A strain of Enterobacter cholerae and its application in promoting plant growth

Abstract

This invention belongs to the technical field of agricultural microbiology, specifically relating to a strain of *Enterobacter holmieae* and its application in promoting plant growth. This invention provides a strain of *Enterobacter holmieae* IVF-WK118, with the preservation number CGMCC No. 28316. Applying an inoculum containing *Enterobacter holmieae* IVF-WK118 to plants promotes plant growth. Experiments show that compared to techniques without *Enterobacter holmieae* application, the technique provided by this invention increased cucumber yield by 8.6%, single fruit weight by 7.5%, and the number of fruits per acre by 1%. Therefore, the *Enterobacter holmieae* provided by this invention can be used to promote plant growth.

Description

Technical Field

[0001] This invention belongs to the technical field of agricultural microbiology, specifically relating to a strain of Enterobacter holmieae and its application in promoting plant growth. Background Technology

[0002] Cucumbers are a common vegetable and fruit, also known as gourd or green cucumber, and are now widely cultivated in temperate and tropical regions. Cucumbers prefer warm climates and are intolerant of cold. Due to their high nutritional value, they have become an indispensable vegetable in modern households, resulting in significant demand. However, due to the influence of growing environment, fertilizer, and human factors, cucumber yields often do not meet expectations.

[0003] Current technology generally agrees that biological measures can not only alleviate agricultural stress but also play a significant role in promoting the healthy development of sustainable agriculture. For example, rhizosphere growth-promoting bacteria can not only colonize the plant rhizosphere, promote plant growth, and enhance the absorption and utilization of mineral nutrients, but also inhibit harmful organisms. However, the effects of different rhizosphere growth-promoting bacteria vary depending on their source. Currently, however, there are no reports of *Enterobacter holmieae* significantly promoting cucumber yield growth. Summary of the Invention

[0004] The purpose of this invention is to provide a strain of Enterobacter cholerae and its application in promoting plant growth, which has the characteristics of promoting cucumber growth and significantly increasing cucumber yield.

[0005] This invention provides an Enterobacter hormaechei IVF-WK118 strain, the preservation number of which is CGMCC No. 28316.

[0006] The present invention provides a bacterial agent containing Enterobacter holmie IVF-WK118 as described in the above technical solution.

[0007] Preferably, the microbial agent comprises a bacterial suspension of Enterobacter holmium IVF-WK118 and / or a fermentation broth of Enterobacter holmium IVF-WK118.

[0008] Preferably, the effective viable count of Enterobacter holmie IVF-WK118 in the bacterial culture of Enterobacter holmie IVF-WK118 is ≥10. 7 cfu / mL.

[0009] This invention provides the application of the above-described Enterobacter holmie IVF-WK118 or the described bacterial agent in promoting plant growth.

[0010] Preferably, the plant includes cucumber.

[0011] Preferably, the promotion of plant growth includes one or more of the following: increasing plant height, increasing plant stem diameter, increasing plant fruit set, increasing plant female flower rate, increasing plant leaf area, increasing plant dry weight, increasing plant fresh weight, and increasing plant root length.

[0012] This invention provides a method for promoting plant growth, comprising the following steps:

[0013] The microbial agent described in the above technical solution is applied to plants.

[0014] Preferably, the method of application includes root irrigation.

[0015] Preferably, when the applied bacterial agent is a bacterial suspension of Enterobacter holmium IVF-WK118, the amount of bacterial suspension applied is 50 mL / strain, and the frequency of application is once every 1 to 2 weeks.

[0016] Beneficial effects:

[0017] This invention provides a strain of Enterobacter holmieae IVF-WK118, with the preservation number CGMCC No. 28316. This bacterium has the effect of promoting plant growth and increasing crop yield.

