Rahnella Y17 as well as bacterial liquid and application thereof

Abstract

The invention relates to the technical field of microbial growth promotion, and particularly discloses a Rahnella Y17 and a bacterial liquid and application thereof, the Rahnella Y17 is preserved in China General Microbiological Culture Collection Center on April 15, 2025, the preservation number is CGMCC No.34219, and the preservation number is CGMCC No.34219. The Rahnella Y17 is preserved in China General Microbiological Culture Collection Center on April 15, 2025. The Rahnella sp is classified and named as Rahnella sp. The Rahnella sp is used for promoting growth of cherry plants and germination of apple seeds.

Description

Technical Field

[0001] The present invention relates to the technical field of microbial growth promotion, and in particular to a strain of Rahn's bacterium Y17, a bacterial liquid thereof, and an application thereof. Background Art

[0002] Cherry is one of the earliest deciduous fruit trees to mature, with a cultivation history of at least 2,000 years in my country. Long-term cherry cultivation has revealed that its root system is relatively weak compared to other fruit trees, with shallow root distribution, few fibrous roots, and low root density. This makes it poorly adaptable to adverse soil environments such as drought and waterlogging. After bearing large quantities of fruit, it is prone to premature aging and a short economic fruiting period, among other industry issues. Sweet cherry, the primary cultivated fresh cherry species, boasts vigorous natural growth and towering stature. Since its introduction into my country, various rootstocks have been tested and applied across the country, including the Northeastern Mountain Cherry, Daqingye, Corte, Mahali, and Gisela series, as well as the domestically bred Landin series.

[0003] Plant growth-promoting rhizobacteria (PGPR) are a class of beneficial bacteria that promote plant growth. Their species and growth-promoting functions are diverse. Cherry is an economic crop, so developing growth-promoting bacteria to promote cherry growth is of great significance. Summary of the Invention

[0004] To develop a growth-promoting bacterium for promoting cherry growth, the present invention provides a strain of Rahnella Y17, its bacterial solution, and its application. The Rahnella provided by the present invention is used to promote the growth of cherry plants and the germination of apple seeds.

[0005] The present invention provides a strain of Raenella Y17, which was deposited in the General Microbiology Center of China National Committee for Microbiological Culture Collection on April 15, 2025, with a deposit number of CGMCC No. 34219 and a classification name of Raenella Rahnella sp.

[0006] The Rahn's bacterium provided by the present invention promotes the growth of cherry plants by increasing the root vitality of cherry seedlings, increasing the number of root tips of cherry seedlings, increasing the respiration rate of the PPP pathway of the root system of cherry seedlings, increasing the plant height of cherry seedlings, and increasing the chlorophyll content of cherry plant leaves, and promotes the germination of apple seeds by increasing the radicle length and plumule length of apple seeds and thickening the plumule.

[0007] The present invention also provides a bacterial liquid containing the Rahn's bacterium Y17.

[0008] Furthermore, the OD of the bacterial solution 600 The value is 0.8~1.

[0009] The present invention also provides a plant growth-promoting product, which contains the Rahn's bacterium Y17 as an effective ingredient.

[0010] The present invention also provides a use of the Rahn's bacterium Y17, the bacterial liquid or the plant growth-promoting product in promoting the growth of cherry plants.

[0011] Furthermore, the Rahnella Y17, bacterial liquid or plant growth promotion product is used to improve the root vitality of cherry seedlings, increase the number of root tips of cherry seedlings, increase the respiration rate of the PPP pathway of the cherry seedling roots, increase the plant height of cherry seedlings, and increase the chlorophyll content of cherry plant leaves.

[0012] The present invention also provides a use of the Rahn's bacterium Y17, the bacterial liquid or the plant growth-promoting product in promoting apple seed germination.

