Microbial plant growth promoter for acid, alkali and salt environment, preparation method and application thereof
By preparing an aqueous suspension of Serratia marcescens XJ108, the problem of soil improvement under acidic, alkaline, and saline environments was solved, and the effect of promoting plant growth in these environments was achieved, especially the growth of sorghum, corn, and wheat.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JINAN JINNIU BIOTECH CO LTD
- Filing Date
- 2025-03-31
- Publication Date
- 2026-07-03
AI Technical Summary
Existing technologies have failed to effectively address soil improvement methods in acidic, alkaline, and saline environments, especially the application of Serratia marcescens in these environments, which leads to limited plant growth.
A microbial plant growth promoter with a concentration of 1×10⁹ CFU/ml was prepared by using Serratia marcescens XJ108 as an aqueous suspension, and then activated, cultured in a shaker and centrifuged. It is suitable for acidic, alkaline and saline environments and promotes plant growth.
It significantly promotes plant root growth in acidic, alkaline, and saline environments, and improves plant adaptability and growth performance in extreme soil environments.
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Abstract
Description
Technical Field
[0001] This invention relates to the technical field of agriculture, specifically to a microbial plant growth promoter for acidic, alkaline, and saline environments, its preparation method, and its application. Background Technology
[0002] Plants primarily grow by fixing carbon dioxide from the atmosphere into carbohydrates through photosynthesis. The carbon in plant nutrition mainly comes from the atmosphere, while water and other essential inorganic minerals for plant growth and physiological activities originate from the soil. Various types of challenging soils exist in agricultural production, including acidic and saline-alkali soils.
[0003] Soil acidification refers to the process by which the pH value and base saturation of soil decrease due to hydrogen ions generated within the soil and introduced from the outside. It is the most significant obstacle soil condition in southern regions. Under natural conditions, in humid climates, base ions in soil are leached away by rainwater, leading to an increase in the concentration of acidifying ions (aluminum ions and hydrogen ions), which can cause soil acidification. Anthropogenic factors contributing to soil acidification mainly include: ① Excessive application of ammonium nitrogen fertilizer. Plants absorb cationic ammonium nitrogen, which then secretes hydrogen ions into the soil, leading to acidification. ② Ammonium nitrogen applied to the soil readily undergoes strong nitrification under aerobic conditions, converting to nitrate nitrogen, a process that releases hydrogen ions. Nitrate nitrogen is easily leached away, and along with nitrate leaching, base ions such as potassium, sodium, calcium, and magnesium are simultaneously removed from the soil, easily causing soil acidification. ③ Plants absorb more cations than anions; the harvesting of straw and grains removes a large number of base ions, and the failure to return straw to the field also contributes to soil acidification. Soil acidification easily leads to poor soil aggregate structure, soil compaction, and severe pest and disease outbreaks. It also affects the soil environment and the transformation of various elements in the soil, directly impacting soil fertility, crop yield, and agricultural product quality. The remediation of acidic soils such as red and yellow soils, as well as acidified vegetable fields in various regions, has always been a focus of agricultural production.
[0004] Saline and alkaline soils are another type of obstacle soil where excessive accumulation of base ions in the topsoil negatively impacts the soil's physical, chemical, and biological properties, thus affecting plant growth. Generally, soils with a soluble salt content greater than 2 g / kg that hinders normal crop development are called saline soils. Based on the composition and degree of salt and their different effects on soil properties, the soluble salts in saline soils are mainly chlorides and sulfates, and the pH is generally neutral; while in alkaline soils, the soluble salts are mainly sodium carbonate and sodium bicarbonate, with exchangeable sodium ions accounting for more than 20% of soluble cations, and the pH value is generally greater than 8.5. Saline and alkaline soils are collectively referred to as saline-alkali soils. The formation of saline-alkali soils mainly includes the following reasons: ① Climatic factors: In arid and semi-arid regions, annual evaporation far exceeds annual rainfall, causing a large amount of salt to move upwards with the evaporation of soil moisture and accumulate in the surface layer, forming salinization. ② Hydrogeology: In areas with high groundwater levels and high groundwater mineralization, salts in shallow aquifers can reach the surface through soil capillary pores, resulting in salt accumulation. The higher the groundwater mineralization, the more severe the soil salinization. ③ Topography: Plains, lowlands, water-eroded depressions, or enclosed basins, influenced by geological conditions, accumulate water and salt from mountains or rivers, making salt drainage difficult and leading to severe soil salinization. ④ Human factors: Due to unreasonable fertilization and irrigation practices, salts accumulate on the surface after intense evaporation, forming secondary soil salinization. Saline and alkaline soils, due to high salt ion concentrations and high osmotic pressure in the soil solution, have large soil particle dispersion and poor physical structure. Plant roots cannot absorb water and salts, and the richness of the soil microbial community is also poor, severely impacting soil productivity.
