KR101700619B1 - Hox25 gene and transgenic plant transformed with hox25-overexpression vector - Google Patents

Abstract

The present invention relates to a plant having an increased number of tRNAs by transformation with a recombinant expression vector containing the HOX25 gene having the nucleotide sequence shown in SEQ ID NO: 1. The plant of the present invention is characterized in that the flowering time is increased by one week or more in addition to the increase in number of tillering. The present invention also relates to a method for increasing plant turnover by overexpressing a gene comprising a nucleotide sequence of SEQ ID NO: 1 encoding HOX25 protein consisting of the amino acid sequence of SEQ ID NO: 2 in a plant.

Description

[0002] HOX25 GENE AND TRANSGENIC PLANT TRANSFORMED WITH HOX25-OVEREXPRESSION VECTOR [0003]

FIELD OF THE INVENTION [0002] The present invention relates to a rice-derived gene HOX25, which increases the number of tillering, and transgenic plants produced using the same.

A tiller is a term referring to the stem of a plant. The tibia of the lower part of the stem grows to form several stalks. The tibia formed in each stem in the base of the plant is called tiller bud, and it develops into a new till by environment and hormone stimulation. The main genes (D3, D10, D27, HTD1, HTD2, and TB1) that regulate the tillering of rice were identified through mutant analysis of rice, which is highly similar to the stem formation regulatory genes revealed in Arabidopsis and corn (Zou et al 2006, Arite et al., 2007, 2009. Liu et al., 2009, Lin et al., 2009). The fact that the dysplasia and monocotyledonous stem regulating mechanisms are shared in common suggests that the genes or substances involved may have a wide agricultural applicability in controlling the tillering or geodetic differentiation of various crops.

In rice, barley, etc., 4 to 10 tribes are produced from a single plant by the usual cultivation method, and the tribe in which the ear does not run is called the invalid tribe. The tangent or the 23rd tangent from the upper node of the base is likely to become invalid. Although the number of tillers varies depending on the variety, the number of tillers is reduced due to shortage of sunshine, excess or shortage of water in the soil, low temperature, late vegetation, and dense vegetation. Since tulle formation determines the number of the most important ears among the quantity-related elements of the paddy plants, interest in controlling tulip formation is great.

The inventors of the present invention have studied to find a method of improving productivity by controlling the growth of rice, and confirmed that the productivity of rice can be improved by increasing the number of tillering of the rice using the HOX25 gene.

1. Korean Patent Publication No. 2010-0035688 2. Korean Patent Publication No. 2011-0082315

An object of the present invention is to provide a plant having an increased number of tRNAs by transforming with a recombinant expression vector containing the HOX25 gene having the nucleotide sequence shown in SEQ ID NO:

Another object of the present invention is to provide a method for overexpressing a gene comprising the nucleotide sequence of SEQ ID NO: 1 encoding the HOX25 protein consisting of the amino acid sequence of SEQ ID NO: 2 to increase the number of tillers of the plant.

A further object of the present invention is to provide a composition for increasing the number of tillers of a plant comprising a gene consisting of the nucleotide sequence of SEQ ID NO: 1 encoding the HOX25 protein consisting of the amino acid sequence of SEQ ID NO: 2.

In order to achieve the above object,

And transformed with a recombinant expression vector comprising the HOX25 (Homeobox25) gene having the nucleotide sequence shown in SEQ ID NO: 1, thereby providing a plant having an increased number of tillers. The plant of the present invention may be characterized in that the flowering time is increased by one week or more in addition to the increase in the number of tillering.

The plant cell into which the recombinant expression vector of the present invention is introduced is not particularly limited to a specific form as long as the cell can be regenerated as a plant. These cells include, for example, cultured cell suspension, protoplasts, leaf sections and callus. The plant may be, but is not limited to, rice, corn, sugarcane, barley or mill, preferably rice.

More specifically, the plant having an increased number of tillers according to the present invention can be obtained by transformation of a plant with a recombinant expression vector containing the HOX25 gene, followed by induction of callus, rooting and soil purification according to a conventional method.

The present invention also provides a HOX25 protein having an amino acid sequence represented by SEQ ID NO: 2. The present invention includes homologous proteins having homology with the above proteins.

The protein having the amino acid sequence represented by SEQ ID NO: 2 is composed of 261 amino acids.

