Plant growth components

Abstract

The present invention aims to provide a plant growth composition that contains a fusion peptide that has a stomatal density-increasing effect and can be secreted extracellularly when produced by microorganisms, and that has excellent storage stability. [Solution] A fusion peptide or a salt thereof, or a solvate thereof, containing a tag peptide and one of the peptides (A1) to (A3), from the amino terminus to the carboxyl terminus, A plant growth composition comprising a preservative, wherein the preservative is one or more selected from the group consisting of potassium pyrosulfite, potassium sorbate, potassium gluconate, and sodium benzoate, and the total weight percentage of the preservative in the plant growth composition is 0.5 to 5% by weight based on the weight of the plant growth composition.

Description

Technical Field

[0001] The present invention relates to a composition for plant growth.

Background Art

[0002] In recent years, functional peptides have attracted attention and are used in fields such as food and medicine. In plant research, peptides with physiological activity have also been identified. Stomagen is an endogenous peptide that has the effect of increasing the stomatal density of plants. As one of the mechanisms for regulating stomatal differentiation, when epidermal pattern formation factors (EPF1, EPF2) bind as ligands to the cell surface receptors TOO MUCH MOUTH (TMM) and ERECTA family receptor-like kinases (ER, ERL1, ERL2), they act as negative regulators of stomatal density, while when Stomagen binds, it acts as a positive regulator of stomatal density, and it has been reported that Stomagen and EPF1 and EPF2 compete with each other and have antagonistic effects on the receptor TMM (Non-Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the stomatal density increases in plants, the uptake of carbon dioxide increases, photosynthesis is promoted, and an increase in the crop yield (harvest number) and an increase in the sugar content (sucrose concentration) are expected. Therefore, there is a demand for industrially producing Stomagen that positively regulates stomatal density.

[0005] Furthermore, Stomagen is highly degradable, and improved storage stability has been desired.

[0006] The present invention aims to provide a plant growth composition that contains a fusion peptide that has a stomatal density-increasing effect and can be secreted extracellularly when produced by microorganisms, and that has excellent storage stability. [Means for solving the problem]

[0007] The inventors of this invention arrived at the present invention as a result of diligent research to solve the above problems. In other words, the present invention relates to a plant growth composition comprising a fusion peptide or a salt thereof, or a solvate thereof, which includes a tag peptide and any of the peptides (A1) to (A3) below, arranged from the amino terminus to the carboxyl terminus, and a preservative, wherein the preservative is one or more selected from the group consisting of potassium pyrosulfite, potassium sorbate, potassium gluconate, and sodium benzoate, and the total weight percentage of the preservative in the plant growth composition is 0.5 to 5% by weight based on the weight of the plant growth composition. (A1) A peptide consisting of the amino acid sequence shown in Sequence ID No. 1 (A2) A peptide consisting of an amino acid sequence in which 1 to 4 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 1. (A3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in Sequence ID No. 1. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a plant growth composition that contains a fusion peptide that has a stomatal density-increasing effect and can be secreted extracellularly when produced by microorganisms, and that has excellent storage stability. [Modes for carrying out the invention]

[0009] The present invention relates to a plant growth composition containing a fusion peptide or a salt thereof, or a solvate thereof, and a preservative. The aforementioned fusion peptide comprises a tag peptide and one of the following peptides (A1) to (A3), arranged from the amino terminus to the carboxyl terminus. (A1) A peptide consisting of the amino acid sequence shown in Sequence ID No. 1 (A2) A peptide consisting of an amino acid sequence in which 1 to 4 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 1. (A3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in Sequence ID No. 1. The fusion peptide in this invention is a polypeptide, and can also be described as a fusion protein.

[0010] In this specification, unless otherwise specified, the amino acid sequences of peptides are shown using the following conventional single-letter notation: A: alanine residue, R: arginine residue, N: asparagine residue, D: aspartic acid residue, C: cysteine ​​residue, Q: glutamine residue, E: glutamic acid residue, G: glycine residue, H: histidine residue, I: isoleucine residue, L: leucine residue, K: lysine residue, M: methionine residue, F: phenylalanine residue, P: proline residue, S: serine residue, T: threonine residue, W: tryptophan residue, Y: tyrosine residue, V: valine residue

[0011] In this specification, the amino acid sequence of a peptide follows the convention of peptide notation, with the leftmost end being the amino terminus and the rightmost end being the carboxyl terminus. In this invention, if an amino acid may have optical isomers, the L-isomer is referred to unless otherwise specified.

[0012] In this specification, the addition of amino acids includes insertion into a sequence. In the present invention, the deletion, substitution, or addition of one or more amino acids in an amino acid sequence means that there is a deletion, substitution, or addition of one or more amino acids at any position in one or more amino acid sequences within the same sequence, and two or more types of deletion, substitution, and addition may occur simultaneously. For example, the deletion, substitution, or addition of one to four amino acids in an amino acid sequence means that there is a deletion, substitution, or addition of one to four amino acids at any position in one to four amino acid sequences within the same sequence, and two or more types of deletion, substitution, and addition may occur simultaneously.

[0013] The peptide (A2) described above is preferably an amino acid sequence in which 1 to 3 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 1, and is a peptide that has a porosity-increasing effect; more preferably an amino acid sequence in which 1 to 2 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 1, and is a peptide that has a porosity-increasing effect; and even more preferably an amino acid sequence in which 1 amino acid is deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 1, and is a peptide that has a porosity-increasing effect.

[0014] The sequence identity of the peptide (A3) described above is 90% or more, preferably 91% or more or 92% or more, more preferably 93% or more or 94% or more, even more preferably 95% or more, 96% or more or 97% or more, even more preferably 98% or more, and particularly preferably 99% or more.

[0015] The identity of amino acid sequences and base sequences can be calculated using analysis software such as BLAST with default parameters.

[0016] The peptide (A1) described above is a peptide that has a stomatal density-increasing effect. The peptides (A2) to (A3) can be any peptide that has a stomatal density-increasing effect. The peptides (A1) to (A3) are polypeptides and can also be described as proteins. In the present invention, the stomatal density-increasing effect can be confirmed, for example, by increasing the expression level of TOO MUCH MOUTH (TMM) in plants. TOO MUCH MOUTH (TMM) is a transmembrane protein present in plant cell membranes that possesses an extracellular receptor site. When TMM expression is promoted, intracellular signaling via ERECTA family receptor-like kinases activates transcription factors involved in stomatal formation, leading to an increase in stomatal density. The peptides (A1) to (A3) described above can promote TMM expression in plants when applied to those plants. In this invention, if TMM expression is promoted to some extent (expression level increases) in plants to which a certain substance has been applied compared to plants to which the substance has not been applied, then that substance can be said to have a stomatal density-increasing effect. It is preferable that the peptides (A1) to (A3) described above have a stomatal differentiation-promoting effect or a photosynthesis-promoting effect.

