A lysogenic phage community, its extraction method and application

Abstract

A lysogenic phage community, its extraction method and application. The tangential flow technology is used to proportionally isolate bacteria and phage communities from in-situ soil, and single-bacteria communities and single-phage communities are obtained through enrichment and concentration. At the same time, mitomycin C is added to the single-bacteria community for lysogenic induction, and then the tangential flow system is used again for filtration and enrichment to obtain a high-throughput lysogenic phage community. Finally, we obtain single-bacteria communities, bacteria-phage mixed communities, and bacteria-lysogenic phage mixed communities. The phage transplantation technology can promote the participation of indigenous microorganisms in the process of promoting plant growth and development. The transplanted lysogenic phages can participate in the synthesis and metabolism of host plant hormones by optimizing the microbial network structure and injecting auxiliary metabolic genes. This method provides a long-term and environmentally friendly microbial synergistic growth promotion technology for the development of green agriculture in China.

Description

Technical Field

[0001] The present invention belongs to the technical field of phages, and particularly relates to a lysogenic phage community, and a method for extracting and applying the same. Background Art

[0002] The soil layer closely connected to the roots in the soil, a microdomain environment different from the bulk soil in physical, chemical, and biological properties, is called the rhizosphere. Among them, plants secrete sediments through their roots to increase the diversity and abundance of molecules in the rhizosphere, and then selectively recruit soil microorganisms to shape the rhizosphere microbial community structure. Recently, extensive research reports on the rhizosphere microbiota have revealed the general patterns of microorganisms in terms of structure, composition, dynamics, and functions in different plant environments, as well as the role played by the microbiota in promoting plant nutrition and growth.

[0003] Cross-kingdom interactions among microbial taxa can promote phage-mediated regulation of bacterial metabolism. Bacteriophages (referred to as phages for short) and their host bacteria are typical examples of cross-kingdom interactions. Phages are organisms that specifically prey on living host bacteria for survival and are widely distributed in soil, air, and water. It is estimated that their total amount reaches 10 31 orders of magnitude. At the same time, phages have two lifestyles: lysis and lysogeny. Lysogeny refers to the integration of phage genetic material into the genome of the host bacteria, forming a structure called a "prophage". This integration enables the phage genome to stably exist in the host bacteria genome, and at the same time, the genetic material of the prophage can be passed on along with the reproduction of the bacteria. In this way, lysogenic phages can serve as a stable genetic carrier, carrying auxiliary metabolic genes (AMGs). In some cases, the prophage of lysogenic phages can re-enter the lysis cycle under specific conditions, release new phage particles, and infect other bacteria. This process can spread phages with specific genetic information to new host bacteria, thereby promoting horizontal gene transfer and reshaping host metabolism. Therefore, phages can reshape or accelerate host metabolism by means of lysogeny through the expression of auxiliary metabolic genes, assist the host in plant hormone biosynthesis functions, and ultimately achieve the purpose of promoting plant growth.

[0004] Phage community transplantation refers to an emerging biological technology that efficiently enriches the overall phage community in the environment and then transplants it into a specified target host environment for colonization and function. Soil phage transplantation evolved from the concept of faecal microbiota transplantation in the medical field for treating human diseases. The advantages of soil phage transplantation technology are: it can quantitatively analyze the roles and functions of phages in the soil microbiome, facilitating the use of the specificity and selectivity of phages to improve the soil environment, control diseases, and increase plant productivity.

[0005] Through relevant literature reviews and patent searches, no publications or applications have been found regarding the use of lysogenic phage community transplantation to promote the growth and development of crops in farmland soil and enhance agricultural yields. The closest existing method to the present invention is: using phages to inhibit the growth of harmful plant pathogens, thereby maintaining plant health. For example, invention publication number CN110679805A applies phages to plants or soil to inhibit the growth of pathogenic bacteria, thereby improving plant health and growth status. By controlling pathogens, plants can better absorb nutrients and water, thereby promoting plant growth and development. Invention publication number CN106220428A prepares a plant disease control agent containing phages for preventing and controlling plant diseases and promoting plant growth. At the same time, this patent also covers the preparation method and application strategy of the control agent. Invention publication number CN109051089A uses a combination of different phages to improve the inhibitory effect on specific pathogenic bacteria. Invention publication numbers CN103972752A, CN105202323A, and CN107179434A all only involve a phage specific to a particular plant pathogen and its application in plant disease control, so the broad-spectrum nature is weak. In addition to preparing phages as plant disease control agents, there are also many inventions that use soil phages to maintain plant health through other means. For example, invention publication number CN110214764A optimizes phages through genetic engineering means to make them have stronger inhibitory ability against plant pathogens, thereby providing a method for modifying the control effect of plant diseases by phages. Moreover, this method involves high costs due to genetic engineering means. These methods all indicate that phages have the ability to promote the healthy growth of crops, but there is generally a lack of applications regarding the synergistic interaction between lysogenic phages widely present in the soil and hosts to promote plant growth.