The "homologous protein" has a sequence homology of preferably 80% or more, more preferably 90% or more, still more preferably 95% or more, most preferably 99% or more with the amino acid sequence of SEQ ID NO: 2 Refers to a protein that exhibits substantially the same function as the HOX25 protein of the present invention.

The present invention also encompasses the HOX25 gene having the nucleotide sequence shown in SEQ ID NO: 1 and its equivalents. The equivalents include homologous genes having homology.

The HOX25 gene having the nucleotide sequence shown in SEQ ID NO: 1 or its homologous gene is encoded by a protein. SEQ ID NO: 1 consists of 783 nucleotides.

The "homologous gene" is a gene having a sequence homology of preferably 80% or more, more preferably 90% or more, still more preferably 95% or more, most preferably 99% or more with the nucleotide sequence of SEQ ID NO: 1 Refers to a gene that exhibits substantially the same function as the OsTCP6 gene of the present invention. Sequence homology can be analyzed by methods known in the art.

The "substantially homogeneous function" means to be involved in an increase in the number of tillers. Such functional equivalents include, for example, amino acid sequence variants in which some of the amino acids of the amino acid sequence of SEQ ID NO: 2 are substituted, deleted or added. Substitution of amino acids is preferably conservative substitution. Examples of conservative substitutions of amino acids present in nature are as follows: (Gly, Ala, Pro), hydrophobic amino acids (Ile, Leu, Val), aromatic amino acids (Phe, Tyr, Trp), acidic amino acids (Asp, Glu), basic amino acids (His, Lys, Arg, Gln, Asn ) And sulfur-containing amino acids (Cys, Met). Deletion of the amino acid is preferably located at a site that is not directly involved in the activity of HOX25 of the present invention. Also included within the scope of the functional equivalents are protein derivatives in which the basic skeleton of HOX25 and some of its chemical structures are modified while maintaining its physiological activity. These include, for example, fusion proteins made by fusion with other proteins such as GFP, while retaining the structural modification and physiological activity to change the stability, storage stability, volatility or solubility of the protein of the present invention.

The present invention also provides a method for increasing plant turnover by overexpressing a gene comprising a nucleotide sequence of SEQ ID NO: 1 encoding HOX25 protein comprising the amino acid sequence of SEQ ID NO: 2 in a plant.

A method of overexpressing the gene may include transforming the plant with a recombinant expression vector in which the gene is operably linked to a promoter. The target plants according to the present invention include, but are not limited to, rice, maize, sugar cane, barley, wheat and the like, preferably rice.

In an embodiment of the present invention, the recombinant expression vector containing the HOX25 gene having the nucleotide sequence shown in SEQ ID NO: 1 was prepared and the expression level of the HOX25 protein in rice cells was increased by transforming rice cells.

The transformant according to the present invention is not only a gene having the nucleotide sequence of SEQ ID NO: 1 but also a modified sequence in which some bases of SEQ ID NO: 1 are substituted, deleted or added, A nucleotide sequence encoding a protein exhibiting an activity equivalent to an activity of a protein encoded by the plant, that is, an increase in plant tear production, can be used.

The HOX25 gene according to the present invention can be inserted into a suitable expression vector, i.e., a recombinant expression vector, to transform the plant cell.

More specifically, in another aspect, the present invention also provides a gene encoding a HOX25 protein having an amino acid sequence represented by SEQ ID NO: 2, or a gene encoding a HOX25 gene having a nucleotide sequence represented by SEQ ID NO: 1 Lt; RTI ID = 0.0 > expression vector. ≪ / RTI >

The expression vector means a plasmid, virus or other medium known in the art to which the gene according to the present invention can be inserted or introduced. A gene according to the present invention may be operably linked to an expression control sequence, wherein the operably linked gene sequence and expression control sequence are contained within an expression vector containing a selection marker and a replication origin .

The term "operably linked" means that one nucleic acid fragment is associated with another nucleic acid fragment so that its function or expression is affected by other nucleic acid fragments.

The expression control sequence is a DNA sequence that regulates the expression of a gene operably linked to a particular host cell. Such a regulatory sequence includes a promoter for transcription, an arbitrary operator sequence for regulating transcription , Sequences that encode suitable mRNA ribosome binding sites, and sequences that control the termination of transcription and translation.

