Streptomyces scabies bacteriophage ZB-1 and application thereof

Abstract

The invention relates to the technical field of microorganisms, and discloses a streptomyces scabies phage (Streptomyces scabies phage) ZB-1 and an application of the streptomyces scabies phage ZB-1. Wherein the streptomyces scabies bacteriophage ZB-1 is preserved in the China General Microbiological Culture Collection Center (CGMCC), the preservation number is CGMCC NO.46275, and the preservation date is December 23, 2024. The streptomyces scabies bacteriophage ZB-1 shows a good inhibition effect on streptomyces scabies ZRIMU932, can obviously improve potato scab caused by the streptomyces scabies ZRIMU932, is wide in applicable temperature and pH range, especially has long survival time under strong ultraviolet rays, and has good application prospects. Therefore, the method has high application value in the aspect of improving the yield and quality of the planted potatoes.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms, in particular to a Streptomyces scabies phage ZB-1 and an application thereof. Background Art

[0002] Potato common scab (PCS) is a plant disease caused by Streptomyces that harms potato tubers, causing nearly circular to irregular corky, scab-like, light brown spots or patches on the tuber surface, thereby reducing the commercial value and marketability of potatoes and leading to huge economic losses.

[0003] Phage-mediated biocontrol is a relatively new and environmentally friendly PCS management strategy that exhibits many advantages. Compared with traditional chemical fungicides, bacteriophages, as naturally occurring organisms in nature, are harmless to human health. In an environment lacking host bacteria, the number of phages will naturally decrease, thus avoiding long-term negative impacts on the ecology. In addition, phages can rapidly proliferate after adsorbing to the host, significantly enhancing the effectiveness of treatment. However, phage-mediated biocontrol also has some challenges. For example, phages are specific, and suitable phages need to be screened for specific hosts. In addition, some phages are easily deactivated under extreme temperatures, pH values, and direct sunlight. Therefore, in addition to lytic activity, the stability of the phage must also be considered in its application.

[0004] In summary, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a Streptomyces scabies phage ZB-1 and its application, aiming to solve the problems of the existing Streptomyces scabies phage being insufficient and having poor stability.

[0006] The technical solutions of the present invention are as follows:

[0007] In the first aspect, a Streptomyces scabies phage ZB-1 is provided. The Streptomyces scabies phage ZB-1 is deposited in the General Microbiology Center of the China Culture Collection Administration of Microorganisms, with a deposit number of CGMCCNO.46275 and a deposit date of December 23, 2024.

[0008] In a second aspect, a phage composition is provided, wherein the phage composition comprises the Streptomyces scabies phage ZB-1 according to the first aspect.

[0009] In a preferred technical solution, the phage composition further comprises an agriculturally acceptable auxiliary material.

[0010] According to a preferred technical solution, the agriculturally acceptable auxiliary material is selected from one or more of a dispersant, a stabilizer, a filler and a solvent.

[0011] In a third aspect, there is provided use of the Streptomyces scab phage ZB-1 as described in the first aspect or the phage composition as described in the second aspect in the prevention and treatment of potato scab.

[0012] According to a preferred technical solution, when the Streptomyces scabies phage ZB-1 or the phage composition is used, the temperature of the system is 10-60°C.

[0013] In a preferred technical solution, when the Streptomyces scabies phage ZB-1 or the phage composition is used, the pH of the system is 3-12.

[0014] Beneficial Effects: The present invention isolates a Streptomyces scab phage ZB-1 from soil that exhibits a strong inhibitory effect against Streptomyces scab. The biological characteristics, morphological observation, and control efficacy of Streptomyces scab phage ZB-1 were studied. The results show that the Streptomyces scab phage ZB-1 screened by the present invention exhibits a strong inhibitory effect against Streptomyces scab ZRIMU932, significantly improving potato scab caused by Streptomyces scab ZRIMU932. Furthermore, the phage is applicable over a wide temperature and pH range, and has a long survival time under strong ultraviolet light. Therefore, it has high application value in improving the yield and quality of potato cultivation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the plaque image of Streptomyces scabies phage ZB-1 in Example 1.

[0016] Figure 2 This is a transmission electron micrograph of the Streptomyces scabies phage ZB-1 in Example 2.