[0013] Furthermore, the Rahn's bacterium Y17, bacterial liquid or plant growth promotion product is used to promote the radicle growth, plumule growth and plumule thickening of Pingyi sweet tea seeds.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a strain of Rahnella Y17 with high IAA production. The Rahnella Y17 promotes the growth of cherry plants by increasing the root vitality of cherry seedlings, increasing the number of root tips of cherry seedlings, increasing the respiration rate of the PPP pathway of the cherry seedling roots, increasing the plant height of cherry seedlings, and increasing the chlorophyll content of cherry plant leaves. It also promotes the germination of apple seeds by increasing the radicle length and plumule length of apple seeds and thickening the plumule.

[0015] The present invention uses a bacterial solution prepared by Laenella Y17 to act on Pingyi sweet tea seeds. It was found that the bacterial solution increased the radicle length, plumule length, and plumule thickness, and the Laenella Y17 bacterial solution is beneficial for promoting the germination of Pingyi sweet tea seeds. The Laenella Y17 bacterial solution is applied to cherry seedlings, improving the root vitality of the cherry seedlings, increasing the number of root tips of the cherry seedlings, increasing the respiration rate of the cherry seedling root PPP pathway, increasing the plant height of the cherry seedlings, and increasing the chlorophyll content of the cherry plant leaves, thereby promoting the growth and development of the cherry seedlings as a whole.

[0016] Information on the deposit of biological materials Y17, referred to in this application as Raenella Y17, was deposited on April 15, 2025, at the General Microbiology Center of the China Culture Collection Administration, with the deposit number CGMCC No. 34219. The depository address is the Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing, Postal Code: 100101. The strain is classified as Raenella Rahnella sp. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Physiological and biochemical identification and phylogenetic tree of Rahnella Y17; In the figure, A is the qualitative screening result of IAA secretion by Rahn's bacterium Y17; B is the colony morphology of Raenella Y17 on a nitrogen-fixing plate; C is the colony morphology of Raenella Y17 on an organophosphate plate; D is the colony morphology of Raenella Y17 on an inorganic phosphate plate; E is the phylogenetic tree of Raenella Y17.

[0019] Figure 2 This is the effect of Laenella Y17 on the root activity of cherry seedlings from 0 to 30 days after treatment.

[0020] Figure 3 The root system and root hair growth of cherry trees after being treated with Rahnella Y17; In the figure, A is a scan of the cherry root system after 60 days of sterile water treatment; B is a scan of the cherry root system after 60 days of treatment with Rahnella Y17; C shows the root hair growth of cherry capillary roots after 60 days of sterile water treatment; D shows the root hair growth of cherry capillary roots after 60 days of treatment with Rahnella Y17.

[0021] Figure 4 This shows the growth of cherry plants 60 days after treatment with Rahn's bacteria Y17.

[0022] Figure 5 The effect of Rahnella Y17 on the respiration rate of cherry plant roots; In the figure, A shows the effect of Rahnella Y17 on the total respiration rate of cherry plant roots; B shows the effect of Rahnella Y17 on the respiration rate of various biochemical pathways in the roots of cherry plants.

[0023] Figure 6 The effect of Rahnella Y17 on the pH of the rhizosphere soil of cherry plants.

[0024] Figure 7 This is the growth-promoting effect of Raenella Y17 on Pingyi sweet tea.

[0025] Figure 8 This is the growth-promoting effect of Rahnella Y17 on cucumber. DETAILED DESCRIPTION

[0026] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited by the specific embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified, and the materials, reagents, etc. used in the following embodiments can be obtained from commercial sources unless otherwise specified.

[0027] Example 1: Isolation and identification of a strain of Rahn's bacterium Y17.

[0028] 1. Isolation, screening and identification of strains 1. Strain isolation and screening Soil samples were collected on June 28, 2022, from sweet cherry orchards in Yuyao Village, Jiangkui Village, and Paoya Village in Pulandian District, Dalian City, Liaoning Province. Well-grown sweet cherry grafted trees rootstocked with 'Gisela 6' were selected for sampling. 5–10 cm of topsoil were removed, and a 10–20 cm thick layer of rhizosphere soil was collected using a sterile shovel and placed in a sterile bag. This was then stored at -20°C for subsequent isolation and culture of rhizosphere microorganisms.

