Grafting improvement agent

Abstract

The present invention addresses the problem of providing a grafting-improving agent, and the problem can be solved by a grafting-improving agent comprising at least one component selected from the group consisting of (a) Nicotiana benthamiana β-1,4-glucanase comprising the amino acid sequence A represented by SEQ ID NO: 1, (b) a β-1,4-glucanase comprising an amino acid sequence B for a β-1,4-glucanase gene belonging to a clade including only a gene for the amino acid sequence A among Nicotiana benthamiana genes in a plant gene tree, (c) a β-1,4-glucanase comprising an amino acid sequence C that has a 90% or higher identity with the amino acid sequence A or the amino acid sequence B, and (d) an expression promotor for the Nicotiana benthamiana β-1,4-glucanase (a), the β-1,4-glucanase (b) or the β-1,4-glucanase (c).

Description

[Technical Field] 【0001】 This invention relates to grafting improvement agents, etc. [Background technology] 【0002】 Grafting is a technique that surgically fuses two or more plants into one. Grafting is generally performed on gymnosperms and angiosperms and is widely used in horticulture and agriculture. Generally, grafting involves creating a plant that combines the superior abilities of both the rootstock (which forms the root system) and the scion (which forms the above-ground part). The purposes and methods of grafting are diverse. For example, branch mutations and new varieties of fruit trees are often propagated clonally through grafting. In addition, in vegetables such as those in the Solanaceae and Cucurbitaceae families, utilizing useful root systems through grafting has been achieved to acquire disease resistance and improve the quality and productivity of fruits and other produce. [Prior art documents] [Non-patent literature] 【0003】 [Non-Patent Document 1] Simon, SV Jahrb. wiss. Bot., 1930. 72, 137-160. [Non-Patent Document 2] Nickell LG, Science, 1948. 108. 389. [Overview of the project] [Problems that the invention aims to solve] 【0004】 However, it is known that grafting can be hampered by a phenomenon called graft incompatibility, where grafting fails or is infrequently successful depending on the combination of plants, and this has been a technical limiting factor. Generally, grafting becomes less successful between plants of the same species, then within the same genus, and then within the same family. Although there have been exceptional cases of grafting between plants of different families (Non-Patent Documents 1 and 2), the combinations of different families that can be grafted are limited. Furthermore, even within the same family, the problem of graft incompatibility exists. 【0005】 In the course of research focusing on the above-mentioned problems, the present invention realized that any substance having a grafting-improving effect that enhances grafting efficiency, etc., could solve the above problems. 【0006】 Therefore, the object of the present invention is to provide a grafting improvement agent. [Means for solving the problem] 【0007】 The inventors diligently conducted research despite the many unknown aspects of the grafting mechanism. As a result, they found that the above problem can be solved with a grafting improvement agent containing at least one selected from the group consisting of (a) β-1,4-glucanase containing amino acid sequence A shown in Sequence ID No. 1, (b) β-1,4-glucanase containing amino acid sequence B of a β-1,4-glucanase gene belonging to a clade in the plant gene phylogenetic tree that contains only the gene with amino acid sequence A among the β-1,4-glucanase genes, (c) β-1,4-glucanase containing amino acid sequence C having 90% or more identity with amino acid sequence A or amino acid sequence B, and (d) an expression promoter of β-1,4-glucanase (a), β-1,4-glucanase (b), or β-1,4-glucanase (c). Based on this finding, the inventors furthered their research and completed the present invention. 【0008】 In other words, the present invention encompasses the following aspects. 【0009】 Item 1. (a) Benthamiana tobacco β-1,4-glucanase containing amino acid sequence A shown in Sequence ID No. 1, (b) In the plant gene phylogenetic tree, a β-1,4-glucanase gene containing amino acid sequence B, belonging to a clade that includes only the gene with amino acid sequence A in the tobacco benthamiana gene, (c) β-1,4-glucanase comprising an amino acid sequence C having 90% or more identity with the amino acid sequence A or the amino acid sequence B, and (d) An agent that promotes the expression of benthamiana tobacco β-1,4-glucanase (a), β-1,4-glucanase (b), or β-1,4-glucanase (c). A grafting improvement agent containing at least one selected from the group consisting of the following. 【0010】 Item 2. A grafting agent as described in Item 1, for use in grafting within the same family or in grafting with different families. 【0011】 Item 3. The grafting improvement agent according to item 1 or 2, wherein the expression promoter (d) is an expression cassette. 【0012】 Item 4. The grafting improvement agent according to any one of items 1 to 3, wherein the amino acid sequence B is the amino acid sequence shown in any of sequence numbers 2 to 14. 【0013】 Item 5. A method for producing a plant body or plant substructure for grafting, comprising applying or introducing a grafting improvement agent described in any of Items 1 to 4 to a plant body or plant substructure. 【0014】 Item 6. A plant body or plant substructure for grafting obtained by the method described in Item 5. 【0015】 Item 7. A method for producing a grafted plant, comprising applying or introducing a grafting improvement agent described in any of Items 1 to 4 to the grafted plant, and / or grafting a grafted plant or grafted plant substructure described in Item 6 with another plant or another plant substructure. 【0016】 Item 8. A grafted plant body obtained by the method according to Item 7. 【0017】 Item 9. (a) A Nicotiana benthamiana β-1,4-glucanase containing the amino acid sequence A shown in SEQ ID NO: 1, (b) A β-1,4-glucanase containing the amino acid sequence B of a β-1,4-glucanase gene belonging to a clade containing only the gene of the amino acid sequence A among Nicotiana benthamiana genes in a plant gene phylogenetic tree, (c) A β-1,4-glucanase containing an amino acid sequence C having 90% or more identity to the amino acid sequence A or the amino acid sequence B, and (d) An expression promoter of the Nicotiana benthamiana β-1,4-glucanase (a), the β-1,4-glucanase (b), or the β-1,4-glucanase (c) Use of at least one selected from the group consisting of for improving grafting. 【0018】 Item 10. (a) A Nicotiana benthamiana β-1,4-glucanase containing the amino acid sequence A shown in SEQ ID NO: 1, (b) A β-1,4-glucanase containing the amino acid sequence B of a β-1,4-glucanase gene belonging to a clade containing only the gene of the amino acid sequence A among Nicotiana benthamiana genes in a plant gene phylogenetic tree, (c) A β-1,4-glucanase containing an amino acid sequence C having 90% or more identity to the amino acid sequence A or the amino acid sequence B, and (d) An expression promoter of the Nicotiana benthamiana β-1,4-glucanase (a), the β-1,4-glucanase (b), or the β-1,4-glucanase (c) Use of at least one selected from the group consisting of for the production of a grafting improver. 【0019】 Item 11. (a) A Nicotiana benthamiana β-1,4-glucanase containing the amino acid sequence A shown in SEQ ID NO: 1, (b) In the plant gene phylogenetic tree, a β-1,4-glucanase gene containing amino acid sequence B, belonging to a clade that includes only the gene with amino acid sequence A in the tobacco benthamiana gene, (c) β-1,4-glucanase comprising an amino acid sequence C having 90% or more identity with the amino acid sequence A or the amino acid sequence B, and (d) An agent that promotes the expression of benthamiana tobacco β-1,4-glucanase (a), β-1,4-glucanase (b), or β-1,4-glucanase (c). A grafting improvement method comprising applying or introducing at least one selected from the group consisting of the following to a plant body or plant substructure. [Effects of the Invention] 【0020】 According to the present invention, a grafting improvement agent can be provided. Furthermore, according to the present invention, it is also possible to provide grafting plant tissue and a method for producing the same, grafted plants and a method for producing the same, etc., utilizing the grafting improvement agent. [Brief explanation of the drawing] 【0021】 [Figure 1] Figure 1A shows the plant phylogenetic tree created in Experimental Example 2. The clade enclosed by the dotted line is the clade identified as a result of the phylogenetic analysis in Experimental Example 2, containing only the Niben101Scf01180g16001 gene of the glycoside hydrolase 9B family from Nicotiana benthamiana (Nb). Figure 1B is a magnified view of the clade enclosed by the dotted line in Figure 1A. [Figure 2] The transcriptome analysis results of the Nb gene (Niben101Scf01180g16001) in Nb / Nb grafts and Nb / At grafts are shown (Experiment Example 2). The vertical axis shows FPMK (Fragments per Kilobase per Million-read). In the horizontal axis, control represents the ungrafted sample, and 1d, 3d, and 7d represent the number of days elapsed since grafting. [Figure 3]The transcriptome analysis results of the Gm gene (GLYMA04G12290.1) in Gm / Gm grafting are shown (Experiment Example 2). The vertical and horizontal axes are the same as in Figure 2. [Figure 4] The transcriptome analysis results for the In gene (INIL08g27364.t1) in In / In grafting are shown (Experiment Example 2). The vertical and horizontal axes are the same as in Figure 2. [Figure 5] The transcriptome analysis results of the Pj gene (Pjv1_00028629-RA) in Pj / Pj grafts and Pj / At grafts are shown (Experiment Example 2). The vertical and horizontal axes are the same as in Figure 2. [Figure 6] The transcriptome analysis results of the At gene (AT1G71380.1) in At / At grafting are shown (Experiment Example 2). The vertical and horizontal axes are the same as in Figure 2. [Figure 7] The scheme and results of Test Example 4-1 are shown. A shows a schematic diagram of grafting. B shows photographs of successful grafting (○) and unsuccessful grafting (×). C shows the relative amount of Niben101Scf01180g16001 mRNA at the graft site (vertical axis). On the horizontal axis, No graft represents ungrafted samples, No virus represents grafted samples without