[0006] The main defects of the existing technology are as follows: Since phages have a high specificity for specific bacteria, but there are a wide variety of bacteria in plant roots and soil, the effects of phages may be unstable or limited under different environmental conditions. In addition, the introduction of exogenous phages may disrupt the natural balance of soil microbial communities, leading to potential negative ecological consequences, such as the impact on non-target bacteria, and there may be a risk of damaging the local soil microbial structure. Moreover, phages may be difficult to survive or be effective in soil for a long time, resulting in the promotion effect of phages on plant growth may weaken over time. At the same time, the production and application costs of phages may be relatively high, so there are generally problems of high costs and insufficient universality in large-scale agricultural production.

[0007] The main reasons for the defects are as follows: Although people are gradually recognizing the ecological status and influence of phages in soil, scientific researchers have relatively less attention and research on the regulation of host metabolism by soil phages to promote plant growth. First, since phages can only infect specific bacteria, and the pH, humidity, temperature and other environmental factors of soil will affect the survival and activity of phages, resulting in their possible loss of efficacy under different environmental conditions, so their applicability to diverse soil microbial communities is limited. Second, the introduction of exogenous phages may disrupt the natural microbial balance in soil, affect the growth and functions of other beneficial microorganisms, and single phage addition may be rapidly degraded in soil or consumed by soil microorganisms and chemical substances, thus reducing its persistence and effects. Therefore, it is of great significance to extract high-lysogenic phage communities from in-situ soil, develop highly efficient enriched and concentrated phage soil additives to promote plant growth, and at the same time reduce the ecological risks of soil phage plant boosters. Summary of the Invention

[0008] Technical problems to be solved: The invention aims at the above-mentioned defects of the existing technology and provides a lysogenic phage community, its extraction method and application. This method first extracts, enriches and concentrates the bacterial and phage communities in in-situ soil through membrane packages with different pore sizes, then uses mitomycin C for lysogenic induction to obtain high-throughput lysogenic phages, and then injects a microbial extractant into its target soil. By means of the cooperation between the lysogenic phages injected into AMGs and host bacteria, it remodels or accelerates host metabolism. At the same time, the phages have the function of regulating soil microbial communities from bottom to top, further optimizing the indigenous bacterial symbiotic network, and promoting crop growth and development. This technology is a lysogenic phage technology with good growth promotion effect, low price and environmental friendliness.

[0009] Technical solution: A method for extracting a lysogenic phage community, the steps are as follows: Mix the in-situ soil with a buffer solution evenly to obtain a soil suspension. After centrifugation and standing, take the supernatant. Use tangential flow systems with different pore sizes to separate bacteria and phage communities respectively: First, the enriched solution obtained by passing the supernatant through a 0.2 μm filter membrane is a bacterial suspension. Subsequently, add mitomycin C to the bacterial suspension to a final concentration not exceeding 0.1 μg mL -1 , and incubate with shaking at room temperature. Then use a 30 - 100 kDa filter membrane for enrichment again to obtain a lysogenic phage community.

[0010] Preferably, the volume ratio of the above-mentioned in-situ soil to the buffer solution is 1:1, and the buffer solution is Tris - HCl with a pH of 7.5, containing 68 mM NaCl and 10 mM MgSO4.

[0011] Preferably, the above-mentioned centrifugation conditions are 4°C and centrifugation at 4500 G for 20 minutes.

[0012] The lysogenic phage community prepared by the above extraction method.

[0013] The application of the above lysogenic phage community in the preparation of products for enhancing plant growth.

[0014] The above plants are Arabidopsis thaliana, Chinese cabbage, lettuce or chili pepper.

