to a corresponding control plant; or   v) a nucleic acid encodes a DOF domain transcription factor polypeptide comprising feature (1) as follows, and additionally either feature (2) or (3) as follow:
 (1) at least 60% sequence identity to either the DOF domain of SEQ ID NO: 200 or SEQ ID NO: 228; and 
 (2) at least 70% sequence identity to the DOF domain of SEQ ID NO: 200; or 
 (3) Motif I: KALKKPDKILP (SEQ ID NO: 229) with no changes, or with one or more conservative change at any position, or with one, two or three non-conservative change(s) at any position; and/or Motif II: DDPGIKLFGKTIPF (SEQ ID NO: 230) with no changes, or with one or more conservative change at any position, or with one, two or three non-conservative change(s) at any position, 
   and wherein said plant has increased yield relative to a corresponding control plant, preferably said increased yield occurs under conditions of mild drought stress.   
     
     
         16 . The method of  claim 15 , further comprising obtaining a seed or progeny of said plant. 
     
     
         17 . A transgenic plant having improved growth characteristics and/or yield relative to a corresponding control plant resulting from increased expression of a nucleic acid encoding a Growth-Related Protein (GRP) polypeptide as defined in  claim 11 , wherein said nucleic acid encoding a GRP polypeptide is:
 a) a nucleic acid encoding a SYR polypeptide or a homologue thereof which is not the protein of SEQ ID NO: 26, wherein said transgenic plant has increased seed yield and/or increased growth rate relative to a corresponding control plant;   b) a nucleic acid encoding a CYP90B polypeptide or a homologue thereof non-constitutively, wherein said transgenic plant has increased yield relative to a corresponding control plant;   c) a nucleic acid encoding a CDC27 polypeptide having at least one inactive TPR domain in the NH2 terminal region of the polypeptide, wherein said nucleic acid is operably linked to an apical shoot meristem-specific promoter, and wherein said transgenic plant has increased seed number relative to a corresponding control plant;   d) a nucleic acid encoding a polypeptide comprising an AT-hook domain and a DUF296 domain, wherein said nucleic acid is preferentially expressed in endosperm tissue of said plant, wherein said plant is a monocotyledonous plant, and wherein said transgenic plant has increased seed yield relative to a corresponding control plant; or   e) a nucleic acid encodes a DOF domain transcription factor polypeptide comprising feature (1) as follows, and additionally either feature (2) or (3) as follow:
 (1) at least 60% sequence identity to either the DOF domain of SEQ ID NO: 200 or SEQ ID NO: 228; and 
 (2) at least 70% sequence identity to the DOF domain of SEQ ID NO: 200; or 
 (3) Motif I: KALKKPDKILP (SEQ ID NO: 229) with no changes, or with one or more conservative change at any position, or with one, two or three non-conservative change(s) at any position; and/or Motif II: DDPGIKLFGKTIPF (SEQ ID NO: 230) with no changes, or with one or more conservative change at any position, or with one, two or three non-conservative change(s) at any position, 
   and wherein said plant has increased yield relative to a corresponding control plant, in said plant, or a transgenic plant cell obtained from said transgenic plant.   
     
     
         18 . The transgenic plant of  claim 17 , wherein:
 a) said nucleic acid encodes a SYR polypeptide or a homologue thereof, and wherein said plant is a monocotyledonous plant or a cereal, or wherein said plant is sugarcane, rice, maize, wheat, barley, millet, rye, oats or sorghum;   b) said nucleic acid encodes a CYP90B polypeptide or a homologue thereof, and wherein said plant is a monocotyledonous plant or a cereal, or wherein said plant is sugarcane, rice, maize, wheat, barley, millet, rye, oats or sorghum;   c) said nucleic acid encodes a CDC27 polypeptide having at least one inactive TPR domain in the NH2 terminal region of the polypeptide, and wherein said plant is monocotyledonous plant or a cereal, or wherein said plant is sugarcane, rice, maize, wheat, barley, millet, rye, oats or sorghum;   d) said nucleic acid encodes a polypeptide comprising an AT-hook domain and a DUF296 domain, and wherein said plant is a cereal, or wherein said plant is rice, maize, sugarcane, wheat, barley, millet, rye, sorghum, grasses or oats; or   e) said nucleic acid encodes a DOF domain transcription factor polypeptide, and wherein said plant is a monocotyledonous plant or a cereal, or wherein said plant is sugarcane, rice, maize, wheat, barley, millet, rye, oats or sorghum.   
     
     
         19 . Harvestable parts of the transgenic plant of  claim 17 , wherein said harvestable parts are preferably seeds. 
     
     
         20 . Products obtained from the transgenic plant of  claim 17  and/or harvestable parts of said transgenic plant. 
     
     
         21 . An isolated polypeptide comprising:
 a) the amino acid sequence of SEQ ID NO: 44;   b) an amino acid sequence having at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% or more sequence identity to the amino acid sequence of SEQ ID NO 44;   c) the amino acid sequence of SEQ ID NO: 72;   d) a signal sequence, one or more FG-GAP domains and a transmembrane domain located in the C-terminal half of the polypeptide, wherein said polypeptide comprises at least one of SEQ ID NO: 73 to SEQ ID NO: 76;   e) an active fragment of an amino acid sequence defined in c) or d), which active fragment comprises a signal sequence, one or more FG-GAP domains and a transmembrane domain located in the C-terminal half of the polypeptide;   f) an amino acid sequence encoded by the nucleotide sequence of SEQ ID NO: 117; or   g) (i) CYP domains A to D; (ii) an N-terminal hydrophobic anchor domain; (iii) a transition domain; and (iv) within the A domain, the consensus sequence Phe-Ala-Gly-His-Glu-Thr-Ser-Ser (SEQ ID NO: 290), allowing for one amino acid change at any position, and having at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 118.   
     
     
         22 . An isolated nucleic acid molecule comprising:
 a) a nucleotide sequence encoding the isolated polypeptide of  claim 21 ;   b) the nucleotide sequence of SEQ ID NO: 43, SEQ ID NO: 72 or SEQ ID NO: 117, or the complement thereof; or   c) a nucleic acid capable of hybridizing with the nucleotide sequence of a) or b) under stringent conditions, wherein said nucleic acid encodes a SYR polypeptide, a polypeptide comprising a signal peptide, one or more FG-GAP domains and a transmembrane domain located in the C-terminal half of the polypeptide, or a polypeptide comprising (i) CYP domains A to D; (ii) an N-terminal hydrophobic anchor domain; (iii) a transition domain; and (iv) within the A domain, the consensus sequence Phe-Ala-Gly-His-Glu-Thr-Ser-Ser (SEQ ID NO: 290), allowing for one amino acid change at any position, and having at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 118.