JP2017186304A - Novel agricultural application of rahnella bacteria - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart various favorable properties to agriculturally useful plants by microbiological means.SOLUTION: The present invention provides a method that artificially infects agriculturally useful plants such as Liliaceae plants with Rahnella bacteria to promote the growth of these plants and/or increase the yields, and microbial formulations comprising Rahnella bacteria.SELECTED DRAWING: None

Description

  The present invention relates to a method of artificially infecting a plant with an endophyte Rahnella genus bacterium to promote the growth of the plant, a method of increasing the yield of the plant, and the like.

  So far, pest control technology centered on chemical pesticides has contributed to efficient food security. However, in recent years, not only the efficiency of cultivation, but also environmentally friendly agriculture using pesticide-free and reduced pesticides, including areas such as safety and security, has been desired, and pest control technology (for example, microbial pesticides) and productivity improvement technology suitable for it. Is needed.

  In the agricultural field, chemical fertilizers are still used to promote the growth of crops, and chemically synthesized pesticides are used for pests. In addition, microbial pesticides using microorganisms and substances produced by microorganisms are also known in part. However, when the raw material of the agricultural chemical is produced by chemical synthesis, there are a problem that a large amount of energy is input, a problem that a load on the environment is large, and the like. On the other hand, microbial pesticides that are currently used with a low environmental load are expensive, and a stable control effect cannot be obtained.

  In such a situation, among endophytes that are microorganisms symbiotic to plants, microorganisms that impart beneficial characteristics to plants such as pest control and increase in yield have been reported (Patent Documents 1 to 9). . However, since there are few known types of endophytes, the search and application of microorganisms with high possibility of practical use are required for practical use in this field.

JP 2013-042695 A JP 2011-051902 A JP2009-232721 JP 2009-067717 JP 2009-051771 A JP 2009-050206 A JP 2003-300805 JP JP2003-274779 JP 2002-223747

  The present invention aims to impart beneficial properties to agriculturally useful plants by microbiological means.

  In particular, a technique for increasing the yield of the Rahnella genus bacteria related to the present invention on plants such as liliaceae and promoting growth is not known so far.

The present invention includes the following aspects.
(1) Agriculturally useful, comprising the step of artificially infecting the plant with bacteria that belong to the genus Rahnella and have the ability to symbiotically grow in the agriculturally useful plant and increase the yield of the plant A method to increase plant yield.
(2) Agriculturally useful, comprising the step of artificially infecting the plant with a bacterium belonging to the genus Rahnella and having the ability to symbiotically grow in the agriculturally useful plant and promote the growth of the plant. A method of promoting plant growth.
(3) An agriculturally useful plant is a plant selected from the group consisting of leguminous plants, gramineous plants, liliaceae plants, cruciferous plants, asteraceae plants, solanaceous plants, cucurbitaceae plants, and cericaceae plants. The method according to (1) or (2).
(4) The method according to any one of (1) to (3), wherein the bacterium has 16S rDNA containing a base sequence having 97% or more identity with the base sequence shown in SEQ ID NO: 1.
(5) The ability of the bacterium to coexist in Rahnella sp. MYK106 (Accession No. NITE P-02062) or an agriculturally useful plant to increase the yield of the plant and / or promote the growth of the plant The method according to any one of (1) to (4), which is a mutant strain having ability.
(6) It belongs to the genus Rahnella and contains as an active ingredient a bacterium that has the ability to symbiotically grow in an agriculturally useful plant and increase the yield of the plant and / or promote the growth of the plant. An agriculturally useful microbial formulation for plants.
(7) An agriculturally useful plant is a plant selected from the group consisting of leguminous plants, gramineous plants, liliaceae plants, cruciferous plants, asteraceae plants, solanaceous plants, cucurbitaceae plants, and cericaceae plants. The microorganism preparation according to (6).
(8) The microorganism preparation according to (6) or (7), wherein the bacterium has 16S rDNA containing a base sequence having 97% or more identity with the base sequence shown in SEQ ID NO: 1.
(9) The ability of the bacterium to coexist in Rahnella sp. MYK106 (Accession No. NITE P-02062) or an agriculturally useful plant to increase the yield of the plant and / or promote the growth of the plant The microorganism preparation according to any one of (6) to (8), which is a mutant strain having ability.
(10) Rahnella sp. MYK106 (Accession No. NITE P-02062), or the ability to increase the yield of the plant by symbiosis in an agriculturally useful plant and / or the ability to promote the growth of the plant , Its mutants.