[0015] A soil conditioner for enhancing plant growth, containing the above lysogenic phage community and bioactive components that contribute to plant growth and development.

[0016] The application of the soil conditioner, injecting the soil conditioner into the target soil.

[0017] The working principle of the present invention is as follows: 1. Bacteriophages are a type of bacterial virus composed of a protein capsid (60%) and an internal nucleic acid genetic material (40%), without a complete mature cell structure, and can be divided into lytic and lysogenic types; 2. Lysogenic bacteriophages can achieve horizontal gene transfer by integrating their genomes into the chromosomes of host bacteria, affecting the metabolic processes of the host bacterial community. Auxiliary metabolic genes (AMGs) are gene fragments present on the bacteriophage genome, usually randomly packaged and assembled into the bacteriophage genome during the synthesis of bacteriophage particles. The auxiliary metabolic genes carried by bacteriophages can have an important impact on the metabolic processes of host bacteria. These genes usually encode substances that can help bacteria utilize or process the substances required by bacteriophages, enhancing the adaptability of bacteria. For example, bacteriophages may carry genes that promote the metabolic ability of host bacteria to specific nutrients, or help bacteria resist the immune response of the host. The presence of these genes can improve the survival and reproductive ability of host bacteria, and may also affect the metabolites and overall physiological state of host bacteria; 3. Broad-spectrum bacteriophages refer to bacteriophages that can infect two or more host bacteria with similar homology or between different species and genera, which is conducive to the horizontal gene transfer of lysogenic bacteriophages and widely improves the potential of co-metabolism of different hosts; 4. The selected bacteriophages "come from the soil and return to the soil" without any modification, which is environmentally friendly; 5. The length of bacteriophages is about 20 - 200μm, which is equivalent to one-hundredth to one-thousandth of bacteria, so they can achieve wide migration in the soil, which is conducive to saving the application cost. 6. The bacteriophage community obtained through the tangential flow system is active and complete, and can quickly adapt to the action environment.

[0018] Beneficial effects: In response to the need to promote plant growth, the present invention provides the application of lysogenic bacteriophage community transplantation in promoting plant growth and development. Its characteristics are as follows: 1. The acquisition of a complete and active bacteriophage community weakens the problem of rapid degradation of a single bacteriophage in the soil, and optimizes the microbial community structure from the perspective of species cooperation; 2. A high proportion of lysogenic bacteriophages can promote the host metabolic process through AMG injection, effectively synthesize secretions to promote plant growth and development; 3. The materials for preparing the microbial separation liquid are easily available, convenient for storage, transportation, simple to operate, and can effectively control costs. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the application technology of bacteriophage community extraction to promote plant growth.

[0020] Figure 2 It is the number of siliques of Arabidopsis thaliana 21 days after the injection of the microbial agent into the soil of the experimental base.

[0021] Figure 3is the average content of auxin in the soil 21 days after the injection of the microbial agent into the soil of the experimental base.

[0022] Figure 4 is the change in bacterial α-diversity in the soil 21 days after the injection of the microbial agent into the soil of the experimental base.

[0023] Figure 5 is the fresh weight of the above-ground part of lettuce 28 days after the injection of the microbial agent into the soil at Fengqiu Station, Henan Province.

[0024] Figure 6 is the average content of auxin in the soil 28 days after the injection of the microbial agent into the soil at Fengqiu Station, Henan Province.

[0025] Figure 7 is the change in bacterial α-diversity in the soil 28 days after the injection of the microbial agent into the soil at Fengqiu Station, Henan Province.

[0026] Figure 8 is the fresh weight of the above-ground part of Chinese cabbage 28 days after the injection of the microbial agent into the soil of the vegetable base in Zhangye City, Gansu Province.

[0027] Figure 9 is the average content of auxin in the soil 28 days after the injection of the microbial agent into the soil of the vegetable base in Zhangye City, Gansu Province.

[0028] Figure 10 is the change in bacterial α-diversity in the soil 28 days after the injection of the microbial agent into the soil of the vegetable base in Zhangye City, Gansu Province.

[0029] Figure 11 is the fresh weight of chili peppers 90 days after the injection of the microbial agent into the soil of the vegetable base in Wuhan City, Hubei Province.

[0030] Figure 12 is the average content of auxin in the soil 90 days after the injection of the microbial agent into the soil of the vegetable base in Wuhan City, Hubei Province.