The term "promoter" refers to a DNA sequence that controls the expression of a gene operably linked to a specific host cell. As the promoter, a constitutive promoter that induces the expression of the target gene at all times at any time, or an inducible promoter that induces the expression of the target gene at a specific position and time can be used. However, A promoter that induces expression of a gene is used, and examples thereof include, but are not limited to, a p35S promoter. In addition, a ubiquitin promoter can be used to overexpress genes in monocotyledonous plants or woody plants.

The introduction of the recombinant expression vector into a plant can be carried out by a method known in the art. For example, but not limited to, Agrobacterium sp. -Mediated methods, particle gun bombardment, silicon carbide whiskers, sonication, heat shock A heat shock, an electroporation method and a precipitation method using PEG (Polyethylenglycol) can be used. In one embodiment of the present invention, a plant cell is transformed into a recombinant vector of the present invention by a method of Agrobacterium-mediated method, that is, a method of transforming plant cells using Agrobacterium to which an expression vector according to the present invention is introduced, But the present invention is not limited thereto.

In an embodiment of the present invention, we introduced a recombinant expression vector containing the HOX25 gene into Agrobacterium and transformed into rice using the introduced Agrobacterium. When the HOX25 gene overexpressing transformant was obtained and the number of tillers thereof was analyzed, it was confirmed that the number of transformed rice bran was greatly increased compared to the wild type. It was also confirmed that the flowering time of rice was accelerated by one week to two weeks.

The present invention also provides a composition for increasing the number of tillers of a plant comprising a gene consisting of the nucleotide sequence of SEQ ID NO: 1 encoding the HOX25 protein consisting of the amino acid sequence of SEQ ID NO: 2. In the composition of the present invention, the HOX25 gene may comprise the nucleotide sequence of SEQ ID NO: 1. The composition of the present invention contains HOX25 gene derived from rice as an active ingredient, and the number of tillering of rice can be increased by transforming the gene into a plant.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is well known and commonly used in the art.

The present invention can provide a method for increasing the number of tillers in a plant, and can speed up the flowering time for a week or more, thereby enabling early harvesting. Therefore, it ultimately provides an effect that can be utilized for increasing the productivity of rice.

Figure 1 shows the results of analysis of the domain of the HOX25 gene of the present invention.
Fig. 2 shows the results of analysis of HOX25 gene expression by qPCR.
FIG. 3 is a schematic diagram of a HOX25 over-expression transformed binary vector prepared using the HOX25 gene and the pCAMBIA3300PT vector.
FIG. 4 shows the results of confirming insertion of the rice transformant HOX25 gene by PCR.
Fig. 5 is a photograph showing the flowering time of the transgenic rice plants transformed with the HOX25 gene. (Left: Dong Jinbin; right: HOX25 gene transformant)
FIG. 6 is a photograph showing the elongation and tillering phenotype of a rice plant transformed with the HOX25 gene (DJ: Dong Jinbin (control), HOX25: transformant, right: magnification)
FIG. 7 is a graph comparing stem growth lengths of HOX25 transgenic plants and Dongjin bean (control). (HOX25-21-3, HOX25-35-3, HOX25-40-2, HOX25-41-1, HOX25-42-2, HOX25-43-2: HOX25 gene inserted transformant line number)
FIG. 8 is a graph comparing the lengths of eggs of HOX25 gene transformants and Dongjin bean (control).
Fig. 9 is a graph comparing the number of eggs of HOX25 transgenic plants and Dongjin rice (control group).

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are merely illustrative of the present invention and that the scope of the present invention is not construed as being limited by these embodiments.

Example  1. Rice Agronomic Traits HOX25  Characterization of genes

Among the HOX gene families, the HOX25 gene, whose expression level is increased in the order of leaf, stem, and root, was selected for HOX gene family belonging to group I.

To confirm the function of the HOX25 gene, the domain was analyzed at the NCBI domain analysis site (Fig. 1). As a result, HOX25 gene is a transcription factor gene including domains such as Homeobox and HALZ, and it is a gene belonging to a family group of typical HOX gene having homeome domain.

To analyze the expression pattern of HOX25 gene, qPCR method was used.