[0017] In this invention, TMM expression promotion includes the promotion of TMM mRNA expression and the promotion of TMM protein expression. In this invention, if, when a certain substance is used on a plant, TMM expression is promoted to some extent (expression level increases) compared to when the substance is not used, then the substance can be said to have a TMM expression promoting effect (exhibit an expression promoting effect). TMM expression promotion can also be expressed as an increase in the expression level of TMM or an increase in TMM expression. The plant may be the whole plant or a part of the plant. Parts of the plant include leaves, stems, flowers, fruits, trunks, branches, seeds, roots, buds, etc.

[0018] In one aspect, the peptides of (A1) to (A3) above are preferably peptides having an action of promoting the expression of sucrose transporters. A sucrose transporter (sucrose transporter) is a protein that exists in the cell membrane of plants and transports sucrose. Sucrose transporter 1 (SUT1) can be mentioned as a sucrose transporter. When the peptides of (A1) to (A3) above are used for plants, it is preferable to promote the expression of sucrose transporters in the plants. Among the peptides of (A1) to (A3) above, the peptide of (A1) above is preferable.

[0019] In the present invention, the promotion of the expression of sucrose transporters includes the promotion of the expression of mRNA of sucrose transporters and the promotion of the expression of proteins. In the present invention, when a certain substance is used for plants, if the expression of sucrose transporters is promoted (the expression level increases) to some extent compared with the case where the substance is not used, it can be said that the substance has an action of promoting the expression of sucrose transporters (shows an action of promoting expression). The promotion of the expression of sucrose transporters can also be referred to as an increase in the expression level of sucrose transporters or an increase in the expression of sucrose transporters. The plant may be the whole plant or a part of the plant. The parts of the plant include leaves, stems, flowers, fruits, trunks, branches, seeds, roots, buds, etc.

[0020] The fusion peptide in the present invention contains a tag peptide at the amino-terminus of any of the peptides (A1) to (A3) above. The tag peptide can also be described as a tag protein. The tag peptide used in the fusion peptide of the present invention is a tag peptide that can be used in the production of recombinant peptides by microorganisms such as E. coli, and when positioned at the amino-terminus of the peptides (A1) to (A3) above, the fusion protein containing the tag peptide and any of the peptides (A1) to (A3) exhibits a porosity-increasing effect. Furthermore, as the tag peptide, a peptide can be used that, when a microorganism is made to produce the fusion peptide containing the tag peptide, causes the fusion peptide to be secreted outside the host microorganism's cell. Secretion outside the microbial cell includes secretion into the periplasm. As the tag peptide in the present invention, a tag peptide consisting of 20 to 130 amino acids (polypeptide tag) is preferred, and a tag peptide consisting of 30 to 120 amino acids is more preferred. As the tag peptide in the present invention, a soluble tag peptide is also preferred. A soluble tag peptide is a peptide that enhances the solubility of a fusion peptide containing the tag peptide. Fusion peptides containing a soluble tag peptide at the amino-terminus of the peptides (A1) to (A3) above are easily expressed in a soluble form (soluble peptide) in microorganisms. A soluble tag peptide that enhances the expression stability of the fusion peptide containing the tag peptide within the host is preferred.Examples of the tag peptides that can be used in the present invention include, for example, PelB tag (PelB tag peptide), the peptide encoded by the Fh8 gene of Fasciola hepatica (Fh8 tag peptide), ZZ tag (ZZ tag peptide), Z tag (Z tag peptide), His tag (His tag peptide), P17 tag (P17 tag peptide), Thioredoxin (Trx tag peptide), Maltose binding protein (MBP tag peptide), Small ubiquitin related modifier (SUMO tag peptide), Glutathione S-transferase (GST tag peptide), Nutilization substance A (Nus tag peptide), N-terminal extension sequence (NEXT tag peptide), and the like. In the present invention, these tag peptides can be used as tag peptides alone or in combination of two or more.

[0021] As the tag peptide in the present invention, one or two peptides selected from the group consisting of the following (B1) to (B3), (C1) to (C3), (D1) to (D3), and (E1) to (E) are preferable. (B1) A peptide consisting of the amino acid sequence shown in SEQ ID NO: 2 (B2) A peptide consisting of an amino acid sequence in which 1 to 2 amino acids are deleted, substituted, or added in the amino acid sequence shown in SEQ ID NO: 2 (B3) A peptide consisting of an amino acid sequence having 90% or more sequence identity to the amino acid sequence shown in SEQ ID NO: 2 (C1) A peptide consisting of the amino acid sequence shown in SEQ ID NO: 3 (C2) A peptide consisting of an amino acid sequence in which 1 to 6 amino acids are deleted, substituted, or added in the amino acid sequence shown in SEQ ID NO: 3 (C3) A peptide consisting of an amino acid sequence having 90% or more sequence identity to the amino acid sequence shown in SEQ ID NO: 3 (D) A peptide consisting of the amino acid sequence shown in SEQ ID NO: 4 (D2) A peptide consisting of an amino acid sequence in which 1 to 11 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 4. (D3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 4. (E1) A peptide consisting of the amino acid sequence shown in Sequence ID No. 5. (E2) A peptide consisting of an amino acid sequence in which 1 to 5 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 5. (E3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in Sequence ID No. 5.

[0022] The peptide (B1) above is a PelB-tagged peptide. The peptide (C1) above is an Fh8-tagged peptide. The peptide (D1) above is a ZZ-tagged peptide. The peptide (E1) above is a Z-tagged peptide. The fusion protein may contain any one of the following tag peptides: (B1), (C1), (D1), (E1), (B2), (C2), (D2), and (E2). Alternatively, the tag peptides may include (B1) and (C1), (B1) and (D1), (B1) and (E1), (C1) and (D1), (C1) and (E1), (D1) and (E1), (B2) and (C1), (B2) and (D1), (B2) and (E1), (C2) and (B1), (C2) and (D1), (C2) and (E1), The fusion peptide may contain (D2) and (B1), (D2) and (C1), (D2) and (E1), (E2) and (B1), (E2) and (C1), (E2) and (D1), (B2) and (C2), (B2) and (D2), (B2) and (E2), (C2) and (D2), (C2) and (E2), or two types of (D2) and (E2). When the tag peptide contains the above peptides, when the fusion peptide is expressed in microorganisms such as E. coli, the extracellular secretion of the fusion peptide is further promoted. This makes purification easier when producing the fusion peptide by microorganisms. Furthermore, it is preferable for the fusion protein to contain the above tag peptides because it increases the solubility of the fusion protein. It is also preferable for the fusion protein to contain the above tag peptides because it improves the expression stability in E. coli.