[0017] Figure 3 This is a graph showing the results of determining the multiplicity of infection of Streptomyces scabies phage ZB-1 in Example 4.

[0018] Figure 4 This is a graph showing the results of the thermal stability test of Streptomyces scabies phage ZB-1 in Example 5.

[0019] Figure 5 This is a graph showing the results of the pH stability measurement of Streptomyces scabies phage ZB-1 in Example 6.

[0020] Figure 6 This is a graph showing the results of the ultraviolet sensitivity test of Streptomyces scabies phage ZB-1 in Example 7.

[0021] Figure 7This is a graph showing the one-step growth curve of Streptomyces scabies phage ZB-1 in Example 8.

[0022] Figure 8 This is a diagram showing the in vitro effect of the Streptomyces scabies phage ZB-1 in Example 9 as a Streptomyces scabies control agent.

[0023] Figure 9 This is the phylogenetic tree of Streptomyces scabies phage ZB-1 in Example 10.

[0024] Figure 10 This is a diagram showing the control effect of Streptomyces scab phage ZB-1 on potato scab in a potted plant experiment in Example 11. DETAILED DESCRIPTION

[0025] The present invention provides Streptomyces scabies phage ZB-1 and its application. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below.

[0026] The embodiment of the present invention provides Streptomyces scabies phage ZB-1, which is deposited in the General Microbiology Center of the China Culture Collection Administration of Microorganisms, with a deposit number of CGMCCNO.46275 and a deposit date of December 23, 2024.

[0027] Specifically, the Streptomyces scab phage ZB-1 isolated from soil samples from a potato plot in Zhangjiakou City, Hebei Province, in the present invention, showed a maximum similarity of approximately 94% with existing Streptomyces phages through genome comparison analysis, making it a novel Streptomyces scab phage. Studies have shown that the Streptomyces scab phage ZB-1 screened in the present invention exhibits a strong inhibitory effect against Streptomyces scab ZRIMU932, significantly improving potato scab caused by Streptomyces scab ZRIMU932 and reducing the incidence of potato scab, thereby improving the yield and quality of potato cultivation.

[0028] An embodiment of the present invention provides a phage composition, which includes the Streptomyces scabies phage ZB-1 described above.

[0029] In one embodiment, the phage composition further comprises an agriculturally acceptable adjuvant.

[0030] In one embodiment, the agriculturally acceptable adjuvant is selected from one or more of a dispersant, a stabilizer, a filler and a solvent.

[0031] The present invention provides an embodiment of the present invention providing the use of the Streptomyces scab phage ZB-1 or the phage composition described above in the prevention and treatment of potato scab. Specifically, the potato scab is caused by Streptomyces scab ZRIMU932.

[0032] In one embodiment, when the Streptomyces scabies phage ZB-1 or the phage composition is used, the temperature of the system is 10 to 60°C, for example, 10°C, 20°C, 30°C, 40°C, 50°C, or 60°C, but not limited thereto; preferably, the temperature of the system is 20 to 40°C, for example, 20°C, 25°C, 30°C, 35°C, or 40°C, but not limited thereto; further preferably, the temperature of the system is 20°C or 30°C, but not limited thereto.

[0033] In one embodiment, when the Streptomyces scabies phage ZB-1 or the phage composition is used, the pH of the system is 3 to 12, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, but not limited thereto; preferably, the pH of the system is 4 to 9, for example, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, or 9, but not limited thereto; further preferably, the pH of the system is 7, but not limited thereto.

[0034] The present invention will be further described below with reference to specific examples.

[0035] In the following embodiments, the materials and components involved are as follows:

[0036] The potato variety is Favorita. Streptomyces scabies ZRIMU932 was isolated from potato tubers in Heilongjiang Province in September 2022. Streptomyces scabies phage ZB-1 was isolated from a potato field in Zhangjiakou City, Hebei Province in September 2023 and was deposited with the General Microbiology Center of the China Culture Collection Administration on December 23, 2024, at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, with the deposit number CGMCC NO. 46275.

[0037] Gao's solid medium No. 1: soluble starch 20.0 g / L, sodium chloride (NaCl) 0.5 g / L, potassium nitrate (KNO3) 1.0 g / L, potassium hydrogen phosphate trihydrate (K2HPO4·3H2O) 0.5 g / L, magnesium sulfate heptahydrate (MgSO4·7H2O) 0.5 g / L, ferrous sulfate heptahydrate (FeSO4·7H2O) 0.01 g / L, agar 20 g / L.