[0005] Compared with the direct application of acidic or alkaline conditioners, screening suitable acid- or salt-tolerant microorganisms and combining them with other physical or chemical conditioners to form compound conditioners, establishing suitable microbial communities in the soil, and improving the overall physical, chemical, and biological properties of the soil is the most suitable solution for improving obstacle soils.
[0006] Serratia marcescens or Serratia spathulata have the effect of promoting plant growth. Patent CN202310586269.1 discloses that Serratia marcescens AWH-NS6 has salt tolerance, alkali lovage, and inorganic phosphorus solubility effects, which can promote the growth of alfalfa. Patent CN202310783140.X discloses that Serratia marcescens has phosphorus solubility and indoleacetic acid (IAA) production effects, which can promote tobacco growth. Patent CN202010484966.2 discloses that Serratia spathulata is effective in controlling corn curvature leaf spot disease. However, none of the above patents involve the protection and application of Serratia spathulata in crops under acidic, alkaline, and high salinity environments. Summary of the Invention
[0007] To address the existing technical problems, this invention provides a microbial plant growth promoter for acidic, alkaline, and saline environments, its preparation method, and its application, thereby solving the aforementioned problems.
[0008] The technical solution of this invention is as follows:
[0009] In a first aspect, the present invention provides a microbial plant growth promoter for use in acidic, alkaline, and saline environments. The plant growth promoter is an aqueous suspension containing *Serratia marcescens* XJ108. *Serratia marcescens* (… Serratia marcescens XJ108 is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 29557, deposited on January 10, 2024. The address of the depository is No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing.
[0010] Furthermore, the bacterial concentration of *Serratia marcescens* XJ108 in the aqueous suspension was 1 × 10⁻⁶. 9 CFU / ml.
[0011] Secondly, the present invention provides a method for preparing a microbial plant growth promoter for acidic, alkaline, and saline environments, as detailed below:
[0012] Activation of Serratia marcescens XJ108: Streak the Serratia marcescens XJ108 bacterial mixture stored in cryovials onto LB agar plates and incubate at 28°C to activate Serratia marcescens XJ108.
[0013] Preparation of seed culture: After single colonies grow on LB plates, pick a single colony and put it into 5 mL of LB liquid medium. Incubate at 28°C and 180 rpm for 12 h to prepare seed culture.
[0014] Preparation of fermentation broth: Take the seed culture and inoculate it into Erlenmeyer flasks containing LB liquid medium at a ratio of 1% to 5%. Incubate at 28°C and 180 rpm on a shaker. Collect the cells after 48 hours. Generally, 150 mL of fermentation broth is placed in a 500 mL Erlenmeyer flask, and 300 mL of fermentation broth is placed in a 1 L Erlenmeyer flask.
[0015] Cell collection: Transfer the fermentation broth to centrifuge tubes or centrifuge cylinders at room temperature, centrifuge at 7000 rpm for 15 minutes or 12000 rpm for 10 minutes, remove the supernatant, and suspend the cells in a certain volume of sterile water or sterile physiological saline to prepare a cell concentration of 1×10⁻⁶. 9 CFU / ml.
[0016] Thirdly, the present invention provides an application of the above-mentioned microbial plant growth promoter in promoting plant root growth.
[0017] Furthermore, the plant is sorghum.
[0018] Fourthly, the present invention provides an application of the above-mentioned microbial plant growth promoter in promoting plant growth in an acidic environment.
[0019] Fifthly, the present invention provides an application of the above-mentioned microbial plant growth promoter in promoting plant growth in an alkaline environment.
[0020] Sixthly, the present invention provides an application of the above-mentioned microbial plant growth promoter in promoting plant growth in a high-salinity environment.
[0021] Furthermore, the plants are sorghum, corn, or wheat.
[0022] The beneficial effects of this invention are as follows:
[0023] This invention provides a microbial plant growth promoter for acidic, alkaline, and saline environments, with its active ingredient being *Serratia marcescens* XJ108. The microbial plant growth promoter provided by this invention can not only adapt to various extreme soil environments, including acidic, alkaline, and highly saline environments, but also promote plant growth in these extreme environments. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a colony morphology diagram of Serratia marcescens XJ108 in Example 1 of the present invention.