[0023] If the tag peptide contains two of the above (B1)~(B3), (C1)~(C3), (D1)~(D3), and (E1)~(E3), it is preferable that the tag peptide contains (B1) or (B2) and (C1), (C2), (D1), (D2), (E1) or (E2), and more preferably (B1) or (B2) and (C1), (D2) or (E1). In this case, it is preferable that the tag peptide contains (B1) or (B2) at the amino terminal. (B1) or (B2) and (C1), (C2), (D1), (D2), (E1) or (E2) may be linked via the His tag (SEQ ID NO: 6). In one embodiment, the tag peptide is preferably a peptide comprising (B1) or (B2) above, a His tag (SEQ ID NO: 6), and (C1), (D2), or (E1). In one embodiment, the peptide (C2) or (E2) above is preferred as the tag peptide.

[0024] The peptides (B2), (B3), (C2), (C3), (D2), (D3), (E2), and (E3) above may include peptides that promote extracellular secretion of the fusion peptide when the fusion peptide containing the peptide is expressed, for example, in E. coli. These tag peptides preferably have a solubility-enhancing effect. The peptides (B2), (B3), (C2), (C3), (D2), (D3), (E2), and (E3) above preferably have an effect of improving the expression stability of the fusion peptide containing it in microorganisms (preferably E. coli).

[0025] In the peptide described in (B2) above, preferably one amino acid is deleted, substituted, or added. The peptide described in (B2) above is preferably a peptide consisting of an amino acid sequence in which one to two amino acids (preferably glutamic acid or aspartic acid) are added to the carboxyl terminus of the amino acid sequence shown in Sequence ID No. 2. In the peptide (C2) described above, the number of deleted, substituted, or added amino acids is preferably 1 to 5, more preferably 1 to 4, even more preferably 1 to 3, particularly preferably 1 to 2, and most preferably 1. As the peptide (C2) described above, a peptide consisting of an amino acid sequence in which one amino acid (preferably methionine) is added to the amino terminus of the amino acid sequence shown in SEQ ID NO: 3 is preferred. In the peptide (D2) described above, the number of deleted, substituted, or added amino acids is preferably 1 to 10 or 1 to 9, more preferably 1 to 8 or 1 to 7, even more preferably 1 to 6, still more preferably 1 to 5, even more preferably 1 to 4, even more preferably 1 to 3, particularly preferably 1 to 2, and most preferably 1. In one embodiment, the peptide (D2) described above is preferably a peptide consisting of an amino acid sequence in which 1 to 3 amino acids are added to the carboxyl terminus of the amino acid sequence shown in SEQ ID NO: 4. In another embodiment, the peptide (D2) described above is preferably a peptide consisting of an amino acid sequence in which 1 amino acid (preferably methionine) is added to the amino terminus of the amino acid sequence shown in SEQ ID NO: 4, and 1 to 3 amino acids are added to the carboxyl terminus. In the peptide (E2) described above, the number of deleted, substituted, or added amino acids is preferably 1 to 4, more preferably 1 to 3, even more preferably 1 to 2, and particularly preferably 1.

[0026] The sequence identity of the peptides (B3), (C3), (D3), and (E3) described above is 90% or more, preferably 91% or more or 92% or more, more preferably 93% or more or 94% or more, even more preferably 95% or more, 96% or more or 97% or more, even more preferably 98% or more, and particularly preferably 99% or more.

[0027] In the present invention, the peptides described above are more preferably (B1) (PelB tag peptide), (C1) (Fh8 tag), (D1) (ZZ tag peptide), and (E1) (Z tag peptide), with the peptides described above (B1) and (C1) being even more preferred. The peptides described above (B1), (C1), (D1), and (E1) are also preferred from the viewpoint of not affecting the porosity-increasing effect, TMM expression-promoting effect, and sucrose transporter expression-promoting effect of the peptides described above (A1) to (A3).

[0028] In the present invention, the fusion peptide has a tag peptide and one of the peptides (A1) to (A3) arranged in this order from the amino terminus to the carboxyl terminus. The fusion peptide in the present invention has a TMM expression promoting effect by containing one of the peptides (A1) to (A3). The fusion peptide in the present invention has a porosity increasing effect. From the viewpoint of obtaining the porosity increasing effect by the peptides (A1) to (A3) above more sufficiently, it is preferable that the peptides (A1) to (A3) above be located at the carboxyl terminus of the fusion peptide. It is preferable that the fusion peptide in the present invention has one of the peptides (A1) to (A3) above at the carboxyl terminus. Furthermore, it is preferable that the fusion peptide in the present invention has the tag peptide at the amino terminus.

[0029] In the fusion peptide of the present invention, the tag peptide and any of the peptides (A1) to (A3) above may be directly linked by an amide bond. Alternatively, the tag peptide and any of the peptides (A1) to (A3) above may be linked via a peptide consisting of one amino acid or 2 to 20 amino acids (peptide linker). Known peptide linkers can be used. A peptide consisting of 3 to 15 amino acids is preferred as the peptide linker, and a peptide consisting of 5 to 10 amino acids is preferred. The fusion peptide of the present invention may have an acetylated amino terminus or an amidated carboxyl terminus. In one embodiment, the fusion peptide of the present invention is preferably a peptide in which the carboxyl-terminal amino acid of the tag peptide and the amino-terminal amino acid of any of the peptides (A1) to (A3) above are (directly) linked by an amide bond.

[0030] In one embodiment, the fusion peptide in the present invention is preferably composed of a tag peptide and any of the peptides (A1) to (A3) above. The fusion peptide composed of a tag peptide and any of the peptides (A1) to (A3) above has the tag peptide at its amino terminus and any of the peptides (A1) to (A3) above at its carboxy terminus.

[0031] In one embodiment, the fusion peptide in the present invention is preferably a peptide consisting of the amino acid sequence shown in SEQ ID NO: 12. The amino acid sequence of SEQ ID NO: 12 is the amino acid sequence of a fusion peptide consisting of the peptide (B1) above, a His-tagged peptide, the peptide (C1), and the peptide (A1).