To separate RNA from leaves, stems, and roots, each sample was placed in a mortar bowl filled with liquid nitrogen, finely divided, and placed in a 2 ml tube in an appropriate volume. 800 ㎕ of Trizol (Takara, Japan) (vortex). 400 μl of chloroform was added to the same tube and vortexed briefly, followed by centrifugation at 13,000 rpm for 10 minutes using a 4 ° C centrifuge. After repeating this process one more time, 375 μl of isopropanol was added to the final supernatant, and the mixture was well mixed and centrifuged at 13,000 rpm for 10 minutes at 4 ° C. The supernatant was discarded and the RNA precipitate was washed with 1 ml of 70% ethanol. After centrifugation at 13,000 rpm at 4 ° C, the supernatant was completely removed and the RNA precipitate was dried at 37 ° C for 30 minutes. 50 μl of ddH 2 O or 1 × TE buffer was added and vortexed to completely dissolve RNA, followed by incubation at 60 ° C. for 10 minutes in an incubator. After centrifugation at 13,000 rpm at 20 ° C, the supernatant was transferred to a new 1.5-ml tube and the amount of RNA was quantitated by a spectrophotometer and stored at -70 ° C.

First-strand cDNA was synthesized using Sprint RT Complete-Oligo (dT) (Clontech kit) for cDNA synthesis. 80 μl of water was added to the synthesized cDNA, and the reaction solution diluted 5-fold was mixed with SYBR Premix Ex Taq (Takara) and subjected to qPCR using a real-time qPCR (Biorad) apparatus. (SEQ ID NO: 3) of the HOX25 gene and the antisense primer: 5'-AAGACGGAGGAAGAGGGGTA-3 '(SEQ ID NO: 4) After 5 minutes of dissociation, the reaction was repeated 40 times at 95 ° C for 10 seconds, 58 ° C for 30 seconds, and 72 ° C for 35 seconds, followed by reaction at 95 ° C for 1 minute and at 55 ° C for 1 minute, followed by reaction at 65 ° C for 10 seconds. Respectively.

As a result of qPCR analysis, the HOX25 gene was confirmed to be a gene expressed in leaves, stems, and root tissues of rice (Fig. 2).

ABI 3700 sequencer was used to analyze the nucleotide sequence, and it was confirmed that it was the HOX25 gene through BLAST search of NCBI. HOX25 gene was determined using ABI 3700 sequencer. As a result, HOX25 was a gene having a nucleotide sequence of 783 nucleotides (SEQ ID NO: 1) and having 261 amino acid residues (SEQ ID NO: 2) .

Example  2. HOX25  Overexpression vector production of genes

 The HOX25 gene was cloned into the binary vector pCAMBIA3300PT vector to obtain a rice transformant for functional analysis of the HOX25 gene (Fig. 3).

Specifically, to insert the HOX25 gene into the pCAMBIA3300PT vector, the HOX25 gene amplified by RT-PCR was cloned into the pCR8 / GW / TOPO vector. In order to produce a binary vector for transformation of rice, pCAMBIA3300PT, which is a target vector, and HOX25 gene cloned in a pCR8 / GW / TOPO vector were mixed and reacted in a LR (Invitrogen) reaction solution according to a gateway system And transformed. To confirm whether the HOX25 gene was inserted into the pCAMBIA3300PT vector, a binary vector into which the HOX25 gene was inserted was performed after colony PCR (FIG. 3).

Freeze and thaw were repeated 2-3 times to transform the completed binary vector into Agrobacterium (LBA4404), followed by heat shock method at 37 ° C And colonies were identified after overnight incubation in YEP medium (Yeast 10 g, NaCl 5 g, peptone 10 g, agar 15 g / 1 L) overnight. A colony transformed by colony PCR was transformed into AB medium <AB buffer (K ₂ HPO ₄ 60 g, NaH ₂ PO ₄ 20 g / 1 L), AB Salts (NH ₄ Cl 60 g, MgSO ₄揃 7H ₂ O 6 g, KCl 3 g, CaCl ₂揃 2H ₂ O 0.265 g, FeSO ₄ .7H ₂ O 50 mg / 1 L), and glucose 5 g / 1 L).

Example  3. HOX25  Genetically overexpressed transgenic rice production

Example  3-1. Somatic cell culture

For transgenic transformation with Agrobacterium, the seeds were washed in lactose and appropriately dried to prepare a medium supplemented with 2,4-D hormone in 2N6 medium (Duchefa's CHU (N6) vitamin-containing medium) . The seeds were cultured at 28 ° C for about 7 days, and then the embryos were harvested and used for infection with Agrobacterium containing the HOX25 gene.