  As used herein, the term “Rahnella bacterium” refers to an endophyte bacterium having the ability to symbiotically grow in an agriculturally useful plant to increase the yield of the plant and / or promote the growth of the plant. . In general, the term “endophyte” refers to a microorganism symbiotic to a plant.

  In accordance with the present invention, by promoting microbiological means, i.e. Rahnella spp. (E.g. Rahnella sp. MYK106 strain), which can be used as endophyte, for agriculturally useful plants, promoting the growth of said plants, and It is possible to increase the yield of the plant.

1. Bacteria Bacteria that can be used in the present invention are bacteria belonging to the genus Rahnella, such as Rahnella aquatilis, and are useful in agriculture such as legumes, grasses, liliaceae, rape. Ability to promote symbiosis in the body of a plant selected from the group consisting of a family plant, asteraceae plant, solanaceous plant, cucurbitaceae plant, and celery family plant, and / or promote the growth (growth) of the plant, and / or The bacterium is not particularly limited as long as it has the ability to increase plant yield.

  In this specification, the yield of a plant refers to the yield of plant components such as seeds, leaves (including bulbs), berries, stems, roots, and flowers.

  As used herein, a Rahnella genus bacterium is an endophyte bacterium that can confer any one or more of the above-mentioned abilities to a plant, not only a bacterium isolated from the natural world, Variants produced by mutating such bacteria are also included.

  As a specific example of the bacterium, Rahnella sp. MYK106 (Accession No. NITE P-02062; hereinafter, simply referred to as “MYK106 strain” or “NITE P-02062 strain”) is a bacterium belonging to the genus Rahnella. Alternatively, a mutant strain thereof having any one or more of the above-mentioned capabilities can be mentioned.

  The above-mentioned Rahnella sp. MYK106 is a strain isolated from a lily family that grows naturally. Rahnella sp. MYK106 is an international depositary organization under the Budapest Treaty on June 9, 2015. It is an independent administrative agency, the National Institute for Product Evaluation Technology and the Patent Microorganism Depositary Center (Kazusa, Kisarazu City, Chiba Prefecture 292-0818, Japan). It has been deposited by the present applicant in 2-5-8) and has been given the deposit number NITE P-02062.

  This NITE P-02062 strain is a 16S rDNA partial sequence (in this case, Rahnella sp. MYK106 (accession number NITE P-02062) 16S rDNA partial nucleotide sequence for various bacterial genera and species ( As a result of homology search using a comparison with SEQ ID NO: 1), Rahnella aquatilis strain T4 (Accession No .: KF465846.1, homology) : 99%), Rahnella aquatilis strain P32 (Accession No .: KF465839.1, homology: 99%), Rahnella sp. XL-1 (Accession No .: KJ710698.1, homology: 99%), Rahnella aquatilis strain GABIT-M100 (Accession No .: KM977991.1, homology: 99%), Rahnella aquatilis partial 16S rRNA gene, strain TS18 (Accession No .: FM209488.1, homology: 99%) were observed. It was found to be a bacterium belonging to the genus Rahnella. Moreover, from this result, it was considered that the MYK106 strain was highly likely to be Rahnella aquatilis.