virus introduction, Vector control represents grafted samples with control virus introduction, and VIGS for Cellulase represents samples in which Niben101Scf01180g16001 was knocked down by virus introduction. D shows the grafting success rate, with the horizontal axis being the same as in C. [Figure 8] The results of Test Example 4-2 are shown. The vertical axis shows the grafting success rate. The horizontal axis shows the scion plants, with WT representing wild plants and BG KO representing Niben101Scf01180g16001 destroyed plants. * indicates that the P-value compared to WT is less than 0.05. [Figure 9]The results for Test Example 4-3 are shown. The vertical axis shows the ratio of shoot weights (grafted / ungrafted). The horizontal axis shows the plants used for grafting, with WT representing the wild-type plant and cel3 representing the Cel3 gene-deficient plant. #1 and #2 represent different plants, respectively. * indicates a P-value less than 0.05 compared to WT, and ** indicates a P-value less than 0.01 compared to WT. [Figure 10] The results of Test Example 5-1 are shown. The vertical axis represents adhesive strength. The horizontal axis represents the graft combination. [Figure 11] The results of Test Example 5-2 are shown. The vertical axis represents the adhesive strength, and the horizontal axis represents the graft combination. [Figure 12] The results of Test Example 5-3 are shown. A represents the grafting success rate, and B represents the shoot weight ratio (grafted / ungrafted). WT represents the case where wild plants were grafted together, while BG-OX and OX represent the case where Arabidopsis thaliana plants overexpressing Niben101Scf01180g16001 were grafted together. In A, * indicates that the P-value compared to WT is less than 0.05. [Modes for carrying out the invention] 【0022】 In this specification, the terms “contains” and “includes” include the concepts of “contains,” “includes,” “substantially consist of,” and “consist solely of.” 【0023】 1.Definition In this specification, the terms “contains” and “includes” include the concepts of “contains,” “includes,” “substantially consist of,” and “consist solely of.” 【0024】 In this specification, "and / or" is a term that encompasses both "and" and "or." That is, A and / or B encompasses three meanings: A only, B only, and A and B. 【0025】 In this specification, "identity" of amino acid sequences refers to the degree of agreement between two or more comparable amino acid sequences. Therefore, the higher the agreement between two amino acid sequences, the higher their identity or similarity. The level of amino acid sequence identity can be determined, for example, using the sequence analysis tool FASTA with default parameters. Alternatively, it can be determined using the BLAST algorithm by Karlin and Altschul (Karlin S, Altschul SF. "Methods for assessing the statistical significance of molecular sequence features by using general scoring schemes" Proc Natl Acad Sci USA. 87:2264-2268 (1990), Karlin S, Altschul SF. "Applications and statistics for multiple high-scoring segments in molecular sequences." Proc Natl Acad Sci USA. 90:5873-7 (1993)). Programs called blastp and tblastn have been developed based on this BLAST algorithm. The specific methods for these analyses are publicly known and can be found on the National Center of Biotechnology Information (NCBI) website (http: / / www.ncbi.nlm.nih.gov / ). Furthermore, the "identity" of the base sequence is defined in accordance with the above. 【0026】 In this specification, "conservative substitution" means that an amino acid residue is substituted for an amino acid residue having a similar side chain. For example, substitutions between amino acid residues having basic side chains, such as lysine, arginine, and histidine, are considered conservative substitutions. Other examples of conservative substitutions include amino acid residues with acidic side chains, such as aspartic acid and glutamic acid; amino acid residues with non-charged polar side chains, such as glycine, asparagine, glutamine, serine, threonine, tyrosine, and cysteine; amino acid residues with non-polar side chains, such as alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, and tryptophan; amino acid residues with β-branched side chains, such as threonine, valine, and isoleucine; and amino acid residues with aromatic side chains, such as tyrosine, phenylalanine, tryptophan, and histidine. 【0027】 In this specification, proteins such as β-1,4-glucanase may be chemically modified, provided that their activity is not significantly impaired. Proteins and peptides have a carboxyl group (-COOH) or carboxylate (-COO) at their C-terminus. - ), amide (-CONH2), or ester (-COOR) may be any of these. Here, R in the ester is, for example, C such as methyl, ethyl, n-propyl, isopropyl, n-butyl. 1-6 Alkyl groups; for example, cyclopentyl, cyclohexyl, etc. 3-8 Cycloalkyl groups; for example, phenyl, α-naphthyl, etc. 6-12 Aryl group; for example, phenyl-C such as benzyl and phenethyl. 1-2 Alkyl groups; such as α-naphthylmethyl and α-naphthyl-C 1-2 C such as alkyl groups 7-14An aralkyl group; a pivaloyloxymethyl group or the like is used. For proteins and peptides, carboxyl groups (or carboxylates) other than the C-terminus may be amidated or esterified. As the ester in this case, for example, the above-described ester at the C-terminus is used. Further, for proteins and peptides, the amino group of the N-terminal amino acid residue may be protected with a protecting group (for example, a C 1-6 alkanoyl such as C 1-6 acyl group or the like), the N-terminal glutamine residue that can be generated by cleavage in vivo is pyroglutaminated, substituents on the side chains of amino acids in the molecule (for example, -OH, -SH, amino group, imidazole group, indole group, guanidino group, etc.) are protected with appropriate protecting groups (for example, a C 1-6 alkanoyl group such as C 1-6 acyl group or the like), or complex proteins / peptides such as so-called glycoproteins / peptides to which sugar chains are bound are also included. 【0028】 In this specification, proteins such as β-1,4-glucanase may have other amino acid sequences added as long as their activities are not significantly impaired. Examples of other sequences include various signal sequences (for example, nuclear translocation signals, nuclear export signals, etc.), protein tags (for example, biotin, His tag, FLAG tag, Halo tag, MBP tag, HA tag, Myc tag, V5 tag, PA tag, etc.), labeled protein sequences (for example, fluorescent proteins, luminescent enzyme proteins, etc.), protein destabilizing sequences (for example, PEST sequences, etc.), protein stabilizing sequences, and the like. 【0029】 In this specification, the "coding sequence" is a base sequence that encodes the amino acid sequence of a protein, and is not particularly limited as long as it is so. 【0030】 In this specification, polynucleotides may be single-stranded or double-stranded. They may also be linear or cyclic. Furthermore, the polynucleotides of the present invention include not only DNA and RNA, but also those that have been chemically modified as shown below. To prevent degradation by hydrolytic enzymes such as nucleases, the phosphate residue of each nucleotide may be replaced with a chemically modified phosphate residue such as phosphorothioate (PS), methylphosphonate, or phosphorodithionate. In addition, the hydroxyl group at position 2 of the sugar (ribose) of each ribonucleotide may be replaced with -OR (where R represents, for example, CH3(2'-O-Me), CH2CH2OCH3(2'-O-MOE), CH2CH2NHC(NH)NH2, CH2CONHCH3, CH2CH2CN, etc.). Furthermore, the base portion (pyrimidine, purine) may be chemically modified, for example, by introducing a methyl group or cationic functional group at the 5th position of the pyrimidine base, or by substituting the carbonyl group at the 2nd position with a thiocarbonyl group. In addition, the phosphate portion or hydroxyl portion may be modified with, for example, biotin, an amino group, a lower alkylamine group, or an acetyl group, but is not limited to these. Also, the term "polynucleotide" includes not only natural nucleic acids but also BNA (Bridged Nucleic Acid), LNA (Locked Nucleic Acid), PNA (Peptide Nucleic Acid), etc. 【0031】 In this specification, proteins such as β-1,4-glucanase and polynucleotides may be in the form of pharmaceutically acceptable salts with acids or bases. The salts are not particularly limited as long as they are agriculturally acceptable salts. Both acidic and basic salts can be used. Examples of acidic salts include inorganic acid salts such as hydrochloride, hydrobromide, sulfate, nitrate, and phosphate; organic acid salts such as acetate, propionate, tartrate, fumarate, maleate, malate, citrate, methanesulfonate, and p-toluenesulfonate. Examples of basic salts include alkali metal salts such as sodium and potassium salts; alkaline earth metal salts such as calcium and magnesium salts; salts with ammonia; and salts with organic amines such as morpholine, piperidine, pyrrolidine, monoalkylamine, dialkylamine, trialkylamine, mono(hydroxyalkyl)amine, di(hydroxyalkyl)amine, and tri(hydroxyalkyl)amine. 【0032】 In this specification, proteins such as β-1,4-glucanase and polynucleotides may be in the form of solvates. The solvent is not particularly limited as long as it is agriculturally acceptable, and examples include water, ethanol, glycerol, and acetic acid. 【0033】 In this specification, proteins such as β-1,4-glucanase and polynucleotides may have functional substances attached to them. The functional substances are not particularly limited and include, for example, labeling substances and carriers. Functional substances are usually linked directly or indirectly (for example, via linkers) to proteins and polynucleotides. Examples of labeling substances include fluorescent substances (e.g., fluorescein, rhodamine, Texas Red, tetramethylrhodamine, carboxyrhodamine, phycoerythrin, 6-FAM(trademark), Cy(registered trademark)3, Cy(registered trademark)5, Alexa Fluor(registered trademark) series, etc.) and enzymes (e.g., β-galactosidase, alkaline phosphatase, glucose oxidase, peroxidase, polyphenol oxidase, etc.). The carriers are not particularly limited as long as they can support polypeptides and polynucleotides. The material of the carriers is not particularly limited and includes, for example, organic materials such as various resins, and inorganic materials such as silicon materials and metals. 