[0032] The fusion peptide in the present invention may be in the form of a salt. The salt of the peptide in the present invention is not particularly limited and may be either an acidic salt or a basic salt. Examples of acidic salts include inorganic acid salts such as hydrochloride, sulfate, nitrate, and phosphate; organic acid salts such as formate, acetate, citrate, maleate, malate, oxalate, lactate, succinate, fumarate, and propionate; and amino acid salts such as aspartate and glutamate. Examples of basic salts include alkali metal salts such as sodium salt and potassium salt; alkaline earth metal salts such as calcium salt and magnesium salt; ammonium salt; and salts with organic bases such as triethylamine, triethanolamine, and pyridine. These salts are usable in plants and can be used as salts of the fusion peptide in the present invention. Among these, hydrochloride, formate, acetate, phosphate, citrate, lactate, aspartate, glutamate, sodium salt, and potassium salt are preferred as salts of the fusion peptide, and hydrochloride, formate, and acetate are more preferred.

[0033] The fusion peptide or salt thereof in the present invention may be in the form of a solvate. The solvent that forms the solvate is not particularly limited and includes, for example, water, ethanol, methanol, glycerol, etc., and is preferably water.

[0034] The fusion peptide in this invention can be biosynthesized using microorganisms. When using microorganisms, an expression vector into which the gene encoding the fusion peptide of this invention, as described later, is introduced is prepared, and the expression vector is introduced into a host microorganism to produce a transformant. The transformant can be cultured, and the fusion peptide of this invention can be purified from the culture. Alternatively, the fusion peptide in this invention can also be produced by known peptide synthesis methods, for example. When obtaining the fusion peptide in this invention by peptide synthesis, it can be synthesized by either a solid-phase or liquid-phase method. The peptide can be purified by known purification methods such as reverse-phase high-performance liquid chromatography or affinity chromatography. Salts and solvates of the fusion peptide can be readily prepared by those skilled in the art by any method known in the art. The fusion peptide, its salts, and their solvates in this invention are preferably used in plants, as described later.

[0035] The fusion peptide, its salt, or its solvate in the present invention has the effect of increasing TMM expression. When the fusion peptide, its salt, or its solvate in the present invention is used in plants, TMM expression can be increased. As described above, when TMM expression is increased in plants, stomatal density increases. The fusion peptide, its salt, or its solvate in the present invention can be preferably used in plants. When the fusion peptide, its salt, or its solvate in the present invention is used in plants, stomatal density can be increased in those plants. The plants are not particularly limited, but it is preferable that they be at least one selected from the group consisting of Cucurbitaceae, Solanaceae, Convolvulaceae, Salicaceae, Rutaceae, Fabaceae, Rosaceae, Asteraceae, Amaranthaceae, Musaceae, Poaceae, and Amaryllidaceae. Examples of these plants are listed below. When used on any of these plants, it is preferable to increase stomatal density or promote TMM expression in the plant. Among these, plants of the Cucurbitaceae family, Solanaceae family, and Convolvulaceae family are more preferred, with cucumber (Cucumis sativus) of the Cucurbitaceae family, tomato (Solanum lycopersicum) of the Solanaceae family, and sweet potato (Ipomoea batatas) of the Convolvulaceae family being even more preferred. In one embodiment, the fusion peptide of the present invention is preferably a peptide that increases stomatal density in Cucurbitaceae plants, more preferably cucumber (Cucumis sativus) of the Cucurbitaceae family. In another embodiment, the fusion peptide of the present invention is preferably a peptide that increases stomatal density or promotes TMM expression in Solanaceae plants, more preferably tomato (Solanum lycopersicum) of the Solanaceae family.Furthermore, in one embodiment, the fusion peptide in the present invention is preferably a peptide that increases stomatal density or promotes TMM expression in plants of the Convolvulaceae family, more preferably sweet potato (Ipomoea batatas) of the genus Ipomoea in the Convolvulaceae family.

[0036] In plants, increased stomatal density due to enhanced TMM expression leads to increased carbon dioxide uptake and accelerated photosynthesis. Therefore, increased stomatal density in plants can result in increased yield (number of harvested plants) and higher sugar content (sucrose concentration). Furthermore, increased intracellular sugar content confers, improves, or induces tolerance to environmental stresses, such as osmotic stress (e.g., salt tolerance), drought tolerance, high temperature tolerance, and low temperature tolerance. Thus, increasing stomatal density in plants also provides a plant protection effect against environmental stresses.

[0037] The fusion peptide, its salt, or its solvate in the present invention preferably promotes the expression of sucrose transporters in plants. When the expression of sucrose transporters is promoted in plants, the translocation of sucrose to various organs of the plant is promoted, and the uptake of sucrose into cells increases. As a result, the sucrose content in cells increases, leading to an increase in sugar content. When the sucrose concentration in the plant increases, the osmotic pressure in the plant increases, thus conferring, improving, or inducing tolerance to environmental stresses, such as tolerance to osmotic stress (e.g., salt tolerance), drought tolerance, high temperature tolerance, and low temperature tolerance (cold tolerance). Sucrose transporters are present throughout the plant and transport synthesized sucrose to the sieve tubes, where it is translocated to various organs of the plant. Therefore, promoting the expression of sucrose transporters in plants can result in an increase in sugar content and a plant protection effect against environmental stress. Thus, substances that promote the expression of sucrose transporters in plants are useful, for example, for increasing the sugar content of plants and protecting plants (e.g., improving the plant's tolerance to environmental stress).

[0038] The fusion peptide or its salt, or its solvate, used in this invention may be used individually or in combination of two or more.

[0039] The weight percentage of the fusion peptide or its salt or solvate in the plant growth composition of the present invention is not particularly limited. For example, the total weight percentage of the fusion peptide or its salt or solvate can be 0.0001 to 20% by weight, preferably 0.0005 to 10% by weight, and more preferably 0.001 to 2.5% by weight.