[0018] Based on the above-mentioned technical advantages, this invention also provides a method for promoting plant growth, comprising the following steps: applying a microbial agent containing *Enterobacter holmieae* IVF-WK118 as described in the above-mentioned technical solution to the plants. This invention, by applying a microbial agent containing *Enterobacter holmieae* IVF-WK118 to the plants, effectively promotes plant growth. Experiments show that, compared with the technical solution without the application of *Enterobacter holmieae*, the technical solution provided by this invention increases cucumber yield by 8.6% per mu (approximately 0.067 hectares), single fruit weight by 7.5%, and the number of fruits per mu by 1%.

[0019] Biological Preservation Information

[0020] Enterobacter hormaechei IVF-WK118 was deposited on August 31, 2023, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, with accession number CGMCC No. 28316. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0022] Figure 1 This is a colony morphology diagram of Enterobacter holmie IVF-WK118 in the culture medium in Example 1;

[0023] Figure 2 This is a microscopic image of the colony morphology of Enterobacter holmie IVF-WK118 in Example 1.

[0024] Figure 3 This is a phylogenetic analysis diagram of Enterobacter holometabolum IVF-WK118 in Example 1;

[0025] Figure 4 The effects of different treatments in Example 2 and Comparative Example 1 on cucumber production;

[0026] Figure 5 To compare the effects of the treatments in Example 2 on the growth of cucumber seedlings;

[0027] Figure 6 The effect of the treatment method in Example 3 on the growth of cucumber seedlings;

[0028] Figure 7 To compare the effects of the treatments in Example 2 on the growth of cucumber fruits;

[0029] Figure 8 The effect of the treatment method in Example 3 on the growth of cucumber fruits;

[0030] Figure 9 The effects of the treatments in Example 3, Comparative Example 2, and Comparative Example 3 on cucumber yield per acre;

[0031] Figure 10 The effects of the treatments in Example 3, Comparative Example 2, and Comparative Example 3 on the weight of a single cucumber fruit;

[0032] Figure 11 The effects of the treatment methods in Example 3, Comparative Example 2, and Comparative Example 3 on the number of cucumber fruits set are shown. Detailed Implementation

[0033] This invention provides an Enterobacter hormaechei IVF-WK118 strain, the accession number of which is CGMCC No.28316;

[0034] In this invention, the *Enterobacter holmieae* IVF-WK118 is preferably isolated from the soil of greenhouse cucumbers at the Nankou Pilot Experimental Base of the Chinese Academy of Agricultural Sciences. The colony characteristics of *Enterobacter holmieae* IVF-WK118 on LB solid medium are: smooth surface, neat edges, opaque, and sticky; under a microscope, the bacteria are bluntly round, arranged singly, and without spores. This invention promotes plant growth and increases crop yield.

[0035] The present invention also provides a bacterial agent containing *Enterobacter holmieae* IVF-WK118; the bacterial agent is preferably a bacterial suspension of *Enterobacter holmieae* IVF-WK118 and / or a fermentation broth of *Enterobacter holmieae* IVF-WK118, more preferably a bacterial suspension of *Enterobacter holmieae* IVF-WK118 or a fermentation broth of *Enterobacter holmieae* IVF-WK118; the effective viable count of *Enterobacter holmieae* IVF-WK118 in the bacterial suspension of *Enterobacter holmieae* IVF-WK118 is preferably ≥10. 7 cfu / mL.

[0036] In this invention, the preferred method for preparing the Enterobacter holmium IVF-WK118 bacterial suspension includes: sequentially expanding the IVF-WK118 strain, centrifuging, and resuspending it to obtain the Enterobacter holmium IVF-WK118 bacterial suspension.

[0037] The present invention preferably involves scaling up the culture of strain IVF-WK118; during the scaling up culture, the inoculum amount of strain IVF-WK118 accounts for 1% to 10% of the total volume of the scaling up culture medium, more preferably 1%; the scaling up culture time is preferably 6 to 8 hours, more preferably 8 hours; the scaling up culture rotation speed is preferably 200 to 220 rpm, more preferably 220 rpm; the scaling up culture temperature is preferably 28 to 37°C, more preferably 37°C; the scaling up culture medium is preferably TSB liquid medium; the components and amount of the TSB liquid medium are not particularly required, and techniques well known in the art can be used, and a bacterial solution with an OD value of 1 can be obtained after the above scaling up culture.