【0034】 2. Grafting Improvement Agent In one aspect, the present invention relates to a grafting improvement agent (sometimes referred to as "the grafting improvement agent of the present invention") that contains at least one selected from the group consisting of (a) β-1,4-glucanase of tobacco benthamiana containing amino acid sequence A as shown in Sequence ID No. 1, (b) β-1,4-glucanase of a β-1,4-glucanase gene belonging to a clade in a plant gene phylogenetic tree that contains only the gene with amino acid sequence A among the tobacco benthamiana genes, (c) β-1,4-glucanase containing amino acid sequence C having 90% or more identity with amino acid sequence A or amino acid sequence B, and (d) an expression promoter of tobacco benthamiana β-1,4-glucanase (a), β-1,4-glucanase (b), or β-1,4-glucanase (c). This will be described below. 【0035】 Benthamiana tobacco β-1,4-glucanase (a) is not particularly limited as long as it contains amino acid sequence A shown in SEQ ID NO: 1 (the amino acid sequence of the Niben101Scf01180g16001 gene), and may contain other amino acid sequences in addition to amino acid sequence A. Other amino acid sequences include those described in "1. Definition" above. The coding sequence for amino acid sequence A is the base sequence A shown in SEQ ID NO: 15 (the coding sequence of the Niben101Scf01180g16001 gene). 【0036】 β-1,4-glucanase(b) includes amino acid sequence B of the β-1,4-glucanase gene belonging to a clade in the plant gene phylogenetic tree that includes only the gene with amino acid sequence A in the tobacco benthamiana gene, and is not particularly limited in this respect, and may include other amino acid sequences in addition to amino acid sequence B. Examples of other amino acid sequences include the other amino acid sequences described in "1. Definitions" above. 【0037】 A plant gene phylogenetic tree can be created by preparing the gene sequences and using CLUSTAL 2.1 Multiple Sequence Alignments via biopython1.70 from Python 3.7.4, with default settings. 【0038】 In the constructed phylogenetic tree, the amino acid sequence of the β-1,4-glucanase gene belonging to the largest clade (i.e., the largest clade that does not contain any other β-1,4-glucanase family genes besides Niben101Scf01180g16001) among the Benthamiana tobacco genes (e.g., β-1,4-glucanase family genes, preferably Glycosyl hydrolase 9B family genes) is amino acid sequence B. 【0039】 The Glycosyl hydrolase 9B family gene in Citrus benthamiana is the gene with amino acid sequence A (Niben101Scf01180g16001), Glycosyl hydrolase The 9B family genes are Niben101Scf00023g05010, Niben101Scf05692g04001, Niben101Scf08133g00002, Niben101Scf12797g00006, Niben101Scf08411g00019, Niben101Scf03735g03012, Niben101Scf09458g00004, Niben101Scf03735g03010, Niben101Scf06267g03017, Niben101Scf00152g25013, and Niben101Scf11743g00009. 【0040】 The plant from which amino acid sequence B is derived is not particularly limited, as long as it is a plant other than tobacco. Preferred sources include plants of the Solanaceae, Brassicaceae, Cucurbitaceae, Lamiaceae, Orobanchaceae, Vitaceae, Rutaceae, etc., that can be grafted, but are not limited to these. 【0041】 The Solanaceae family is not particularly limited and includes, for example, the genera Tobacco, Anthocercis, Anthotroche, Crenidium, Cyphanthera, Duboisia, Grammosolene, Symonanthus, Petunia, Benthamiella, Bouchetia, Brunfelsia, Combera, Fabiana, and Fungi. Examples of plants belonging to the genera include Hunzikeria, Leptoglossis, Nierembergia, Pantacantha, Calibrachoa, Plowmania, Capsicum, Lycianthes, Solanum, Jaltomata, Datura, Datura stramonium, Physalis, Physalis, Physalis genus, Scopolia, Hemerocallis, Belladonna, Mandragora, Goji berry, and Calibrachoa.Among these, the genera include Tobacco, Anthocercis, Anthotroche, Crenidium, Cyphanthera, Duboisia, Grammosolen, Symonanthus, Petunia, Benthamiella, Bouchetia, Brunfelsia, and Combera. The genera Fabiana, Hunzikeria, Leptoglossis, Nierembergia, Pantacantha, Calibrachoa, Plowmania, Capsicum, Lycianthes, Solanum, and Jaltomata are preferred, Tobacco, Petunia, Capsicum, and Solanum are more preferred, and Tobacco is even more preferred. 【0042】 The plants belonging to the genus Nicotiana are not particularly limited, and examples include Nicotiana tabacum, Nicotiana umbratica, Nicotiana rustica, Nicotiana acuminata, Nicotiana alata, Nicotiana attenuata, Nicotiana clevelandii, Nicotiana excelsior, Nicotiana forgetiana, Nicotiana glauca, Nicotiana glutinosa, Nicotiana langsdorffii, Nicotiana longiflora, Nicotiana obtusifolia, Nicotiana paniculata, Nicotiana plumbagifolia, Nicotiana quadrivalvis, Nicotiana repanda, Nicotiana suaveolens, Nicotiana sylvestris, and Nicotiana tomentosa. Among these, Nicotiana tabacum, Nicotiana umbratica, and Nicotiana rustica are preferred. 【0043】 The plants belonging to the genus Petunia (or Petunia genus) are not particularly limited and include, for example, Petunia × atkinsiana (petunia), Petunia alpicola, Petunia axillaris, Petunia bajeensis, Petunia bonjardinensis, Petunia exserta, Petunia guarapuavensis, Petunia inflata, Petunia integrifolia, Petunia interior, Petunia ledifolia, Petunia littoralis, Petunia mantiqueirensis, Petunia occidentalis, Petunia patagonica, Petunia reitzii, Petunia riograndensis, Petunia saxicola, Petunia scheideana, and Petunia villadiana. Among these, Petunia × atkinsiana is preferred. 【0044】 The plants belonging to the genus Capsicum are not particularly limited and include, for example, Capsicum annuum L. (e.g., 'Grossum' (bell pepper), 'Abbreviatum', 'Acuminoum', 'Cerasiforme', 'Conoides', 'Fasciculatum', 'Longum', 'Nigrym', 'Parvo-acuminatum', etc.), Capsicum baccatum, Capsicum cardenasii, Capsicum chinense Jacq. Heser & Smith, Capsicum frutescens L., and Capsicum pubescens Ruiz & Pav., etc. Among these, Capsicum annuum L. is preferred, and Capsicum annuum L. 'Grossum' (bell pepper) is more preferred. 【0045】 Plants belonging to the genus Solanum are not particularly limited, and examples include Solanum lycopersicum L (tomato), Solanum melongena L (eggplant), Solanum tuberosum L, Solanum acaule Bitt, Solanum aethiopicum L, Solanum betaceum Cav, Solanum jasminoides Paxt, Solanum mammosum L, Solanum muricatum Aiton, Solanum nigrum L, Solanum pseudocapsicum L, and Solanum ptychanthum Dunal. Among these, Solanum lycopersicum L (tomato) and Solanum melongena L (eggplant) are preferred. 【0046】 The Brassicaceae family is not particularly limited and includes, for example, the genera Arabidopsis, Brassica, Capsella, Cardamine, Thuja, Thymus, Horseradish, Rorippa, Nasturtium, Rorippa, Leucanthemum, Scutellaria, Scutellaria, Leucanthemum, Scutellaria, Scutellaria, Scutellaria, Scutellaria, Scutellaria, Scutellaria, Scutellaria, and Scutellaria. Examples of plants belonging to the genera *Zishiro*, *Raphanus*, *Raphanus*, *Citrus*, *Citrus*, *Miyagara*, *Mustard*, *Wasabi*, *Tetramorium*, *Arabis*, *Purple Lasso*, *Dog's Tear*, *White Lasso*, *Alpinia*, *Tomosiris*, *Dwarf Wallflower*, *Mustard*, *Mustard*, *Raphanus*, *Horned Lasso*, and *Gouda* are examples. Among these, the genera Arabidopsis, Thaliana, Brassica, Thaliana, Rhapis excelsa, Raphanus, Raphanus genus, Mustard, Rorippa indica, Capsella, Cardamine, Horseradish, Rorippa indica, Nasturtium, and Rorippa indica are preferred, Arabidopsis, Brassica, Capsella, and Cardamine are more preferred, Arabidopsis and Brassica are even more preferred, and Arabidopsis is even more preferred. 【0047】 The plants belonging to the genus Arabidopsis are not particularly limited, and examples include Arabidopsis thaliana, Arabidopsis arenicola, Arabidopsis arenosa, Arabidopsis cebennensis, Arabidopsis croatica, Arabidopsis halleri, Arabidopsis lyrata, Arabidopsis neglecta, Arabidopsis pedemontana, and Arabidopsis suecica. Among these, Arabidopsis thaliana is preferred. 【0048】 Plants belonging to the genus Brassica are not particularly limited, and examples include Brassica Oleracea (e.g., broccoli, cauliflower, cabbage, etc.), Brassica Napus (e.g., rapeseed, etc.), Brassica Barrelieri, Brassica carinata, Brassica elongata, Brassica fruticulosa, Brassica juncea, Brassica narinosa, Brassica nigra, Brassica nipposinica, Brassica rapa, Brassica rupestris, and Brassica Tournefortii. Among these, Brassica Oleracea and Brassica Napus are preferred, Brassica Oleracea is more preferred, and broccoli is even more preferred. 【0049】 The genus Capsella is not particularly limited and includes, for example, Capsella rubella, Capsella abscissa, Capsella andreana, Capsella australis, Capsella austriaca, Capsella bursa-pastoris, Capsella divaricata, Capsella draboides, Capsella gracilis, Capsella grandiflora, Capsella humistrata, Capsella hybrida, Capsella hyrcana, Capsella integrifolia, Capsella lycia, Capsella mexicana, Capsella orientalis, Capsella pillosula, Capsella pubens, Capsella puberula, Capsella schaffneri, Capsella stellata, Capsella tasmanica, Capsella thomsoni, Capsella thracica, Capsella viguieri, and Capsella villosula. Among these, Capsella rubella is preferred. 【0050】 The plants belonging to the genus Cardamine are not particularly limited, and examples include Cardamine hirsuta, Cardamine anemonoides, Cardamine appendiculata, Cardamine arakiana, Cardamine dentipetala, Cardamine dentipetala var. longifructa, Cardamine fallax, Cardamine impatiens, Cardamine kiusiana, Cardamine leucantha, Cardamine lyrata, Cardamine niigatensis, Cardamine nipponica, Cardamine pratensis, Cardamine regeliana, Cardamine schinziana, Cardamine scutata, Cardamine tanakae, Cardamine torrentis, and Cardamine valida. Among these, Cardamine hirsuta is preferred. 【0051】 The Lamiaceae family is not particularly limited and includes, for example, the genera Lamiaceae, Lavandula, Callicarpa, Vitex, Cheek, Clerodendrum, Ajuga, Clerodendrum, Caryopteris, Mentha, Scutellaria, Elsholtzia, Lingonberry, Lamiaceae, Nelumbo, Oregano, Mentha, Glechoma, Glechoma, Willowherb, Prunella, Lycopodium, Lycopodium, Scutellaria, Mentha, Centaurea, Salvia, Trifolium, Rosemary, Thymus Examples include plants belonging to the genera Clinopodium, Mentha japonica, Ocimum sanguineum, Ocimum basil, Scutellaria indica, Stachyurus japonica, Lamium amplexicaule, Lamium purpureum, Thymus vulgaris, Lysimachia japonica, Leonurus chinensis, Leonurus chinensis, Mentha japonica, and Mentha japonica. Among these, the genera Lamiaceae, Lavandula, Lysimachia, Elsholtzia, Lamiaceae, Nepeta, Oregano, Mentha, Gentiana, Glechoma, Mentha, Prunella, Lysimachia, Lysimachia, Mentha, Salvia, Salvia, Rosmarinus, Thymus, Clinopodium, Mentha, Oenothera, Ocimum, Ocimum, and Ocimum, among others are preferred, Lamiaceae and Lavandula are more preferred, and Lamiaceae is even more preferred. 