Example  3-2. Agrobacterium infection and induction of transformants

Embryogenesis embryogenesis embryogenesis and Agrobacterium transformed genes were cultured in AB liquid culture medium for 20 min, then cultured in medium supplemented with Acetosyringone in 2N6 medium for 7 days. After Agrobacterium infection, the cells were cultured in 2N6 medium supplemented with cefotaxime and PPT (Phosphinotricine) for 2 weeks. For the induction of shooting, the embryo was transferred to medium containing MSR-cell cefotaxime and PPT (Phosphinotricine) and cultured for 2-3 weeks. After shooting, Purification treatment was carried out before transfer to the greenhouse.

Example  3. Rice Transformants HOX25  Check for gene insertion

The insertion of HOX25 gene was confirmed in the rice transformants obtained by Agrobacterium.

Specifically, genomic DNA (Qiagen kit) was extracted from 23 lines of transgenic rice plants obtained by Agrobacterium. (SEQ ID NO: 5) and antisense primer 5'-AAAGCAGGGCATGCCTCAATTCCAGAACCACTCCC-3 '(SEQ ID NO: 6) were mixed with a PCR (Takara kit) reaction solution to confirm the insertion of the HOX25 gene Reaction conditions After dissociation at 94 ° C for 5 minutes, the reaction was repeated for 35 cycles at 94 ° C for 30 seconds, 58 ° C for 30 seconds, and 72 ° C for 1 minute, followed by extension reaction at 72 ° C for 5 minutes and electrophoresis using 1% agarose gel Insertion of the HOX25 gene in line 19 was confirmed (FIG. 4).

Example  4. HOX25  Phenotypic phenotypic analysis of genes in rice

23 plants transformed by the Agrobacterium method were obtained and it was confirmed whether or not the HOX25 gene was inserted. As a result, insertion of the HOX25 gene in line 19 was confirmed as the result of Example 3 above. For the phenotypic analysis of the identified 19 line transformants, T2 plant was planted in the GMO package and phenotypic analysis was performed.

As a result, it was confirmed that the flowering time of the HOX25 gene-overexpressing transformant was faster than that of the comparative group, Dongjinbari, by about one week to two weeks (FIG. 5). This is presumably due to the function of the Homeobox domain encoded in the HOX25 gene.

In addition, an analysis of the expression pattern of 19 lines among the overexpressing transformants of the HOX25 gene revealed that the number of tillers was larger than that of Dongjinbyeo (Figs. 6 and 7). The length of the ears was the same or longer than that of the comparative group, Dongjin (Fig. 8). This suggests that the HOX25 gene was continuously expressed by the constant expression promoter and thus affected the growth.

In addition, it was confirmed that the number of tillers of HOX25 gene and the number of tillering of Dongjinbyeo were 5 or more than that of control group, Dongjinbyeon (Fig. 9). This suggests that the continuous expression of the HOX25 gene by the constant expression promoter may have influenced the increase in the number of tears.