[0038] After the expansion culture, the present invention preferably performs a first centrifugation, rinsing, and a second centrifugation on the bacterial solution with an OD value of 1; the speed of the first centrifugation is preferably 3000-6000g, more preferably 5000g; the time of the first centrifugation is preferably 5-15min, more preferably 10min; the solvent for rinsing is preferably sterile water; the object of rinsing is preferably the precipitate after the first centrifugation; there are no special requirements for the amount of sterile water and the rinsing method, and techniques well known in the art can be used; the speed and time of the second centrifugation are the same as those of the first centrifugation, and will not be repeated here; after the above operations, a precipitate containing strain IVF-WK118 can be obtained.

[0039] After the second centrifugation, the precipitate is preferably resuspended; the resuspension reagent is preferably sterile water; the amount of sterile water used is sufficient to obtain a *Enterobacter holmieae* IVF-WK118 bacterial suspension with an OD value of 0.02; thus, an effective viable count ≥10⁻⁶ can be prepared. 7 CFU / mL of Enterobacter holmium IVF-WK118 bacterial culture.

[0040] After obtaining the *Enterobacter holmieae* IVF-WK118 bacterial culture with an OD value of 0.02, it can be directly applied to plants and used to prepare *Enterobacter holmieae* IVF-WK118 fermentation broth. The preferred method for preparing the *Enterobacter holmieae* IVF-WK118 fermentation broth of this invention includes: aerobic fermentation of the *Enterobacter holmieae* IVF-WK118 bacterial culture with an OD value of 0.02 to obtain the *Enterobacter holmieae* IVF-WK118 fermentation broth.

[0041] The aerobic fermentation culture medium of the present invention uses water as a solvent, and preferably includes the following components by weight percentage per 1000 mL of water: corn flour 1.0%, glucose 0.5%, soybean meal 2%, fish meal 1%, calcium carbonate 1%, ammonium sulfate 0.1%, dipotassium hydrogen phosphate 0.03%, magnesium sulfate 0.03%, and manganese sulfate 0.03%. During the aerobic fermentation, the inoculum volume ratio of Enterobacter holometabolum IVF-WK118 to the volume of the aerobic fermentation culture medium is preferably 1-2:10-30, more preferably 1:10. The aerobic fermentation time is preferably 10-16 h, more preferably 12 h. The aerobic fermentation speed is preferably 200-220 rpm, more preferably 220 rpm. The aerobic fermentation temperature is preferably 28-37℃, more preferably 37℃, thereby obtaining the fermentation broth of Enterobacter holometabolum IVF-WK118.

[0042] After obtaining the fermentation broth, the present invention preferably dilutes the fermentation broth; the solvent for dilution is preferably sterile water; the volume ratio of the amount of sterile water to the volume of the aerobic fermentation medium is 10-30:1-2, more preferably 10:1, so that the fermentation broth diluted in this way can be directly applied to plants.

[0043] This invention also provides the application of *Enterobacter holmieae* IVF-WK118 or the *Enterobacter holmieae* IVF-WK118 inoculum described in the above-mentioned technical solution in promoting plant growth. The plant growth promotion described in this invention preferably includes one or more of the following: increasing plant height, increasing stem diameter, increasing fruit set, increasing female flower rate, increasing leaf area, increasing dry weight, increasing fresh weight, and increasing root length; more preferably, increasing fresh weight. The plant is preferably cucumber; the cucumber variety is preferably a variety intolerant to low temperature and low light; more preferably, it is Deruit 89. By adopting the technical solution provided by this invention, it is beneficial to promote the growth of cucumbers intolerant to low temperature under low temperature and low light conditions.