[0038] Gao's liquid medium No. 1: soluble starch 20.0 g / L, sodium chloride (NaCl) 0.5 g / L, potassium nitrate (KNO3) 1.0 g / L, dipotassium hydrogen phosphate trihydrate (K2HPO4·3H2O) 0.5 g / L, magnesium sulfate heptahydrate (MgSO4·7H2O) 0.5 g / L, ferrous sulfate heptahydrate (FeSO4·7H2O) 0.01 g / L.

[0039] Yeast malt extract (YME) medium was prepared with water and included 5 g / L peptone, 3 g / L yeast extract, 3 g / L malt extract, and 10 g / L glucose.

[0040] The phage buffer was prepared with water and included: sodium chloride (NaCl) 87.4 g / L, magnesium chloride hexahydrate (MgC12·6H2O) 20.4 g / L, calcium chloride (CaC12) 2.2 g / L, and tris(hydroxymethyl)aminomethane (Trisbase) 60.6 g / L.

[0041] The method for preparing a suspension of Streptomyces scabies ZRIMU932 includes: removing Streptomyces scabies ZRIMU932 from a -80°C strain library in the laboratory and placing it in a -20°C refrigerator overnight to slowly thaw. After thawing, the bacterial liquid is diluted and spread on Gao's solid culture medium No. 1, and then cultured in a 28°C constant temperature incubator for 3 to 5 days. Subsequently, a single colony is picked for plate streak purification, and this is repeated 3 to 4 times to ensure that a pure strain is obtained. Finally, the purified single colony of Streptomyces scabies ZRIMU932 is inoculated into Gao's liquid culture medium No. 1, placed on a shaker with a speed of 200 rpm / min, and cultured at 28°C for 3 to 5 days to obtain a suspension of Streptomyces scabies ZRIMU932.

[0042] Example 1

[0043] In this example, Streptomyces scabies phage ZB-1 was isolated and purified as follows:

[0044] Soil samples were collected from a potato plot in Zhangjiakou City, Hebei Province. 3.5 g of soil sample was mixed with 500 μL of a Streptomyces scabies ZRIMU932 suspension and 6 mL of phage buffer (pH 7.5). The mixture was amplified at 200 rpm and 28°C for 2–3 days. After amplification, the mixture was allowed to stand for 30 minutes, and the supernatant was filtered through a 0.22 μm filter to obtain the phage culture.

[0045] The gradient dilution plating method was used for purification, that is, 500 μL of phage culture and 500 μL of Streptomyces scabies ZRIMU932 suspension were mixed, and 5 mL of YME medium containing 0.45% (w / v) agar was added, and then poured onto a YME medium plate containing 2% (w / v) agar. After culturing at 30°C for 2 days, a sterile toothpick was used to gently dip the center area of the plaque and placed in an EP tube containing 1 mL of phage buffer (pH = 7.5). The obtained phage liquid was diluted and plated again, and iterative purification was performed until the plaque size was consistent to obtain the purified Streptomyces scabies phage ZB-1. The plaques of Streptomyces scabies phage ZB-1 are as follows: Figure 1 As shown. Figure 1 It can be seen that the plaques of Streptomyces scabies phage ZB-1 are transparent and have a diameter of about 220 mm.

[0046] To obtain a high-concentration suspension of Streptomyces scabies phage ZB-1, the purified Streptomyces scabies phage ZB-1 was co-cultured with Streptomyces scabies ZRIMU932 using a double-layer agar plate method for 3 days. The upper agar layer was harvested, crushed, and mixed with an appropriate amount of phage buffer (pH = 7.5). The supernatant was centrifuged (10,000 g, 15 minutes, 4°C) and filtered through a 0.22 μm needle sterile filter (Merck Millipore, USA) to obtain a suspension of Streptomyces scabies phage ZB-1, which was stored at 4°C until use.