[0040] The plant growth composition of the present invention contains a preservative. The preservative is one or more selected from the group consisting of potassium pyrosulfite, potassium sorbate, potassium gluconate, and sodium benzoate. From the viewpoint of suppressing the decomposition of fusion peptides or their salts, or their solvates, it is preferable that the preservative contains potassium pyrosulfite. The total weight percentage of preservatives in the plant growth composition is 0.5 to 5% by weight, based on the weight of the plant growth composition. If the total weight percentage of preservatives in the plant growth composition is less than 0.5% by weight based on the weight of the plant growth composition, the decomposition of the fusion peptide or its salt or solvate cannot be suppressed, and if it exceeds 5% by weight, it may adversely affect plant growth. From the viewpoint of suppressing the decomposition of the fusion peptide or its salt or solvate and promoting plant growth, the total weight percentage of preservatives in the plant growth composition is preferably 0.5 to 3% by weight, and more preferably 0.5 to 1.5% by weight based on the weight of the plant growth composition.

[0041] The total weight percentage of preservatives in the plant growth composition is preferably 17 to 200% by weight, based on the total weight of the fusion peptide or its salt, or its solvate. When the total weight percentage of preservatives is within this range, the stability of the fusion peptide or its salt, or its solvate, is improved.

[0042] The plant growth composition of the present invention preferably further contains one or more selected from the group consisting of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and potassium benzoate. Furthermore, it is preferable that the total weight percentage of one or more selected from the group consisting of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and potassium benzoate is 0.1 to 5% by weight based on the weight of the plant growth composition. When one or more selected from the group consisting of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and potassium benzoate are included in the above weight percentages, the stability of the fusion peptide or its salt, or its solvate, is improved.

[0043] The plant growth composition of the present invention can take various forms depending on the method of application to plants. The dosage form of the plant growth composition of the present invention is not limited, but it can be a solid (e.g., tablet, granule, powder) or a liquid. When applying to plants by spraying, a liquid or a dosage form that can be made liquid at the time of application is preferred. The plant growth composition of the present invention can also be used, for example, as a tablet, granule, powder, or concentrated liquid during distribution and storage, and dissolved or suspended in water at the time of use to obtain an appropriate concentration.

[0044] When the plant growth composition of the present invention is a liquid preparation, the total content of the fusion peptide or its salt or its solvate is preferably 0.0005 to 20% by weight, and more preferably 0.001 to 2.5% by weight, as the content of the fusion peptide in the plant growth composition. When the plant growth composition of the present invention is a solid preparation, the total content of the fusion peptide or its salt or its solvate is preferably 0.0001 to 1% by weight, and more preferably 0.001 to 0.1% by weight, as the content of the fusion peptide in the plant growth composition.

[0045] The plant growth composition of the present invention may contain other optional components, depending on the dosage form and shape, as long as they do not impair the effects of the present invention. Examples of other optional components include liquid carriers, spreading agents, emulsifiers, dispersants, fillers, bulking agents, binders, humidifying agents, disintegrants, lubricants, diluents, excipients, amino acids, peptides (peptides different from the fusion peptide of the present invention), fertilizer elements, and components derived from natural products. Examples of liquid carriers include media capable of dissolving or dispersing the fusion peptide of the present invention or its salt, or its solvate, as described above. Examples include water; alcohols such as 1-propanol and butanol; polyhydric alcohols such as ethylene glycol and propylene glycol; and hydrocarbons such as xylene.

[0046] The plant growth composition of the present invention may contain other active ingredients, as long as they do not impair the effects of the present invention. For example, it may contain known agents for plant diseases. The plant growth composition of the present invention may be used alone on plants, or it may be used in combination with other agricultural materials such as fertilizers, soil conditioners, and horticultural potting soils.

[0047] The plant growth composition of the present invention is a composition used to improve plant growth. The plant growth composition of the present invention can be used, for example, to increase stomatal density in plants. In one embodiment, the plant growth composition of the present invention can be used to promote TMM expression in plants. The composition of the present invention can be preferably used, for example, to increase the sugar content of plants, protect plants, or increase plant yield. In one embodiment, the plant growth composition of the present invention is preferably used as a composition for increasing the sugar content of plants, a composition for protecting plants, or a composition for increasing plant yield. The composition for increasing the sugar content of plants can also be called a plant sugar content increasing agent. The composition for protecting plants can also be called a plant protective agent. The composition for increasing plant yield can also be called a crop yield increasing agent.

[0048] Plant protection includes improving the plant's defense mechanisms and enhancing its adaptive responses. The plant growth composition of the present invention can be used, for example, to improve the plant's defense mechanisms or its adaptive responses. Improving the plant's defense mechanisms includes improving resistance to diseases and pests. Improving the plant's adaptive responses includes improving its adaptive responses to environmental stresses. Furthermore, plant protection includes improving tolerance to abiotic stresses and improving tolerance to biological stresses. Examples of tolerance to abiotic stresses include tolerance to environmental stresses, such as tolerance to osmotic stress (e.g., salt tolerance), drought tolerance, high temperature tolerance, and low temperature tolerance. Examples of biological stresses include pathogens and pests. In one embodiment, the plant growth composition of the present invention can be preferably used to improve tolerance to abiotic stresses such as environmental stresses. In one embodiment, the plant protection composition is preferably a biostimulant. Also in one embodiment, the plant growth composition of the present invention can be preferably used to increase stomatal density in parts of a plant, such as leaves. Furthermore, in one embodiment, the plant growth composition of the present invention can be preferably used to increase the sugar content of plant parts, such as fruits or roots (tubers).

[0049] The method of applying the plant growth composition of the present invention to plants is not particularly limited and can be applied by general methods. Examples include spraying, coating, irrigation, adding to hydroponic solutions, and soil mixing. Among these, the plant growth composition of the present invention is preferably applied to plants by foliar spraying or irrigation. A suitable formulation for foliar spraying is a liquid formulation. If the target plant is cultivated in soil, irrigation of the soil is also preferable. When applying by irrigation, the plant growth composition of the present invention can be mixed with water and the resulting liquid solution can be irrigated onto the plants. The total content of the fusion peptide or its salt or its solvate in the composition used for foliar spraying (preferably a liquid formulation) is preferably 0.0005 to 20% by weight, and more preferably 0.001 to 2.5% by weight, as the content of the fusion peptide. When applied to plants by irrigation, the total content of the fusion peptide, its salt, or its solvate in the irrigation solution is preferably 0.0005 to 20% by weight, and more preferably 0.001 to 2.5% by weight, as the content of the fusion peptide.

[0050] The timing of application of the plant growth composition of the present invention to plants is not particularly limited, but application from the seedling stage to before harvest is preferred. Furthermore, the frequency of application of the plant growth composition of the present invention to plants is not particularly limited, but it is preferably applied once every 1 to 30 days, and more preferably once every 7 to 14 days. The application amount of the plant growth composition of the present invention can be appropriately set according to the plant and is not particularly limited. In one embodiment, the application amount of the fusion peptide in the plant growth composition of the present invention is preferably 0.01 to 20 mg per plant, and more preferably 0.05 to 10 mg per application.