  Examples of the bacterium that can be used in the present invention include a bacterium having the ability to promote the growth (growth) of a plant equivalent to the Rahnella genus MYK106 strain or the present strain and / or increase the yield of the plant. As a bacterium that can be used in the present invention, for example, it belongs to the genus Rahnella, has any one or more of the above-described capabilities, and has at least a part of the base sequence shown in SEQ ID NO: 1 or a sequence equivalent to the base sequence. A bacterium having 16S rDNA, and a bacterium belonging to the genus Rahnella, having any one or more of the above-mentioned properties, and having the same or substantially the same substrate assimilating property as MYK106 strain For example, but not limited to. Here, the sequence equivalent to the base sequence shown in SEQ ID NO: 1 is preferably 97% or more, 98% or more, or 99% or more, more preferably 99.5% or more, 99.7% or more with the base sequence shown in SEQ ID NO: 1. , 99.8% or higher, or 99.9% or higher. The identity value indicates a value calculated with default settings using software (for example, FASTA, DANASYS, and BLAST) that calculates identity between a plurality of base sequences. Further, having substantially the same substrate assimilation ability means that the number of substrates to be assimilated and / or not assimilated is less than several, for example, 3 or less, compared to the substrate assimilation of MYK106 strain, Means two or fewer or one different.

  Furthermore, the MYK106 strain is a mutant strain produced by artificial mutagenesis, and is an agriculturally useful plant such as legumes, grasses, liliaceae, cruciferous plants, asteraceae. A plant, a solanaceous plant, a cucurbitaceae plant, and a plant selected from the group consisting of sericaceae, having the ability to symbiotically promote the growth of the plant and / or increase the yield of the plant Variants can also be used in the present invention.

  When isolating Rahnella genus bacteria that can be used in the present invention from the natural world, bacteria that are symbiotic to the plant are isolated from the plant constituent parts such as roots, stems, and leaves of agriculturally useful plants, and the above-mentioned ability A selection test can be performed for any of the above and / or the sequence identity with the base sequence shown in SEQ ID NO: 1 above.

  In the case of carrying out a mutagenesis treatment, the MYK106 strain can be mutated using any appropriate mutagen.

  Here, the term “mutagen” has a broad meaning, and includes not only a drug having a mutagenic action but also a treatment having a mutagenic action such as irradiation with high energy rays such as UV irradiation. Examples of suitable mutagens include nucleotide base analogs such as ethyl methanesulfonate, UV irradiation, gamma irradiation, X-ray irradiation, heavy ion beam irradiation, N-methyl-N'-nitro-N-nitrosoguanidine, bromouracil. , And acridines, but any other effective mutagen can also be used.

  Alternatively, another means for introducing a mutation into a bacterium is a method using a gene recombination method.

  The bacterium used in the present invention can be cultured under the conditions normally used for Rahnella bacteria by a conventional culture method such as shaking culture. As a medium for culturing, saccharides such as glucose, sucrose, starch and dextrin as carbon sources, ammonium salts such as ammonium sulfate, ammonium chloride and ammonium nitrate as nitrogen sources, inorganic nitrogen sources such as nitrates, yeast extract, corn Organic nitrogen sources such as steep leaker, meat extract, wheat germ, polypeptone, sugar cane squeezed (bacus), beer casks, soy flour, rice bran, fish meal, etc., and inorganic salts such as monopotassium phosphate, magnesium sulfate, manganese sulfate, sulfuric acid Examples thereof include synthetic or natural media containing salts containing phosphorus, potassium, manganese, magnesium, iron, etc., such as monoiron. The culture temperature is usually 20 to 37 ° C., preferably 27 to 32 ° C., and can be performed under aerobic conditions for 12 to 48 hours.

  In the method of the present invention, a bacterial culture solution can be used as it is, but a high bacterial concentration obtained by separating the bacterial culture solution by a method such as membrane separation, centrifugation, or filtration separation can also be used. .

  In the method of the present invention, a dried bacterial culture solution can also be used. Moreover, what dried by making it adsorb | suck to porous adsorbents, such as activated carbon, diatomaceous earth, talc, a zeolite, peat moss, perlite, bentonite, montmorillonite, vermiculite, can be used. One kind of porous adsorbent may be used, or a plurality of carriers may be used in combination. The drying method may be a normal method, for example, freeze drying or vacuum drying. These dried products may be further pulverized by a pulverizing means such as a ball mill after drying.