[0047] Example 2

[0048] In this example, the morphology of Streptomyces scabies phage ZB-1 was observed, as follows:

[0049] The morphology of Streptomyces scabies phage ZB-1 was observed using a transmission electron microscope (TEM). The sample preparation process was as follows: PEG8000 (Merck millipore, USA) was added to the suspension of Streptomyces scabies phage ZB-1 to a final concentration of 10% (w / v) and NaCl to a final concentration of 0.5M, and precipitation was carried out at 4°C overnight. Subsequently, the suspension was centrifuged at 4°C and 11,000g for 30 minutes, and the precipitate was resuspended in phage buffer (pH = 7.5). After the resuspension was extracted with equal volumes of chloroform three times, the prepared Streptomyces scabies phage ZB-1 was added dropwise to a copper mesh carbon support membrane (Beijing Daji Keyi Technology Co., Ltd., China) for adsorption, and then the unadsorbed Streptomyces scabies phage ZB-1 was absorbed using filter paper. In the negative staining, the Streptomyces scabies phage ZB-1 adsorbed on the carbon film was treated with 1% (w / v) phosphotungstic acid solution (Sigma, USA) for 1 minute, and then the excess staining solution was removed with filter paper. The morphology of the Streptomyces scabies phage ZB-1 was observed using TEM at an accelerating voltage of 60 kV. Figure 2 As shown. Figure 2 It can be seen that the head of Streptomyces scabies phage ZB-1 has an icosahedral structure and a long tail, and its head diameter is about 50 nm.

[0050] Example 3

[0051] This example determines the host range of Streptomyces scabies phage ZB-1, as follows:

[0052] In addition to Streptomyces scabies ZRIMU932, the infection activity of Streptomyces scabies phage ZB-1 against 38 common potato strains was tested. The process is as follows: First, the target strain was cultured in YME medium for 5 days to obtain a bacterial solution. Then, 500 μL of the bacterial solution was mixed with 5 mL of YME medium containing 0.45% (w / v) agar and poured onto a YME medium plate containing 2% (w / v) agar. After that, 10 μL of the Streptomyces scabies phage ZB-1 suspension (~10 8 PFU / mL) and ensure that the plate contains the target strain. The inoculated plates were incubated at 37°C for 2 days and then observed for plaque formation. The results are shown in Tables 1 to 3. In Table 1, "√" indicates infection and "×" indicates non-infection.

[0053] Table 1 Streptomyces infected by Streptomyces scabies phage ZB-1

[0054] Strain number (ZRIMU) Classification and naming Infectious activity of ZB-1 523 Streptomyces pratensis √ 1502 Streptomyces brasiliscabiei √ 1199 Streptomyces caniscabiei √ 1509 Streptomyces griseochromogenes √ 1190 Streptomyces stelliscabiei √ 897 Streptomyces rubiginosohelvolus √ 366 Streptomyces purpurascens √ 246 Streptomyces massasporeus √ 368 Streptomyces flavidovirens √ 1601 Streptomyces galilaeus √ 808 Streptomyces luteogriseus √ 1632 Streptomyces beijiangensis √ 5056 Streptomyces bobili √ 637 Streptomyces violaceoruber √ 1328 Streptomyces europaeiscabiei √ 1080 Streptomyces acidiscabies √

[0055] Table 2 Streptomyces not infected by Streptomyces scabies phage ZB-1

[0056] Strain number (ZRIMU) Classification and naming Infectious activity of ZB-1 1644 Streptomyces acrimycini × 1359 Streptomyces turgidiscabies × 653 Streptomyces violaceoruber × 700 Streptomyces acidiscabies × 1572 Streptomyces galilaeus × 1196 Streptomyces deccanensis × 1073 Streptomyces venezuelae × 365 Streptomyces purpurascens × 260 Streptomyces ambofaciens × 5050 Streptomyces bobili × 508 Streptomyces acidiscabies × 791 Streptomyces deccanensis × 1350 Streptomyces turgidiscabies × 1650 Streptomyces bobili × 871 Streptomyces turgidiscabies × 1656 Streptomycesgalilaeus ×

[0057] Table 3 Non-Streptomyces that were not infected by Streptomyces scabies phage ZB-1

[0058] Strain number (ZRIMU) Classification and naming Infectious activity of ZB-1 1006 Pectobacterium carotovorum × 1119 Enterobacter ludwigii × 1150 Pectobacterium atrosepticum × 1222 Pectobacterium polaris × 1366 Pectobacteriumversatile × 5045 Pectobacterium brasiliense ×

[0059] As shown in Tables 1 to 3, the Streptomyces scabies phage ZB-1 can lyse a variety of Streptomyces species and is a polyvalent phage with a broad host range.