【0052】 The plants belonging to the genus Perilla are not particularly limited, and examples include Perilla frutescens (e.g., shiso, egoma, etc.). Among these, Perilla frutescens is preferred, and shiso is even more preferred. 【0053】 Plants belonging to the genus Lavandula are not particularly limited and include, for example, Lavandula angustifolia (lavender), Lavandula latifolia, Lavandula stoechas, Lavandula multifida, and Lavandula × intermedia. Among these, Lavandula angustifolia (lavender) is preferred. 【0054】 The Orobanchaceae family is not particularly limited and includes, for example, plants belonging to genera such as Pedicularis, Castilleja, Orthocarpus, Agalinis, Aureolaria, Esterhazya, Seymeria, Lamourouxia, Cordylanthus, Triphysaria, Orobanche, Orobanche, Orobanche, Euphrasia, Orobanche, Melampyrum, Gardenia, Artemisia, Pedicularis, Artemisia, and Striga. Among these, genera such as Pedicularis, Pedicularis, Castilleja, Orthocarpus, Agalinis, Aureolaria, Esterhazya, Seymeria, Lamourouxia, Cordylanthus, and Triphysaria are preferred, with Pedicularis being more preferred. 【0055】 The plants belonging to the genus Phtheirospermum are not particularly limited, and examples include Phtheirospermum japonicum, Phtheirospermum glandulosum, Phtheirospermum muliense, Phtheirospermum parishii, and Phtheirospermum tenuisectum. Among these, Phtheirospermum japonicum is preferred. 【0056】 The plants in the Vitaceae family are not particularly limited and include, for example, plants belonging to the genera Vitis, Vitis coignetiae, Cayratia, Cyphostemma, Ivy, and Celtis. Among these, the genus Vitis is preferred. 【0057】 Vitis acerifolia Raf., Vitis aestivalis Michx. Vitis aestivalis Michx. var. argentifolia (Munson ex LH Bailey) Fernald、Vitis aestivalis Michx. var. bourquiniana (Munson) Bailey、Vitis aestivalis Michx. var. smalliana (LH Bailey) Comeaux、Vitis aestivalis Michx. subsp. sola (LH Bailey) WM Rogers、Vitis amazonica (Linden) G. Nicholson、Vitis amurensis Rupr.、Vitis amurensis Rupr. var. dissecta Skvortsov、Vitis arizonica Engelm.、Vitis dancer Munson、Vitis balance Planch. Vitis balance Planch. var. ficifolioides (WT Wang) CL Li, Vitis bashanica PCHe, Vitis bellula (Rehder) WT Wang, Vitis berlandieri Planch., Vitis betulifolia Diels & Gilg, Vitis biformis Rose, Vitis bloodwothiana Comeaux, Vitis bourgaeana Planch Vitis bryoniifolia var. ternata (WT Wang) CL Li、Vitis californica Benth.、Vitis chontalensis Seem.、Vitis chunganensis Hu、Vitis chungii FP Metcalf、Vitis cinerea (Engelm.) Engelm. ex Millardet Vitis cinerea var.canescens (Engelm.) LH Bailey, Vitis cinerea var. helleri (LH Bailey) MO Moore, Vitis cissoides (Blume) Backer, Vitis coignetiae Pulliat ex Planch., Vitis cordifolia Lam. Vitis cordifolia var. solonis (Planch.) Planch., Vitis davidii (Rom.Caill.) Foex Vitis davidii var. cyanocarpa (Gagnep.) Sarg., Vitis enneaphylla (Vell.) Eichler, Vitis erythrophylla WT Wang, Vitis fengqinensis CL Li, Vitis ficifolia Bunge, Vitis heyneana subsp. ficifolia (Bunge) CL Li Vitis ficifolia Bunge var. izu-insularis (Tuyama) H.Hara, Vitis ficifolia Bunge var. ganebu Hatus., Vitis ficifolia var. lobata (Regel) Nakai, Vitis figariana (Webb) Baker, Vitis flexuosa Thunb., Vitis flexuosa Thunb. var. rufotomentosa (Makino) Murata, Vitis flexuosa Thunb. var. tsukubana Makino, Vitis girdiana Munson, Vitis hancockii Hance, Vitis heyneana Roem. & Schult. Vitis heyneana subsp. ficifolia (Bunge) CL Li, Vitis heyneana var. glabra (R. Parker) Naithani & Biswas, Vitis hui WC Cheng, Vitis jacquemontii R.Parker, Vitis jinggangensis WT Wang, Vitis jinzhaiensis XS Shen, Vitis labrusca L., Vitis labrusca f. alba (Prince) Fernald, Vitis labruscana LH Bailey, Vitis lanceolatifoliosa CL Li, Vitis linsecomii Buckley, Vitis longquanensis PL Chiu, Vitis luochengensis WT Wang, Vitis menghaiensis CL Li, Vitis mengziensis CL Li, Vitis monticola Buckley, Vitis mustangensis Buckley Vitis mustangensis var. diversa (LH Bailey) Shinners, Vitis nesbittiana Comeaux, Vitis × novae-angliae Fernald (pro sp.), Vitis papillosa (Blume) Backer, Vitis piasezkii Maxim., Vitis pilosonerva FP Metcalf, Vitis popenoei JL Fennell, Vitis pseudoreticulata WT Wang, Vitis pubescens (Schltdl.) Miq., Vitis quinqueangularis Rehder, Vitis retordii Rom. Caill. ex Planch., Vitis rhomboidea (E. Mey. ex Harv.) Szyszy., Vitis romanetii Rom. Caill., Vitis rotundifolia Michx., Vitis rufotomentosa Small, Vitis rupestris Scheele, Vitis rupestris f. dissecta (Eggert ex LH Bailey) Fernald, Vitis ruyuanensis CLLi, Vitis saccharifera Makino, Vitis shenxiensis CL Li, Vitis shuttleworthii House, Vitis silvestrii Pamp., Vitis sinocinerea WT Wang, Vitis sinuata (Pursh) G. Don, Vitis thunbergii Siebold & Zucc., Vitis thunbergii var. sinuata (Regel) Rehder, Vitis tiliifolia Humb. & Bonpl. ex Schult., Vitis treleasei Munson ex LH Bailey, Vitis tsoi Merr., Vitis tsukubana (Makino) Maekawa, Vitis unifoliata (Harv.) Kuntze, Vitis vinifera L., Vitis vinifera L. var. multiloba (Raf.) Kuntze, Vitis vinifera L. var. palmata (Vahl) Kuntze、Vitis vulpina L.、Vitis wenchowensis C. Ling、Vitis wilsoniae HJ Veitch、Vitis wuhanensis CL Li、Vitis yuenlingensis WT Wang、Vitis zhejiang-attastricta PL Chiu etc. 【0058】 The Rutaceae family is not particularly limited and includes, for example, the genera Citrus, Trifoliate Orange, Agathosma, Amyris, Asterorasia, Atalantia, Pineapple, White Iron, Boronia, Carodendrum, Choisia, Wanpi, Coreonema, Correa, Crowea, Cuspuria, Hakusen, Dictyoloma, Diosma, Eriostemon, Erythrochiton, Esenbecchia, and Ogasawaragoshi. Examples of plants include those belonging to the genera Citrus, Frindelsia, Fortunella, Galibera, Leptotylsa, Macrostylis, Awadan, Micromerum, Murraya, Zanthoxylum, Peltostigma, Febrile, Phellodendron, Pilocarpus, Trifoliate Orange, Hops, Lawenia, Rue, Skimmia, Evodia, Thamnus, Citrus, Weplis, and Zanthoxylum. Among these, the Citrus genus is preferred. 【0059】 Examples of plants belonging to the Citrus genus include Iyokan (Citrus iyo), Unshu mandarin (Citrus unshiu), orange (Citrus sinensis), Kabosu (Citrus sphaerocarpa), Kishu mandarin (Citrus kinokuni), Chinotto (Citrus chinotto), grapefruit (Citrus X paradisi), Koji (Citrus leiocarpa), Sanbokan (Citrus sulcata), Citron (Citrus medica), Jabara (Citrus jabara), Sudachi (Citrus sudachi), Daidai (Citrus aurantium), Tachibana (Citrus tachibana), Tangor (Citrus reticulata), Natsumikan (Citrus natsudaidai), Hassaku (Citrus Examples include hassaku, hanayu (Citrus hanayu), hyuga tama (Citrus tamurana), hiramile lemon (shikuwasa) (Citrus depressa), buntan (Citrus maxima), ponkan (mandarin orange) (Citrus reticulata), yuzu (Citrus junos), lime (Citrus aurantifolia), lemon (Citrus limon), and clementine. 【0060】 In addition to the seven families listed above (Solanaceae, Brassicaceae, Cucurbitaceae, Lamiaceae, Orobanchaceae, Vitaceae, and Rutaceae), there are also other families such as Malvaceae, Brassicaceae, Asteraceae, Salicaceae, Ranunculaceae, Lauraceae, Chloranthaceae, Saururaceae, Araceae, Lamiaceae, Violaceae, Apiaceae, Buxaceae, Ericaceae, Polygonaceae, and Amaranthaceae. Family: Convolvulaceae, Rosaceae, Sandalwoodaceae, Capranaceae, Geraniaceae, Fagaceae, Caprifoliaceae, Dipsacaceae, Fabaceae, Sapindaceae, Proteaceae, Saxifragaceae, Apocynaceae, Gentianaceae, Dryopteridaceae, Cupressaceae, Solanaceae, Pedagoaceae, Plantaginaceae, Orobanchaceae, Linderniaceae, Capranaceae, Calycera Examples of families include Goodeniaceae, Menyanthaceae, Stylidaceae, Polygalaceae, Surianaceae, Muntingiaceae, Cytinaceae, Dipterocarpaceae, Sarcolaenaceae, Russulaceae, Sphaeroceparaceae, Tetrameresaceae, Begoniaceae, Datiscaceae, Berberidaceae, Menispermaceae, Hybrinaceae, Stilbeaceae, Scrophulariaceae, Mazusaceae, Phrymaceae, Paulowniaceae, Piperaceae, Didymeraceae, Dryopteridaceae, Nephrolepidae, Polypodiaceae, Davalliaceae, Dryopteridaceae, Nephrolepidae, Polypodiaceae, Polypodiaceae, Davalliaceae, etc. 【0061】 For example, The amino acid sequence shown in SEQ ID NO: 2 (amino acid sequence of the AT1G71380.1 gene), the amino acid sequence shown in SEQ ID NO: 3 (amino acid sequence of the AT1G22880.1 gene), the amino acid sequence shown in SEQ ID NO: 4 (amino acid sequence of the GLYMA04G12290.1 ​​gene), the amino acid sequence shown in SEQ ID NO: 5 (amino acid sequence of the GLYMA06G48140.1 gene), the amino acid sequence shown in SEQ ID NO: 6 (amino acid sequence of the Zm00001d025475_T001 gene), the amino acid sequence shown in SEQ ID NO: 7 (amino acid sequence of the INIL08g27364.t1 gene), the amino acid sequence shown in SEQ ID NO: 8 (INIL12g24789.t Examples include the amino acid sequence of one gene), the amino acid sequence shown in SEQ ID NO: 9 (amino acid sequence of the Pjv1_00028629-RA gene), the amino acid sequence shown in SEQ ID NO: 10 (amino acid sequence of the Pjv1_00026451-RA gene), the amino acid sequence shown in SEQ ID NO: 11 (amino acid sequence of the Pjv1_00026452-RA gene), the amino acid sequence shown in SEQ ID NO: 12 (amino acid sequence of the Pjv1_00028828-RA gene), the amino acid sequence shown in SEQ ID NO: 13 (amino acid sequence of the Pjv1_00028626-RA gene), the amino acid sequence shown in SEQ ID NO: 14 (amino acid sequence of the LiPhGnB1_1726 gene), and so on. Among these, preferred examples include the amino acid sequence shown in SEQ ID NO: 2, the amino acid sequence shown in SEQ ID NO: 4, the amino acid sequence shown in SEQ ID NO: 7, the amino acid sequence shown in SEQ ID NO: 9, and so on. 【0062】 For example, the coding sequence for amino acid sequence B is The coding sequence shown in SEQ ID NO: 16 (coding sequence of the AT1G71380.1 gene), the coding sequence shown in SEQ ID NO: 17 (coding sequence of the AT1G22880.1 gene), the coding sequence shown in SEQ ID NO: 18 (coding sequence of the GLYMA04G12290.1 ​​gene), the coding sequence shown in SEQ ID NO: 19 (coding sequence of the GLYMA06G48140.1 gene), the coding sequence shown in SEQ ID NO: 20 (coding sequence of the Zm00001d025475_T001 gene), the coding sequence shown in SEQ ID NO: 21 (coding sequence of the INIL08g27364.t1 gene), the coding sequence shown in SEQ ID NO: 22 (INIL12g2478 Examples include the coding sequence of the t1 gene, the coding sequence shown in SEQ ID NO: 9.t1, the coding sequence of the Pjv1_00028629-RA gene (SEQ ID NO: 23), the coding sequence shown in SEQ ID NO: 24 (SEQ ID NO: 24), the coding sequence of the Pjv1_00026451-RA gene (SEQ ID NO: 25), the coding sequence of the Pjv1_00026452-RA gene (SEQ ID NO: 26), the coding sequence of the Pjv1_00028828-RA gene (SEQ ID NO: 27), the coding sequence of the Pjv1_00028626-RA gene (SEQ ID NO: 28), and the coding sequence of the LiPhGnB1_1726 gene (SEQ ID NO: 28). 