[0029] Weigh 5g of soil sample and place it in a 250mL Erlenmeyer flask filled with 45mL of sterilized water. Shake it in a shaker at 30℃ and 180r / min for 20min and let it stand for 10min to obtain a soil bacterial suspension. -2 ~10 -8 After gradient dilution, the plate was spread on NB medium, and then the plate was inverted and cultured in a 37°C incubator for 48 hours. Single colonies of different morphologies were picked and purified on the plate for qualitative screening of IAA-producing bacteria.

[0030] Qualitative screening of IAA-producing bacteria: Purified bacteria were inoculated into NB liquid medium containing L-tryptophan (100 mg / L). Three replicates of each strain were cultured at 37°C, 180 rpm, and shaker shaker for 24 hours. A 50 μL droplet of the bacterial culture was then placed on a white ceramic plate. An equal volume of Salkowski colorimetric solution was added. A mixture of 50 μL of uninoculated NB liquid medium and an equal volume of colorimetric solution was used as a control. The white ceramic plate was placed in the dark at room temperature for 30 minutes and then observed. A pink color change was considered positive, indicating IAA secretion. A darker color indicates a stronger secretion. No color change was considered negative, indicating IAA insufficiency.

[0031] 2. 16S rDNA Identification of Strain Preparation of bacterial suspension: The activated strain was inoculated into 50 mL of beef extract peptone liquid medium, cultured on a shaker (37°C, 180 rpm) for 24 h, centrifuged at 10,000 rpm for 10 min, discarded the supernatant to collect the bacteria, and then rinsed repeatedly with sterile water and centrifuged at 10,000 rpm for 10 min. The rinsing step was repeated three times, and the OD value of the bacterial suspension was adjusted with sterile water. 600 The value is 0.8, for backup.

[0032] The bacterial suspension of the strain to be tested was used as a template, and the universal primers 27F / 1492R were used to amplify 16S rDNA. The complete sequence of 16S rDNA of each strain was then obtained by bidirectional sequencing and splicing. The sequences were aligned in the NCBI database, and the neighbor-joining method was used to construct a phylogenetic tree using MEGA7.0 software.

[0033] 3. Determination of IAA production capacity and identification of physiological characteristics of strain Y17 Preparation of IAA standard curve: The IAA standard curve is prepared using IAA standard drugs. First, weigh 15 mg of IAA standard drugs and dissolve it in 50 mL of anhydrous ethanol to prepare an IAA mother solution with a concentration of 300 mg / L. Then dilute it into 15, 30, 60, 90, 120, and 150 mg / L standard IAA solutions according to the dilution rates of 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5, respectively. Then, take 3 mL of IAA standard solutions of different concentrations and add an equal volume of Salkowski color developer. At the same time, take 3 mL of anhydrous ethanol and add an equal volume of Salkowski color developer as a zero control. Place the mixed solution at room temperature in a dark environment to react for 30 minutes, and immediately measure its OD with a spectrophotometer after taking it out. 530 Finally, according to the OD of IAA standard solution with different concentrations 530 The IAA standard curve was drawn.

[0034] Quantitative method: The IAA-producing strains screened qualitatively were used as IAA quantitative test strains. The test strains were inoculated into NA liquid medium containing L-tryptophan, with 3 replicates for each strain. After shaking culture (37°C, 180r / min) for 12h, 24h, 36h, and 48h, 5mL of bacterial solution was taken from each 10mL centrifuge tube and centrifuged at 10000r / min for 10min. 3mL of supernatant was taken, an equal volume of Salkowski colorimetric reagent was added, and the tube was kept in the dark for 30min to measure its OD. 530 The IAA content per unit volume of bacterial solution was calculated by comparing with the standard curve.

[0035] Nitrogen fixation: Inoculate the strain to be tested into beef extract peptone liquid medium and activate it in a shaker at 37°C, 180 rpm, for 24 hours. Use an inoculating loop to streak the strain onto Axubei solid medium and incubate in a 37°C incubator. After four days, observe whether the strain grows on the Axubei solid medium. Record the number of any growing strains, take photos, and select strains with good growth for the next test.