[0060] Example 4

[0061] In this example, the optimal multiplicity of infection (MOI) of Streptomyces scabies phage ZB-1 was determined as follows:

[0062] The suspension of Streptomyces scab ZRIMU932 (~10 8 CFU / mL) were added to 10 mL of YME medium and incubated at 30°C for 6 hours to promote spore germination, and the germinated host bacterial solution (~10 7 CFU / mL). Subsequently, 100 μL of host bacterial liquid and 100 μL of different concentrations of Streptomyces scabies phage ZB-1 suspension were added to 20 mL of YME medium to form different multiplicities of infection (including 1000, 100, 10, 1, 0.1, 0.01 and 0.001). These mixed cultures were incubated at 30°C and 200 rpm for 1 day. The supernatant was filtered through a 0.22 μm needle filter to remove the host cells and obtain a phage lysate. The filtered phage lysate was gradiently diluted to determine the titer of Streptomyces scabies phage ZB-1, and the multiplicity of infection with the highest titer was defined as the optimal MOI. Among them, the titer was determined using the double-layer agar plate method, which is briefly described as follows: 500 μL of Streptomyces scabies ZRIMU932 suspension (~10 8 CFU / mL), add 5mL YME medium containing 0.45% (w / v) agar, mix thoroughly, and pour into a YME medium plate containing 2% (w / v) agar. After the agar is completely solidified, add 10μL of the gradient diluted phage lysate to the surface of the plate. Then, incubate the plate at 30℃ for 48 hours and count the plaques. The results are as follows: Figure 3 As shown. Figure 3 It can be seen that the optimal multiplicity of infection of Streptomyces scabies phage ZB-1 is 0.1.

[0063] Example 5

[0064] This example measures the thermal stability of Streptomyces scabies phage ZB-1, as follows:

[0065] The suspension of Streptomyces scabies phage ZB-1 (~5×10 9 The titer of PFU / mL) was determined after culturing at 10, 20, 30, 40, 50, 60 and 70 °C for 12 hours to observe the effect of different temperatures on the stability of Streptomyces scabies phage ZB-1. Figure 4 As shown. Figure 4 It can be seen that the Streptomyces scabies phage ZB-1 can survive in the temperature range of 10-60℃, reaches the highest activity at 20℃ and 30℃, the titer decreases significantly at 10℃, 40℃ and 50℃, and completely loses activity at 70℃.

[0066] Example 6

[0067] This example measures the pH stability of Streptomyces scabies phage ZB-1, as follows:

[0068] 100 μL of Streptomyces scabies phage ZB-1 suspension (~5×10 9 PFU / mL) was mixed with 900 μL of phage buffer with a specific pH value (pH = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13) to obtain a mixture. These mixtures were incubated at 28°C for 12 hours to evaluate the survival of Streptomyces scabies phage ZB-1 under different pH conditions. The results are shown in Figure 2. Figure 5 As shown. Figure 5 It can be seen that the Streptomyces scabies phage ZB-1 can survive under conditions of pH values of 3 to 12, and its activity reaches the highest at pH 7; under extremely acidic (pH = 1 and 2) and extremely alkaline (pH = 13) conditions, its activity will be completely lost.

[0069] Example 7

[0070] This example measures the UV sensitivity of Streptomyces scabies phage ZB-1, as follows:

[0071] The suspension of Streptomyces scabies phage ZB-1 (~5×10 9 PFU / mL) were placed 12 cm from two TUV 15W / G15 T8 lamps (Philips, The Netherlands) with a wavelength of 253.7 nm to simulate natural UV exposure conditions. The experiment was conducted at room temperature, and the pH of the Streptomyces scabies phage ZB-1 suspension was 7.5. The samples were exposed to UV light for 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 hours to investigate the effects of different exposure times on phage stability. The results are shown in Figure 2. Figure 6As shown. Figure 6 It can be seen that the Streptomyces scabies phage ZB-1 has a high UV tolerance. Under UV light, its activity decreases slightly at the beginning, stabilizes during 2 to 6 hours, and then decreases again. Its activity stabilizes again during 7 to 8 hours, and then decreases sharply, and finally loses its activity completely after 11 hours.