[0051] The plants to which the plant growth composition of the present invention is applied are not particularly limited, but examples include plants of the Cucurbitaceae family, Solanaceae family, Convolvulaceae family, Salicaceae family, Rutaceae family, Fabaceae family, Rosaceae family, Asteraceae family, Amaranthaceae family, Musaceae family, Poaceae family, Amaryllidaceae family, and the like. In the present invention, at least one plant selected from the group consisting of Cucurbitaceae, Solanaceae, Convolvulaceae, Salicaceae, Rutaceae, Fabaceae, Rosaceae, Asteraceae, Amaranthaceae, Musaceae, Poaceae, and Amaryllidaceae is preferred as the plant, with Cucurbitaceae, Solanaceae, or Convolvulaceae being more preferred.

[0052] Examples of plants belonging to the Cucurbitaceae family include the cucumber (Cucumis sativus) of the genus Cucumis. Examples of plants belonging to the Solanaceae family include the tomato (Solanum lycopersicum) and the potato (Solanum tuberosum), with the tomato being preferred. Examples of plants belonging to the Convolvulaceae family include sweet potato (Ipomoea batatas) of the Ipomoea genus. Examples of plants belonging to the Salicaceae family include poplars (Populus) of the genus Populus or Populus. Examples of plants belonging to the Rutaceae family include the Satsuma mandarin (Citrus unshiu) of the Citrus genus. Examples of plants belonging to the Fabaceae family include the pea (Pisum sativum) of the genus Pisum. Examples of plants belonging to the Rosaceae family include the strawberry (Fragaria), which belongs to the genus Fragaria. Examples of plants belonging to the Asteraceae family include burdock (Arctium lappa) of the genus Arctium. Examples of plants belonging to the Amaranthaceae family include sugar beet (Beta vulgaris ssp. vulgaris) of the genus Beta. Examples of plants belonging to the Musaceae family include the banana (Musa spp.), which belongs to the genus Musa. Examples of plants belonging to the grass family (Poaceae) include rice (Oryza sativa) of the genus Oryza, maize (Zea mays subsp. mays) of the genus Zea, and wheat (Triticum) of the genus Triticum. Examples of plants belonging to the Amaryllidaceae family include the onion (Allium cepa) of the genus Allium.

[0053] In one embodiment, the plant growth composition of the present invention can be used, for example, to promote the expression of TMM, increase stomatal density, or increase yield (number of harvested fruits) in cucumber (Cucumis sativus) of the Cucurbitaceae family. In another embodiment, the plant growth composition of the present invention can be used, for example, to promote the expression of TMM, increase stomatal density, increase sugar content (preferably, increase sugar content of the fruit), or improve salt tolerance in tomato (Solanum lycopersicum) of the Solanaceae family. In yet another embodiment, the plant growth composition of the present invention can be used, for example, to promote the expression of TMM, increase stomatal density, increase sugar content (preferably, increase sugar content of the root (tuber)), or improve salt tolerance in sweet potato (Ipomoea batatas) of the Convolvulaceae family.

[0054] This specification discloses the following: (1) The present disclosure is a plant growth composition comprising a fusion peptide or a salt thereof, or a solvate thereof, which comprises a tag peptide and any of the peptides (A1) to (A3) below, arranged from the amino terminus to the carboxy terminus, and a preservative, wherein the preservative is one or more selected from the group consisting of potassium pyrosulfite, potassium sorbate, potassium gluconate, and sodium benzoate, and the total weight percentage of the preservatives in the plant growth composition is 0.5 to 5% by weight based on the weight of the plant growth composition. (A1) A peptide consisting of the amino acid sequence shown in Sequence ID No. 1 (A2) A peptide consisting of an amino acid sequence in which 1 to 4 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 1. (A3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in Sequence ID No. 1.

[0055] Disclosure (2) further contains one or more selected from the group consisting of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and potassium benzoate, wherein the total weight percentage thereof is 0.1 to 5% by weight based on the weight of the plant growth composition, as described in Disclosure (1).

[0056] Disclosure (3) is a plant growth composition according to Disclosure (1) or (2), wherein the tag peptide is one or two peptides selected from the group consisting of (B1) to (B3), (C1) to (C3), (D1) to (D3) and (E1) to (E3) below. (B1) A peptide consisting of the amino acid sequence shown in Sequence ID No. 2 (B2) A peptide consisting of an amino acid sequence in which 1 to 2 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 2. (B3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in Sequence ID No. 2. (C1) A peptide consisting of the amino acid sequence shown in SEQ ID NO: 3 (C2) A peptide consisting of an amino acid sequence in which 1 to 6 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 3. (C3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 3. (D1) A peptide consisting of the amino acid sequence shown in SEQ ID NO: 4 (D2) A peptide consisting of an amino acid sequence in which 1 to 11 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 4. (D3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 4. (E1) A peptide consisting of the amino acid sequence shown in Sequence ID No. 5. (E2) A peptide consisting of an amino acid sequence in which 1 to 5 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No. 5. (E3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in Sequence ID No. 5. [Examples]

[0057] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0058] <Manufacturing Example 1> Preparation of PelB-His-Fh8-Stomagen: A polynucleotide encoding a fusion peptide in which a tag peptide was attached to the amino terminus of Stomagen was constructed and expressed in E. coli. The amino acid sequences of the PelB tag peptide and the Fh8 tag peptide are described below. PelB-tagged peptide: MKKKKPTAAAGLLLLAAQPAMA (SEQ ID NO: 2) Fh8 tag:PSVQEVEKLLHVLDRNGDGKVSAEELKAFADDSKCPLDSNKIKAFIKEHDKNKDGKLDLKELVSILSS (Sequence ID 3) His tag: HHHHHH (Sequence number 6)