[0036] Phosphate solubility assay: Inoculate the test strain into 50 mL of beef extract peptone broth and activate at 37°C, 180 rpm / min, and shake for 24 hours. Use a pipette to aspirate 2.5 μL of the bacterial suspension and dropwise plate onto PKO inorganic phosphate plates and Montgena organic phosphate plates. Incubate in a 37°C incubator. After 4–5 days, observe and record the formation of a phosphate solubility ring. The presence of a transparent phosphate solubility ring indicates phosphate solubilization.

[0037] 2. Experimental Results 1. Strain isolation and screening A strain of IAA-secreting bacteria was isolated and screened and named Y17. Molecular identification of this strain identified it as Raenella spp. Rahnella sp), phylogenetic tree see Figure 1 E.

[0038] 2. Qualitative screening and physiological characteristics identification of IAA bacteria The qualitative screening results of IAA bacteria are shown in Figure 1 A. Laenella Y17 has the ability to secrete IAA. The quantitative test results are shown in Table 1.

[0039] Table 1 Quantitative results of IAA production by Rahnella Y17 (mg / L) Note: Data are expressed as mean ± standard deviation (n=3). Different lowercase letters in the same column represent significant differences between different treatments. p <0.05.

[0040] As shown in Table 1, Rahn's Y17 has a good ability to produce IAA, and the yield after shaking for 48 hours reaches 18.7 mg / L.

[0041] Table 2 Qualitative results of nitrogen fixation, phosphorus solubility and potassium solubility of strains Note: In the above table, “+” indicates that this growth-promoting property exists, and “-” indicates that this growth-promoting property does not exist.

[0042] The results of physiological characteristics identification are shown in Table 2 and Figure 1 B. Figure 1 C and Figure 1 As shown in D. Raenella Y17 grew well on nitrogen-free medium plates (nitrogen-fixing plates), Montkina organophosphate solid medium plates (organic phosphorus plates), and PKO inorganic phosphorus solid medium plates (inorganic phosphorus plates), indicating that Raenella Y17 has good nitrogen-fixing and phosphorus-solubilizing properties.

[0043] Example 2: Application of Rahnella Y17 in promoting the growth of 'Gisela 6' seedlings.

[0044] 1. Experimental Methods 1. Study on the effect of Laenella Y17 on the growth promotion of 'Gisela 6' seedlings The 'Gisela 6' cherry seedlings were planted in nutrient pots in advance (the cultivation medium was garden soil: sand = 2:1, and the organic matter content of the mixed medium was 17.42 g·kg -1 , alkaline nitrogen content 127.33 mg•kg -1 , available phosphorus content 173.42 mg•kg -1 , fast-acting potassium content 123.75 mg•kg -1 ). In the experiment, potted seedlings of 'Gisela No. 6' with uniform growth (new shoot length 10 cm) were selected as test materials. The strain Y17 solution was applied to the roots of the 'Gisela No. 6' seedlings by root irrigation. The control was treated with sterile water. In this preliminary test, 5 seedlings were treated with each strain, and the OD of the solution was 0.05 for each treatment. 600 The value was approximately 0.8. The volume of bacterial solution applied to the treatment group was 50 mL, and treatment was performed once every 5 days for a total of 4 treatments, with a total duration of 20 days. After the treatment, relevant physiological indicators such as root activity, root respiration, root architecture, chlorophyll content, and plant biomass of the seedlings in the control group and each treatment group were measured to preliminarily determine the initial growth-promoting effect of the strain on cherry seedlings.

[0045] Determination of plant biomass: Plant height was measured with a tape measure and an electronic vernier caliper on day 20 of treatment.

