Novel allorhizobium vitis strain and uses thereof

Abstract

This novel nonpathogenic bacterial strain exhibiting a controlling effect on crown gall disease in plants and tomato canker disease is the Allorhizobium vitis A3 strain (accession number: NITE BP-041154).

Description

Novel Allorizobium vitis strain and its use

[0001] This invention relates to a novel Allorizobium vitis strain and its use. This application claims priority under Japanese Patent Application No. 2024-160974, filed in Japan on September 18, 2024, the contents of which are incorporated herein by reference.

[0002] Traditionally, techniques for controlling plant diseases have been known that utilize bacteria capable of suppressing the growth of pathogens by antagonizing them.

[0003] For example, Patent Document 1 discloses a technique for controlling crown gall disease using the ARK-1, ARK-2, and / or ARK-3 strains of Rhizobium vitis.

[0004] Crown gall disease is a disease caused by bacteria of the Rhizobium genus, which causes galls called crown galls to form on the roots and stems of plants. In this specification, the causative agent of crown gall disease is also referred to as the "crown gall bacterium." The crown gall bacterium has a wide host range (infection range), invading various plants such as fruit trees like apples, grapes, peaches, pears, and cherries, flowering plants like chrysanthemums, and vegetables like tomatoes and potatoes, causing poor growth and even death.

[0005] On the other hand, Non-Patent Document 1 describes a technique for controlling wilt disease (tomato canker) caused by Clavibacter michiganensis subsp. michiganensis using bacteria of the genus Pseudomonas.

[0006] Republished Gazette WO2012-067127

[0007] Salma B. et al., Modes of Action of Biocontrol Agents and Elicitors for sustainable Protection against Bacterial Canker of Tomato. Microorganisms, 11(3), 726, 2023.

[0008] However, there is still much room for development in technologies that use bacteria to control plant diseases caused by bacteria.

[0009] This invention has been made in view of these circumstances, and aims to provide a novel non-pathogenic bacterial strain that exhibits a control effect against plant diseases caused by bacteria (in other words, plant diseases in which bacteria are pathogens), and a novel technology using said bacterial strain.

[0010] The inventors isolated 331 strains of Alorizobium vitis from grapes and, from among these strains, discovered strain A3, which is not pathogenic to plants and exhibits a control effect against plant diseases caused by bacteria, thereby completing the present invention. That is, one aspect of the present invention that solves the above problems includes the following aspects.

[0011] [1] Allorhizobium vitis A3 strain (Accession number: NITE BP-04154).

[0012] [2] A control agent for bacterial plant diseases, containing the Alorizobium vitis A3 strain described in [1] as the active ingredient.

[0013] [3] A plant crown gall disease control agent containing the Alorizobium vitis A3 strain described in [1] as the active ingredient.

[0014] [4] The plant crown gall disease control agent for the plant described in [3], wherein the plant is a fruit tree, a flowering plant, or a vegetable.

[0015] [5] A control agent for tomato canker containing the Alorizobium vitis A3 strain described in [1] as the active ingredient.

[0016] [6] A control agent for tomato crown gall disease and tomato canker, comprising the Alorizobium vitis A3 strain described in [1] as the active ingredient.

[0017] [7] The control agent according to [2], wherein the bacteria are bacteria of the genus Pseudomonas, Xanthomonas, or Ralstonia.

[0018] [8] The control agent according to [2] or [7], wherein the plant disease is black spot bacterial disease, black rot disease or bacterial wilt disease.

[0019] [9] The control agent according to [2], [7] or [8], wherein the plant disease is black spot bacterial disease, and the plants to be controlled are cruciferous plants, solanaceous plants, asteraceae plants or leguminous plants.

[0020]

[10] The control agent according to [2], [7] or [8], wherein the plant disease is black rot disease, and the plants to be controlled are cruciferous plants.

[0021]

[11] The control agent according to [2], [7] or [8], wherein the plant disease is bacterial wilt disease, and the plants to be controlled are solanaceous plants or zingiberaceae plants.

[0022]

[12] A method for controlling a plant disease caused by bacteria, comprising the step of inoculating or attaching the control agent according to any one of [2], [7], [8], [9],

[10] and

[11] to (the plants to be controlled) plants.

[0023]

[13] A method for controlling crown gall disease of plants, comprising the step of inoculating or attaching the control agent according to [3] or [4] to plants.

[0024]

[14] A method for controlling tomato damping-off disease, comprising the step of inoculating or attaching the control agent according to [5] to tomatoes.

[0025]

[15] A method for controlling crown gall disease and tomato damping-off disease of tomatoes, comprising the step of inoculating or attaching the control agent according to [6] to tomatoes.

[0026]

[16] The control method according to

[12] , wherein the bacterium is a bacterium belonging to the genus Pseudomonas, Xanthomonas or Ralstonia.

[0027]

[17] The control method according to

[12] or

[16] , wherein the plant disease is black spot bacterial disease, black rot disease or bacterial wilt disease.

[0028]

[18] The method of control according to

[12] ,

[16] or

[17] , wherein the plant disease is bacterial black spot disease, and the plant to which the control agent is inoculated or applied is a Brassicaceae plant, a Solanaceae plant, a Asteraceae plant, or a Fabaceae plant.

[0029]

[19] The method of control according to

[12] ,

[16] or

[17] , wherein the plant disease is black rot and the plant to which the control agent is inoculated or applied is a Brassicaceae plant.

[0030]

[20] The method of control according to

[12] ,

[16] or

[17] , wherein the plant disease is bacterial wilt and the plant to which the control agent is inoculated or applied is a Solanaceae plant or a Zingiberaceae plant.

[0031]

[21] Cultivation soil containing the Alorizobium vitis A3 strain described in [1].

[0032]

[22] A soil conditioner containing the Alorizobium vitis A3 strain described in [1].

[0033]

[23] Plant seeds with the Alorizobium vitis A3 strain described in [1] attached to their surface.

[0034]

[24] The seed according to

[23] , wherein the plant is a tomato.

[0035]

[25] A seedling of a plant having the Alorizobium vitis A3 strain described in [1].

[0036]

[26] The seedling according to

[25] , wherein the plant is a fruit tree, an ornamental plant, or a vegetable.

[0037] According to the present invention, it is possible to provide a novel non-pathogenic bacterial strain that exhibits a control effect against plant diseases caused by bacteria, and a novel technology using said bacterial strain.

[0038] Figure 1 shows an image of a tomato stem from the control group inoculated with the crown gall fungus. Figure 2 shows an image of a tomato stem from the experimental group inoculated with Alorizobium vitis A3 strain and the crown gall fungus. Figure 3 is a graph showing the diameter distribution and average diameter of the galls formed in the experimental group tomatoes and the control group tomatoes. Figure 4 shows an image of a grape stem from the control group inoculated with the crown gall fungus. Figure 5 shows an image of a grape stem from the experimental group inoculated with Alorizobium vitis A3 strain and the crown gall fungus. Figure 6 is a graph showing the diameter distribution and average diameter of the galls formed in the experimental group grapes and the control group grapes. Figure 7 shows an image of the roots of a control group grape seedling that was immersed in sterile water and then cultivated for 5 months in contaminated soil containing the crown gall fungus. Figure 8 shows the roots of grape seedlings from an experimental plot immersed in a fungal solution containing Alorizobium vitis A3 strain, after being cultivated for five months in soil contaminated with crown gall fungus. Figure 9 shows tomato seedlings from a control plot sprayed with sterilized water and tomato canker fungus, and tomato seedlings from an experimental plot sprayed with Alorizobium vitis A3 strain and tomato canker fungus. Figure 10 shows tomato seedlings from a control plot in another test plot, sprayed with sterilized water and tomato canker fungus. Figure 11 shows tomato seedlings from an experimental plot in another test plot, sprayed with Alorizobium vitis A3 strain and tomato canker fungus. Figure 12 shows the condition of tomato seedlings from a control plot immersed in sterilized water, after being cultivated for one month in soil contaminated with tomato canker fungus. Figure 13 shows the condition of tomato seedlings from the experimental group that were immersed in a fungal solution containing Alorizobium vitis A3 strain, after being cultivated for one month in contaminated soil containing tomato canker fungus. Figure 14 shows the area around the inoculation site of Chinese cabbage from the experimental group and the control group that were inoculated with Chinese cabbage black spot bacterial disease fungus. Figure 15 shows the leaves of Chinese cabbage from the experimental group and the control group that were sprayed with Chinese cabbage black spot bacterial disease fungus. Figure 16 shows the leaves of Chinese cabbage from the experimental group and the control group that were sprayed with Chinese cabbage black rot fungus. Figure 17 shows tomato seedlings from the experimental group and the control group that were planted in contaminated soil containing tomato bacterial wilt fungus. Figure 18 shows the stems of chrysanthemums from the experimental group and the control group that were inoculated with crown gall fungus.Figure 19 is a graph showing the diameter distribution and average diameter of crown galls formed in chrysanthemums from the experimental group and the control group. Figure 20 is an image showing the roots of tomato seedlings from the experimental group that were immersed in a fungal solution containing Allorizobium vitis A3 strain, and tomato seedlings from the control group that were immersed in sterile water, after being cultivated for 5 months in contaminated soil containing crown gall fungus. Figure 21 is an image showing the stems of chrysanthemums from the experimental group and the control group that were inoculated with crown gall fungus. Figure 22 is a graph showing the diameter distribution and average diameter of crown galls formed in chrysanthemums from the experimental group and the control group.

[0039] Preferred embodiments of the present invention will be described in detail below.

[0040] [A3 strain] A novel strain according to one embodiment of the present invention is Allorhizobium vitis A3 strain (accession number: NITE BP-04154). In this specification, Allorhizobium vitis A3 strain is also simply referred to as "A3 strain".