  Bacteria can be used for the purposes of the present invention alone as the above culture solution, high-concentration product, or dry product, but in the same form as normal microbial preparations (for example, powders) in combination with other optional components. , Wettable powders, granules, emulsions, solutions, suspensions, flowables, coatings, etc.). Examples of optional components that can be used in combination include materials that can be applied to plants such as solid carriers and adjuvants.

2. Agriculturally useful plants The target plants that can be used in the method of the present invention are not limited to the following. For example, legumes, gramineous plants, liliaceae plants, cruciferous plants, asteraceae plants, solanaceous plants, Agriculturally useful plants selected from the group consisting of cucurbitaceae plants and celery family plants can be mentioned. Preferably, the agriculturally useful plant is selected from the group consisting of liliaceae plants, cruciferous plants, asteraceae plants, and solanaceous plants.

  As used herein, “agriculturally useful plants” refers to plants to be produced in agriculture such as crops such as vegetables and cereal plants, and fruit trees.

  Examples of the grass family include cereals such as rice, wheat, barley, rye, triticale, pearl barley, sorghum, oat, corn, sugarcane, millet, and millet. Examples of grasses include feeds and grasses such as buckwheat, buffalo grass, bermuda grass, weeping grass, centipede grass, carpet grass, dalice grass, chrysanthemum grass and St. Augustine grass.

  Examples of legumes include soybean, azuki bean, peanut, kidney bean, pea, pea bean, broad bean, cowpea, chickpea, mung bean, lentil, lentil and bambara bean.

  In this specification, a lily family plant is a plant (for example, APG system) classified into a lily family plant in an old classification (Clonquist system etc.) in addition to a plant classified into a lily family plant in a new classification (APG system). (Amaricaceae and Phylcaceae). In the present specification, examples of the lily family include onions (APG family: Amaryllidaceae), leeks (APG system: Amaryllidaceae), Rakkyo (APG system: Amaryllidaceae), garlic (APG system: Amaryllidae), leek (APG As for the system, there are Amaranthaceae), Asatsu (APG system: Amaryllidaceae), Lily, Asparagus (APG system: Phyloriaceae), Shallot (APG system: Amaryllidaceae), Wakegi (APG system: Amaryllidae).

  Examples of the Brassicaceae plants include: Brassica, Turnip, Chingensai, Nozawana, Mustard, Takana, Kobutana, Mizuna, Kohl Rabbi, Arugula, Watercress, Taasai, Cauliflower, Cabbage, Kale, Chinese cabbage, Komatsuna, Daikon, Hatsukadaikon, Broccoli, Mekabetsu, Wasabi , Horseradish, and Arabidopsis thaliana.

  Examples of the Asteraceae plants include lettuce, sunny lettuce, garlic, chrysanthemum and the like.

  Examples of solanaceous plants include eggplant, tomato, pepper, shishito, chili, potato, wolfberry, paprika, jalapeno, habanero and the like.

  Examples of the cucurbitaceae plant include cucumber, pumpkin, bitter gourd, watermelon, zucchini, tougan, loofah, melon, yugao and the like.

  Examples of the celery family include carrot, honey bee, parsley, celery, celery, ashitaba, soup celery, charbell, fennel and the like.

3. Microbiological method for increasing yield and promoting growth The method of the present invention comprises the genus Rahnella and is capable of symbiotic in the body of the above-mentioned plant useful in agriculture and increasing the yield of the plant, and / or Artificially infecting the plant with bacteria having the ability to promote the growth of the plant.

  Increasing the yield of a plant is, for example, for vegetables, for example, edible parts such as leaves (including bulbs), roots, rhizomes, seeds, flowers, for cereals, for seeds, for fruit trees, It means to increase the yield of fruits.

  Promoting plant growth (growth) means that the growth of the plant is accelerated compared to a control not inoculated with the bacteria of the present invention.