[0044] This invention provides a method for promoting plant growth, comprising the following steps: applying a bacterial agent containing *Enterobacter holmieae* IVF-WK118 as described in the above technical solution to the plant. The types and preparation methods of the bacterial agent containing *Enterobacter holmieae* IVF-WK118 described in this invention have been described in detail above and will not be repeated here.

[0045] In this invention, the plant is preferably cucumber; the cucumber variety is preferably Deruit 89; the application method is preferably root irrigation; when the applied inoculant is a bacterial solution of Enterobacter holometabolum IVF-WK118, the application amount of the bacterial solution is preferably 10-100 mL / plant, more preferably 50 mL / plant, and the application frequency is once every 1-2 weeks, more preferably once a week; when the IVF-WK118 fermentation dilution prepared in this invention is applied, the application amount of the fermentation dilution is preferably 70-120 mL / plant, more preferably 100 mL / plant; the application frequency is preferably once every 1-2 weeks, more preferably once a week; the application period is preferably the seedling stage, flowering stage, and fruit setting stage of cucumber. By applying the inoculant containing Enterobacter holometabolum IVF-WK118 to the plant, the plant growth can be significantly promoted.

[0046] Experiments show that, compared with the technical solution without the application of *Enterobacter holmiereus*, the technical solution provided by this invention increased cucumber yield by 8.6% per mu (667 square meters), single fruit weight by 7.5%, and the number of fruits per mu by 1%. Therefore, *Enterobacter holmiereus* IVF-WK118 or *Enterobacter holmiereus* IVF-WK118 inoculant can be used to promote plant growth and significantly increase crop yield.

[0047] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, describes a strain of Enterobacter holmieae provided by the present invention and its application in promoting plant growth, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1

[0049] Origin and identification of Enterobacter holmie IVF-WK118

[0050] 1. Source of Enterobacter hopterii IVF-WK118

[0051] Strains from different cucumber rhizosphere samples were isolated and cultured on LB solid medium using the streak method. The cucumbers were collected from the greenhouse of the Nankou Pilot-Scale Experimental Base of the Chinese Academy of Agricultural Sciences.

[0052] 2. Morphological identification

[0053] A small amount of the target strain was picked up with an inoculation loop and streaked onto LB solid medium. After incubation at 28°C for 20 hours, the morphology, shape, size, edge, surface, raised shape, transparency, colony size, and color of the medium were observed (see results). Figure 1 After culturing for 24 hours, the bacteria were examined under a microscope, and their morphology was recorded (see results below). Figure 2 ).

[0054] Depend on Figure 1 and Figure 2It can be seen that after culturing in LB solid medium for 24 hours, the colonies of the target strain are round, with smooth surfaces, neat edges, opaque, and sticky; they are Gram-negative, and under an optical microscope, the cells are bluntly round, arranged singly, and without spores.

[0055] 3. Molecular biological identification

[0056] (1) DNA extraction

[0057] Genomic DNA of the target strain IVF-WK118 was extracted using the TIANamp Bacteria DNAkit kit, which was purchased from Tiangen Biotech (Beijing) Co., Ltd.

[0058] (2) PCR amplification and sequencing

[0059] Using the genomic DNA extracted in step (1) as a template, PCR amplification was performed using universal primers:

[0060] Upstream primer: 5'-AGAGTTTGATCCTGGCTCAG-3' (SEQ ID NO.1);

[0061] Downstream primer: 5'-AAGGAGGTGATCCAGCCGCA-3' (SEQ ID NO.2);

[0062] The PCR reaction system is in 25 μL volume, including 1 μL template DNA, 1 μL of 10 μmol / L upstream primer, 1 μL of 10 μmol / L upstream primer, 12.5 μL of Novizan 2×Taq PCR Master Mix, and ddH2O to make up to 25 μL.

[0063] The PCR reaction program was as follows: 94℃ pre-denaturation for 5 min; 94℃ denaturation for 30 s, 55℃ annealing for 1 min; 72℃ extension for 2 min, 30 cycles; 72℃ extension for 10 min.