[0046] Chlorophyll content determination: Weigh 0.5 g of fresh 'Gisela No. 6' leaf sample, chop it, and place it in a mortar. Add 5 ml of 80% acetone, a small amount of CaCO₃, and quartz sand. Grind thoroughly to a homogenous slurry, then filter it through a funnel into a 10 ml graduated cylinder. Be sure to clean the mortar by adding a small amount of 80% acetone, transfer the mortar and filter it into the graduated cylinder, and bring the volume up to 10 ml. Mix the extract in the graduated cylinder, carefully pipette 5 ml into a 25 ml graduated cylinder, and then add 80% acetone to bring the volume up to 25 ml (the final plant material to extract ratio is 1:100).

[0047] Measurement of plant root system architecture and topology: Root surface area, volume, and total length were measured using a digital scanner. Roots were rinsed with distilled water and immersed in a transparent tray filled with distilled water. Images were acquired using a digital scanner (Epson, Long Beach, USA) and quantitatively analyzed using WinRhizo PRO 2016 analysis software (Regent Instruments, Quebec, Canada). Root topology was categorized as multibranched or herringbone-shaped in terms of branching structure. External link length (Pe) was the sum of the number of links in the path from each external link to the base link.

[0048] Root activity assay: Weigh 0.5 g of fresh root sample and add 5 mL of triphenyltetrazolium chloride (0.4% mass-to-volume ratio) and 5 mL of pH 7.0 phosphate buffer. Incubate at 37°C for 4 h. Then, terminate the reaction by adding 2 mL of 1 mol / L H₂SO₄ solution. Remove the root sample, dry it, and return it to the original tube. Extract it overnight with 10 mL of 95% ethanol. Once the solution turns red, perform colorimetric analysis at 485 nm.

[0049] Root respiration was measured using the Hansatech (UK) OxyTrace+ liquid-phase oxygen electrode automated measurement system. Sodium fluoride (0.5 mol / L), malonic acid (0.5 mol / L), and sodium phosphate (0.5 mol / L) were sequentially added to the liquid-phase oxygen electrode reaction chamber to measure the respiration rates of the glycolysis pathway, the tricarboxylic acid cycle pathway, and the pentose phosphate pathway. 2 mL of phosphate buffer was added to the oxygen electrode reaction chamber, and approximately 0.05 g of young 'Gisela No. 6' cherry roots were weighed and added to the reaction chamber. After the slope stabilized, the slope was intercepted using the OxyTrace+ software (Version: v1.0.48). The total root respiration rate (R) was calculated based on the decreasing slope of oxygen concentration. total = -2 * 0.001 * slope / root fresh weight. Add 50 μL of sodium fluoride (0.5 mol / L) and wait until the slope stabilizes. Then intercept the slope and substitute it into the total respiration rate formula.

[0050] The calculation process of the respiration rate of the glycolysis pathway is as follows: R EMP =R total -R NaF ; R TCA =R total -R EMP -R 丙二酸 ; R PPP =R total -R EMP –R TCA -RNa3PO4 ; Among them, R total represents the total respiratory rate; R EMP represents the glycolysis (EMP) respiration rate; R NaF represents the respiratory rate after inhibition of the EMP pathway; R TCA represents the tricarboxylic acid cycle (TCA) respiration rate; R 丙二酸 represents the respiratory rate after inhibition of the TCA pathway; R PPP represents the pentose phosphate pathway (PPP) respiration rate; R Na3PO4 Represents the respiratory rate after inhibition of the PPP pathway.

[0051] 2. Experimental Results 1. Growth-promoting effect of Rahnella Y17 on 'Gisela 6' seedlings The results are as follows Figure 2 As shown in the figure, the root activity of cherries treated with Laenella Y17 was significantly higher than that of the control group, and Laenella Y17 had a significant promoting effect on root activity.

[0052] The results are shown in Table 3. The number of root tips of cherry seedlings significantly increased after treatment with Rahnella Y17, which increased by 42.07% compared with CK. Figure 3 .

[0053] Table 3 Effects of Rahnella Y17 on the root topology of cherry seedlings Note: Data are expressed as mean ± standard deviation (n=3). Different lowercase letters in the same column represent significant differences between different treatments. p <0.05.