[0031] Figure 13 is the change in bacterial α-diversity in the soil 90 days after the injection of the microbial agent into the soil of the vegetable base in Wuhan City, Hubei Province. Detailed implementation mode

[0032] The following detailed implementation modes do not limit the technical solutions of the present invention in any form. Any technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

[0033] Example 1:

[0034] The soil for the test potted plants was collected from the soil of the experimental base. The plant to be planted was Arabidopsis thaliana of the Columbia type ( Arabidopsis thaliana (Columbia) ). Basic physical and chemical properties of the soil: sand grains 20.1%, silt grains 36.8%, clay grains 37.4%, pH 7.18, total nitrogen 1.61 g·kg-1 , water-soluble nitrogen 1.55 g·kg -1 , total phosphorus 1.63 g·kg -1 , total potassium 16.48 g·kg -1 , CEC 12.76 cmol·kg -1 .

[0035] Weigh out 1000.0 g of in-situ soil and divide it into four 500 mL Erlenmeyer flasks. Add 250 mL of phage buffer (68 mM NaCl, 10 mM MgSO4, Tris-HCl pH 7.5) to the samples, mix thoroughly for 20 min, and then centrifuge. The supernatant obtained by centrifugation is filtered using a tangential flow filtration system. The enriched solution obtained by passing through a 0.2 μm filter membrane is the bacterial suspension (bacterial community), and the enriched solution obtained by further passing the filtrate through a 30 kDa filter membrane is the phage suspension (viral community). Subsequently, mitomycin C is added to some single-bacterial communities to a final concentration of 0.1 μg mL -1 , and after shaking and culturing at room temperature for 24 h, enrichment is carried out again using a 30 kDa filter membrane to obtain a high-lysogenic phage community (prophagecommunity).

[0036] A total of four groups of treatments were set up in the experiment: ① Control group (CK): Plant 3 Arabidopsis thaliana plants in each pot (cover the seeds with 0.5 - 1 cm of soil, room temperature 23 ± 1℃); ② Only bacterial community transplantation (B1): On the basis of the control group, inoculate 100 mL of the separated bacterial community extract; ③ Transplantation of bacterial-phage mixture (B1V1): On the basis of the control group, inoculate 100 mL of the separated bacterial community extract and 15 mL of the separated phage community extract; ④ Transplantation of bacterial-lysogenic phage mixture (B1P1): On the basis of the control group, inoculate 100 mL of the separated bacterial community extract and 10 mL of the separated phage community extract; After observing Arabidopsis thaliana on the 21st day of its growth, it was found that the number of siliques per plant of Arabidopsis thaliana under the four treatments of CK, B1, B1V1, and B1P1 were 14.2 per plant, 19.4 per plant, 23.5 per plant, and 27.1 per plant ( Figure 2 ). The number of siliques of Arabidopsis thaliana in the soil of the B1P1 treatment group was significantly increased compared with the control group ( p <0.05). The average contents of auxin in the soil of the treatment group and the control group were measured as: 0.06 μg·mL -1 , 0.13 μg·mL -1 , 0.18 μg·mL -1 , 0.26 μg·mL -1 ( Figure 3), the auxin content in the B1P1 treatment was significantly increased compared with the control group ( p <0.05). At the same time, 16S determination of the rhizosphere soil found that the α-diversities of bacteria under the four treatments of CK, B1, B1V1, and B1P1 were 35.31, 35.88, 36.26, and 36.72 (Shannon index, Figure 4 ). The overall results showed that after the mixed transplantation of the bacterial-lytic phage community and culturing for 21 days, the number of Arabidopsis pods increased by 12.9 per plant compared with the treatment without phage transplantation. At the same time, the increase in microbial diversity in the B1P1 treatment indicated that the phage community transplantation significantly increased the yield of Arabidopsis (the increase in the number of pods) and was beneficial to the stability of the microbial community.

[0037] Example 2:

[0038] Target soil: Basic physical and chemical properties of the soil: pH 6.8, organic matter 21.1 g·kg -1 , total nitrogen 4.8 g·kg -1 , total phosphorus 2.1 g·kg -1 , the soil mechanical composition is 45.1% sand grains (sandy soil), 22.8% silt grains, and 32.1% clay grains.

[0039] The preparation method of the high-lysogenic phage community is the same as that in Example 1.