[0064] The obtained PCR products were detected by agarose gel electrophoresis under standard conditions, and then sent to Beijing Ruiboxing Biotechnology Co., Ltd. for sequencing. The sequencing results were processed and compared with GenBank.

[0065] (3) Construction of phylogenetic tree

[0066] The sequencing results were compared with those in NCBI to preliminarily determine the species. Standard sequences of each known Bacillus were obtained from GenBank. The sequences were aligned using Readseqn software, and sequence similarity was calculated and phylogenetic analysis was performed using MEGA 5.01 (results are shown in [link to results]). Figure 3 ).

[0067] Depend on Figure 3 It can be seen that the target strain IVF-WK118 is at the same developmental level as Enterobacter holmie and is most closely related, which is consistent with the physiological and biochemical identification results. Therefore, the target strain is Enterobacter holmie and is named Enterobacter holmie IVF-WK118.

[0068] Example 2

[0069] The growth-promoting effect of Enterobacter holmieae IVF-WK118 bacterial suspension in seedling trays on cucumber seedlings.

[0070] Experimental materials: The main commercial cucumber varieties grown in northern China, including the low-temperature and low-light tolerant variety Deruit 89, were used as experimental materials.

[0071] Experimental setup:

[0072] a. Seed pretreatment: Soak seeds in an Erlenmeyer flask containing 50℃ warm water for 30 minutes, then soak in 75% alcohol for 15 seconds, rinse once with sterile water, and then soak in 6% sodium hypochlorite for 15 minutes, shaking occasionally during this time. Discard the sodium hypochlorite and rinse 6-8 times with sterile water. Then place the seeds in a 100×100mm petri dish, add two layers of filter paper to the bottom, and add an appropriate amount of sterile water. Place the dish in a dark incubator at 30℃ and wait for germination. After germination, select seeds with uniform growth for later use.

[0073] b. Experimental setup: Sterilized Flora gard peat moss seedling substrate was filled into 8-well trays. Then, cucumber seeds that had been germinated and showed uniform growth in step a were sown, one seed per well, with each plant constituting one biological replicate. The trays were then placed in an artificial climate chamber for cultivation (day and night temperatures of 28℃ and 23℃, 16 hours of light per day, and 80% soil moisture).

[0074] c. Preparation of Enterobacter holmie IVF-WK118 bacterial suspension: The IVF-WK118 strain was cultured in Tryptic SoyBroth (TSB) liquid medium at an inoculum size of 1%, a rotation speed of 220 rpm, a temperature of 37℃, and a time of 6 h to obtain a bacterial suspension with an OD of 1. The bacterial suspension was centrifuged at 5000g for 10 min, washed with 25 mL of sterile water, and then centrifuged again at 5000g for 10 min. After discarding the waste liquid, the bacterial suspension was resuspended in sterile water to obtain a bacterial suspension with an OD of 0.02.

[0075] d. Fertilization: After the cucumber cotyledons have unfolded as described in step b, begin applying the bacterial solution from step c. Use the root irrigation method to apply 50 mL of the bacterial solution (10 mL / min) to each cucumber seedling hole. 7 Add bacterial solution (CFU / g substrate) every 7 days, 50 mL / cell each time. Manage normally according to local planting needs without applying other fertilizers.

[0076] Comparative Example 1

[0077] The difference from Example 2 is that step c is omitted; in step d, 50 mL of sterile water is added instead of the bacterial solution, and 50 mL of sterile water is added every 7 days. Without applying any other fertilizers, normal management should be carried out according to local planting needs.