[0041] The inventors deciphered the 1264 bp base sequence of the 16S rRNA of strain A3 and performed a homology search using BLAST (Basic Local Alignment Search Tool). As a result, they found a 100% homology match with the base sequence of Agrobacterium vitis strain NBRC 1514016S rRNA (GenBank access No. NR 113735.1, Agrobacterium vitis is the former name of Allorhizobium vitis), thus identifying strain A3 as Allorhizobium vitis.

[0042] The inventors attempted to PCR amplify the virC gene of strain A3 using primers capable of amplifying the virC gene, one of the pathogenicity-related genes encoded on a Ti plasmid that induces carcinoma formation. As a result, no amplification product was obtained, confirming that strain A3 of Allorizobium vitis does not possess pathogenicity to plants.

[0043] As will be detailed later in the examples, various plant diseases caused by bacteria (in other words, diseases with bacteria as pathogens) can be effectively controlled by inoculating or attaching the A3 strain to plants. Examples of plant diseases that can be controlled by the A3 strain include, but are not limited to, crown gall, tomato canker, bacterial black spot, black rot, and bacterial wilt. In this specification, "control" refers to preventing or suppressing diseases.

[0044] The inventors inoculated strain A3 into the center of a culture medium and then inoculated a pathogenic strain of Allorizobium vitis (the same species as Rhizobium vitis described in Patent Document 1) around it. The proliferation of the pathogenic strain was suppressed in the vicinity of the Allorizobium vitis A3 strain. Therefore, as will be detailed later in the embodiments of the control method, inoculating or attaching strain A3 to plants is expected to have a control effect on crown gall disease, regardless of the plant species. While not bound by any specific theory, it is possible that the control effect on crown gall disease is exerted by strain A3 antagonizing the pathogenic strain. Similarly, for other plant diseases such as tomato canker, bacterial black spot, black rot, and bacterial wilt, it is possible that strain A3 exerts a control effect by antagonizing the pathogens that cause each disease.

[0045] Strain A3 is a motile, Gram-negative bacterium that forms milky white to cream-colored, glossy colonies on potato dextrose agar.

[0046] The culture conditions for strain A3 are not particularly limited as long as they are effective in controlling plant diseases caused by bacteria; for example, it can be cultured under general conditions used when culturing Allorizobium vitis. One example of culture conditions is static culture on potato dextrose agar (PDA) under aerobic conditions of pH 6 and 28°C.

[0047] Strain A3 has been deposited, and the deposit information is as follows: International Depository: National Institute of Technology and Evaluation (NITE) Patent Microbial Depository Center Address of Depository: Room 122, 2-5-8 Kazusa Kamatari, Kisarazu City, Chiba Prefecture, Japan 292-0818, Japan Accession Number: NITE BP-04154 Identification: Allorhizobium vitis strain A3 International Deposit Date (Receipt Date): September 12, 2024 Depositor: President, National Agriculture and Food Research Organization

[0048] The embodiments of each control agent containing the A3 strain live fungus, as detailed above, will be explained in detail below.

[0049] [Control agent for plant diseases caused by bacteria] In one embodiment, the present invention provides a control agent for plant diseases caused by bacteria (in other words, a pathogenic agent for bacteria), which contains the above-mentioned Allorizobium vitis A3 strain as an active ingredient.

[0050] As will be detailed later in the examples, it has been confirmed that inoculating or attaching strain A3 to plants can control plant diseases caused by a total of five genera of bacteria: Allorhizobium, Clavibacter, Pseudomonas, Xanthomonas, and Ralstonia. These five genera are phylogenetically quite distant from each other. In addition, the disease control effect of strain A3 has been confirmed in four plant species that are phylogenetically quite distant: tomato, Chinese cabbage, grape, and chrysanthemum. From the above, it is expected that strain A3 can control diseases in a wide variety of plant species, not just the four species mentioned above, by antagonizing a diverse range of pathogenic bacteria, not just the five genera mentioned above.

[0051] Therefore, the types of plant diseases caused by bacteria that are controlled by the control agent of this embodiment are not particularly limited, but may include, for example, crown gall, tomato canker, bacterial black spot, black rot, or bacterial wilt, or bacterial black spot, black rot, or bacterial wilt.

[0052] The control agent of this embodiment may be a control agent for controlling plant diseases caused by bacteria, a control agent for controlling crown gall disease, a control agent for controlling tomato canker, a control agent for controlling bacterial black spot disease, a control agent for controlling black rot, or a control agent for controlling bacterial wilt.

[0053] The plants whose diseases are controlled by the use of the control agent of this embodiment may be plants that have not yet developed crown gall, tomato canker, bacterial black spot, black rot, and bacterial wilt, or they may be plants that have already developed crown gall, tomato canker, bacterial black spot, black rot, and / or bacterial wilt.

[0054] If the plants to be treated with the control agent of this embodiment are not infected with the pathogens of crown gall, tomato canker, bacterial spot disease, black rot, and bacterial wilt, using the control agent of this embodiment can prevent the onset of these diseases or reduce the symptoms if they do occur. If the plants to be treated with the control agent of this embodiment are infected with the pathogens of crown gall, tomato canker, bacterial spot disease, black rot, and / or bacterial wilt, using the control agent of this embodiment is expected to completely cure these diseases or reduce the symptoms.

[0055] Furthermore, the bacteria (pathogens) controlled by the control agent of this embodiment are not particularly limited, but may be, for example, bacteria of the genus Allorhizobium, Clavibacter, Pseudomonas, Xanthomonas, or Ralstonia.

[0056] Furthermore, the plants that can be controlled by the control agent of this embodiment are not particularly limited, but may include, for example, fruit trees, flowering plants, or vegetables, and may also include plants belonging to the asterids, roses, caryophyllales, or monocots.

[0057] Examples of plants belonging to the Asteraceae family include plants of the Asteraceae family, plants of the Apiaceae family, plants of the Campanulaceae family such as Codonopsis lanceolata, plants belonging to the Lamiidae family, plants of the Solanaceae family, plants of the Convolvulaceae family, and plants belonging to the Ericales order.

[0058] Examples of plants belonging to the rose family include cucurbitaceae, legumes, brassicas, roses, citrus, grapes, mallows, okra, molokhia, and cacao, and mulberries and figs.

[0059] Plants belonging to the order Caryophyllales include Amaranthaceae plants such as spinach and sea blite, Dianthusaceae plants such as carnations and so-called pinks, Basellaceae plants such as Malabar spinach, and Cactaceae plants such as cacti and night-blooming cereus.

[0060] Examples of plants belonging to the monocotyledonous order include gingeral plants such as turmeric, ginger, Japanese ginger, and banana, as well as grasses, lilies, amaryllidaceae, orchids, and other non-grass plants of the order Poales such as pineapple.

[0061] If the control agent of this embodiment is a control agent for bacterial black spot disease, the causative agent of bacterial black spot disease may be, for example, a bacterium of the genus Pseudomonas, such as Pseudomonas syringae pv. maculicola, or Pseudomonas viridiflava.

[0062] If the control agent of this embodiment is a control agent for bacterial black spot disease, the plants targeted for control of bacterial black spot disease (plants to be controlled) may be, for example, plants of the Brassicaceae, Solanaceae, Asteraceae, or Fabaceae families, but are not limited to these.

[0063] Examples of plants in the Brassicaceae family include broccoli, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, mizuna, komatsuna, turnip, radish, bok choy, radish, arugula, watercress, zha cai, or mustard greens.

[0064] Examples of plants in the Solanaceae family include eggplant, bell pepper, shishito pepper, chili pepper, potato, tomato, tobacco, jimsonweed, or petunia.

[0065] Examples of plants in the Asteraceae family include chrysanthemums, dahlias, marguerites, sunflowers, garland chrysanthemums, lettuce, burdock, and chicory.

[0066] Examples of leguminous plants include broad beans, kidney beans, adzuki beans, peas, sweet peas, soybeans, sword beans, and peanuts (Arachis hypogaea).

[0067] If the control agent of this embodiment is a control agent for black rot, the causative agent of black rot may be, for example, a bacterium of the genus Xanthomonas, or it may be Xanthomonas campestris pv. campestris.

[0068] If the control agent of this embodiment is a control agent for black rot, the plants targeted for control of black rot (plants to be controlled) may be, for example, plants of the Brassicaceae family. Examples of plants of the Brassicaceae family include the plants mentioned above.

[0069] If the control agent of this embodiment is a control agent for bacterial wilt, the causative agent of bacterial wilt may be, for example, a bacterium of the genus Ralstonia, or Ralstonia solanacearum (for example, Ralstonia pseudosolanacearum).

[0070] If the control agent of this embodiment is a control agent for bacterial wilt, the plants targeted for control of bacterial wilt (plants to be controlled) may be, for example, plants of the Solanaceae family or the Zingiberaceae family. Examples of plants of the Solanaceae family include the plants mentioned above.

[0071] Examples of plants in the Zingiberaceae family include ginger, Japanese ginger (myoga), turmeric, cardamom, ginger lily (Alpinia speciosa), and curcuma.

[0072] The type of control agent in this embodiment is not particularly limited, but may be, for example, a culture solution containing strain A3 or a diluted or concentrated solution thereof, a bodily fluid obtained from a plant inoculated with the control agent, water to which strain A3 has been added, or dried bacterial powder of strain A3.

[0073] The control agent of this embodiment may contain other components in addition to the aforementioned A3 strain, as long as they do not inhibit the control effect of A3 strain. Examples of components other than A3 strain include, but are not limited to, solvents such as water, carriers that are permissible for agricultural and horticultural use according to the conventional methods for agricultural and horticultural disease control agents, such as solid carriers, liquid carriers, gaseous carriers, etc., and components that serve as nutrients for A3 strain.