[0054] The effect of Rahnella Y17 on the height of cherry plants is shown in Figure 4 After 60 days of CK treatment, the plant height was 28.41±1.55 cm, and after 60 days of Laenella Y17 treatment, the plant height of cherry seedlings was 42.26±6.18 cm. After 60 days of Laenella Y17 treatment, the plant height of cherry seedlings was significantly increased.

[0055] The effects of Rahnella Y17 on the chlorophyll content in cherry plant leaves are shown in Table 4.

[0056] Table 4 Effects of Rahnella Y17 treatment on chlorophyll content in cherry leaves Note: Data are expressed as mean ± standard deviation (n=3). Different lowercase letters in the same column represent significant differences between different treatments. p <0.05.

[0057] As shown in Table 4, the total chlorophyll, chlorophyll a, and chlorophyll b contents of cherry seedlings after treatment with single strain Y17 increased by 17.58%, 16.30%, and 20.83% compared with those of CK, respectively, and the differences were significant. It has a good effect on improving the chlorophyll content of seedlings.

[0058] Effects of Rahnella Y17 on the respiratory metabolism of cherry plant roots Figure 5 As shown in the results, treatment with Laenella Y17 affected the total respiration rate and the respiration rates of various biochemical pathways in the roots of 'Gisela 6' cherry seedlings. After treatment with Laenella Y17, the TCA pathway became the main respiration pathway in the roots of cherry seedlings, and was significantly increased by 142.42% compared with the CK.

[0059] Effects of Raenella Y17 on pH of rhizosphere soil of cherry plants Figure 6 As shown in the figure, the pH value of the rhizosphere soil treated with strain Y17 decreased most significantly, down 10.24% compared with CK.

[0060] In conclusion, Laenella Y17 significantly promoted the growth and development of the cherry plant 'Gisela 6', providing a growth-promoting bacterial resource for cherry cultivation.

[0061] Example 3: Application of Rahnella Y17 in promoting seed germination and seedling growth of Pingyi sweet tea.

[0062] 1. Experimental Methods 1. Preparation of Raenella Y17 bacterial solution Preparation of Laenella Y17 bacterial suspension: The activated Laenella Y17 was inoculated into 50 mL of beef extract peptone liquid culture medium, cultured at 37°C and 180 r / min on a shaker for 24 h, centrifuged at 10,000 r / min for 10 min, discarded the supernatant to collect the bacteria, and then rinsed repeatedly with sterile water and centrifuged at 10,000 r / min for 10 min. The rinsing step was repeated three times, and the OD value of the bacterial suspension was adjusted with sterile water. 600 The value is 0.8, for backup.

[0063] 2. The promoting effect of Laenella Y17 bacterial solution on Pingyi sweet tea seeds The seeds of Pingyi sweet tea were collected and soaked in water for 24 hours, then buried in wet sand and placed in a 4°C environment for stratification. After 30 days of stratification, the seeds that had initially turned white were selected for preliminary growth promotion screening.

[0064] Selected seeds were surface disinfected by soaking in 2% NaClO for 5 minutes and rinsing three times with sterile water. The seeds were then soaked in 75% alcohol for 30 seconds and then rinsed six times with sterile water. Finally, the seeds were blotted dry with sterile absorbent paper for later use. The disinfected seeds were placed in Petri dishes lined with two sheets of sterile moistened filter paper, with 15 seeds per dish, and three replicates per treatment. A pre-prepared strain of Rahn's Y17 was added dropwise to each seed, with 100 μL of the solution added every three days for a total of three treatments. An equal amount of sterile water was added as a control. Sterile water was sprayed regularly throughout the treatment period to ensure adequate moisture and humidity for seedling germination and growth. After each treatment, the growth of the seedlings was observed, and relevant indicators such as radicle length, plumule length, plumule diameter, and cotyledon width were measured.

[0065] 2. Experimental Results 1. The promoting effect of Raenella Y17 on Pingyi sweet tea seeds The growth-promoting effect of the strain of Laenella Y17 on the seedlings of Pingyi sweet tea is shown in Table 5 and Figure 7 shown.