[0078] Results and Analysis:

[0079] When cucumber seedlings reached the three-leaf-one-heart stage (a significant difference from the standard), the plant height, stem diameter, leaf area, dry weight, fresh weight, and root length of the cucumber seedlings in Example 2 and Example 1 were measured to evaluate the seedling growth-promoting effect of the tested strains or synthetic microbial groups. The results are shown in Table 1. Figure 4 ( Figure 4 Figure A shows the growth of cucumbers under different treatments; Figure 4 (B in the chart represents a bar chart showing different measurement standards for cucumbers under different treatments). The specific measurement standards are as follows:

[0080] Plant height: The height from the surface of the substrate in the seed tray to the growth point is used as the standard;

[0081] Stem diameter: Measured with vernier calipers, close to the lower part of the cotyledon node;

[0082] Leaf area: Take a picture of the largest true leaf after it is laid flat, and use ImageJ software to calculate the area.

[0083] Root length: After washing the roots, measure the length of the main root with vernier calipers;

[0084] Fresh weight: After washing the whole plant, shake off the excess water and weigh it using an electronic balance.

[0085] Dry weight: The whole plant was blanched at 105℃ for 15 minutes and dried at 70℃ for more than 48 hours until constant weight was achieved. Among them, plant height and stem diameter were analyzed and statistically analyzed from 8 replicates. Leaf area, root length, whole plant fresh weight and whole plant dry weight were randomly selected from 8 replicates for statistical analysis.

[0086] Table 1 Effects of different treatments on cucumber growth

[0087]

[0088]

[0089] From Table 1 and Figure 4It can be seen that the average plant height of the aseptic control was 7.63±0.67 cm, the average stem diameter was 4.45±0.48 cm, the average root length was 10.40±1.04 cm, the average fresh weight of the whole plant was 6.86±1.69 g, the average leaf area was 111.58±11.81 g, and the average dry weight of the whole plant was 0.60±0.19 g. The cucumber seedlings with *Enterobacter holmieae* IVF-WK118 strain had an average plant height of 11.33±0.78 cm, which increased the plant height growth promotion efficiency by 48% compared to the aseptic control; the average stem diameter was 4.94±0.55 cm. Compared with the aseptic control, stem diameter increased by 11% in promoting growth; root length averaged 13.33±1.15 mm, increasing by 28% in promoting growth compared with the aseptic control; whole plant fresh weight averaged 9.21±0.71 mm, increasing by 34% in promoting growth compared with the aseptic control; leaf area averaged 216.89±18.79 mm, increasing by 94% in promoting growth compared with the aseptic control; and whole plant dry weight averaged 0.80±0.23 mm, increasing by 64% in promoting growth compared with the aseptic control.

[0090] Example 3

[0091] Growth-promoting effect of Enterobacter hooligans IVF-WK118 on cucumbers in greenhouse

[0092] Experimental materials: The main commercial cucumber varieties grown in northern China, including the low-temperature and low-light tolerant variety Deruit 89, were used as experimental materials.

[0093] Experimental setup:

[0094] a. Planting: Cucumbers were planted using local planting methods, taking into account the area of ​​the experimental plots.

[0095] b. Preparation of Cronobacter holmie IVF-WK118 fermentation broth:

[0096] Preparation of fermentation medium: Each 1000mL of water contains 10g corn flour, 5g glucose, 20g soybean meal, 10g fish meal, 10g calcium carbonate, 1g ammonium sulfate, 0.3g dipotassium hydrogen phosphate, 0.3g magnesium sulfate, and 0.3g manganese sulfate.

[0097] Take 20 mL of the *Enterobacter holmium* IVF-WK118 bacterial culture with an OD of 0.02 prepared in step c of Example 2, add it to 200 mL of fermentation medium (using a 500 mL Erlenmeyer flask as the culture container), and incubate overnight at 37°C and 220 rpm. Dilute the fermented broth with 2 L of sterile water and set aside.

[0098] c. Fertilization: Use the diluted fermentation liquid obtained in step b to irrigate the cucumber seedlings in plot 1, applying 100 mL of the inoculum per seedling. Fertilize once a week throughout the cucumber's growth period, applying 100 mL per seedling each time. Without applying any other fertilizers, manage the plant normally according to local planting needs.