[0074] Nutrients for strain A3 include, but are not limited to, components of the culture medium such as carbon sources (e.g., sugars), nitrogen sources, minerals, and vitamins.

[0075] The control method using the control agent of this embodiment will be described in detail later in the embodiment of the control method.

[0076] [Plant Crown Leaf Disease Control Agent] In one embodiment, the present invention provides a plant crown leaf leaf disease control agent containing the above-mentioned Alorizobium vitis A3 strain as an active ingredient. Currently, there are no commercially available pesticides for controlling crown leaf leaf disease, so the crown leaf leaf disease control agent of this embodiment is extremely useful.

[0077] <Plants targeted by the crown gall disease control agent> The plants targeted for controlling crown gall disease using the control agent of this embodiment may be plants that have not yet developed crown gall disease, or plants that have already developed crown gall disease.

[0078] If the target plant is not infected with the crown gall fungus, using a crown gall control agent can prevent the onset of crown gall disease or reduce the symptoms if the disease does develop. If the target plant is infected with the crown gall fungus, using a crown gall control agent is expected to completely cure the disease, reduce its symptoms, and suppress the formation of new crown galls.

[0079] Three species of pathogens are known to cause crown gall disease: Allorhizobium vitis, Rhizobium rhizogenes, and Rhizobium radiobacter. The control agent of this embodiment is useful for controlling any of these pathogens.

[0080] The types of plants that can be controlled for crown gall disease using crown gall disease control agents are not particularly limited; for example, they may be vegetables, fruit trees, flowering plants, or even hops (scientific name: Humulus lupulus) of the Cannabaceae family.

[0081] (Vegetables) Examples of vegetables include, but are not limited to, plants of the daisy family. Examples of plants of the daisy family include plants of the nightshade family (tomatoes or potatoes, etc.), plants of the daisy family (garland chrysanthemum, etc.), and plants of the carrot family (carrots, etc.).

[0082] (Fruit trees) Examples of fruit trees include apples, pears, peaches, plums, cherries, and apricots of the Rosaceae family, or almonds, as well as grapes (Vitis spp.) of the Vitaceae family and kiwifruit of the Actinidiaceae family, but are not limited to these. Furthermore, plants targeted for control of crown gall disease may also be plants of the Vitaceae family.

[0083] (Flowering plants) Examples of flowering plants include chrysanthemums, marguerites, or dahlias of the Asteraceae family, and roses of the Rosaceae family, but are not limited to these.

[0084] The form of the crown gall control agent is not particularly limited and may be a liquid, powder, granule, tablet, etc. The same applies to the [tomato canker control agent] and [tomato crown gall and tomato canker control agent] which will be explained later.

[0085] The type of control agent in this embodiment is not particularly limited, but may be, for example, a culture solution containing strain A3 or a diluted or concentrated solution thereof, a bodily fluid obtained from a plant inoculated with the control agent, water to which strain A3 has been added, or dried bacterial powder of strain A3. The same applies to the [control agent for tomato canker] and [control agent for tomato crown gall and tomato canker] which will be explained later.

[0086] <Components other than strain A3> The control agent of this embodiment may contain other components in addition to strain A3, as long as they do not inhibit the control effect of strain A3. Examples of components other than strain A3 include, but are not limited to, solvents such as water, carriers that are permissible for agricultural and horticultural use in accordance with the conventional methods for agricultural and horticultural disease control agents, such as solid carriers, liquid carriers, gaseous carriers, etc., and components that serve as nutrients for strain A3.

[0087] Nutrients in the A3 strain include, but are not limited to, components of the culture medium such as carbon sources like sugars, nitrogen sources, minerals, and vitamins. The above details concern components other than those in the A3 strain, and the same applies to the control agents for tomato canker and tomato crown gall and tomato canker, which will be described in detail later.

[0088] The control method using the control agent of this embodiment will be described in detail later in the embodiment of the control method.

[0089] [Control agent for tomato canker] In one embodiment, the present invention provides a control agent for tomato canker containing the above-mentioned Alorizobium vitis A3 strain as an active ingredient.

[0090] (Plants targeted by the control agent) The plant targeted by the control agent for controlling tomato canker in this embodiment is the tomato (scientific name: Solanum lycopersicum).

[0091] The tomatoes targeted for control of tomato canker using the control agent of this embodiment may be tomatoes that have not yet developed tomato canker, or tomatoes that have already developed tomato canker.

[0092] If the tomatoes to be controlled are not infected with tomato canker, using the control agent of this embodiment can prevent the onset of tomato canker or reduce the symptoms even if wilting symptoms occur. If the tomatoes to be controlled are infected with tomato canker, using the control agent of this embodiment can be expected to completely cure the disease or reduce its symptoms.

[0093] The control method using the control agent of this embodiment will be described in detail later in the embodiment of the control method.

[0094] [Control agent for tomato crown gall disease and tomato canker disease] In one embodiment, the present invention provides a control agent for tomato crown gall disease and tomato canker disease, comprising the above-mentioned Alorizobium vitis A3 strain as an active ingredient.

[0095] (Plants targeted by the control agent) The plant targeted by the control agent in this embodiment for controlling crown gall disease and tomato canker is the tomato (scientific name: Solanum lycopersicum).

[0096] The tomatoes targeted for control of crown gall disease and tomato canker disease using the control agent of this embodiment may be tomatoes that have not yet developed crown gall disease and / or tomato canker disease, or tomatoes that have already developed crown gall disease and / or tomato canker disease.

[0097] If the tomato plants to be controlled are not infected with crown gall disease and tomato canker, using the control agent of this embodiment can prevent the onset of crown gall disease and tomato canker, or reduce the symptoms if the disease does develop. If the tomato plants to be controlled are infected with crown gall disease and / or tomato canker, using the control agent of this embodiment can be expected to completely cure or reduce the symptoms of crown gall disease and / or tomato canker.

[0098] The control agent of this embodiment is particularly useful as a control agent for crown gall disease caused by Allorizobium vitis, but similar control effects can be expected against crown gall disease caused by other crown gall disease fungi.

[0099] The control method using the control agent of this embodiment will be described in detail later in the embodiment of the control method.

[0100] [Method for controlling plant diseases caused by bacteria, method for controlling crown gall disease of plants] In one embodiment, the present invention provides a method for controlling plant diseases caused by bacteria, comprising the step of inoculating or attaching a control agent, as detailed in the above-described embodiment of [Control agent for plant diseases caused by bacteria], to a plant. Examples of plant diseases controlled by this control method include those detailed in the embodiment of [Control agent for plant diseases caused by bacteria], such as bacterial black spot, black rot, or bacterial wilt.

[0101] The pathogenic bacteria (causative agents) to be controlled by this control method are not particularly limited to bacteria, but may include, for example, bacteria of the genus Allorhizobium, Clavibacter, Pseudomonas, Xanthomonas, or Ralstonia, or may be pathogenic bacteria (causative agents) as detailed in the embodiments of [Control agents for plant diseases caused by bacteria].

[0102] The types of plants that can be controlled by this control method include the plant species detailed in the embodiment of [Control agent for plant diseases caused by bacteria]. For example, if the plant disease is bacterial black spot, the plants to which the control agent is inoculated or applied may be Brassicaceae, Solanaceae, Asteraceae, or Fabaceae plants. For example, if the plant disease is black rot, the plants to which the control agent is inoculated or applied may be Brassicaceae plants. For example, if the plant disease is bacterial wilt, the plants to which the control agent is inoculated or applied may be Solanaceae or Zingiberaceae plants.

[0103] Furthermore, in one embodiment, the present invention provides a method for controlling crown gall disease in plants, comprising the step of inoculating or attaching a control agent, as detailed in the above-described embodiment of [plant crown gall disease control agent], to a plant. Examples of plant types include, but are not limited to, vegetables, fruit trees, or flowers, as described above. Hereinafter, the step of inoculating or attaching a control agent, as detailed in the embodiment of [plant disease control agent caused by bacteria], or as detailed in the embodiment of [plant crown gall disease control agent], to a plant will also be referred to as the "inoculation / attachment step." The inoculation / attachment step will be described in detail below.

[0104] <Inoculation / Application Process> (Example of Inoculation Method) In inoculation of plants with a pesticide, the pesticide containing strain A3 is supplied into the plant to be controlled. The method of inoculation of the pesticide is not particularly limited, but examples include applying the pesticide to the tip of a needle and then piercing the plant with the tip of the needle, applying the bodily fluids of a plant that has already been inoculated with the pesticide (an example of the pesticide) to the plant to be controlled, or injecting the pesticide into the plant using a syringe. In addition, if the roots of a plant are immersed in the pesticide, the pesticide will be supplied into the plant through wounds in the roots.

[0105] When applying plant sap to a plant to be controlled, it is preferable to pre-abrase the surface of the application area on the plant with an abrasive such as carborundum. This allows the control agent to be efficiently delivered into the plant.

[0106] (Examples of application methods) On the other hand, methods of applying the control agent include, for example, immersing the plant roots in a liquid control agent (for example, a bacterial solution containing strain A3 or water to which strain A3 has been added), spraying the control agent on the above-ground parts of the plant (stem and leaves), or pouring the liquid control agent around the base of the plant. In particular, by applying the control agent to the roots of the plants before planting them in the field, it is possible to effectively prevent or suppress the infection of pathogenic bacteria such as crown gall fungus from the roots through the growing medium such as soil. It should be noted that strain A3 attached to the plant may also enter the plant body through stomata or wounds and multiply.