[0059] As a polynucleotide encoding a fusion peptide containing a PelB-tagged peptide (SEQ ID NO: 2), an Fh8 tag (SEQ ID NO: 3), a His tag (SEQ ID NO: 6), and Stomagen (SEQ ID NO: 1), we constructed a polynucleotide (PelB-His-Fh8-Stomagen) with the base sequence shown in SEQ ID NO: 13. PelA AAGATCAAGGCGTTTATCAAAGAGCACGATAAAAACAAGGACGGCAAGCTCGACCTTAAGGAGCTGGTGTCGATCCTGTCTAGCATTGGTAGCACGGCTCCGACCTGTACCTATAACGAGTGCAGAGGCTGCCGCTACAAGTGCCGCGCAGAGCAGGTTCCGGTTGAAGGTAACGATCCGATTAACAGCGCGTACCATTATCGTTGCGTCTGTCATCGT (SEQ ID NO: 13) The amino acid sequence of the fusion peptide encoded by the above polynucleotide (PelB-His-Fh8-Stomagen) is shown below. The underlined portion is the amino acid sequence of Stomagen (SEQ ID NO: 1). MKKKKPTAAAGLLLLAAQPAMAHHHHHHPSVQEVEKLLHVLDRNDGKVSAEELKAFADDSKCPLDSNKIKAFIKEHDKNKDGKLDLKELVSILSS IGSTAPTCTYNECRGCRYKCRAEQVPVEGNDPINSAYHYRCVCHR (Sequence ID 12)

[0060] Vector cloning: A plasmid containing a fusion peptide encoding Stomagen (PelB-His-Fh8-Stomagen) was synthesized on a contract basis by Eurofins Genomics Co., Ltd. (Plasmid name: pEX-A2J2-pelB-His-FH8-Stomagen).

[0061] pEX-A2J2-pelB-His-FH8-Stomagen was digested with NdeI and HindIII restriction enzymes, and agarose gel electrophoresis was performed. Each gene fragment and the pET22b vector fragment (5400 bp) were recovered from the gel.

[0062] Each DNA fragment was extracted from the gel and ligated to create pET22b (pelB-His-FH8-Stomagen). Each plasmid was transformed into E. coli DH5a strain, and colonies were sorted on ampicillin-containing LB agar plates.

[0063] Colony PCR was performed using T7pro(5'-TAATACGACTCACTATAGGG-3') and T7term(5'-ATGCTAGTTATTGCTCAGCGG-3') primers to confirm gene transfer in each plasmid. Furthermore, colonies in which gene transfer was confirmed were grown, the plasmids were recovered from the bacterial cells, and it was confirmed that the target nucleotide sequence had been introduced. Each pET22b (pelB-His-FH8-Stomagen) strain, whose base sequence was confirmed, was transformed into the Lemo21(DE3) strain and culture was initiated.

[0064] In this culture, the pH was maintained at 6.5–7.0 for 9–12 hours after the start of culture. Then, the pH was increased to 8.0–9.5 and maintained until the end of culture. Cell density was maintained until the OD600 reached 15–20 at 6 hours after the start of culture. Three hours after the start of culture, isopropyl-β-thiogalactopyranoside (IPTG) was added to the culture medium to a concentration of 0.1–1 mM to promote the production of the target fusion peptide. 22–26 hours after the addition of IPTG, the culture medium in the culture vessel was centrifuged (13000 rpm) to separate the supernatant fraction from the precipitate. The fusion peptide contained in the supernatant and precipitate was confirmed by SDS-PAGE.

[0065] Purification of the supernatant fraction: The recovered supernatant fraction was desalted and concentrated using a desalting and concentration device (AKTA flux™s, Cytiva, Global Life Science Technologies Japan Co., Ltd.) with a UF membrane (MWCO 5000). Desalting was continued until the electrical conductivity was 5 mS / cm. A fusion peptide (PelB-His-Fh8-Stomagen) was obtained (a fusion peptide in which a PelB-tagged peptide and an Fh8-tagged peptide are bound to the amino-terminus of Stomagen). The fusion peptide is a peptide consisting of the amino acid sequence shown in Sequence ID No. 12.

[0066] <Example 1> Composition (A1) for plant growth was obtained by mixing 85 parts by weight of the fusion peptide obtained above, 1.5 parts by weight of potassium pyrosulfite (manufactured by Tokyo Chemical Industry Co., Ltd.), and 13.5 parts by weight of deionized water.

[0067] <Evaluation of peptide retention rate> The obtained plant growth composition (A1) was left to stand for 9 weeks in an artificial climate chamber set at 40°C, and the peptide concentration after standing was quantitatively evaluated by electrophoresis (pelB-His-FH8-Stomagen (MW=15.0 kDa)). The peptide retention rate was calculated using the following formula. The results are shown in Table 1. Peptide retention rate (%) = Peptide concentration at week 9 / Peptide concentration at day 0 × 100

[0068] <Cultivation experiment> Tomato (variety: Regina) seeds were sown on a water-soaked Kimwipe placed in a petri dish and germinated in an artificial climate chamber. The sown tomatoes were cultivated in the artificial climate chamber (7:00 AM - 8:00 AM 20°C, 8:00 AM - 9:00 AM 22.5°C, 9:00 AM - 7:00 PM 25°C, 12 hours of light; 60% humidity, 7:00 PM - 7:00 AM 12 hours of darkness; 16°C; 60% humidity). After two weeks, the germinated seedlings were transplanted into Jiffy containers and continued to be cultivated in the artificial climate chamber. Tomato seedlings that were 70 days old after sowing and had about 6 true leaves were selected. Plant growth composition (A1) 10 μM, which had been tested for peptide retention (after standing for 9 weeks), was applied as a foliar spray at a concentration of 2.1 mL / plant at 0 days and 1 week after the start of the experiment. The increase in height (cm) and the wet weight (gFW) of the above-ground and underground parts were measured after 2 weeks.

[0069] <Gene activity evaluation> Tomato (variety: Regina) seeds were sown on a water-soaked Kimwipe placed in a petri dish and germinated in an artificial climate chamber. The sown tomatoes were cultivated in the artificial climate chamber (7:00 AM - 8:00 AM 20°C, 8:00 AM - 9:00 AM 22.5°C, 9:00 AM - 7:00 PM 25°C, 12 hours of light; 60% humidity, 7:00 PM - 7:00 AM 12 hours of darkness; 16°C; 60% humidity). After two weeks, the germinated seedlings were transplanted into Jiffy containers and continued to be cultivated in the artificial climate chamber. Tomato seedlings that were 70 days old and had about 6 true leaves were selected, and 10 μM of the plant growth composition (A1), which had been tested for peptide retention (after 9 weeks of standing), was foliar-sprayed at a concentration of 2.1 mL / plant on day 0 and 1 week after the start of the experiment. Two days after spraying (45-48 hours later), two young leaves and two newer leaves of the tomato plants were punched out and collected.