  Examples of the application method to the plant include seed coating, irrigation to young plants, application, immersion of the root of the plant in a bacterial solution, or spraying. In particular, a method in which seeds or plants are artificially damaged as necessary, and spraying and applying a bacterial solution is preferable. As other application conditions, it is desirable to apply before planting at the time of sowing, seedling raising, etc. Furthermore, high expression of the effect can be expected by spraying the plant, and in some cases, the soil around the root of the plant during field cultivation.

  As one example, artificial infection of the bacterium of the present invention to a plant involves spraying a bacterial solution onto young seedlings (for example, seedlings at the time when 1 to 4 true leaves appear) before planting in the field. Can be performed. About 1 to 15 days after spraying, seedlings can be planted in the field. It is thought that the bacteria that invaded the plant body will eventually coexist with the plant.

The concentration of the bacterial solution may be 1 × 10 ⁵ to 1 × 10 ¹² cells / ml, such as 1 × 10 ⁸ to 1 × 10 ¹⁰ cells / ml or more, but is not limited to these concentration ranges. The medium for suspending bacteria is preferably water, a buffer solution, or a medium. Usually, a high concentration bacterial solution can be used by diluting to a predetermined concentration with water or a medium.

  Specifically, the method of the present invention includes the following aspects.

  According to the first aspect, the method of the present invention artificially infects a plant belonging to the genus Rahnella and has the ability to symbiotically grow in an agriculturally useful plant and increase the yield of the plant. And a method for increasing the yield of agriculturally useful plants.

  According to the second aspect, the method of the present invention artificially infects the plant with a bacterium belonging to the genus Rahnella and having the ability to promote symbiosis in the agriculturally useful plant body and promote the growth of the plant. And a method for promoting the growth of an agriculturally useful plant.

  The method of the present invention may include a step of cultivating an agriculturally useful plant after the infection step. Agriculturally useful plants can be cultivated by conventional methods. After the infection process, it may be once cultivated in a pot or the like and then transferred to the field, or directly transferred to the field and the cultivation process may be performed.

4). Microbial preparation The present invention further relates to a bacterium belonging to the genus Rahnella and capable of increasing the yield of the plant by symbiosis in an agriculturally useful plant and / or promoting the growth of the plant. The present invention provides an agriculturally useful microbial preparation for plant containing as an active ingredient.

  Examples of agriculturally useful plants consist of legumes, grasses, liliaceae, solanaceous plants, cucurbitaceae, cruciferous plants, asteraceae and celeryaceae plants specifically exemplified above. A plant selected from the group.

  Preferred bacteria are Rahnella sp. MYK106 (Accession No. NITE P-02062), or the ability to symbiotically grow in an agriculturally useful plant and increase the yield of the plant and / or the ability to promote the growth of the plant. It has its mutant strain.

  As the microbial preparation, a high concentration of bacteria, a dried culture solution of bacteria, or the like can be used. Moreover, what dried by making it adsorb | suck to porous adsorbents, such as activated carbon, diatomaceous earth, talc, a zeolite, peat moss, perlite, bentonite, montmorillonite, vermiculite, can be used. One kind of porous adsorbent may be used, or a plurality of carriers may be used in combination. The drying method may be a normal method, for example, freeze drying or vacuum drying. These dried products may be further pulverized by a pulverizing means such as a ball mill after drying.

  Bacteria can be used for the purposes of the present invention alone as the above culture solution, high-concentration product, or dry product, but in the same form as normal microbial preparations (for example, powders) in combination with other optional components. , Wettable powders, granules, emulsions, solutions, suspensions, flowables, coatings, etc.). Examples of optional components that can be used in combination include materials that can be applied to plants such as solid carriers and adjuvants.

  The present invention further provides the ability to increase the yield of Rahnella sp. MYK106 (Accession No. NITE P-02062) or an agriculturally useful plant to increase the yield of the plant, and / or the ability to promote the growth of the plant. A mutant strain thereof is provided.