[0107] (Parts to which the control agent is inoculated or applied) The parts of the plant to which the control agent is inoculated or applied are not particularly limited, and may be, for example, the stem, roots, leaves, flowers, fruits, or seed coats.

[0108] (Timing of inoculation or application of control agents) The growth stage of the plants to which the control agents are inoculated or applied is not particularly limited; for example, they may be seeds, seedlings, young trees, plants after planting, or older plants (old trees).

[0109] (Amount of control agent inoculated or applied) The amount of A3 strain contained in the control agent inoculated or applied to the plant is not particularly limited, but if the control agent is in liquid form, for example, 1 × 10 ７ It may be 5 × 10 ７ It may be 1 × 10⁻⁶ or more, ８ The concentration may be higher than cells / mL. Furthermore, the amount of control agent inoculated or applied should be such that, for example, the number of bacteria in strain A3 is 1 × 10⁻⁶. ３ The amount may be greater than or equal to cells, and the number of bacteria in strain A3 is 1 x 10 ４ The amount may be greater than or equal to cells, 1 × 10 ５ The quantity may be greater than or equal to the number of cells, but is not limited to these quantities.

[0110] The above describes in detail the inoculation / adhesion process in embodiments of methods for controlling plant diseases caused by bacteria and plant crown gall disease. The same applies to the inoculation / adhesion process in the methods for controlling tomato canker and tomato crown gall disease, which are described in detail below. However, the type of plant to which the control agent is inoculated or applied is the tomato.

[0111] [Method for controlling tomato canker] In one embodiment, the present invention provides a method for controlling tomato canker, comprising the step of inoculating or attaching a tomato canker control agent containing Alorizobium vitis A3 strain as an active ingredient to tomatoes. The control agent is the control agent described in detail in the above embodiment of [Tomato Canker Control Agent].

[0112] According to the control method of this embodiment, by inoculating or applying a control agent containing strain A3 to tomatoes, the pathogen of tomato canker (Clavibacter miciganensis subsp. miciganensis) can be controlled, preventing tomato canker, and suppressing wilting symptoms.

[0113] [Method for controlling tomato crown gall disease and tomato canker] In one embodiment, the present invention provides a method for controlling tomato crown gall disease and tomato canker, comprising the step of inoculating or attaching a control agent for tomato crown gall disease and tomato canker, which contains Alorizobium vitis A3 strain as an active ingredient, to tomatoes. The control agent is the control agent described in detail in the above embodiment of [Control agent for tomato crown gall disease and tomato canker].

[0114] According to the control method of this embodiment, by inoculating or applying a control agent containing strain A3 to tomatoes, crown gall disease and tomato canker can be prevented, and the symptoms are expected to be suppressed.

[0115] [Cultivation soil] In one embodiment, the present invention provides cultivation soil containing the above-mentioned Allorizobium vitis A3 strain.

[0116] The specific type of growing soil is not particularly limited, but may include, for example, Kanuma soil, Kuroboku soil, Akadama soil, baked Akadama soil, vermiculite, perlite, zeolite, compost, leaf mold, pumice, peat moss, pulp, straw, bagasse, charcoal, or a mixture of one or all of these, or it may be so-called potting soil for horticulture.

[0117] The growing medium may also contain fertilizer components. Examples of fertilizer components include, but are not limited to, oil cake, fish meal, bone meal, chicken manure, cow manure, and various chemical fertilizers.

[0118] The growing medium may also contain components that serve as nutrients for the A3 strain. Examples of components that serve as nutrients for the A3 strain include the growing medium components mentioned above.

[0119] The growing medium may be growing medium used for growing fruit trees, flowers, or vegetables, or it may be growing medium used for growing tomatoes.

[0120] By using the cultivation soil of this embodiment for plant cultivation, it is expected that the onset of plant diseases caused by soil-borne bacteria, such as crown gall, tomato canker, bacterial black spot, black rot, and bacterial wilt, can be prevented or their symptoms can be suppressed.

[0121] [Soil Conditioner] In one embodiment, the present invention provides a soil conditioner containing the above-mentioned Allorizobium vitis A3 strain. The soil is agricultural soil, and the soil conditioner of this embodiment contains Allorizobium vitis A3 strain as an active ingredient for soil improvement.

[0122] The amount (percentage) of A3 strain in the soil conditioner is not particularly limited, but may be, for example, 0.01 to 100% by mass, 0.01 to 90% by mass, 0.1 to 70% by mass, 1 to 50% by mass, 0.1 to 10% by mass, 0.01 to 0.5% by mass, 10 to 100% by mass, or 30 to 100% by mass.

[0123] The soil conditioner may contain other components besides strain A3, as long as they do not inhibit the control effect of strain A3. The types of other components are not particularly limited, but examples include surfactants, pH adjusters, oils and fats, plant fiber materials, solidifying agents, preservatives, carriers, defoaming agents, binders, stabilizers, and components that serve as nutrients for strain A3. Examples of components that serve as nutrients for strain A3 include the culture medium components mentioned above.

[0124] By mixing the soil conditioner of this embodiment into field soil or cultivation soil, it is possible to prevent the onset of plant diseases caused by bacteria, such as crown gall, tomato canker, bacterial black spot, black rot, and bacterial wilt. Furthermore, even in soil where these pathogens have already proliferated, it is possible to suppress the growth of these pathogens and thus suppress plant diseases caused by bacteria.

[0125] [Seeds] In one embodiment, the present invention provides plant seeds on which the above-mentioned Allorizobium vitis A3 strain is attached to the surface.

[0126] By sowing seeds with A3 strain attached to the surface (surface of the seed coat), A3 strain can be attached to the leaves, stems, and / or roots of the seedlings at or after germination. Furthermore, since A3 strain is also attached to the soil near the sown seeds, it is possible to suppress the growth of bacteria that cause plant diseases after germination, such as crown gall, tomato canker, bacterial black spot, black rot, and bacterial wilt. This effectively prevents the onset of plant diseases caused by bacteria in plants germinated from these seeds, and also reduces the symptoms if the disease does occur.

[0127] The plant species of the seeds are not particularly limited, but may be, for example, the plants detailed in the embodiment of [a control agent for plant diseases caused by bacteria], such as fruit trees, flowering plants, or vegetables; may be plants belonging to the asterids, roses, caryophyllales, or monocots; may be plants of the Vitaceae, Brassicaceae, Asteraceae, or Solanaceae families; and may be grapes, Chinese cabbage, chrysanthemums, and tomatoes.

[0128] Methods for attaching strain A3 to plant seeds include, but are not limited to, immersing the seeds in the aforementioned control agents such as a bacterial solution of strain A3 or water to which strain A3 has been added; rolling the seeds on a solid culture medium on which colonies of strain A3 have formed; sprinkling dried bacterial powder of strain A3 on the seeds; or spraying the aforementioned control agents.

[0129] [Seedling] In one embodiment, the present invention provides a plant seedling having the above-described Alorizobium vitis A3 strain.

[0130] The seedlings of this embodiment have A3 plants either inside or on the surface of the plant. Methods for producing such seedlings include, but are not limited to, the methods detailed in the inoculation / attachment step described above, or the method for germinating seeds detailed in the [seed] embodiment described above.

[0131] Seedlings containing the A3 strain can prevent the onset of plant diseases caused by bacteria, such as crown gall, tomato canker, bacterial black spot, black rot, and bacterial wilt, compared to seedlings without the A3 strain. Furthermore, even if the disease does occur, the symptoms can be mitigated.

[0132] The plant species of seedlings in this embodiment are not particularly limited, but may be plants as detailed in the embodiment of [a control agent for plant diseases caused by bacteria], for example, plants belonging to the asterids, plants belonging to the roses, plants belonging to the caryophyllales, or plants belonging to monocots, or they may be fruit trees, flowering plants, or vegetables, or they may be plants of the Vitaceae, Brassicaceae, Asteraceae, or Solanaceae families, or they may be grapes, Chinese cabbage, chrysanthemums, or tomatoes.

[0133] [Other Embodiments] In another embodiment, the present invention provides the use of the above-described Alorizobium vitis A3 strain for producing a control agent for bacterial plant diseases. This "control agent for bacterial plant diseases" is the same as the control agent detailed in the above-described embodiment of the [control agent for bacterial plant diseases]. Therefore, the control agent produced by this use may be used, for example, to control crown gall, tomato canker, bacterial spot disease, black rot, or bacterial wilt, or to control bacterial spot disease, black rot, or bacterial wilt. The control agents produced by this use may be used, for example, to control diseases in fruit trees, flowers, or vegetables; to control diseases in plants belonging to the asterids, roses, caryophyllales, or monocots; to control diseases in plants of the vitaceae, brassicaceae, daisyaceae, or nightshadeaceae families; and to control diseases in grapes, Chinese cabbage, chrysanthemums, or tomatoes.

[0134] In another embodiment, the present invention provides the use of the above-described Alorizobium vitis A3 strain for producing a plant crown gall disease control agent. This "plant crown gall disease control agent" is the same as the control agent detailed in the above-described [plant crown gall disease control agent]. Therefore, the types of plants may include, but are not limited to, fruit trees, flowering plants, or vegetables.

[0135] In another embodiment, the present invention provides the use of the above-described Alorizobium vitis A3 strain for producing a tomato canker control agent. This "tomato canker control agent" is the same as the control agent detailed above in [Tomato Canker Control Agent].

[0136] In another embodiment, the present invention provides the use of the above-described Alorizobium vitis A3 strain for producing a control agent for tomato crown gall disease and tomato canker disease. This "control agent for tomato crown gall disease and tomato canker disease" is the same as the control agent detailed above in [Control agent for tomato crown gall disease and tomato canker disease].