<110> REPUBLIC OF KOREA <120> HOX25 GENE AND TRANSGENIC PLANT TRANSFORMED WITH          HOX25-OVEREXPRESSION VECTOR <130> P14R12D1380 <160> 6 <170> Kopatentin 2.0 <210> 1 <211> 783 <212> DNA <213> Oryza sativa L. <400> 1 atggaggacc tcgtcgacga gctgtacggc gtcgacgagc aggggtcgtc gtcagcggcg 60 gcgaggaagc ggcggctgac agcggagcag gtgcgagcgc tggagcggag cttcgaggag 120 gagaagcgga agctggagcc ggagcggaag agcgagctgg cgcggcgtct cgggatcgcg 180 ccgcggcagg tggccgtgtg gttccagaac cgccgcgcga ggtggaagac gaagcagctc 240 gagctcgact tcgaccgcct ccgggccgcc cacgacgagc tcctcgccgg ccgcgccgcg 300 ctcgccgccg acaacgagag cctccgatct caggtgatcc tattaaccga gaagctgcaa 360 gctaatggga agtcaccgtc accgtcgccg gcgccggcgg agcaaaccgc cgtgccagcc 420 gcacctgaaa gcgccaagtc gtttcagctc gaagaaggtc gctgcctcta cgacgccgcc 480 gggagcacca ccaccaccaa cggcggcggc ggcggcgtcg cgatgccggc ggcgcgcgtg 540 gcggcggcaa gagcggccag caacgacagc cccgagtcct acttcgccgg cgctcgctcg 600 ccgccctcgt cgtcggagga cgactgcggc ggcgccggca gcgacgacga ctacccctct 660 tcctccgtct tactcccggt cgacgctacg ctcgtcggcg acgccttcga gcacgccgtg 720 gcggcgacgg tggcggcgga tgaggaggcg ccgctaaaca gctgggagtg gttctggaat 780 tga 783 <210> 2 <211> 260 <212> PRT <213> Oryza sativa L. <400> 2 Met Glu Asp Leu Val Asp Glu Leu Tyr Gly Val Asp Glu Gln Gly Ser   1 5 10 15 Ser Ser Ala Ala Ala Arg Lys Arg Arg Leu Thr Ala Glu Gln Val Arg              20 25 30 Ala Leu Glu Arg Ser Phe Glu Glu Glu Lys Arg Lys Leu Glu Pro Glu          35 40 45 Arg Lys Ser Glu Leu Ala Arg Arg Leu Gly Ile Ala Pro Arg Gln Val      50 55 60 Ala Val Trp Phe Gln Asn Arg Arg Ala Arg Trp Lys Thr Lys Gln Leu  65 70 75 80 Glu Leu Asp Phe Asp Arg Leu Arg Ala Ala His Asp Glu Leu Leu Ala                  85 90 95 Gly Arg Ala Ala Leu Ala Ala Asp Asn Glu Ser Leu Arg Ser Gln Val             100 105 110 Ile Leu Leu Thr Glu Lys Leu Gln Ala Asn Gly Lys Ser Pro Ser Pro         115 120 125 Ser Pro Ala Pro Ala Glu Gln Thr Ala Val Pro Ala Ala Pro Glu Ser     130 135 140 Ala Lys Ser Phe Gln Leu Glu Glu Gly Arg Cys Leu Tyr Asp Ala Ala 145 150 155 160 Gly Ser Thr Thr Thr Asn Gly Gly Gly Gly Gly Gly Val Ala Met Pro                 165 170 175 Ala Ala Arg Val Ala Ala Ala Arg Ala Ala Ser Asn Asp Ser Pro Glu             180 185 190 Ser Tyr Phe Ala Gly Ala Arg Ser Pro Pro Ser Ser Ser Glu Asp Asp         195 200 205 Cys Gly Gly Ala Gly Ser Asp Asp Asp Tyr Pro Ser Ser Ser Val Leu     210 215 220 Leu Pro Val Asp Ala Thr Leu Val Gly Asp Ala Phe Glu His Ala Val 225 230 235 240 Ala Ala Thr Val Ala Ala Asp Glu Glu Ala Pro Leu Asn Ser Trp Glu                 245 250 255 Trp Phe Trp Asn             260 <210> 3 <211> 20 <212> DNA <213> Artificial Sequence <220> <223> HOX25 sense primer <400> 3 accgagaagc tgcaagctaa 20 <210> 4 <211> 20 <212> DNA <213> Artificial Sequence <220> <223> HOX25 antisense primer <400> 4 aagacggagg aagaggggta 20 <210> 5 <211> 35 <212> DNA <213> Artificial Sequence <220> <223> HOX25 sense primer <400> 5 gggtacccgg ggatcatgga ggacctcgtc gacga 35 <210> 6 <211> 35 <212> DNA <213> Artificial Sequence <220> <223> HOX25 antisense primer <400> 6 aaagcagggc atgcctcaat tccagaacca ctccc 35

Claims (7)

A plant having an increased number of tRNAs by transformation with a recombinant expression vector comprising a HOX25 (Homeobox25) gene having the nucleotide sequence shown in SEQ ID NO: 1. The plant according to claim 1, wherein the plant has a flowering time of at least one week. The plant according to claim 1, wherein the plant is rice, corn, sugar cane, barley or wheat. 1. A method for overexpressing a gene comprising the nucleotide sequence of SEQ ID NO: 1 encoding the HOX25 protein comprising the amino acid sequence of SEQ ID NO: 2 in a plant to increase the number of tillering of the plant. 5. The method of claim 4, wherein the gene overexpression comprises transforming the plant with a recombinant expression vector in which the gene is operably linked to a promoter. 5. The method according to claim 4, wherein the plant is rice, corn, sorghum, barley or wheat. 1. A composition for increasing the number of tillers of a plant comprising a gene consisting of the nucleotide sequence of SEQ ID NO: 1 encoding the HOX25 protein consisting of the amino acid sequence of SEQ ID NO: 2.

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