  The bacterium of the present invention can be cultured under the above-mentioned conditions as commonly used for Rahnella bacteria by a conventional culture method such as shaking culture.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the technical scope of the present invention is not limited by these examples.

[Example 1]
<Acquisition of Rahnella sp. MYK106 (Accession Number NITE P-02062)>
Liliaceae growing naturally were collected and cut. Surface sterilization was performed by immersing the cut lily family plant in 70% ethanol for 30 seconds and in 2.5% sodium hypochlorite solution for 5 minutes. Thereafter, the plant body was transferred to a mortar and ground while adding 1 ml of sterilized physiological saline and an appropriate amount of sea sand. 100 μl of the ground supernatant was applied to NA (Nutrient Agar) medium, cultured at 30 ° C. for several days, and a single colony was isolated to obtain the title MYK106 strain.

[Example 2]
<Determination of 16S rDNA base sequence of MYK106 strain>
1) Method
Rahnella sp. MYK106 strain cells were suspended in 500 μl of 0.85% NaCl aqueous solution, and the supernatant was removed after centrifugation. 20 μl of sterilized water, 25 μl of BL buffer (40 mM Tris, 1% Tween 20, 0.5% Nonidet P-40, 1 mM EDTA, pH 8.0) and 5 μl of proteinase K (1 mg / ml) were added to the cells and suspended briefly. After standing at 60 ° C. for 20 minutes and then at 105 ° C. for 5 minutes, the mixture was centrifuged and the supernatant was used as a DNA extract.

  6.95 μl of sterilized water, 1 μl of Ex Taq Buffer (20 mM), 0.8 μl of dNTP Mixture (dATP, dCTP, dGTP, dTTP 2.5 mM each), 0.05 μl of Ex Taq (5 units / μl), 100 nM primer (5'- 1 μl of AGAGTTTGATCCTGGCTCAG-3 ′ (SEQ ID NO: 2) and 5′-GGCTACCTTGTTACGACTT-3 ′ (SEQ ID NO: 3)) was mixed with 1 μl of a DNA extract diluted 10-fold with sterile water, and PCR was performed. The reaction was carried out at 94 ° C for 5 minutes in one cycle, 94 ° C for 60 seconds, 55 ° C for 60 seconds, 72 ° C for 90 seconds, 35 cycles, 72 ° C for 2 minutes in one cycle.

  The solution after PCR was electrophoresed on an agarose gel, and the target DNA fragment portion (about 1400 bp) was excised. A DNA fragment was extracted from the gel and used to determine the base sequence.

2) Results The determined base sequence of 16S rDNA consisted of the sequence of SEQ ID NO: 1.

  For the MYK106 strain, the obtained 16S rDNA base sequence was compared with the DDBJ, EMBL, and GenBank databases. As a result, Rahnella aquatilis strain T4 (Accession No .: KF465846.1, homology: 99%), Rahnella aquatilis strain P32 (Accession No .: KF465839.1, homology: 99%) in descending order of homology , Rahnella sp. XL-1 (Accession No .: KJ710698.1, homology: 99%), Rahnella aquatilis strain GABIT-M100 (Accession No .: KM977991.1, homology: 99%), Rahnella aquatilis partial 16S rRNA Since it was gene, strain TS18 (Accession No .: FM209488.1, homology: 99%), it was found to be a bacterium belonging to the genus Rahnella. Moreover, from this result, it was considered that the MYK106 strain was highly likely to be Rahnella aquatilis.

[Example 3]
<Growth promotion of onion by Rahnella sp. MYK106 1>
1) Method Onion variety: Turbo endophyte strain: MYK106 strain Inoculation date: November 2011 Inoculation method: 1 x 10 ⁸ cells / ml of bacterial suspension was sprayed at 50 ml / m ² in the field by spraying .
Date of planting: November 2011 Field: Aichi Prefectural measurement item: 2 crops were harvested in 2m in the range of 2m, and the number and weight of each standard were investigated.
Harvest survey date: June 19, 2012

2) Results The whole amount was harvested and the number and weight of each standard were measured (Table 1). Spheres classified as 2L, L, M, and S in terms of size and appearance were included in the standard, and other small and poor-appearance balls were excluded from the standard.