[0072] Example 8

[0073] In this example, the one-step growth curve of Streptomyces scabies phage ZB-1 was measured, as follows:

[0074] The suspension of Streptomyces scab ZRIMU932 (~10 8 CFU / mL) were added to 10 mL of YME medium and incubated at 30°C for 6 hours to promote spore germination, and the germinated host bacterial solution (~10 7 CFU / mL). The germinated host bacterial liquid was mixed with Streptomyces scabies phage ZB-1 at the optimal MOI and incubated at 28°C for 20 minutes to complete the adsorption process. The unadsorbed Streptomyces scabies phage ZB-1 was removed by centrifugation, and the precipitate was washed and resuspended using YME medium. This process was repeated three times. Subsequently, the treated sample was added to 50 mL of YME medium for culture. From the start of infection (denoted as t=0), 200 μL of samples were collected every 120 minutes from 0 to 480 minutes to determine the titer of Streptomyces scabies phage ZB-1. 200 μL of samples were collected every 60 minutes from 480 to 660 minutes to determine the titer of Streptomyces scabies phage ZB-1 until the end of the experiment (i.e., 660 minutes). All samples were filtered through a 0.22 μm sterile membrane and then gradiently diluted. The titer of Streptomyces scabies phage ZB-1 was determined using the double-layer agar plate method. The results are shown in the figure. Figure 7 As shown. Figure 7 It can be seen that the incubation period of Streptomyces scabies phage ZB-1 is relatively long, and the titer increases slowly within 360 minutes, then increases rapidly to 480 minutes, and then tends to be stable.

[0075] Example 9

[0076] This example evaluates the in vitro effect of Streptomyces scabies phage ZB-1 as a Streptomyces scabies control agent, as follows:

[0077] Surface-sterilized "Han Meiyu" radish seeds were placed on moist filter paper for 24 hours to promote germination. After germination, seeds with consistent growth were selected and transplanted into culture tubes containing 1.5% (w / v) agar. The three groups were divided into: a blank control group, a ZB-1 group (negative control), a ZRIMU932 group (positive control), and a ZRIMU932+ZB-1 group. The blank control group received no treatment, while the ZB-1 group received 5×10 7 CFU Streptomyces scabies phage ZB-1, 200 μL of Streptomyces scabies ZRIMU932 suspension was added to the plant crown in the ZRIMU932 group, and 5×10 7 CFU of Streptomyces scabies phage ZB-1 and 200 μL of Streptomyces scabies ZRIMU932 suspension. All test tubes were arranged according to the principles of randomized block design and placed at 30°C with a photoperiod of 16 hours of light and 8 hours of darkness for 5 days. After the experiment, the control effect of Streptomyces scabies ZRIMU932 on radish seedlings was evaluated by measuring the growth inhibition of radish seedlings. The test results are shown in the figure below. Figure 8 As shown. Figure 8 It can be seen that after the introduction of Streptomyces scabies phage ZB-1 treatment, the growth inhibition of radish seedlings caused by Streptomyces scabies ZRIMU932 was significantly improved.

[0078] Example 10

[0079] In this example, whole genome sequencing and bioinformatics analysis of Streptomyces scabies phage ZB-1 were performed, as follows:

[0080] Genomic DNA was extracted from Streptomyces scabies phage ZB-1 using the λ phage genomic DNA rapid extraction kit (Beijing Zhuangmeng International Biogene Technology Co., Ltd., Cat. No. ZP317) according to the manufacturer's instructions. Genome sequencing was performed on an Illumina Novaseq PE150 platform (Shanghai Tanpu Biotechnology Co., Ltd.), resulting in a full genome sequence of 18,465 base pairs. Comparative BLAST analysis of Streptomyces scabies phage ZB-1 with other phages in the NCBI database revealed that Streptomyces phage WheeHeim (GenBank No. NC_055060.1) showed the highest similarity to Streptomyces scabies phage ZB-1, with 94.29% identity and 93% query coverage. In order to obtain the evolutionary affiliation of Streptomyces scabies phage ZB-1 and its evolutionary distance from other Streptomyces phages, a phylogenetic tree was constructed based on the maximum likelihood method (ML). Figure 9 These results indicate that Streptomyces scabies phage ZB-1 is a novel phage. Furthermore, Prokka software was used to predict the coding genes in the ZB-1 genome. The results showed that no lysogenic genes, antibiotic resistance genes, or virulence genes were found in the ZB-1 genome, indicating a certain safety profile.