[0026] Figure 2 This is a diagram showing the growth status of sorghum roots in Embodiment 2 of the present invention.
[0027] Figure 3 This is a diagram showing the growth of wheat in an acidic environment in Example 3 of the present invention.
[0028] Figure 4 This is a diagram showing the growth of corn in an acidic environment in Example 3 of the present invention.
[0029] Figure 5 This is a diagram showing the root growth of wheat in an alkaline environment in Example 4 of the present invention.
[0030] Figure 6 This is a diagram showing the growth of wheat in a high-salinity environment in Embodiment 5 of the present invention. Detailed Implementation
[0031] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.
[0032] Example 1
[0033] 1. Isolation and identification of Serratia marcescens XJ108
[0034] (1) Sampling: Soil was collected in a vegetable greenhouse in Urumqi, Xinjiang Uygur Autonomous Region in 2023 and stored in a self-sealing bag for later use.
[0035] (2) Separation:
[0036] Take 5g of soil collected in step (1) and add it to an Erlenmeyer flask containing 95mL of sterile pure water. Incubate at 28℃ and 180 rpm for half an hour. Use the tenfold dilution method to obtain samples of different concentration gradients. Take 100μL of each dilution and spread it on LB agar plates. Incubate upside down at 37℃. When a single colony grows on the agar plate, pick the single colony and transfer it to a new LB agar plate.
[0037] (3) Purification: Each single colony of the strain was purified by streaking on LB agar plates at least three times until the colony morphology on the medium was uniform and free of contaminants. A pure culture was then considered obtained. The colony morphology of the microbial strains of this invention on LB agar plates is as follows: Figure 1 As shown, the colonies are round with neat edges, and the surface is moist, smooth, and without wrinkles. After 48 hours of incubation, the colonies turn red.
[0038] (4) Preservation: Pick a single colony and inoculate it into LB liquid medium. Incubate at 37°C and 180 rpm for 24 hours. Mix with an equal volume of sterile 50% glycerol to prepare a bacterial mixture with a final glycerol concentration of 25%. Store at -20°C and -80°C for later use.
[0039] (5) Molecular identification
[0040] The 16S rDNA of this bacterium was amplified by PCR using universal primers 27F (5'-AGAGTTTGATCCTGGCTCAG-3', SEQ ID NO.2) and 1492R (5'-GGTTACCTTGTTACGACTT-3, SEQ ID NO.3). The amplified products were sent to Beijing Tianyi Huiyuan Biotechnology Co., Ltd. for sequencing. After forward and reverse splicing, the 16S rDNA sequence of this bacterium was obtained by sequencing, as shown in SEQ ID NO.1.
[0041] The sequence obtained from sequencing was compared for homology using the NCBI online Blastn program, and the strain was preliminarily identified as *Serratia marcescens*. Serratia marcescens Serratia marcescens ( ) Serratia marcescens XJ108 is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 29557, deposited on January 10, 2024. The address of the depository is No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing.
[0042] Example 2
[0043] The specific steps for preparing an aqueous suspension of Serratia marcescens XJ108 are as follows:
[0044] Activation of Serratia marcescens XJ108: Streak the Serratia marcescens XJ108 bacterial mixture stored in cryovials onto LB agar plates and incubate at 28°C to activate Serratia marcescens XJ108.
[0045] Preparation of seed culture: After single colonies grow on LB plates, pick a single colony and put it into 5 mL of LB liquid medium. Incubate at 28°C and 180 rpm for 12 h to prepare seed culture.
[0046] Preparation of fermentation broth: Take the seed liquid and inoculate it into an Erlenmeyer flask containing LB liquid medium at a ratio of 1%. Incubate at 28°C and 180 rpm on a shaker. Collect the cells after 48 hours.
[0047] Cell collection: Transfer the fermentation broth to a centrifuge tube at room temperature, centrifuge at 12,000 rpm for 10 minutes, remove the supernatant, and suspend the cells in sterile water or sterile physiological saline to prepare a cell concentration of 1×10⁻⁶. 9 CFU / ml yielded an aqueous suspension of Serratia marcescens XJ108.