  As a result of the yield survey, the average ball weight increased in the MYK106 treated group compared with the untreated group, and the yield ratio also increased by 3.3% (Table 2).

[Example 4]
<Growth promotion of onion by Rahnella sp. MYK106 2>
1) Method Onion variety: Turbo endophyte strain: MYK106 Inoculation date: November 20, 2012 Inoculation method: The root of the seedling before planting is immersed overnight in a suspension of 1 x 10 ⁸ cells / ml did.
Date of planting: November 21, 2012 Field: Aichi Prefectural measurement item: 2 crops were harvested in 2 ranges within the range of 2m, and the number and weight of each standard were investigated.
Harvest survey date: June 18, 2013

2) Results The whole amount was harvested and the number and weight of each standard were measured (Table 3). Spheres classified as 2L, L, M, and S in terms of size and appearance were included in the standard, and other small and poor-appearance balls were excluded from the standard.

  As a result of the yield within the specifications of the yield survey, the average sphere weight increased in the MYK106 treated group compared with the untreated group, and the yield ratio also increased by 12.4% (Table 4).

[Example 5]
<Growth promotion of onion by Rahnella sp. MYK106 strain 3>
1) Method Onion variety: Turbo endophyte strain: MYK106 Inoculation date: October 26, 2013 Inoculation method: 1 × 10 ⁸ cells / ml of bacterial suspension was sprayed on seedlings at 26.7 ml / m ² .
Date of planting: October 26, 2013 Field: Aichi Prefectural measurement items: 2 crops were harvested in 2 m in the range of 2m, and the number and weight of each standard were investigated.
Harvest survey date: June 6, 2014

2) Results The whole amount was harvested, and the number and weight of each standard were measured (Table 5). Spheres classified as 2L, L, M, and S in terms of size and appearance were included in the standard, and other small and poor-appearance balls were excluded from the standard.

  As a result of the yield within the specifications of the yield survey, the average sphere weight increased in the MYK106 treated group compared with the untreated group, and the yield ratio also increased by 6.3% (Table 6).

[Example 6]
<Promoting growth of Komatsuna in pot test with Rahnella sp. MYK106>
1) Method Komatsuna variety: Natsu Rakuten Endophyte strain: MYK106 strain Test scale: 9 strains in 1 treatment area
A non-woven fabric cut into approximately 2 cm squares was drawn on the bottom of a cell tray prepared to have 5 × 5 cells (25 cells in total) and filled with tanemaki culture soil (Takii Seed Co., Ltd.). 2 seeds per cell were seeded and covered with tanemaki soil. The seeding date was set to day 0, and thinning was made around day 7 after seeding to make 1 strain / cell. In the MYK106 inoculation zone, 2 to 3 true leaves were developed on the 14th day after sowing, and 10 ml per cell was inoculated with 1 x 10 ⁸ cells / ml prepared using pure water. . Cultivation was carried out in a glass greenhouse heated so that the temperature did not fall below 15 ° C, and cultivated until 4 or more true leaves were developed. Thereafter, nine strains excluding the outer periphery were cut from the ground and the dry weight was measured.

2) Results
After cultivation for 27 days, the dry weight increased by 7.9% in the MYK106 inoculated group when the non-inoculated group was taken as 100 (Table 7).

[Example 7]
<Growth promotion of lettuce in pot test with Rahnella sp. MYK106>
1) Method A test was conducted in the same manner as in Example 6 except that lettuce (variety: green wave) was used, and the dry weight was measured.

2) Results
After 24 days of cultivation, it was shown that the dry weight increased by 27.8% in the MYK106 strain inoculated group when the non-inoculated group was taken as 100 (Table 8).