[0137] In another embodiment, the present invention can provide the above-described Allorizobium vitis A3 strain for controlling bacterial plant diseases. Bacterial plant diseases are as detailed in the embodiment of the "Control Agent for Bacterial Plant Diseases".

[0138] The present invention is not limited to the embodiments described above, and it goes without saying that various modifications are possible within the scope of the invention as described in the claims, and these modifications are also included within the scope of the present invention.

[0139] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0140] [Experimental Example 1] In this experiment, tomato stems were inoculated with the crown gall fungus and strain A3, and the presence or absence of galls and the diameter of the galls were checked.

[0141] In detail, first, a bacterial suspension of Alorizobium vitis strain A3 and a bacterial suspension of Alorizobium vitis strain VAT03-9 (crown gall disease fungus) were mixed in a 1:1 ratio. For each bacterial suspension, colonies obtained by culturing strain A3 or VAT03-9 on potato dextrose agar plates (Potato Dextrose Agar, PDA, 4.0 g potato starch, 20.0 g dextrose, 15.0 g agar) at 27°C for 48 hours were scooped out with a platinum loop and suspended in sterile water. ８ This is a bacterial suspension adjusted to a concentration of cell / mL.

[0142] The resulting mixture was applied to the tip of a needle, and the tip of the needle was used to inoculate the stems of tomato plants (Solanum lycopersicum) (experimental group). A control group was also prepared in which the tomatoes were inoculated with a mixture of sterile water and the VAT03-9 strain instead of the above mixture. In both the experimental and control groups, 10 tomato seedlings were provided, and each seedling's stem was inoculated in a total of 5 places, resulting in a total of 50 inoculation sites.

[0143] Approximately four weeks after the administration of the mixed solution, the presence or absence of tumors at each injection site was checked, and if tumors had developed, their diameter was confirmed.

[0144] Figure 1 is an image showing the stem of a tomato in the control group inoculated with the crown gall bacterium. Figure 2 is an image showing the stem of a tomato in the experimental group inoculated with Agrobacterium vitis A3 strain and the crown gall bacterium. In Table 1 below, for the tomatoes in the experimental group and the control group, the number of seedlings with tumor 1 formed and the number of seedlings without tumor 1 formed are shown. Regarding the presence or absence of tumor 1 formation in the experimental group and the control group, a significant difference was observed by Fisher's Exact Test with p < 2.2×10 －１６ and a significant difference was observed.

[0145]

[0146] As shown in Figure 1 and Table 1, tumor 1 formation was observed at the inoculation site 3 on the stems of most seedlings in the control group inoculated with the crown gall bacterium. In contrast, only wounds caused by needle punctures remained at the inoculation site 3 in Figure 2 on the stems of most seedlings in the experimental group inoculated with A3 strain and the crown gall bacterium, and no tumor 1 formation was observed.

[0147] In Table 2 below, for the tomatoes in the experimental group and the control group, the proportion of seedlings with tumor 1 formed and the risk ratio of tumor 1 formation are shown. The risk ratio of tumor 1 formation is the value obtained by dividing the value of the proportion of seedlings with tumor 1 formed in the experimental group by the value of the proportion of seedlings with tumor 1 formed in the control group.

[0148]

[0149] As shown in Table 2, the risk of tumor 1 formation in tomatoes inoculated with A3 strain is 0.04 times that of tomatoes not inoculated with A3 strain. By inoculating with A3 strain, the risk of tumor 1 formation in tomatoes decreased to 0.04. This indicates that the disease suppression rate of crown gall disease by A3 strain is 96%.

[0150] Figure 3 is a graph showing the diameter distribution and average diameter of tumor 1 formed in tomatoes in the experimental group and the control group. In Figure 3, "***" indicates a significant difference by t-test with p < 2.2×10 －１６ and indicates a significant difference.

[0151] As shown in Figure 3, the tumor 1 formed in the experimental tomatoes was significantly smaller than the tumor 1 formed in the control tomatoes.

[0152] From these results, it was revealed that inoculating tomatoes with the Alorizobium vitis A3 strain effectively suppresses the formation of crown gall 1 and thus controls crown gall disease.

[0153] [Experimental Example 2] In this experiment, grape seedlings were used instead of tomato seedlings, but the experiment was the same as in Experimental Example 1.

[0154] Figure 4 shows an image of grape stems in the control group inoculated with the crown gall fungus. Figure 5 shows an image of grape stems in the experimental group inoculated with Alorizobium vitis A3 strain and the crown gall fungus.

[0155] Table 3 below shows the number of seedlings that developed gall tumors and the number of seedlings that did not develop gall tumors for both the experimental and control groups. The presence or absence of gall tumors in the experimental group and the control group was determined by Fisher's Exact Test to be p < 2.2 × 10⁻⁶. －１６ A statistically significant difference was observed.

[0156]

[0157] As shown in Figure 4 and Table 3, in the control group, where most seedlings were inoculated with a mixture of sterile water and crown gall bacterium (VAT03-9 strain), tumor formation 1 was observed at inoculation site 3. In contrast, in the experimental group, where most seedlings were inoculated with strain A3 and crown gall bacterium, only needle puncture wounds remained at inoculation site 3 as shown in Figure 5, and no tumor formation 1 was observed.

[0158] Table 4 below shows the percentage of seedlings in which gall 1 was formed and the risk ratio for gall 1 formation for grapes in the experimental group and the control group. The risk ratio for gall 1 formation is calculated by dividing the percentage of seedlings in the experimental group in which gall 1 was formed by the percentage of seedlings in the control group in which gall 1 was formed.

[0159]

[0160] As shown in Table 4, the risk of crown gall 1 formation in grapes inoculated with strain A3 was 0.065 times that of grapes not inoculated with strain A3, indicating that inoculation with strain A3 reduced the risk of crown gall 1 formation in grapes to 0.065. This demonstrates that strain A3 suppresses the development of crown gall disease in 93.5% of cases.

[0161] Figure 6 is a graph showing the diameter distribution and average diameter of tumor 1 formed in grapes from the experimental group and the control group. In Figure 6, "***" indicates that p < 2.2 × 10⁻¹⁶ was determined by a t-test. －１６ This indicates a statistically significant difference.

[0162] As shown in Figure 6, the tumor 1 formed in the experimental grapes was significantly smaller than the tumor 1 formed in the control grapes.

[0163] The results above clearly demonstrate that inoculating grapes with Alorizobium vitis A3 strain effectively suppresses the formation of crown gall 1. Furthermore, since the inhibitory effect on crown gall 1 formation was confirmed in grapes as well as tomatoes, it is suggested that the control effect of A3 strain on crown gall disease is not limited to specific plant species.

[0164] [Experimental Example 3] In this experiment, the effectiveness of immersing the roots of grape seedlings in a fungal solution containing strain A3 in controlling crown gall disease was confirmed.

[0165] In detail, first, the concentration of Allorizobium vitis A3 strain was 10 ８ A bacterial solution was prepared in the same manner as in Experimental Example 1 to achieve a cell / mL concentration, and the roots of grape seedlings were immersed in this solution for one hour (experimental group). A control group was also prepared in which the roots of grape seedlings were immersed in sterile water instead of the bacterial solution of strain A3.

[0166] After immersion in bacterial solution or sterile water, 10 ８ Contaminated soil containing a cellus / mL concentration of Allorizobium vitis VAT03-9 (crown gall disease fungus) was added to the soil, and the contaminated soil was placed in pots. Grape seedlings were then planted in these pots and cultivated for approximately five months. After that, the roots of the grape seedlings were dug up to check for the presence or absence of crown gall formation. Thirty grape seedlings were used in both the experimental and control groups.

[0167] Figure 7 shows the roots of control grape seedlings immersed in sterile water and cultivated for five months in soil contaminated with crown gall fungus. Figure 8 shows the roots of experimental grape seedlings immersed in a bacterial solution containing Allorizobium vitis A3 strain and cultivated for five months in soil contaminated with crown gall fungus. Table 5 below shows the number of seedlings in which crown gall 1 formed and the number of seedlings in which crown gall 1 did not form for the experimental and control grapes. The presence or absence of crown gall 1 in the experimental and control groups was assessed using Fisher's Exact Test, yielding p = 3.72 × 10⁻⁶. －４ A statistically significant difference was observed.

[0168]

[0169] As shown in Figure 7 and Table 5, the formation of gall tumor 1 was observed in the roots of half of the seedlings in the control group immersed in sterile water. In contrast, the formation of gall tumor 1 was not observed in the roots of most of the seedlings in the experimental group immersed in a bacterial solution containing strain A3.

[0170] Table 6 below shows the percentage of seedlings in which gall 1 was formed and the risk ratio for gall 1 formation for grapes in the experimental group and the control group. The risk ratio for gall 1 formation is calculated by dividing the percentage of seedlings in the experimental group in which gall 1 was formed by the percentage of seedlings in the control group in which gall 1 was formed.

[0171]

[0172] As shown in Table 6, the risk of crown gall 1 formation in grapes immersed in a bacterial solution containing strain A3 was 0.133 times that of grapes immersed in sterile water. This indicates that the presence of strain A3 reduced the risk of crown gall 1 formation in grapes to 0.133. This demonstrates that strain A3 suppresses the development of crown gall disease by 86.7%.

[0173] From these results, it became clear that attaching Allorizobium vitis A3 to the roots of grape seedlings effectively suppresses the formation of crown gall 1 and can control crown gall disease.

[0174] [Experimental Example 4] In this experiment, the effectiveness of attaching plant A3 to tomato seedlings in controlling tomato canker was confirmed.