[0048] Example 3
[0049] Tests on the effect of Serratia marcescens XJ108 aqueous suspension on plant root growth
[0050] Two treatments were designed: a blank control group (CK) and a treatment group treated with Serratia marcescens XJ108 aqueous suspension (XJ108). The specific procedure was as follows: Sorghum seeds were disinfected and then germinated. Sterile seed germination bags were first moistened with sterile water, and then the sprouting seeds were placed in the seed germination bags. Eight sprouting sorghum seeds were placed in each bag. The XJ108 treatment group was treated with 1 mL of the Serratia marcescens XJ108 aqueous suspension prepared in Example 2, while the CK group was treated with an equal volume of sterile water. The mixture was incubated at 25°C. The growth of the sorghum roots was observed after 4 days. The results are as follows: Figure 2 As shown.
[0051] In the blank control group (CK), only 6 out of 8 seeds germinated, while all 8 seeds in the group treated with Serratia marcescens XJ108 aqueous suspension germinated. Furthermore, the average root length of sorghum in the blank control group was 5.9 cm, while the average root length in the Serratia marcescens XJ108 aqueous suspension treatment group was 11.98 cm, significantly better than the blank control group. This indicates that Serratia marcescens XJ108 aqueous suspension has a significant promoting effect on sorghum root growth.
[0052] Example 4
[0053] Tests on the effect of Serratia marcescens XJ108 aqueous suspension on plant growth in acidic environments
[0054] 1. The promoting effect of acidic environment on wheat growth
[0055] Two treatments were designed: a blank control group (CK) and a group treated with Serratia marcescens XJ108 aqueous suspension (XJ108).
[0056] The specific procedure was as follows: After disinfecting the surface of wheat seeds, they were germinated. When the roots reached 3-4 cm in length, they were transferred to test tubes containing sterile water with a pH of 3.65. For the *Serratia marcescens* XJ108 group, 100 μL of the *Serratia marcescens* XJ108 aqueous suspension prepared in Example 2 was added to a test tube containing sterile water with a pH of 3.65. An equal volume of sterile water was added to the CK group. The treatment was repeated after 5 days. The plants were incubated at room temperature. After 15 days, photos were taken, and plant height was recorded.
[0057] The results are as follows Figure 3 As shown, wheat in the CK group grew slowly with an average plant height of 13.67 cm, while the average plant height in the XJ108 treatment group was 20.17 cm, which was significantly better than the blank control group.
[0058] These results indicate that strain XJ108 can improve wheat's adaptability to acidic environments and promote wheat growth.
[0059] 2. The promoting effect of acidic environment on corn growth
[0060] Two treatments were designed: a blank control group (CK) and a group treated with Serratia marcescens XJ108 aqueous suspension (XJ108).
[0061] The specific procedure was as follows: After disinfecting the surface of the corn seeds, they were germinated. When the sprouts reached 1-2 cm in length, they were transferred to test tubes containing sterile water with a pH of 3.98. For the *Serratia marcescens* XJ108 group, 100 μL of the *Serratia marcescens* XJ108 aqueous suspension prepared in Example 2 was added to a test tube containing sterile water with a pH of 3.98. An equal volume of sterile water was added to the CK group. The treatment was repeated after 5 days. The plants were incubated at room temperature. After 21 days, photographs were taken, and plant height was recorded.
[0062] The results are as follows Figure 4 As shown, the maize in the CK group grew unevenly, with an average plant height of 12.38 cm. In the Serratia marcescens XJ108 aqueous suspension treatment group, the maize grew uniformly, with an average plant height of 17.84 cm, which was significantly better than the blank control group.
[0063] These results indicate that Serratia marcescens XJ108 aqueous suspension can improve maize's adaptability to acidic environments and promote maize growth.
[0064] Example 5
[0065] Tests on the effect of Serratia marcescens XJ108 aqueous suspension on plant growth in alkaline environment
[0066] The purpose of this embodiment is to evaluate whether Serratia marcescens XJ108 aqueous suspension can promote plant growth in an alkaline environment, using wheat as an example.
[0067] Two treatments were designed: a blank control group (CK) and a treatment group (XJ108) containing Serratia marcescens XJ108 aqueous suspension.
[0068] The specific procedure was as follows: After disinfecting the surface of the wheat seeds, they were subjected to germination treatment. First, sterile seed germination bags were moistened with sterile water at pH=9, and then the sprouting seeds were placed in the seed germination bags. Eight sprouting wheat seeds were placed in each bag. The *Serratia marcescens* XJ108 group used the *Serratia marcescens* XJ108 aqueous suspension prepared in Example 2, while the CK group received an equal volume of sterile water. The mixture was incubated at 25℃. The growth of the wheat roots was observed after 7 days.