[0099] Comparative Example 2

[0100] The difference from Example 3 is that in step c: only a water-soluble compound fertilizer with a nitrogen-phosphorus-potassium mass ratio of 20:10:20 is applied, and the application amount is determined according to the instructions of the water-soluble compound fertilizer.

[0101] Comparative Example 3

[0102] The difference from Example 3 is that in step c, commercial bacterial solution Y1 was used to irrigate the cucumber seedlings in plot 3. The commercial bacterial solution Y1 was a microbial agent purchased from Muen (Guangzhou) Biotechnology Co., Ltd.

[0103] Experimental plot description: The experimental plots are located on the same plot of land in the plastic greenhouse of the Nankou Pilot Base of the Chinese Academy of Agricultural Sciences. One plot is divided into three plots: plot 1 is used for Example 1, plot 2 for Comparative Example 2, and plot 3 for Comparative Example 3. Cucumber 9930 is planted between adjacent plots as a protection row. The area of ​​each plot is 7m². 2 Each plot was planted with 20 cucumber plants, spaced 35cm apart. Except for the different types of microbial agents used in each treatment, all other management practices were the same.

[0104] Results and Analysis:

[0105] Statistical analysis was performed on the cucumbers grown in Example 3, Comparative Example 2, and Comparative Example 3, specifically, the plant height, stem diameter, leaf area, root length, fresh weight of the whole plant, and dry weight of the whole plant were recorded during the cucumber seedling stage. The results are shown in the table below. Figures 4-6 The number of fruits set, yield per plant, and yield per plot during the cucumber fruit-setting period were statistically analyzed. The results are shown in Table 2. Figures 7-11 .

[0106] Table 2. Effects of different treatments on average yield per mu, average single fruit weight, and average number of fruits set in cucumbers at the fruit-setting stage.

[0107] Yield per mu (kg) Single fruit weight / g Fruit set per mu (Comparative Example 2) CK 3190.6 219.1 14560 (Example 3) IVF-WK118 3465 235.7 14700 (Comparative Example 3) Y1 3505.25 256.8 13650

[0108] There is table 2, Figures 5 to 11 It can be seen that under normal fertilizer and water management, the yield per mu of fermentation liquid with added Enterobacter holmium IVF-WK118 increased by 8.6% compared with the control CK, the single fruit weight increased by 7.5%, the number of fruits per mu increased by 1%, and the effect was comparable to that of the commonly used commercial product Y1.

[0109] In summary, the Enterobacter holmie IVF-WK118 provided by this invention can promote plant growth and significantly increase plant yield.

[0110] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An Enterobacter hormaechei IVF-WK118 strain, wherein the accession number of Enterobacter hormaechei IVF-WK118 is CGMCC No. 28316.

2. An inoculum containing the Enterobacter holmie IVF-WK118 as described in claim 1.

3. The microbial agent according to claim 2, characterized in that, The bacterial agent includes a bacterial suspension of Enterobacter holmium IVF-WK118.

4. The microbial agent according to claim 3, characterized in that, The effective viable count of Enterobacter holmie IVF-WK118 in the bacterial culture was ≥10. 7 cfu / mL.

5. The application of the Enterobacter holmie IVF-WK118 of claim 1 or the microbial agent of any one of claims 2 to 4 in promoting plant growth; The promotion of plant growth includes: Increase plant height, increase plant stem diameter, increase plant fruit set, increase plant leaf area, increase plant dry weight, increase plant fresh weight, and increase plant root length (one or more of these). The plant in question is a cucumber.

6. A method for promoting cucumber growth, characterized in that, Includes the following steps: The fungicide according to any one of claims 2 to 4 is applied to cucumber.

7. The method according to claim 6, characterized in that, The application method includes root irrigation.

8. The method according to claim 6, characterized in that, When the applied bacterial agent is a bacterial suspension of Enterobacter holmium IVF-WK118, the application amount is 50 mL / strain, and the application frequency is once every 1 to 2 weeks.

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