[Example 8]
<Growth promotion of leek in pot test with Rahnella sp. MYK106>
1) Method A test was conducted in the same manner as in Example 6 except that leek (variety: all-purpose small leek) was used, and dry weight was measured.

2) Results
After 38 days of cultivation, the dry weight increased by 7.7% in the MYK106 strain inoculated group when the non-inoculated group was taken as 100 (Table 9).

[Example 9]
<Tomato growth promotion in pot test with Rahnella sp. MYK106>
1) Method A test was performed in the same manner as in Example 6 except that tomato (variety: CF Momotaro York) was used, and the dry weight was measured.

2) Results
After 24 days of cultivation, the dry weight increased by 3.3% in the MYK106 strain inoculated group when the non-inoculated group was taken as 100 (Table 10).

[Example 10]
<Growth promotion of soybean in pot test with Rahnella sp. MYK106>
1) Method A test was performed in the same manner as in Example 6 except that soybean (variety: Toyomasari) was used, and the dry weight was measured.

2) Results
After 40 days of cultivation, the dry matter weight increased by 2.2% in the MYK106 strain inoculated group when the non-inoculated group was taken as 100 (Table 11).

[Example 11]
<Promotion of rice growth in pot test with Rahnella sp. MYK106>
1) Method Except for using rice (variety: Koshihikari), a test was conducted in the same manner as in Example 6 to measure the dry weight.

2) Results
After 40 days of cultivation, the dry weight increased by 26.7% in the MYK106 strain inoculated group when the non-inoculated group was taken as 100 (Table 12).

  The present invention is agriculturally useful because it artificially infects agriculturally useful plants with the genus Rahnella to promote the growth and / or increase the yield of these plants.

Claims (10)

  Yield of an agriculturally useful plant comprising the step of artificially infecting the plant with a bacterium belonging to the genus Rahnella and having the ability to symbiotically grow in the agriculturally useful plant and increase the yield of the plant How to increase.   Growth of an agriculturally useful plant comprising the step of artificially infecting the plant with a bacterium belonging to the genus Rahnella and having the ability to symbiotically grow in the agriculturally useful plant and promote the growth of the plant How to promote.   Agriculturally useful plant is a plant selected from the group consisting of legumes, gramineous plants, liliaceae plants, cruciferous plants, asteraceae plants, solanaceous plants, cucurbitaceae plants, and cericaceae plants. Item 3. The method according to Item 1 or 2.   The method according to any one of claims 1 to 3, wherein the bacterium has 16S rDNA containing a base sequence having 97% or more identity with the base sequence shown in SEQ ID NO: 1.   The bacterium has Rahnella sp. MYK106 (Accession No. NITE P-02062) or the ability to symbiotically grow in an agriculturally useful plant to increase the yield of the plant and / or the ability to promote the growth of the plant The method according to any one of claims 1 to 4, which is a mutant strain thereof.   Agriculturally belonging to the genus Rahnella and containing as an active ingredient a bacterium that has the ability to symbiotically grow in an agriculturally useful plant and increase the yield of the plant and / or promote the growth of the plant. Useful plant microbial formulations.   Agriculturally useful plant is a plant selected from the group consisting of legumes, gramineous plants, liliaceae plants, cruciferous plants, asteraceae plants, solanaceous plants, cucurbitaceae plants, and cericaceae plants. Item 7. A microorganism preparation according to Item 6.   The microbial preparation according to claim 6 or 7, wherein the bacterium has 16S rDNA comprising a base sequence having 97% or more identity with the base sequence shown in SEQ ID NO: 1.   The bacterium has Rahnella sp. MYK106 (Accession No. NITE P-02062) or the ability to symbiotically grow in an agriculturally useful plant to increase the yield of the plant and / or the ability to promote the growth of the plant The microbial preparation according to any one of claims 6 to 8, which is a mutant strain thereof.   Rahnella sp. MYK106 (Accession No. NITE P-02062) or a variant thereof having the ability to symbiotically grow in an agriculturally useful plant and increase the yield of the plant and / or promote the growth of the plant stock.