【0063】 β-1,4-glucanase(c) includes, and is not particularly limited to, an amino acid sequence C having 90% or more identity with amino acid sequence A or the aforementioned amino acid sequence B. Examples of sequences other than amino acid sequence C include other amino acid sequences as described in "1. Definitions" above. 【0064】 The identity of β-1,4-glucanase(c) is preferably 95% or more, more preferably 97% or more, and particularly preferably 99% or more. β-1,4-glucanase(c) has graft-improving activity, similar to β-1,4-glucanase(a) and β-1,4-glucanase(b). Amino acid mutations in β-1,4-glucanase(c) include substitutions, deletions, insertions, and additions, preferably substitutions, more preferably conservative substitutions. In one embodiment, amino acid sequence C is amino acid sequence C' in which one or more amino acids (e.g., 2 to 20, preferably 2 to 10, more preferably 2 to 5, even more preferably 2 to 3, and even more preferably 2) are substituted, deleted, added, or inserted (preferably conservative substitutions) from amino acid sequence A or amino acid sequence B. In a preferred embodiment, β-1,4-glucanase(c) contains an amino acid sequence C'' which has 90% or more identity with the amino acid sequence shown in any of SEQ ID NOs: 1 to 14. 【0065】 The site of the amino acid mutation is preferably a site different from the pocket site (enzyme active site) where the enzyme takes up the substrate, which is a characteristic of the enzyme's function. Such a pocket site can be determined by structural prediction based on amino acid sequence information. 【0066】 The presence or absence of graft improvement activity can be evaluated using the test system described in Test Example 5 below. 【0067】 The expression promoter (d) is not particularly limited as long as it can promote the expression or production of benthamiana tobacco β-1,4-glucanase (a), β-1,4-glucanase (b), or β-1,4-glucanase (c) (in this specification, these three types of β-1,4-glucanase may be collectively referred to as "the β-1,4-glucanase of the present invention"). For example, an expression cassette of the β-1,4-glucanase of the present invention, or a gene for the β-1,4-glucanase of the present invention that is endogenous in the genome (by genome editing, etc.) in the genome sequence. Examples include polynucleotides such as promoters or cis-elements into which mutations have been introduced (mutations due to introduction of partial sequences, substitution of partial sequences, deletion of partial sequences, etc.), or polynucleotides for introducing such mutations (guide RNA or its expression cassette, donor DNA or its expression cassette), expression cassettes for transcriptional activators of the β-1,4-glucanase gene of the present invention, and expression or functional inhibitors of transcriptional repressors of the β-1,4-glucanase gene of the present invention (e.g., antibodies, siRNA expression cassettes, CRISPR / Cas system expression cassettes, etc.). 【0068】 The expression cassette is not particularly limited as long as it is a polynucleotide capable of expressing a desired protein or peptide (such as a biosynthesis-related gene for components A, B, and C) in a plant, or in a microorganism or virus that can survive within a plant. A typical example of an expression cassette is a polynucleotide comprising a promoter and a coding sequence for the desired protein or peptide placed under the control of the promoter. 【0069】 There are no particular restrictions on the promoters used, and examples include the RPS5A (ribosomal protein) promoter, UBQ (ubiquitin) promoter, ACT (actin) promoter, tubulin promoter, histone promoter, 35S promoter, NOS promoter, WOX promoter, LAT52 promoter, DUO promoter, and plant virus subgenomic promoter. 【0070】 Expression cassettes may contain other nucleotide sequences besides those mentioned above. Other nucleotide sequences include, for example, drug resistance genes, reporter protein coding sequences, their expression cassettes; transcription termination signals; protein tag coding sequences; signal sequence coding sequences; origins of replication; and elemental sequences of binary vectors used in Agrobacterium assays (e.g., left boundary region, right boundary region, etc.). 【0071】 The expression cassette may constitute a vector. The type of vector is not particularly limited and examples include plasmid vectors; Agrobacterium vectors; and plant virus vectors such as tobacco mosaic virus, cucumber mosaic virus, African cassava mosaic virus, apple microglobulin latent virus, barley spotted leaf mosaic virus, bean pod mottle virus, beet curly top virus, brome mosaic virus, cabbage leaf curl virus, cotton leaf crumple virus, cymbidium mosaic virus, grape A virus, pea early browning virus, poplar mosaic virus, potato X virus, rice tungro bacilliform virus, satellite tobacco mosaic virus, tobacco curly shoot virus, and tobacco stem necrosis virus. In addition to vectors suitable for introduction into plants or plant cells, as described above, vectors for transferring expression cassettes into such vectors (e.g., entry clone vectors for gateways®) can also be cited as an example. 【0072】 The grafting improvement agent of the present invention contains at least one selected from the group consisting of tobacco benthamiana β-1,4-glucanase (a), β-1,4-glucanase (b), β-1,4-glucanase (c), and expression promoter (d) as an active ingredient. More specifically, the grafting improvement agent of the present invention can be used, for example, to improve grafting efficiency, to improve grafting success rate, to improve graft compatibility, to improve grafting establishment speed, to reduce grafting failure rate, and for producing grafting plants or grafting plant substructures with improved grafting efficiency, etc. 【0073】 In one embodiment of the present invention, the grafting improvement agent of the present invention can be used for grafting within the same family or across different families. 【0074】 The plants to which the grafting improvement agent of the present invention can be applied are not particularly limited. For example, it can be widely applied to plants such as angiosperms (dicotyledonous plants, monocotyledonous plants, etc.), gymnosperms, and ferns. 【0075】 The target plants, from the perspective of plant classification, include, for example, Malvaceae, Brassicaceae, Asteraceae, Salicaceae, Ranunculaceae, Lauraceae, Chloranthaceae, Saururaceae, Araceae, Lamiaceae, Violaceae, Apiaceae, Buxaceae, Ericaceae, Polygonaceae, Amaranthaceae, Convolvulaceae, Rosaceae, Sandalwoodaceae, Caprifoliaceae, Geraniaceae, Vitaceae, Fagaceae, Caprifoliaceae, Dipsacaceae, Fabaceae, Rutaceae, Sapindaceae, Proteaceae, Saxifragaceae, Apocynaceae, Gentianaceae, Dryopteridaceae, Cupressaceae, Cucurbitaceae, Solanaceae, Pedicularaceae, Plantaginaceae, Orobanchaceae, Linderniaceae, Caprifoliaceae, Pachyceraceae, Goodeniaceae, Menyanthesaceae, Examples of plants belonging to the families Stylidaceae, Polygalaceae, Surianaceae, Muntingiaceae, Cytinaceae, Dipterocarpaceae, Sarcolaenaceae, Lespedeaceae, Russulaceae, Sphaeroceparaceae, Tetrameresaceae, Begoniaceae, Datiscaceae, Berberidaceae, Menispermaceae, Hybrinaceae, Stilbaceae, Scrophulariaceae, Mazusaceae, Phrymaceae, Paulowniaceae, Piperaceae, Didymeraceae, Dryopteraceae, Dryopteridaceae, Nephrolaceae, Polypodiaceae, Davalliaceae, Dryopteridaceae, Nephrolaceae, Polypodiaceae, Davalliaceae, etc. 【0076】 From another classification perspective, for example, tomatoes, bell peppers, chili peppers, eggplants and other eggplant species, cucumbers, pumpkins, melons, watermelons and other gourd species, cabbage, broccoli, Chinese cabbage and other leafy greens, celery, parsley, lettuce and other raw or spicy vegetables, leeks, onions, garlic and other allium species, soybeans, peanuts, green beans, peas, adzuki beans and other legumes, strawberries and other fruit vegetables, radishes, turnips, carrots, burdock and other taproots, taro, cassava, potatoes, sweet potatoes, yams and other root vegetables, asparagus, spinach. Examples include soft vegetables such as Japanese parsley, flowers such as lisianthus, stock, carnation, and chrysanthemum, grains such as rice, wheat, barley, oats, and corn, grasses such as bentgrass and Korean lawn grass, oil crops such as rapeseed and peanuts, sugar crops such as sugarcane and sugar beet, fiber crops such as cotton and rush, fodder crops such as clover, sorghum, and dent corn, deciduous fruit trees such as apples, pears, grapes, and peaches, citrus fruits such as Satsuma mandarins, lemons, and grapefruits, and woody plants such as azaleas, rhododendrons, and cedars. 【0077】 Furthermore, from another classification perspective, the grafting improvement agent of the present invention can be suitably used in grafting of vegetables belonging to the same family, such as Solanaceae (e.g., tomatoes, eggplants, bell peppers, paprikas) and Cucurbitaceae (e.g., cucumbers, watermelons, melons, pumpkins). However, as mentioned above, the target is not limited to vegetables but also includes woody plants such as Rosaceae fruit trees. 【0078】 The grafting improvement agent of the present invention may consist only of an active ingredient, but in addition to the active ingredient, it may also contain various other components depending on the type of active ingredient contained, the dosage form described later, the method of application, etc. The content ratio of the active ingredient (dry weight) in the grafting improvement agent can be appropriately determined depending on the dosage form described later, the method of application, etc., but for example, a range of 0.0001 to 100% by mass can be exemplified. Examples of other components include carriers, fixatives, dispersants, auxiliary agents, etc. Examples of carriers include solid carriers such as bases, solvents, dispersants, emulsifiers, buffers, stabilizers, excipients, binders, disintegrants, lubricants, thickeners, humectants, colorants, fragrances, chelating agents, talc, bentonite, clay, kaolin, diatomaceous earth, white carbon, vermiculite, silica sand, etc.; and liquid carriers such as water-soluble polymer compounds (polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, etc.), water, vegetable oil, liquid animal oil, etc. These can be used individually or in combination as appropriate, depending on their respective purposes. 