[0070] The effect of dispersing fusion peptides on increasing stomatal density was evaluated by measuring the gene expression level of TOO MUCH MOUTH (TMM). The Eppendorf tubes containing the tomato leaves collected as described above were frozen with liquid nitrogen and thoroughly crushed with a pestle until the leaves became powdery. 20-100 mg of the powdered leaves were transferred to 1.5 mL centrifuge tubes, and RNA was extracted using the Maxwell® RSC Plant RNA kit from Promega. The RNA concentration was determined by absorbance (A260).

[0071] For the evaluation of TMM gene expression levels, RNA-direct® SYBR™ Green Realtime PCR Master Mix (manufactured by Toyobo Co., Ltd.) was used, and qRT-PCR was performed using a PCR system (Thermo Fisher Scientific QuantStudio® 3 real-time PCR system). The Actin gene was used as an internal standard. Using the Ct values ​​obtained by qRT-PCR, gene expression levels were compared with the control group using the ΔΔCt method. The primer sequences used are as follows.

[0072] The ability to confer salt tolerance and other resistances through fusion peptide dispersal was evaluated by measuring the gene expression level of sucrose transporter 1 (SUT1). The Eppendorf tubes containing the tomato leaves collected as described above were frozen with liquid nitrogen and thoroughly crushed with a pestle until the leaves became powdery. 20-100 mg of the powdered leaves were transferred to 1.5 mL centrifuge tubes, and RNA was extracted using the Maxwell® RSC Plant RNA kit from Promega. The RNA concentration was determined by absorbance (A260).

[0073] For evaluating the gene expression level of SUT1, RNA-direct(registered trademark) SYBR TMWe performed qRT-PCR using Green Realtime PCR Master Mix (manufactured by Toyobo Co., Ltd.) and a PCR system (QuantStudio® 3 real-time PCR system manufactured by Thermo Fisher Scientific). The Actin gene was used as the internal standard. Using the Ct values ​​obtained by qRT-PCR, we compared gene expression levels with the control group using the ΔΔCt method. The primer sequences used are as follows.

[0074] SlTMM_Fw : cggactccggtgctctagtc (Sequence ID 16) SlTMM_Rv : cgaccacgacaaacatcagg (Sequence ID 17) SlSUT1_Fw : AACTCCCGGAGAAAGAAGAG (Sequence ID 18) SlSUT1_Rv : TACAGTTTCGCATCACCGAC (Sequence ID 19) SlActin_Fw : GGGATGGAGAAGTTTGGTGGTGG (Sequence ID 20) SlActin_Rv : CTTCGACCAAGGGATGGTGTAGC (Sequence ID 21)

[0075] TMM gene evaluation conducted two days after spraying revealed a 1.44-fold increase in gene expression compared to the control group sprayed with water (where expression level is set to 1). Therefore, it was confirmed that Stomagen activity was not lost even after the 9-week stability test.

[0076] SUT1 gene evaluation conducted two days after spraying revealed a 1.32-fold increase in gene expression compared to the control group sprayed with water (where expression level is set to 1). Therefore, it was confirmed that Stomagen activity was not lost even after the 9-week stability test.

[0077] <Examples 2-20 and Comparative Examples 1-4> Except for changing the mixing ratios of various materials as shown in Table 1, plant growth compositions (A2) to (A20) for Examples 2 to 9 and plant growth compositions (A'1) to (A'4) for Comparative Examples 1 to 4 were prepared in the same manner as in Example 1 and evaluated in the same manner as plant growth composition (A1). The results are shown in Table 1. The compounds used were those listed in Table 1. • Potassium sorbate (manufactured by Tokyo Chemical Industry Co., Ltd.) • Potassium gluconate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) • Sodium benzoate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) • Sodium dehydroacetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) • Benzoic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) • Ammonium dihydrogen phosphate (manufactured by Fujifilm Wako Pure Chemical Corporation) • Potassium dihydrogen phosphate (manufactured by Fujifilm Wako Pure Chemical Corporation)

[0078] [Table 1-1]

[0079] [Table 1-2] [Industrial applicability]

[0080] This invention is useful in the fields of agriculture, horticulture, and other areas. Furthermore, it is considered possible to apply it to uses other than plant growth (for example, for animals, microorganisms, and pharmaceuticals).

Claims

1. A fusion peptide or a salt thereof, or a solvate thereof, comprising a tag peptide and one of the peptides (A1) to (A3) below, from the amino terminus to the carboxyl terminus, A plant growth composition containing a preservative, The aforementioned preservative is one or more selected from the group consisting of potassium pyrosulfite, potassium sorbate, potassium gluconate, and sodium benzoate. A plant growth composition wherein the total weight percentage of the preservative in the plant growth composition is 0.5 to 5% by weight, based on the weight of the plant growth composition. (A1) A peptide consisting of the amino acid sequence shown in SEQ ID NO: 1 (A2) A peptide consisting of an amino acid sequence in which 1 to 4 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No.

1. (A3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in Sequence ID No.

1.

2. The plant growth composition according to claim 1, further comprising one or more selected from the group consisting of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and potassium benzoate, wherein the total weight percentage thereof is 0.1 to 5% by weight based on the weight of the plant growth composition.

3. The plant growth composition according to claim 1, wherein the tag peptide is one or two peptides selected from the group consisting of (B1) to (B3), (C1) to (C3), (D1) to (D3), and (E1) to (E3). (B1) A peptide consisting of the amino acid sequence shown in SEQ ID NO: 2 (B2) A peptide consisting of an amino acid sequence in which one or two amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No.

2. (B3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in Sequence ID No.

2. (C1) Peptide consisting of the amino acid sequence shown in SEQ ID NO: 3 (C2) A peptide consisting of an amino acid sequence in which 1 to 6 amino acids are deleted, substituted, or added in the amino acid sequence shown in SEQ ID NO:

3. (C3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO:

3. (D1) A peptide consisting of the amino acid sequence shown in SEQ ID NO: 4 (D2) A peptide consisting of an amino acid sequence in which 1 to 11 amino acids are deleted, substituted, or added in the amino acid sequence shown in SEQ ID NO:

4. (D3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in Sequence ID No.

4. (E1) A peptide consisting of the amino acid sequence shown in Sequence ID No.

5. (E2) A peptide consisting of an amino acid sequence in which 1 to 5 amino acids are deleted, substituted, or added in the amino acid sequence shown in Sequence ID No.

5. (E3) A peptide consisting of an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in Sequence ID No. 5.

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