[0175] In detail, first, the concentration of Allorizobium vitis A3 strain was 10 ８ A bacterial solution prepared in the same manner as in Experimental Example 1 to achieve a cell / mL concentration was sprayed onto the above-ground parts (stem and leaves) of tomato seedlings and air-dried for approximately one hour (experimental group). A control group was also prepared in which sterile water was sprayed instead of the bacterial solution containing strain A3.

[0176] After spraying with a bacterial solution of strain A3 or sterile water, the concentration of the tomato canker fungus (Clavibacter michiganensis subsp. michiganensis CMM16-3 strain) reached 10 ８ A fungal solution adjusted to a concentration of cells / mL was sprayed onto the above-ground parts of the tomato seedlings, and the presence or absence of wilting symptoms was checked approximately four weeks later. Forty tomato seedlings were used in both the experimental and control groups.

[0177] Figure 9 shows images of tomato seedlings in the control group, which were sprayed with sterile water and tomato canker fungus, and tomato seedlings in the experimental group, which were sprayed with Alorizobium vitis A3 strain and tomato canker fungus. Table 7 below shows the number of seedlings in the experimental group and the control group that showed signs of tomato canker disease, as well as the number of seedlings that did not show signs of the disease. The presence or absence of tomato canker disease in the experimental group and the control group was assessed using Fisher's Exact Test, yielding p = 1.1 × 10⁻⁶. －６ A statistically significant difference was observed.

[0178]

[0179] As shown in Figure 9 and Table 7, in the control group sprayed with sterile water and tomato canker fungus, half of the tomato seedlings developed tomato canker disease (wilting symptoms). In contrast, in the experimental group sprayed with A3 strain and tomato canker fungus, no tomato seedlings developed tomato canker disease (wilting symptoms).

[0180] Table 8 below shows the percentage of plants that developed tomato canker and the disease risk ratio for tomatoes in the experimental group and the control group. The disease risk ratio is calculated by dividing the percentage of seedlings that developed tomato canker in the experimental group by the percentage of seedlings that developed tomato canker in the control group.

[0181]

[0182] As shown in Table 8, the risk of developing tomato canker in tomatoes treated with A3 strain was 0. This indicates that the disease suppression rate of tomato canker by applying A3 strain to tomatoes is 100%.

[0183] These results suggest that applying a fungal solution containing Alorizobium vitis A3 strain to tomato seedlings can effectively suppress the development of tomato canker disease.

[0184] [Experimental Example 5] In this experiment, the same experiment as in Experimental Example 4 was carried out in a different test area.

[0185] Figure 10 shows an image of tomato seedlings in a control plot in another test area, where sterile water and tomato canker fungus were sprayed. Figure 11 shows an image of tomato seedlings in an experimental plot in another test area, where Alorizobium vitis A3 strain and tomato canker fungus were sprayed. Table 9 below shows the number of seedlings in the experimental plots and the control plots that showed signs of tomato canker disease, as well as the number of seedlings that did not show signs of the disease. The presence or absence of tomato canker disease in the experimental plots and the control plots was assessed using Fisher's Exact Test with a p-value of 4.2 × 10⁻⁶. －８ A statistically significant difference was observed.

[0186]

[0187] As shown in Figure 10 and Table 9, in the control group sprayed with sterilized water and tomato canker fungus, more than half of the tomato seedlings developed tomato canker disease (wilting symptoms). In contrast, as shown in Figure 11 and Table 9, in the experimental group sprayed with A3 strain and tomato canker fungus, although a small number of seedlings developed tomato canker disease, most tomato seedlings did not develop the disease.

[0188] Table 10 below shows the percentage of plants that developed tomato canker and the disease risk ratio for tomatoes in the experimental group and the control group.

[0189]

[0190] As shown in Table 10, the risk of developing tomato canker in tomatoes treated with A3 strain was 0.08 times that of tomatoes not treated with A3 strain. This indicates that the rate of suppression of tomato canker by applying A3 strain to tomatoes is 92%.

[0191] These results further suggest that applying a fungal solution containing Alorizobium vitis A3 strain to tomato seedlings can effectively suppress the development of tomato canker disease.

[0192] [Experimental Example 6] In this experiment, the effectiveness of immersing tomato seedlings in a fungal solution containing strain A3 in controlling tomato canker was confirmed.

[0193] In detail, first, the concentration of Allorizobium vitis A3 strain was 10 ８ A bacterial solution was prepared in the same manner as in Experimental Example 1 to achieve a cell / mL concentration, and the roots of tomato seedlings were immersed in this solution for one hour (experimental group). A control group was also prepared in which the roots of tomato seedlings were immersed in sterile water instead of the bacterial solution of strain A3.

[0194] Next, 10 ７Tomato seedlings were planted in pots containing soil contaminated with a cellus / mL concentration of Alorizobium vitis VAT03-9 strain (crown gall disease fungus). Tomato seedlings were then cultivated in these pots for approximately one month. Afterward, the presence or absence of tomato canker disease in each seedling was checked. Forty tomato seedlings were used in both the experimental and control groups.

[0195] Figure 12 shows the condition of tomato seedlings from the control group after being immersed in sterile water and cultivated for one month in contaminated soil containing the tomato canker fungus. Figure 13 shows the condition of tomato seedlings from the experimental group after being immersed in a fungal solution containing Alorizobium vitis A3 strain and cultivated for one month in contaminated soil containing the tomato canker fungus. Table 11 below shows the number of seedlings that developed tomato canker disease and the number of seedlings that did not develop tomato canker disease for both the experimental group and the control group. The presence or absence of tomato canker disease in the experimental group and the control group was assessed using Fisher's Exact Test with p = 5.8 × 10⁻⁶. －８ A statistically significant difference was observed.

[0196]

[0197] As shown in Figure 12 and Table 11, tomato canker disease was observed in 4 / 5 of the seedlings in the control group immersed in sterile water. In contrast, in the experimental group immersed in a fungal solution containing strain A3, tomato canker disease was observed in 6 seedlings, but the majority of the seedlings did not develop the disease.

[0198] Table 12 below shows the percentage of seedlings that developed tomato canker disease and the risk ratio of developing tomato canker disease for tomatoes in the experimental group and the control group.

[0199]

[0200] As shown in Table 12, the risk of developing tomato canker in tomatoes immersed in a bacterial solution containing strain A3 was 0.188 times that of tomatoes immersed in sterile water. This indicates that the presence of strain A3 reduced the risk of developing tomato canker in tomatoes to 0.188. This demonstrates that strain A3 suppressed tomato canker by 81.2%.

[0201] From these results, it has become clear that attaching Alorizobium vitis A3 to the roots of tomato seedlings effectively suppresses the onset of tomato canker disease and allows for its control.

[0202] [Experimental Example 7] In this experiment, Chinese cabbage leaves were inoculated with Chinese cabbage black spot bacterial disease fungus and strain A3, and the control effect on black spot bacterial disease was confirmed.

[0203] In detail, first, the concentration of Allorizobium vitis A3 strain was 10 ８ Prepare a bacterial suspension in the same manner as in Experimental Example 1 to a concentration of cells / mL, and add 10 units each of strain A3 and the cabbage black spot bacterial pathogen (Pseudomonas syringae pv. maculicola MAFF302539 strain). ８ The cells were mixed in a 1:1 ratio at a concentration of cells / mL.

[0204] The resulting mixture was applied to the tip of a needle, and the tip of the needle was used to inoculate a Chinese cabbage leaf near the base (number of Chinese cabbage plants n=24, experimental group). A control group was also prepared in which sterile water and Chinese cabbage black spot bacterial pathogen were mixed and inoculated into the Chinese cabbage instead of the above mixture. Approximately 10 days after inoculation of the Chinese cabbage, the presence or absence of the development of black spot bacterial disease was checked.

[0205] Figure 14 shows images of the area around the inoculation site of Chinese cabbage in the experimental and control groups inoculated with the cabbage black spot bacterial disease fungus. In Figure 14, the inoculation site of strain A3 and the pathogen are indicated by arrows. Table 13 below shows the number of plants in the experimental and control groups that developed black spot bacterial disease and the number of plants that did not. The Fisher's Exact Test showed a p-value of 4.6 × 10⁻¹⁰ between the presence or absence of black spot bacterial disease in the experimental group and the presence or absence of black spot bacterial disease in the control group. －６ A statistically significant difference was observed.

[0206]

[0207] As shown in Figure 14 and Table 13, in the control group inoculated with sterile water, dark lesions due to advanced tissue decay were observed near the inoculation site in 3 / 4 of the plants. In contrast, in the experimental group inoculated with strain A3, although the inoculation site was visible, lesion formation was not observed in most plants. Table 14 below shows the percentage of plants that developed bacterial black spot disease and the disease risk ratio for Chinese cabbage in the experimental group and the control group.

[0208]

[0209] As shown in Table 14, the risk of developing bacterial spot disease in plants inoculated with strain A3 was 0.11 times that of plants not inoculated with strain A3. This indicates that the rate of suppression of bacterial spot disease by inoculating with strain A3 is 89%.

[0210] From these results, it became clear that bacterial black spot disease can be controlled by inoculating with the Allorizobium vitis A3 strain.

[0211] [Experimental Example 8] In this experiment, the cabbage leaves were sprayed with the cabbage black spot bacterial disease fungus and strain A3 to confirm the control effect on black spot bacterial disease.

[0212] In detail, first, the concentration of Allorizobium vitis A3 strain was 10 ８ Prepare a bacterial suspension in the same manner as in Experimental Example 1 to a concentration of cells / mL, and add 10 units each of strain A3 and the cabbage black spot bacterial pathogen (Pseudomonas syringae pv. maculicola MAFF302539 strain). ８ Cabbage seedlings were sprayed with a solution at a concentration of cells / mL (experimental group). Four weeks after spraying, the number of leaves that developed bacterial black spot disease was counted. There were 20 cabbage plants, and the presence or absence of disease was checked on 5 leaves per plant (number of leaves n=100). In addition, a control group was set up in which sterile water was sprayed instead of the A3 plants.