[0040] A total of four groups of treatments were set up in the experiment: ① Control group (CK): 3 lettuce plants were planted in each pot (covering the seeds with 0.5 - 1 cm of soil, room temperature 25 ± 1°C); ② Only bacterial community transplantation (B1): 100 mL of the extracted bacterial community solution was inoculated on the basis of the control group; ③ Transplantation of the bacterial-phage mixture (B1V1): 100 mL of the extracted bacterial community solution and 15 mL of the extracted phage community solution were inoculated on the basis of the control group; ④ Transplantation of the bacterial-lysogenic phage mixture (B1P1): 100 mL of the extracted bacterial community solution and 10 mL of the extracted phage community solution were inoculated on the basis of the control group; After 28 days of lettuce growth, the above-ground fresh weight of the lettuce was measured. The average above-ground fresh weights of the lettuce under the four treatments of CK, B1, B1V1, and B1P1 were 30.22 g / plant, 31.43 g / plant, 34.99 g / plant, and 39.28 g / plant ( Figure 5 ). The above-ground fresh weight of the lettuce in the B1P1 treatment group was significantly increased compared with that in the control group ( p <0.05). The average auxin contents in the treatment group and the control group in the soil were: 0.06 μg·mL -1 , 0.16 μg·mL -1 , 0.20 μg·mL -1, 0.27 μg·mL -1 ( Figure 6 ). The auxin content in the B1P1 treatment was significantly increased compared with the control group ( p <0.05). At the same time, 16S determination of rhizosphere soil found that the α-diversities of bacteria under the four treatments of CK, B1, B1V1, and B1P1 were 30.88, 31.05, 31.76, and 32.12 (Shannon index, Figure 7 ). After the bacterial-phage community was mixed and transplanted and cultured for 28 days, the fresh weight of the above-ground part of lettuce increased by 4.77 g / plant compared with the treatment without phage transplantation. At the same time, the increase in microbial diversity in the B1P1 treatment indicated that the transplantation of the phage community significantly increased the yield of lettuce (the increase in the fresh weight of the above-ground part) and was beneficial to the stability of the microbial community.

[0041] Example 3:

[0042] Target soil: Vegetable base soil. Basic physical and chemical properties of the soil: pH 5.8, organic matter 25.1 g·kg -1 , total nitrogen 6.8 g·kg -1 , total phosphorus 2.7 g·kg -1 , and the soil mechanical composition was 39.1% sand particles (sandy soil), 22.8% silt particles, and 38.1% clay particles.

[0043] The preparation method of the high lysogenic phage community was the same as that in Example 1.

[0044] A total of four groups of treatments were set up in the experiment: ① Control group (CK): 3 Chinese cabbages were planted in each pot (covering the seeds with 0.5 - 1 cm of soil, room temperature 20 ± 2°C); ② Only bacterial community transplantation (B1): On the basis of the control group, 100 mL of the extracted bacterial community solution was inoculated; ③ Transplantation of the bacterial-phage mixture (B1V1): On the basis of the control group, 100 mL of the extracted bacterial community solution and 15 mL of the extracted phage community solution were inoculated; ④ Transplantation of the bacterial-lysogenic phage mixture (B1P1): On the basis of the control group, 100 mL of the extracted bacterial community solution and 10 mL of the extracted phage community solution were inoculated; After 30 days of Chinese cabbage growth, the fresh weight of the above-ground part of Chinese cabbage was measured. The average fresh weights of the above-ground parts of Chinese cabbage under the four treatments of CK, B1, B1V1, and B1P1 were 35.46 g / plant, 38.73 g / plant, 48.84 g / plant, and 42.13 g / plant ( Figure 8 ). The fresh weight of the above-ground part of Chinese cabbage in the B1P1 treatment group was significantly increased compared with that in the control group in the soil ( p <0.05). The average contents of auxin in the treatment group and the control group in the soil were: 0.03 μg·mL -1 , 0.17 μg·mL-1 、0.22 μg·mL -1 、0.29 μg·mL -1 ( Figure 9 )。 The content of auxin in the B1P1 treatment was significantly increased compared with the control group ( p <0.05). At the same time, 16S determination of rhizosphere soil found that the α-diversities of bacteria under the four treatments of CK, B1, B1V1, and B1P1 were 31.78, 32.18, 32.69, and 32.99 (Shannon index, Figure 10 ). After the mixed transplantation of the bacterial-phage community and culturing for 28 days, the fresh weight of the above-ground part of Chinese cabbage was increased by 6.67 g / plant compared with the treatment without phage transplantation. At the same time, the increase in microbial diversity in the B1P1 treatment indicated that the transplantation of the phage community significantly increased the yield of Chinese cabbage (the increase in the fresh weight of the above-ground part) by increasing the content of auxin in the soil and was beneficial to the stability of the microbial community.