【0079】 The form of the grafting improvement agent of the present invention is not particularly limited and can be, for example, a dry form, a solution form, or a kit form. The kit may appropriately include nucleic acid introduction reagents, buffers, and other materials, reagents, and equipment necessary for the manufacture of grafting plants, etc., as needed. Furthermore, when applied to plants, the dosage form of the grafting improvement agent of the present invention is not particularly limited as long as it is an agriculturally acceptable dosage form. Examples include granules such as granules, 1 kg granules, 500 g granules, 250 g granules, and jumbo granules; powders such as powders, DL powders, and FD powders; powders such as powder granules, fine granules F, and fine granules F; powders; wettable powders such as wettable powders, flowable sol SC, granular wettable powder, and dry flowable; wettable powders such as water-soluble powders and granular water-soluble powders; emulsions such as emulsions and EW agents; liquids such as liquids and EW agents; oils such as oils and surf agents; aerosols; pastes; microencapsulated formulations; and packs. 【0080】 By applying or introducing the grafting improving agent of the present invention to plants, it is possible to manufacture grafting plant substructures with improved grafting properties with other plants, and it is also possible to manufacture grafted plants more efficiently and improve grafting efficiency. 【0081】 More specifically, for example, a grafting plant or grafting plant substructure with improved graftability with other plants can be produced by a method that includes applying or introducing the grafting improving agent of the present invention to a plant or plant substructure. Furthermore, a grafted plant can be produced more efficiently by a method that includes applying or introducing the grafting improving agent of the present invention to a grafted plant, and / or grafting the grafting plant substructure with another plant substructure. 【0082】 A plant body comprises all the tissues of a plant, and is not particularly limited in this respect. A plant substructure is obtained by removing some tissues / parts from a plant body, and is not particularly limited in this respect. 【0083】 The plant part structure for grafting is not particularly limited as long as it is a plant part structure that can be grafted. Examples include a structure consisting of the entire or a part thereof underground, a structure consisting of the entire or a part thereof underground and the entire or a part thereof above ground, a structure consisting of the entire or a part thereof above ground, etc. In this specification, the underground part is not particularly limited as long as it is a structure that can exist buried underground, and examples include roots, rhizomes, etc. In this specification, the above ground part is not particularly limited as long as it is a structure that can exist exposed above ground, and examples include stems, trunks, branches, petioles, leaves, buds, flowers, etc. 【0084】 The form of the plant substructure for grafting is not particularly limited as long as it is in a form that can be grafted. From the viewpoint of enabling more efficient grafting, it is preferable that the plant substructure for grafting has a surface suitable for grafting in a part of it. Examples of surfaces suitable for grafting include various known forms, such as flat surfaces, V-shaped or other concave surfaces, protruding or convex surfaces, etc., that provide good contact as needed. 【0085】 In this invention, grafting can be carried out in accordance with or in accordance with known methods. In this invention, grafting can typically be carried out by a method comprising the steps of: cutting any part of a plant (for example, any part on the stem) to obtain two or more grafting plant substructures (for example, rootstock, intermediate rootstock, scion, etc.) (step 1); and cultivating the grafting plant substructures with their cut surfaces in contact with each other (step 2). 【0086】 In step 1, it is preferable that the cut surfaces of the plant portion structure for grafting be processed in a way that increases the contact area between the cut surfaces. For example, one can make a cut of about 1 to 2 cm in the center of one cut surface and cut the other cut surface into a V shape. These processes can be carried out, for example, using a single-edged razor. 【0087】 In step 2, the manner in which the cut surfaces come into contact with each other is not particularly limited. It is desirable that the contact be made gently so as not to damage the plant structure of the grafting portion. 【0088】 In step 2, after contact, it is preferable to fix the contact area so that it does not move as much as possible. Fixing can be done, for example, by wrapping the contact area with a sheet-like material such as Parafilm. 【0089】 In the initial stages of cultivation in step 2 (for example, 3 to 14 days after contact), it is desirable to keep the entire above-ground part of the grafting plant structure (e.g., scion, intermediate rootstock, etc.) moist. Moisture can be maintained, for example, by covering the entire above-ground part of the grafting plant structure with a plastic bag sprayed with water. 【0090】 If a moisturizing treatment is applied during the initial stages of cultivation in step 2, it is preferable to cultivate the plants without moisturizing treatment during the later stages of cultivation (for example, up to 30 days after contact). 【0091】 When grafting three plant substructures for grafting, it is desirable to first graft two of the plant substructures using steps 1 and 2 above, and then graft the third plant substructure obtained from the resulting plant body. When grafting four or more plant substructures, it is also desirable to graft them using a similar method. 【0092】 The application method is not particularly limited, as long as the active ingredient can reach the graft surface or the part that will become a graft surface in the future. The application method is not particularly limited as long as it is a known method of using pesticides (or a method that may be developed in the future). Examples include spraying, dropping, coating, mixing or dissolving in the plant growth environment (in soil, water, solid medium, liquid medium, etc.). More specifically, examples include adding to a hydroponic solution, spraying on the soil surface, mixing with fertilizer, etc. In one preferred embodiment, the application method includes spraying, dropping, or coating the graft surface or graft site. 【0093】 The method of introduction is not particularly limited as long as it allows essential components to reach the plant cells, and can be appropriately selected depending on the type of substance to be introduced and the target of introduction. Examples of introduction methods include the floral dip method, floral spray method, Agrobacterium method, particle gun method, infiltration method, toothpick inoculation method, suction injection method, leaf disc method, inflorescence infiltration method, reduced pressure filtration method, and virus-mediated nucleic acid delivery. Among these, the Agrobacterium method is preferred from the viewpoint of simplicity and safety. 【0094】 There are no particular restrictions on the state of the plant to be introduced; it may be undifferentiated plant tissue (e.g., callus) or a mature plant. 【0095】 A more specific example of the implementation method is shown below. 【0096】 One specific example of the introduction method (Introduction Example 1) is a method that includes the steps of: preparing a plasmid containing a promoter (e.g., T7 promoter, T3 promoter, 35S promoter, etc.) and a sequence containing an expression cassette downstream thereof (step a1); obtaining the genomic RNA of a plant virus from the plasmid obtained in step a1 by in vitro transcription (step b1); and inoculating the genomic RNA (active ingredient) obtained in step b1 into a plant (e.g., friction inoculation method, particle gun inoculation method, etc.) (step c1). Alternatively, if the plasmid obtained in step a1 is a Ti plasmid containing a promoter that has transcriptional activation ability in plant cells, such as the 35S promoter, then instead of steps b1 and c1 above, the method can be carried out by, for example, introducing the plasmid obtained in step a1 into Agrobacteria and culturing it (step b2); and inoculating the culture medium (culture medium containing the active ingredient) obtained in step b2 into a plant (e.g., infiltration method, toothpick inoculation method, aspiration injection method, etc.) (step c2). Alternatively, the process can be carried out by a method that includes, for example, a step (step c3) of inoculating a plant with the plasmid (active ingredient) obtained in step a1 (e.g., grinding inoculation method, particle gun inoculation method, etc.) instead of steps b1 and c1 above. Alternatively, the process can be carried out by a method that includes, for example, a step (step c4) of performing a leaf disc method, inflorescence infiltration method, or reduced-pressure filtration method, etc. By these methods, the desired protein or peptide is produced from the genomic RNA, plasmid, T-DNA, etc. introduced into the plant. 【0097】 A second specific example of the introduction method (Introduction Example 2) is a method that includes the steps of collecting a plant virus (step d1) from a plant containing the plant virus (for example, obtained by Introduction Example 1 above), and inoculating the plant with the virus (virus containing the active ingredient) collected in step d1 (step e1). The collection in step d1 can be carried out, for example, by recovering a virus solution obtained by grinding a part of the plant containing the plant virus (for example, a leaf). The inoculation in step e1 can be carried out, for example, by scratching the target part of the plant (for example, a leaf) with an abrasive such as silicon carbide and bringing the virus into contact with it. [Examples] 【0098】 The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. 