[0081] Example 11

[0082] This example evaluated the efficacy of Streptomyces scab phage ZB-1 against potato scab in a potted experiment, as follows:

[0083] First, the potato seeds were surface disinfected. The seeds were soaked in a 1% (v / v) sodium hypochlorite (NaClO) solution for 5 minutes, then rinsed with sterile distilled water and germinated. Afterwards, the germinated seeds were planted in 5L pots containing about 7kg of soil, which was taken from a potato field in Hohhot. Four treatment groups were set up in the experiment: a blank control group, a ZB-1 group (negative control), a ZRIMU932 group (positive control) and a ZRIMU932+ZB-1 group. When the potato plants grew to the stage of three true leaves, 100mL of a solution with a concentration of about 10 was evenly mixed into the soil of the ZRIMU932 group and the ZRIMU932+ZB-1 group. 8 CFU / mL of Streptomyces scab ZRIMU932 suspension. 30 days after planting, 10 9 Potato plants in the blank control and ZRIMU932 groups were treated with PFU of Streptomyces scab phage ZB-1. Equal amounts of sterile distilled water were applied to the crowns of the potato plants. The potato plants were grown under a controlled environment with a 12-hour light cycle (6:00 AM to 6:00 PM) and a day and night temperature range of approximately 20°C to 30°C. During the experiment, routine irrigation and fertilization practices were implemented according to potato management practices. After a 120-day experimental period, potato tubers were harvested and assessed for morbidity and disease index.

[0084] The severity of tuber scab is divided into five grades based on the percentage of lesion area: grade 0 = no symptoms, grade 1 <5%, grade 2 = 5-12.5%, grade 3 = 12.5-25%, grade 4 = 25-50%, and grade 5 >50%.

[0085] The formula for calculating the incidence of potato scab is:

[0086]

[0087] The disease index (DI) of potato scab is calculated according to the following formula:

[0088]

[0089] Where i is the representative value of each level (from 0 to 5), and N is the number of diseased potatoes at each level.

[0090] The experimental results are as follows Figure 10 As shown in , different lowercase letters represent significant differences when P < 0.05. Figure 10 As shown in Figure A, the incidence rate of the ZRIMU932 group was 100%, while the incidence rate of the ZRIMU932+ZB-1 group was 80%, which was significantly lower than that of the ZRIMU932 group (P<0.05). Figure 10 As shown in Figure B, the disease index of the ZRIMU932 group was 92, while that of the ZRIMU932+ZB-1 group was 34, both significantly lower than that of the ZRIMU932 group (P < 0.05). In summary, Streptomyces scab phage ZB-1 performed well in the control of potato scab and has the potential to be used as a biological control agent.

[0091] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. Streptomyces scabies phage ZB-1, characterized in that The Streptomyces scabies phage ZB-1 is deposited in the General Microbiology Center of the China Culture Collection Administration, with the deposit number CGMCCNO.46275 and the deposit date of December 23, 2024.

2. A bacteriophage composition, characterized in that The phage composition comprises the Streptomyces scabies phage ZB-1 according to claim 1.

3. The phage composition according to claim 2, characterized in that The bacteriophage composition further includes an agriculturally acceptable adjuvant.

4. The phage composition according to claim 3, characterized in that The agriculturally acceptable adjuvant is selected from one or more of a dispersant, a stabilizer, a filler and a solvent.

5. Use of the Streptomyces scab phage ZB-1 according to claim 1 or the phage composition according to any one of claims 2 to 4 in the prevention and treatment of potato scab.

6. The use according to claim 5, characterized in that When the Streptomyces scabies phage ZB-1 or the phage composition is used, the temperature of the system is 10-60°C.

7. The use according to claim 5, characterized in that When the Streptomyces scabies phage ZB-1 or the phage composition is used, the pH of the system is 3-12.

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