[0069] The results are as follows Figure 5 As shown, firstly, only 6 out of 8 seeds in the blank control group (CK) germinated, while all 8 seeds in the group treated with Serratia marcescens XJ108 aqueous suspension germinated. Secondly, the average root length of wheat in the blank control group was 8.05 cm, while the average root length in the group treated with Serratia marcescens XJ108 aqueous suspension was 12.18 cm, significantly better than the blank control group.
[0070] These results indicate that the aqueous suspension of Serratia marcescens XJ108 significantly promotes the growth of wheat roots in an alkaline environment.
[0071] Example 6
[0072] The purpose of this embodiment is to evaluate whether Serratia marcescens XJ108 aqueous suspension can promote plant growth in saline soil environments, using wheat as an example.
[0073] Two treatments were designed: a blank control group (CK) and a treatment group containing Serratia marcescens XJ108 aqueous suspension (XJ108). The soil was grown in a greenhouse in Shandong Province, with a pH of 7.81 and a soil electrical conductivity of 1449 μS / cm. According to the soil acidity and alkalinity classification and salinity classification standards, the soil used was classified as alkaline soil and severely salinized soil.
[0074] The specific procedure was as follows: After disinfecting the surface of the wheat seeds, they were treated to promote germination. The germinated wheat seeds were then sown in severely saline soil. Five seeds were placed per pot. For the *Serratia marcescens* XJ108 group, 2 ml of the *Serratia marcescens* XJ108 aqueous suspension prepared in Example 2 was applied per pot. For the control group (CK group), an equal volume of sterile water was added. This treatment was repeated three times, with a one-week interval between each application. The mixture was incubated at 25°C. After one month, the wheat growth was observed, and plant height was measured.
[0075] The results are as follows Figure 6 As shown, the average plant height of wheat in the blank control CK group was 1.38 cm, while the average plant height in the Serratia marcescens XJ108 aqueous suspension treatment group was 5.44 cm, which was significantly better than that of the blank control group.
[0076] The above experimental results indicate that the aqueous suspension of Serratia marcescens XJ108 has a significant promoting effect on the growth of wheat in saline soil.
[0077] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope demonstrated in the present invention should also be covered within the protection scope of the present invention.
Claims
1. A microbial plant growth stimulator for acid, base, salt environment, characterized in that, The plant growth promoter is an aqueous suspension containing Serratia marcescens XJ108. Serratia marcescens ( Serratia marcescens XJ108 is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 29557, deposited on January 10, 2024. The address of the depository is No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing.
2. The microbial-based plant growth stimulator of claim 1, wherein, The bacterial concentration of Serratia marcescens XJ108 in the aqueous suspension was 1 x 10 9 CFU / ml.
3. A method of preparing the microbial plant growth stimulator as claimed in claim 1, wherein, Specifically as follows: Activation of Serratia marcescens XJ108: A mixture of Serratia marcescens XJ108 cells stored in cryovials was streaked onto an LB agar plate and incubated at 28°C to activate Serratia marcescens XJ108. Preparation of seed culture: After single colonies grow on LB solid medium plates, pick a single colony and put it into 5 mL of LB liquid medium. Incubate at 28°C and 180 rpm in a shaker for 12 h to prepare seed culture. Preparation of fermentation broth: Take the seed liquid and inoculate it into an Erlenmeyer flask containing LB liquid medium at a ratio of 1% to 5%. Incubate at 28°C and 180 rpm on a shaker for 48 hours to prepare the fermentation broth. Bacterial cell collection: The fermentation broth was transferred to centrifuge tubes or centrifuge bottles at room temperature, centrifuged at 7000 rpm for 15 minutes or at 12000 rpm for 10 minutes, the supernatant was removed, and the bacterial cells were suspended in a certain volume of sterile water to adjust the bacterial cell concentration to 1 x 10 9 CFU / ml.
4. Use of the microbial plant growth promoter according to claim 1 for promoting root growth of a plant, characterized in that, The plant in question is sorghum.
5. The use of a microbial growth promoter as claimed in claim 1 for promoting plant growth in an acidic environment, characterized in that, The plant in question is sorghum, corn, or wheat.
6. The application of the microbial plant growth promoter as described in claim 1 in promoting plant growth in an alkaline environment, characterized in that, The plant in question is sorghum, corn, or wheat.
7. Use of the microbial plant growth promoter of claim 1 for promoting plant growth in a high salinity environment. The plant in question is sorghum, corn, or wheat.