【0099】 Test Example 1. Identification of the β-1,4-glucanase gene Niben101Scf01180g16001, which functions in grafting of tobacco plants. RNA extraction, cDNA library synthesis, and RNA-Seq analysis were performed on plant samples (time-series samples of graft sites of interfamily grafted N. benthamiana and A. thaliana, time-series samples of graft sites of intrinsic grafted N. benthamiana, time-series samples of graft sites of interfamily grafted soybean and A. thaliana, and time-series samples of wounds treated on the stems of N. benthamiana and soybean). Seq read files, divided into four sections using Trimmomatic (Java), were quality-trimmed. Ends with a #Phred quality score of less than 20 were removed, and the resulting reads with a value of less than 30 nt were also removed. 【0100】 Each trimmed read file was mapped to a genome reference using HISAT2. #Genome references (ref, A. thaliana (At): N. benthamiana (Nb): Niben.genome.v1.0.1.scaffolds.nrcontigs.fasta, A. thaliana (At): Arabidopsis_thaliana.TAIR10.dna.toplevel.fa, G. max (Gm): Gmax_109.fa) were used, and an index was generated for HISAT2. 【0101】 I used Samtools to convert the SAM format mapping data to BAM format, then merged and sorted the four split files. 【0102】 Expression levels (FPKM) were analyzed using Cufflinks. The following annotation files (gtf) were used: Nb: Niben101_annotation.gene_models.gtf, At: Arabidopsis_thaliana.TAIR10.38.gtf, Gm: Gmax_109_gene.gtf. 【0103】 Using cuffdiff, we extracted and tested changes in expression for At and Nb from three replicate experiments. 【0104】 Based on the results from cuffdiff, the following extractions were performed: To evaluate based on the ratio between two samples, genes whose expression was not zero in the control were included in the evaluation (Ctrl>0). (1) The gene showed a pattern of increased expression after grafting compared to the control (Ctrl<1d,3d,5d,7d). (2) The increase in expression was greater at 3 days than at 1 day (1d<3d). (3) The expression level FPKM > 10 from 1d onwards. (4) The expression at 1d was more than twice that of the control (1d / Ctrl>2, p < 0.05). 189 genes that met these conditions were selected as candidate genes. 【0105】 For candidate genes, homology analysis was performed using tblastx on Nb transcripts against At transcripts to obtain the NCBI-ID of the most similar gene. GO enrichment analysis was then performed using the obtained At gene IDs. The results showed that within the cellular component category, 41 genes were classified as extracellular region and 16 genes as cell wall, with enrichment observed with a p value < 0.0001 (a total of 45 genes). 【0106】 For each gene, the expression patterns of the At and Gm orthologues were examined at three points: intact control, 1 day (Days After Grafting), and 3 days. Homological analysis was performed using tblastx based on the Nb transcript, and the top-hit genes were considered to be the respective orthologues. For the candidate genes, the expression patterns were examined in At on the rootstock side of Nb / At allografts and in Gm on the scion side of Gm / At allografts, and 15 genes were extracted according to the following criteria: (1) Nb intact FPKM < 150, (2) Nb 3d FPKM > 20, (3) At 3d FPKM < 50, (4) Excluding genes for which there is no expression data in Gm, (5) Gm 3d FPKM / 1d FPKM < 1.2. Finally, by excluding genes that were expected to be stress-inducible based on gene annotation, the number of candidate genes was narrowed down to 10. Among these, we were able to identify the Niben101Scf01180g16001 gene, which encodes an enzyme that digests cell wall components. 【0107】 Test Example 2. Identification of β-1,4-glucanase involved in the success of grafting in various plants. RNA sequencing analysis (Test Example 1) revealed that when Nicotiana benthamiana (Nb) was grafted with Arabidopsis thaliana (At), the β-1,4-glucanase Niben101Scf01180g16001 showed increased expression. 【0108】 Using tBlastx results based on the transcript sequence of Niben101Scf01180g16001, phylogenetic trees were constructed for homologous genes of Nb, At, soybean (Gm), maize (Zm), morning glory (In), Pedicularis resupinata (Pj), and Lindenbergia (Lp). First, from the tBlastx results for At, Niben101Scf01180g16001 belongs to the Glycosyl hydrolase 9B family, and the amino acid sequences of genes in this family were obtained. Next, tBlastx results for each plant were collected to cover the range in which orthologues of these genes were included, and phylogenetic trees were constructed. For Nb, 12 genes were used in phylogenetic analysis; for At, 11 genes; for Gm, 11 genes; for Zm, 10 genes; for In, 9 genes; for Pj, 13 genes; and for Lp, 3 genes. Specifically, CLUSTAL 2.1 Multiple Sequence Alignments was used via biopython1.70 from Python 3.7.4, with default settings. The resulting phylogenetic tree is shown in Figure 1A. 【0109】 Phylogenetic analysis identified a clade containing only the Niben101Scf01180g16001 gene among the Nb genes. The corresponding clade (Figure 1B) contained two At genes (AT1G71380.1, AT1G22880.1), two Gm genes (GLYMA04G12290.1, GLYMA06G48140.1), one Zm gene (Zm00001d025475_T001), two In genes (INIL08g27364.t1, INIL12g24789.t1), five Pj genes (Pjv1_00028629-RA, Pjv1_00026451-RA, Pjv1_00026452-RA, Pjv1_00028828-RA, Pjv1_00028626-RA), and one Lp gene (LiPhGnB1_1726). 【0110】 To obtain the expression patterns of these genes during grafting within the same family and across different families, a series of grafted samples and samples of wounds treated on the stems were prepared and transcriptome analysis was performed. The transcriptome analysis was performed in the same manner as described above, using I. nil (In): Asagao_1.2.fa, P. japonicum (Pj): PjScaffold_ver1.fasta, and L. philippensis (Lp): LiPhGnB1.fasta as genome references, and In: Asagao_1.2.gtf, Pj: PjScaffold.v1.0.simplified.gtf, and Lp: LiPhGnB1.gtf as annotation files (gtf). 【0111】 The transcriptome analysis results are shown in Figure 2. The gene Niben101Scf01180g16001, which is expected to be involved in the success of interfamily grafting because its expression increases during interfamily grafting in Nb, was found to also show increased expression during self-grafting of other plants of the same family. 【0112】 Test Example 3. Expression analysis of the Niben101Scf01180g16001 homolog gene To evaluate whether genes not included in the clade containing only Niben101Scf01180g16001 among the Nb genes are upexpressed during grafting, transcriptome analysis was performed on the Glycosyl hydrolase 9B family, Glycosyl hydrolase 9A4, and Glycosyl hydrolase 9C1-3 genes in the same manner as in Test Example 2, and the expression patterns for control, 1 day, 3 days, and 7 days were plotted. However, genes with high expression in the control (intact plant) (generally FPKM > 30) and genes showing short-term upexpression after wounding treatment were excluded. 【0113】 Analysis revealed that genes not included in the clade containing only Niben101Scf01180g16001 among the Nb genes did not show increased expression after grafting. 【0114】 Test Example 4. Verification of the causal relationship between the Niben101Scf01180g16001 gene and its homologous gene in grafting success. To investigate whether the identified β-1,4-glucanase genes (or group of genes) actually contribute to grafting, grafting was performed on N. benthamiana with the Niben101Scf01180g16001 gene knocked down, on N. benthamiana with the Niben101Scf01180g16001 gene knocked out, and on Arabidopsis thaliana with the AtCel3 gene knocked out, and the grafting success rates were examined. Specifically, the investigation was conducted as follows. 【0115】 <Test Example 4-1. Effect of Niben101Scf01180g16001 knockdown on the success rate of interfamily grafting of tobacco benthamiana and Arabidopsis thaliana> In tobacco plants, the expression of the β-1,4-glucanase gene (Niben101Scf01180g16001) was suppressed using VIGS. Thirty individuals each of the suppressed expression strains and control strains were grafted onto Arabidopsis thaliana (rootstock). If the plants survived after two weeks, the grafting was considered successful; if they died, it was considered a failure. In addition, the amount of Niben101Scf01180g16001 mRNA at the graft site was measured by real-time PCR two weeks after grafting. The results are shown in Figure 7. 【0116】 <Result> Compared to the untreated group, the VIGS-treated group showed a decrease in the accumulation of Niben101Scf01180g16001 transcripts, and the grafting success rate decreased from 50% to 10%. Fisher's exact test showed significance at the 1% level. Similarly, significance was shown at the 5% level when compared to the vector control group, but significance was rejected for the untreated group and the vector control group. 【0117】 <Test Example 4-2. Effect of Niben101Scf01180g16001 Deficiency on the Success Rate of Interfamily Grafting of Tobacco benthamiana and Arabidopsis thaliana> In tobacco plants, the β-1,4-glucanase gene (Niben101Scf01180g16001) was disrupted by genome editing. 47 disrupted plants and 45 wild-type plants were grafted onto Arabidopsis thaliana (rootstock), and grafting success / failure was determined in the same manner as in Experiment 4-1. The results are shown in Figure 8. 【0118】 <Result> The grafting success rate decreased from 91% to 60% between wild-type and destroyed plants, and Fisher's exact test showed statistical significance at the 5% level. 【0119】 <Test Example 4-3. Effect of AtCel3 Deficiency on the Success Rate of Grafting of Arabidopsis thaliana> The β-1,4-glucanase gene (AtCel3: AT1G71380.1) was disrupted in Arabidopsis thaliana by genome editing. Ten to twelve individuals each of the disrupted plants and wild plants were grafted onto Arabidopsis thaliana (rootstock), and the shoot weight after grafting was measured. Specifically, the test was conducted as follows. 【0120】 Grafting (micrografting) of Arabidopsis thaliana seedlings was performed. For 10DAG grafts, individuals showing shoot and root growth were considered successful, and the shoot weight was measured. The results are shown in Figure 9. 【0121】 <Result> When the expression level of the gene (AtCel3) belonging to the clade containing only Niben101Scf01180g16001 among the Nb genes decreased, the degree of increase in shoot weight after grafting decreased. A significant decrease was observed in both genetically independent lines. 