[0213] Figure 15 shows images of cabbage leaves from the experimental group and the control group, both treated with the cabbage black spot bacterial disease fungus. Table 15 below shows the number of leaves showing symptoms of black spot bacterial disease (infected) and the number of leaves not showing symptoms (not affected) in the cabbage from the experimental and control groups. The Fisher's Exact Test showed a p-value of 3.1 × 10⁻¹⁰ between the presence or absence of black spot bacterial disease symptoms in the experimental group and the control group. －９ A statistically significant difference was observed.

[0214]

[0215] As shown in Figure 15 and Table 15, in the control group sprayed with sterile water, small black spots formed along the veins on about one-third of the leaves, and symptoms of leaf wilting and rot were observed (symptoms of bacterial black spot disease). In contrast, in the experimental group sprayed with strain A3, almost no symptoms of bacterial black spot disease were observed on the leaves.

[0216] Table 16 below shows the percentage of leaves affected by bacterial black spot disease and the disease risk ratio for Chinese cabbage in the experimental group and the control group.

[0217]

[0218] As shown in Table 16, the risk of developing bacterial spot disease when sprayed with strain A3 was 0.09 times that of when not sprayed with strain A3. This indicates that spraying with strain A3 suppresses the development of bacterial spot disease by 91%.

[0219] From these results, it became clear that bacterial black spot disease can be controlled simply by spraying the A3 strain, instead of inoculating it.

[0220] [Experimental Example 9] In this experiment, the cabbage black rot fungus and strain A3 were sprayed onto the leaves of Chinese cabbage to confirm the control effect on black rot disease.

[0221] In detail, first, the concentration of Allorizobium vitis A3 strain was 10 ８Prepare a bacterial suspension in the same manner as in Experimental Example 1 to achieve a cell / mL ratio, and add 10 units each of strain A3 and the cabbage black rot fungus (Xanthomonas campestris pv. campestris MAFF106702 strain). ８ Cabbage seedlings were sprayed with a cellus / mL concentration (experimental group). Four weeks after spraying, the number of leaves that developed black rot was counted. There were 20 cabbage plants, and the presence or absence of disease was checked on 8 leaves per plant (number of leaves n=160). In addition, a control group was set up in which sterile water was sprayed instead of the A3 plants.

[0222] Figure 16 shows images of cabbage leaves from the experimental and control groups treated with the cabbage black rot fungus. Table 17 below shows the number of leaves showing symptoms of black rot (infected) and the number of leaves not showing symptoms (not affected) in the experimental and control groups. The Fisher's Exact Test showed a p-value of 2.7 × 10⁻¹⁰ between the presence or absence of black rot symptoms in the experimental group and the control group. －７ A statistically significant difference was observed.

[0223]

[0224] As shown in Figure 16 and Table 17, in the control group sprayed with sterile water, large yellow or brownish lesions formed on about one-third of the leaves, and leaf rot symptoms were observed (symptoms of black rot). In contrast, in the experimental group sprayed with strain A3, almost no symptoms of black rot were observed on the leaves.

[0225] Table 18 below shows the percentage of leaves affected by black rot and the disease risk ratio for Chinese cabbage in the experimental group and the control group.

[0226]

[0227] As shown in Table 18, the risk of developing black rot when sprayed with strain A3 was 0.30 times that of when not sprayed with strain A3. This indicates that spraying with strain A3 suppresses the incidence of bacterial black spot disease by 70%.

[0228] From these results, it became clear that black rot can be controlled by spraying with strain A3.

[0229] [Experimental Example 10] In this experiment, tomato seedlings were immersed in a solution containing strain A3, and then transplanted into pots containing contaminated soil with tomato bacterial wilt fungus. The effectiveness of this method in controlling bacterial wilt was confirmed.

[0230] In detail, first, the concentration of Allorizobium vitis A3 strain was 10 ８ A bacterial solution was prepared in the same manner as in Experimental Example 1 to achieve a cell / mL concentration, and the roots of tomato seedlings were immersed in this solution for one hour (experimental group). A control group was also prepared in which the roots of tomato seedlings were immersed in sterile water instead of the bacterial solution of strain A3.

[0231] Next, tomato seedlings from the experimental and control groups were infected with the tomato bacterial wilt fungus (Ralstonia solanaceaum (more specifically, Ralstonia pseudosolanaceaum) MAFF106603 strain, 10 ７ Tomato seedlings were transplanted into pots containing contaminated soil (at a concentration of cells / mL) and cultivated for approximately four weeks. Afterward, the presence or absence of bacterial wilt (wilting symptoms) was examined. The number of tomato seedlings in the experimental and control groups was n=40.

[0232] Figure 17 shows images of tomato seedlings from the experimental and control groups planted in soil contaminated with the tomato bacterial wilt fungus. Table 19 below shows the number of plants in the experimental and control groups that showed signs of bacterial wilt (infected) and the number of plants that did not show signs of bacterial wilt. The Fisher's Exact Test showed a p-value of 8.9 × 10⁻¹⁰ between the presence or absence of bacterial wilt in the experimental group and the control group. －１３ A statistically significant difference was observed.

[0233]

[0234] As shown in Figure 17 and Table 19, in the control group where the roots were immersed in sterile water, all plants withered and died while their leaves were still green (symptoms of bacterial wilt). In contrast, in the experimental group where the roots were immersed in a bacterial solution of strain A3, the number of plants that developed bacterial wilt was limited to about one-quarter of the total.

[0235] Table 20 below shows the percentage of plants that developed bacterial wilt and the disease risk ratio for tomatoes in the experimental group and the control group.

[0236]

[0237] As shown in Table 20, the risk of bacterial wilt when roots were immersed in a solution of strain A3 was 0.275 times that of when roots were immersed in sterile water. This indicates that strain A3 suppressed bacterial wilt by 72.5%.

[0238] From these results, it became clear that bacterial wilt can be controlled by attaching the A3 strain to the roots.

[0239] [Experimental Example 11] In this experiment, chrysanthemum stems were inoculated with Rhizobium radiobacter A3 strain, a type of crown gall disease fungus, and the presence or absence of galls and the diameter of the galls were confirmed.

[0240] In detail, first, a bacterial suspension of Rhizobium vitis A3 strain and a bacterial suspension of Rhizobium radiobacter (Ti) CH1 strain isolated from chrysanthemums were mixed in a 1:1 ratio. Colonies obtained by culturing strain A3 or CH1 on potato dextrose agar plates (Potato Dextrose Agar, PDA, 4.0 g potato starch, 20.0 g dextrose, 15.0 g agar) at 27°C for 48 hours were scooped out with a platinum loop and suspended in sterile water. ８ This is a bacterial suspension adjusted to a concentration of cells / mL.

[0241] The resulting mixture was applied to the tip of a needle, and the tip of the needle was used to inoculate the stems of chrysanthemum plants (experimental group). A control group was also prepared in which a mixture of sterile water and the CH1 strain was used to inoculate the stems of chrysanthemum plants instead of the above mixture. In both the experimental and control groups, five chrysanthemum seedlings were provided, and each seedling's stem was inoculated in 10 places, resulting in a total of n = 50 inoculation sites.

[0242] Approximately four weeks after the administration of the mixed solution, the presence or absence of tumors at each injection site was checked, and if tumors had developed, their diameter was confirmed.

[0243] Figure 18 shows images of chrysanthemum stems from the experimental and control groups inoculated with crown gall fungus. Table 21 below shows the number of seedlings with crown gall 1 and the number of seedlings without crown gall 1 for both the experimental and control groups. The presence or absence of crown gall 1 in the experimental group and the control group was assessed using Fisher's Exact Test, yielding p < 2.2 × 10⁻⁶. －１６ A statistically significant difference was observed.

[0244]

[0245] As shown in Figure 18 and Table 21, tumor formation 1 was observed at approximately 4 / 5 of the inoculation sites in the control group inoculated with sterile water and crown gall bacterium. In contrast, tumor formation 1 was not observed at most of the inoculation sites in the experimental group inoculated with strain A3 and crown gall bacterium.

[0246] Table 22 below shows the percentage of inoculation sites where carcinoma 1 formed and the risk ratio of carcinoma 1 formation for each inoculation site in the chrysanthemums of the experimental group and the control group.

[0247]

[0248] As shown in Table 22, the risk of crown gall 1 formation in chrysanthemums inoculated with strain A3 was 0.05 times that of chrysanthemums not inoculated with strain A3, indicating that inoculation with strain A3 reduced the risk of crown gall 1 formation in chrysanthemums to 0.05. This demonstrates that strain A3 suppresses the development of crown gall disease in 95% of cases.

[0249] Figure 19 is a graph showing the diameter distribution and average diameter of carcinoma 1 formed in chrysanthemums from the experimental group and the control group. In Figure 19, "***" indicates that p < 2.2 × 10⁻¹⁰ was determined by a t-test. －１６ This indicates a statistically significant difference.

[0250] As shown in Figure 19, the carcinoma 1 formed in the chrysanthemums of the experimental group was significantly smaller than the carcinoma 1 formed in the chrysanthemums of the control group.

[0251] From these results, it became clear that inoculation with the Alorizobium vitis A3 strain can prevent not only the development of crown gall disease caused by the pathogenic Alorizobium vitis strain used in Experimental Example 1, but also the development of crown gall disease caused by Rhizobium radiobacter (Ti).

[0252] [Experimental Example 12] In this experiment, the roots of tomato seedlings were immersed in a fungal solution containing strain A3, and then planted in contaminated soil containing Rhizobium radiobacter to confirm the control effect of strain A3 on crown gall disease.