[0045] Example 4:

[0046] Target soil: Vegetable base soil. Basic physical and chemical properties of the soil: pH 5.8, organic matter 25.1 g·kg -1 ,total nitrogen 6.8 g·kg -1 ,total phosphorus 2.7 g·kg -1 ,and the soil mechanical composition was 39.1% sand grains (sandy soil), 22.8% silt grains, and 38.1% clay grains.

[0047] The preparation method of the high lysogenic phage community was the same as that in Example 1.

[0048] A total of four groups of treatments were set up in the experiment: ① Control group (CK): 3 chili peppers were planted in each pot (covering the seeds with 0.5 - 1 cm of soil, room temperature 27 ± 2°C); ② Only bacterial community transplantation (B1): On the basis of the control group, 100 mL of the separated bacterial community extract was inoculated; ③ Transplantation of the bacterial-phage mixture (B1V1): On the basis of the control group, 100 mL of the separated bacterial community extract and 15 mL of the separated phage community extract were inoculated; ④ Transplantation of the bacterial-lysogenic phage mixture (B1P1): On the basis of the control group, 100 mL of the separated bacterial community extract and 10 mL of the separated phage community extract were inoculated; After 30 days of Chinese cabbage growth, the fresh weight of the above-ground part of Chinese cabbage was measured. The average fresh weights of the above-ground parts of lettuce under the four treatments of CK, B1, B1V1, and B1V10 were 10.10 g / plant, 10.92 g / plant, 11.82 g / plant, and 13.13 g / plant ( Figure 11 ). The fresh weight of chili peppers in the soil of the B1V1 treatment group was significantly increased compared with the control group ( p(<0.05). The average contents of auxin in the soil of the treatment group and the control group were: 0.04 μg·mL -1 , 0.20 μg·mL -1 , 0.25 μg·mL -1 , 0.31 μg·mL -1 ( Figure 12 ). The auxin content in the B1V1 treatment was significantly increased compared with that in the control group ( p <0.05). At the same time, 16S determination of rhizosphere soil found that the α-diversities of bacteria under the four treatments of CK, B1, B1V1, and B1P1 were 33.38, 33.95, 34.59, and 35.00 (Shannon index, Figure 13 ). After the mixed transplantation of the bacteria-phage community and 90 days of cultivation, the fresh weight of the hot pepper increased by 3.03 g / plant compared with the treatment without phage transplantation. At the same time, the increase in microbial diversity in the B1P1 treatment indicated that the phage community transplantation significantly increased the yield of Chinese cabbage (the increase in the fresh weight of the above-ground part) by increasing the content of auxin in the soil and was beneficial to the stability of the microbial community.

Claims

1. Application of lysogenic phage communities in increasing the content of auxin in soil, wherein the lysogenic phage communities are obtained by the following method: mixing in-situ soil with a buffer solution evenly to obtain a soil suspension, the volume ratio of the in-situ soil to the buffer solution is 1:1, the buffer solution is Tris-HCl with a pH of 7.5, containing 68 mM NaCl and 10 mM MgSO4, taking the supernatant after centrifugation and standing, the centrifugation conditions are 4 °C and centrifugation at 4500 G for 20 minutes, and separating bacteria and phage communities respectively by using a tangential flow system with different pore sizes: First, the enriched solution obtained by passing the supernatant through a 0.2 μm filter membrane is a bacterial suspension, and then mitomycin C is added to the bacterial suspension to a final concentration not exceeding 0.1 μg mL -1 , culturing with shaking at room temperature, and enriching again by using a 30-100 kDa filter membrane to obtain lysogenic phage communities.

2. Application of a soil conditioner, characterized in that, The application is to increase the content of auxin in the soil by injecting a soil conditioner into the target soil. The soil conditioner contains the lysogenic phage community described in claim 1 and bioactive components that contribute to the growth and development of plants.

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