【0122】 Test Example 5. Verification that overexpression of the Niben101Scf01180g16001 gene improves grafting efficiency. We created N. benthamiana and Arabidopsis thaliana transformants that overexpressed the identified Niben101Scf01180g16001 gene, performed grafting on these transformants, and investigated the grafting success rate. Specifically, we investigated as follows: 【0123】 <Test Example 5-1. Effect of Niben101Scf01180g16001 overexpression on the grafting adhesion strength of Tobacco benthamiana grafted to another species> As an overexpression of Niben101Scf01180g16001, a genetically modified plant (Benthamia tobacco) was created by inserting an Ω sequence between the promoter and cDNA of Niben101Scf01180g16001 itself. The Benthamia tobacco plants overexpressing Niben101Scf01180g16001 were grafted in vitro onto chrysanthemum, soybean, lemon, and grape rootstock using a grafting device, and the graft adhesion strength after one week was measured using a force gauge. Specifically, the tests were conducted as follows. 【0124】 After transplanting to pots, the upper 3 cm of the stems of Nb plants, approximately 3 weeks old, were sterilized with 70% ethanol and washed three times with sterile water. The stems were cut into 1.5 mm wide pieces and used as one side of the in vitro graft. For chrysanthemums, soybeans, lemons, and grapes, relatively young stem portions were also excised, cut into 1.5 mm wide pieces, and used as the other side of the in vitro graft. The cut surfaces of the two prepared stem pieces were joined together and fixed to a grafting device. The device was placed in 1 / 2 MS (pH 5.7), 1% agar medium and cultured at 27°C under LL conditions for one week. The adhesive strength between the stems was measured using a force gauge. A tensile test was performed at 300 mm / min, and the adhesive strength (Newtons, N) was measured as "starting point - minimum value". The results are shown in Figure 10. 【0125】 <Result> In cross-grafting of tobacco benthamiana and chrysanthemum, the adhesive strength increased from 0.28 N to 0.63 N in cross-grafts of overexpressing tobacco benthamiana compared to cross-grafts of wild tobacco benthamiana, and this was statistically significant by the Mann-Whitney U test (n = 15 for each, P value = 0.063). 【0126】 In cross-grafting of tobacco benthamiana and soybean, the adhesive strength increased from 0.11 N to 0.18 N in cross-grafted tobacco benthamiana with the overexpressing tobacco benthamiana compared to cross-grafted tobacco benthamiana with the wild-type tobacco benthamiana, and this was statistically significant by the Mann-Whitney U test (n = 15 for each, P value = 0.006). 【0127】 In allografting of tobacco benthamiana and lemon, the adhesive strength increased from 0.4 N to 0.55 N in the allografted tobacco benthamiana with overexpressing tobacco benthamiana compared to the allografted tobacco benthamiana with wild-type tobacco benthamiana. The results of the Mann-Whitney U test were n = 15 for each, P value = 0.17. 【0128】 In cross-grafting of tobacco benthamiana and grape, the adhesive strength increased from 0.13 N to 0.25 N in cross-grafted tobacco benthamiana with the overexpressing tobacco benthamiana compared to cross-grafted tobacco benthamiana with the wild-type tobacco benthamiana, and this was statistically significant by the Mann-Whitney U test (n = 15 for each, P value = 0.005). 【0129】 These results demonstrate that overexpression of Niben101Scf01180g16001 improves graft adhesion in interspecies grafting with various plants. 【0130】 <Test Example 5-2. Effect of Niben101Scf01180g16001 overexpression on the graft adhesion strength of grafts of Benthamiana species.> The Niben101Scf01180g16001 overexpressing tobacco plants prepared in Test Example 5-1 were grafted in vitro using a grafting device, and the graft adhesion strength after one week was measured using a force gauge, in the same manner as in Test Example 5-1. The results are shown in Figure 11. 【0131】 <Result> Compared to grafting between wild-type plants, grafting between overexpressing plants increased the adhesive strength from 0.094 N to 0.55 N, and this was statistically significant by the Mann-Whitney U test (n = 15 for each, P value = 7.72 x 10⁻¹⁰). -5 This indicates that overexpression of Niben101Scf01180g16001 improves graft adhesion. 【0132】 <Test Example 5-3. Effects of Niben101Scf01180g16001 overexpression on Arabidopsis thaliana grafts> As an overexpression of Niben101Scf01180g16001, genetically modified plants (Arabidopsis thaliana) were created in which Niben101Scf01180g16001 cDNA was induced using the RAP2.6L promoter. 64 overexpression Arabidopsis plants were grafted onto each other, or onto wild-type plants, and 102 plants were grafted onto each other. The grafting success rate of the shoots was then tested. The weight of the shoots after grafting was also measured. The test method was the same as in Test Example 4-4, and the growth temperature after grafting was set to 22°C. The results are shown in Figure 12. 【0133】 <Result> The grafting success rate increased from 24% to 45% in the wild-type and overexpressing strains, and this was statistically significant at the 5% level by Fisher's exact test. The increase in shoot weight after grafting was also increased. This indicates that overexpression of Niben101Scf01180g16001 improves grafting success.

Claims

[Claim 1] (a) Benthamiana tobacco β-1,4-glucanase containing amino acid sequence A shown in Sequence ID No. 1, (b) β-1,4-glucanase containing amino acid sequence B as shown in any of SEQ ID NOs: 2-14, (c) β-1,4-glucanase comprising an amino acid sequence C having 90% or more identity with the amino acid sequence A or the amino acid sequence B, and (d) Expression cassette of the benthamiana tobacco β-1,4-glucanase (a), the β-1,4-glucanase (b), or the β-1,4-glucanase (c) A grafting improvement agent containing at least one selected from the group consisting of the following. [Claim 2] The grafting improvement agent according to claim 1, which is for grafting within the same family or for grafting into different families. [Claim 3] A method for manufacturing a plant body or plant substructure for grafting, comprising applying or introducing the grafting improvement agent described in claim 1 or 2 to a plant body or plant substructure. [Claim 4] A plant body or plant part structure for grafting obtained by the method of claim 3, Except for not applying or introducing the grafting improvement agent described in claim 1 or 2, compared to the same grafting plant body or grafting plant substructure, (a) Benthamiana tobacco β-1,4-glucanase containing amino acid sequence A shown in Sequence ID No. 1, (b) β-1,4-glucanase containing amino acid sequence B shown in any of SEQ ID NOs: 2-14, and (c) β-1,4-glucanase containing an amino acid sequence C having 90% or more identity with the amino acid sequence A or the amino acid sequence B, The quantity of at least one selected from the group consisting of the following is increasing. A plant body or plant part structure for grafting. [Claim 5] A method for producing a grafted plant, comprising applying or introducing a grafting improvement agent according to claim 1 or 2 to a grafted plant, and / or grafting a grafted plant or grafted plant substructure according to claim 4 with another plant or another plant substructure. [Claim 6] A grafted plant obtained by the method of claim 5, The method is a method that includes grafting a grafted plant or grafted plant substructure obtained by a method for manufacturing a grafted plant or grafted plant substructure, which includes applying or introducing a grafting improving agent according to claim 1 or 2, including the expression cassette, to the plant or plant substructure, with another plant substructure. Except for not applying or introducing the grafting improvement agent according to claim 1 or 2 which includes the expression cassette, a grafted plant obtained by grafting the same grafted plant or grafted plant substructure as described in claim 4 with another plant or another plant substructure is: (a) Benthamiana tobacco β-1,4-glucanase containing amino acid sequence A shown in Sequence ID No. 1, (b) β-1,4-glucanase containing amino acid sequence B shown in any of SEQ ID NOs: 2-14, and (c) β-1,4-glucanase containing an amino acid sequence C having 90% or more identity with the amino acid sequence A or the amino acid sequence B, The quantity of at least one selected from the group consisting of the following is increasing. Grafted plant. [Claim 7] (a) Benthamiana tobacco β-1,4-glucanase containing amino acid sequence A shown in Sequence ID No. 1, (b) β-1,4-glucanase containing amino acid sequence B as shown in any of SEQ ID NOs: 2-14, (c) β-1,4-glucanase comprising an amino acid sequence C having 90% or more identity with the amino acid sequence A or the amino acid sequence B, and (d) Expression cassette of the benthamiana tobacco β-1,4-glucanase (a), the β-1,4-glucanase (b), or the β-1,4-glucanase (c) At least one type selected from the group consisting of the following, for use in improving grafting. [Claim 8] (a) Benthamiana tobacco β-1,4-glucanase containing amino acid sequence A shown in Sequence ID No. 1, (b) β-1,4-glucanase containing amino acid sequence B as shown in any of SEQ ID NOs: 2-14, (c) β-1,4-glucanase comprising an amino acid sequence C having 90% or more identity with the amino acid sequence A or the amino acid sequence B, and (d) Expression cassette of the benthamiana tobacco β-1,4-glucanase (a), the β-1,4-glucanase (b), or the β-1,4-glucanase (c) Use for the manufacture of a grafting improvement agent, selected from the group consisting of the following. [Claim 9] (a) Benthamiana tobacco β-1,4-glucanase containing amino acid sequence A shown in Sequence ID No. 1, (b) β-1,4-glucanase containing amino acid sequence B as shown in any of SEQ ID NOs: 2-14, (c) β-1,4-glucanase comprising an amino acid sequence C having 90% or more identity with the amino acid sequence A or the amino acid sequence B, and (d) Expression cassette of the benthamiana tobacco β-1,4-glucanase (a), the β-1,4-glucanase (b), or the β-1,4-glucanase (c) A grafting improvement method comprising applying or introducing at least one selected from the group consisting of the following to a plant body or plant substructure.

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