[0066] Table 5 Growth promotion of Pingyi sweet tea by Raenella Y17 The results are shown in Table 5 and Figure 7 As shown, the strain Laenella Y17 significantly increased the radicle length, plumule length and plumule diameter of Pingyi sweet tea seedlings.

[0067] Comparative Example 1: Effect of Rahnella Y17 on cucumber seed germination.

[0068] Preparation of Laenella Y17 bacterial suspension: The activated Laenella Y17 strain was inoculated into 50 mL of beef extract peptone liquid culture medium, cultured at 37°C and 180 r / min on a shaker for 24 h, centrifuged at 10,000 r / min for 10 min, discarded the supernatant to collect the bacteria, and then rinsed repeatedly with sterile water and centrifuged at 10,000 r / min for 10 min. The rinsing step was repeated three times, and the OD value of the bacterial suspension was adjusted with sterile water. 600 The value is 0.8, and the bacterial liquid of Rahn's bacteria Y17 is obtained for later use.

[0069] A germination experiment was conducted using a strain of Rahn's Y17 to test cucumber seed germination. Cucumber seeds of roughly uniform size and plumpness were selected. The seeds were surface-sterilized by soaking them in 2% NaClO for 5 minutes and then rinsing them three times with sterile water. The seeds were then soaked in 75% alcohol for 30 seconds and then rinsed six times with sterile water. Finally, the seeds were blotted dry with sterile absorbent paper and set aside.

[0070] Surface-sterilized cucumber seeds were soaked in a solution of Rahnella Y17 for 6 hours. The seeds were then removed and placed in Petri dishes containing two sterile, moistened filter papers. Fifteen seeds were placed in each dish, with three replicates per treatment. Control seeds were soaked in sterile water for 6 hours and similarly placed in Petri dishes. Finally, the Petri dishes were placed in a 25°C incubator in the dark and observed for germination and growth.

[0071] The results are as follows Figure 8 As shown, Raenella Y17 has no effect on promoting germination and growth of cucumber seeds. It can be seen that the Raenella Y17 provided by the present invention has different growth-promoting mechanisms for different plants. This strain is mainly used to promote the growth and development of cherry and apple plants.

[0072] Although preferred embodiments of the present invention have been described, additional changes and modifications to these embodiments may occur to those skilled in the art once the basic inventive concepts become known.

[0073] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations fall within the scope of the claims and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A strain of Rahn's bacteria ( Rahnella sp) Y17, characterized in that The Laenella Y17 was deposited in the General Microbiology Center of China Culture Collection Administration on April 15, 2025, with the deposit number CGMCC No.34219, and was classified as Laenella Rahnella sp.

2. A bacterial liquid, characterized in that: The bacterial liquid contains the Rahn's bacterium Y17 according to claim 1.

3. The bacterial solution according to claim 2, characterized in that The OD of the bacterial solution 600 The value is 0.8~1.

4. A plant growth promotion product, characterized in that: The plant growth promotion product contains the Rahn's bacterium Y17 described in claim 1 as an active ingredient.

5. Use of the Rahn's bacterium Y17 according to claim 1, the bacterial liquid according to any one of claims 2 to 3, or the plant growth promotion product according to claim 4 in promoting the growth of cherry plants.

6. The use according to claim 5, characterized in that The Rahn's bacterium Y17, bacterial liquid or plant growth promotion product is used to improve the root vitality of cherry seedlings, increase the number of root tips of cherry seedlings, improve the respiration rate of the PPP pathway of the cherry seedling roots, increase the plant height of the cherry seedlings, and improve the chlorophyll content of cherry plant leaves.

7. Use of the Rahn's bacterium Y17 according to claim 1, the bacterial solution according to any one of claims 2 to 3, or the plant growth promotion product according to claim 4 in promoting apple seed germination.

8. The use according to claim 6, characterized in that The Rahn's bacterium Y17, bacterial liquid or plant growth-promoting product is used to promote the growth of the radicle, the growth of the embryo and the thickening of the embryo of Pingyi sweet tea seeds.

Images