[0253] In detail, first, the concentration of Allorizobium vitis A3 strain was 10 ８ A bacterial solution was prepared in the same manner as in Experimental Example 1 to achieve a cell / mL concentration, and the roots of tomato seedlings were immersed in this solution for one hour (experimental group). A control group was also prepared in which the roots of tomato seedlings were immersed in sterile water instead of the bacterial solution of strain A3.

[0254] After immersion in bacterial solution or sterile water, 10 ８ Contaminated soil containing a cellus / mL concentration of Rhizobium radiobacter (Ti) CH1 strain (a crown gall disease bacterium isolated from chrysanthemums) was added to the soil, and tomato seedlings were planted in these pots and cultivated for approximately two months. After that, the roots of the tomato seedlings were dug up to check for the presence or absence of crown gall formation. The number of tomato seedlings n = 20 was used in both the experimental and control groups.

[0255] Figure 20 shows images of the roots of tomato seedlings from an experimental group immersed in a fungal solution containing Allorizobium vitis A3 strain, and tomato seedlings from a control group immersed in sterile water, after being grown for five months in soil contaminated with crown gall fungus.

[0256] Furthermore, Table 23 below shows the number of seedlings in which crown gall 1 formed and the number of seedlings in which crown gall 1 did not form for tomatoes in the experimental group and the control group. The presence or absence of crown gall 1 in the experimental group and the control group was analyzed using Fisher's Exact Test, yielding p = 1.0 × 10⁻⁶. －８ A statistically significant difference was observed.

[0257]

[0258] As shown in Figure 20 and Table 23, most seedlings in the control group immersed in sterile water showed the formation of gall tumor 1. In contrast, no gall tumor 1 was observed in the roots of seedlings in the experimental group immersed in a bacterial solution containing strain A3.

[0259] Table 24 below shows the percentage of seedlings in which crown gall 1 was formed and the risk ratio of crown gall 1 formation for tomatoes in the experimental group and the control group.

[0260]

[0261] As shown in Table 24, the risk of crown gall 1 formation in tomatoes immersed in a fungal solution containing strain A3 was 0. This indicates that the disease suppression rate of crown gall disease by attaching strain A3 to tomatoes is 100%.

[0262] Since chrysanthemums and tomatoes are phylogenetically distant species, the effectiveness of Alorizobium vitis A3 in controlling crown gall disease caused by Rhizobium radiobacter (Ti) is not limited to chrysanthemums, but may be applicable to a variety of plant species.

[0263] [Experimental Example 13] In this experiment, chrysanthemum stems were inoculated with Rhizobium rhizogenes, a type of crown gall fungus, and strain A3, and the presence or absence of galls and the diameter of the galls were confirmed.

[0264] In detail, first, a bacterial suspension of Rhizobium vitis A3 strain and a bacterial suspension of Rhizobium rhizogenes (Ti) MAFF211728 strain isolated from Japanese pear were mixed in a 1:1 ratio. Colonies obtained by culturing strain A3 or CH1 on potato dextrose agar plates (Potato Dextrose Agar, PDA, 4.0 g potato starch, 20.0 g dextrose, 15.0 g agar) at 27°C for 48 hours were scooped out with a platinum loop and suspended in sterile water. ８ This is a bacterial suspension adjusted to a concentration of cells / mL.

[0265] The resulting mixture was applied to the tip of a needle, and the tip of the needle was used to inoculate the stems of chrysanthemum plants (experimental group). A control group was also prepared in which the stems of chrysanthemum plants were inoculated with a mixture of sterile water and the MAFF211728 strain instead of the above mixture. In both the experimental and control groups, 10 chrysanthemum seedlings were provided, and each seedling's stem was inoculated in four places, resulting in a total of n = 40 inoculation sites.

[0266] Approximately four weeks after the administration of the mixed solution, the presence or absence of tumors at each injection site was checked, and if tumors had developed, their diameter was confirmed.

[0267] Figure 21 shows images of chrysanthemum stems from the experimental and control groups inoculated with crown gall fungus. Table 25 below shows the number of seedlings with crown gall 1 and the number of seedlings without crown gall 1 for both the experimental and control groups. The presence or absence of crown gall 1 in the experimental group and the control group was assessed using Fisher's Exact Test, yielding p < 6.0 × 10⁻⁶. －１１ A statistically significant difference was observed.

[0268]

[0269] As shown in Figure 21 and Table 25, tumor formation 1 was observed at all inoculation sites in the control group inoculated with the crown gall bacterium. In contrast, in the experimental groups inoculated with strain A3 and the crown gall bacterium, the proportion of tumor formation at inoculation sites was suppressed to about 3 / 8.

[0270] Table 26 below shows the percentage of inoculation sites where carcinoma 1 formed and the risk ratio of carcinoma 1 formation for each inoculation site in the chrysanthemums of the experimental group and the control group.

[0271]

[0272] As shown in Table 26, the risk of crown gall 1 formation in chrysanthemums inoculated with strain A3 was 0.35 times that of chrysanthemums not inoculated with strain A3, indicating that inoculation with strain A3 reduced the risk of crown gall 1 formation to 0.35. This demonstrates that strain A3 suppresses the development of crown gall disease by 65%.

[0273] Figure 22 is a graph showing the diameter distribution and average diameter of carcinoma 1 formed in chrysanthemums from the experimental group and the control group. In Figure 22, "***" indicates that p < 6.0 × 10⁻¹⁰ was determined by a t-test. －１１ This indicates a statistically significant difference.

[0274] As shown in Figure 22, the carcinoma 1 formed in the chrysanthemums of the experimental group was significantly smaller than the carcinoma 1 formed in the chrysanthemums of the control group.

[0275] From these results, it was confirmed that the control effect of Alorizobium vitis A3 strain on crown gall disease is exerted not only against pathogenic Alorizobium vitis in Experimental Example 1 and Rhizobium radiobacter in Experimental Examples 11 and 12, but also against crown gall disease caused by Rhizobium rhizogenes. Therefore, it was revealed that the control effect of strain A3 on crown gall disease is independent of the type of causative fungus.

[0276] According to the present invention, various plant diseases caused by bacteria can be controlled by inoculating or attaching the Allorizobium vitis A3 strain to plants, making it suitable for industrial use.

[0277] 1...Carcinoma 3...Injection site

Claims

1. Allorhizobium vitis A3 strain (Accession number: NITE BP-04154).

2. A control agent for plant diseases caused by bacteria, comprising the Alorizobium vitis A3 strain described in claim 1 as an active ingredient.

3. A plant crown gall disease control agent comprising the Alorizobium vitis A3 strain described in claim 1 as an active ingredient.

4. The plant crown gall disease control agent according to claim 3, wherein the plant is a fruit tree, a flowering plant, or a vegetable.

5. A control agent for tomato canker, comprising the Alorizobium vitis A3 strain described in claim 1 as an active ingredient.

6. A control agent for tomato crown gall disease and tomato canker, comprising the Alorizobium vitis A3 strain described in claim 1 as an active ingredient.

7. The control agent according to claim 2, wherein the bacteria are bacteria of the genus Pseudomonas, Xanthomonas, or Ralstonia.

8. The control agent according to claim 2, wherein the plant disease is bacterial black spot, black rot, or bacterial wilt.

9. The control agent according to claim 8, wherein the plant disease is bacterial black spot disease, and the plants to be controlled are Brassicaceae plants, Solanaceae plants, Asteraceae plants, or Fabaceae plants.

10. The control agent according to claim 8, wherein the plant disease is black rot and the plant to be controlled is a plant of the Brassicaceae family.

11. The control agent according to claim 8, wherein the plant disease is bacterial wilt and the plant to be controlled is a Solanaceae plant or a Zingiberaceae plant.

12. A method for controlling plant diseases caused by bacteria, comprising the step of inoculating or attaching the control agent described in claim 2 to a plant.

13. A method for controlling crown gall disease of plants, comprising the step of inoculating or attaching the control agent described in claim 3 or 4 to a plant.

14. A method for controlling tomato canker, comprising the step of inoculating or applying the control agent described in claim 5 to tomatoes.

15. A method for controlling crown gall disease and tomato canker disease of tomatoes, comprising the step of inoculating or applying the control agent described in claim 6 to tomatoes.

16. The control method according to claim 12, wherein the bacteria are bacteria of the genus Pseudomonas, Xanthomonas, or Ralstonia.

17. The method for controlling plant diseases according to claim 12, wherein the plant disease is bacterial black spot, black rot, or bacterial wilt.

18. The method for controlling a plant disease according to claim 12, wherein the plant disease is bacterial black spot disease, and the plant to which the control agent is inoculated or applied is a Brassicaceae plant, a Solanaceae plant, a Asteraceae plant, or a Fabaceae plant.

19. The method for controlling a plant disease according to claim 12, wherein the plant disease is black rot, and the plant to which the control agent is inoculated or applied is a Brassicaceae plant.

20. The method for controlling a plant disease according to claim 12, wherein the plant disease is bacterial wilt, and the plant to which the control agent is inoculated or applied is a plant of the Solanaceae family or a plant of the Zingiberaceae family.

21. Cultivation soil containing the Alorizobium vitis A3 strain described in claim 1.

22. A soil conditioner comprising the Allorizobium vitis A3 strain described in claim 1.

23. A plant seed on which the Allorizobium vitis A3 strain described in claim 1 is attached to the surface.

24. The seed according to claim 23, wherein the plant is a tomato.

25. A plant seedling having the Alorizobium vitis A3 strain described in claim 1.

26. The seedling according to claim 25, wherein the plant is a fruit tree, an ornamental plant, or a vegetable.

Images