Arthrobacter HJ1 for preventing and treating rhizoma polygonati root rot and application of arthrobacter HJ1

Abstract

The invention provides arthrobacter HJ1 for preventing and treating fungal root rot of polygonatum sibiricum and application of the arthrobacter HJ1, and belongs to the technical field of disease prevention and treatment. The preservation number of the arthrobacterium HJ1 is CCTCC (China Center For Type Culture Collection) NO: M20251843 The arthrobacter HJ1 has a remarkable inhibition effect on the pathogenic bacterium fusarium oxysporum of the rhizoma polygonati root rot. The arthrobacter HJ1 has a remarkable inhibition effect on the rhizoma polygonati root rot under an in-vitro condition, and can remarkably reduce scab expansion of the rhizoma polygonati root rot caused by fusarium oxysporum. In a field test, by using the arthrobacter HJ1, the morbidity of the rhizoma polygonati root rot can be remarkably reduced, and the control effect on the rhizoma polygonati root rot is improved. A safety test shows that the arthrobacter HJ1 has no adverse effect on the growth of the polygonatum sibiricum and can be safely used for preventing and controlling root rot fungal diseases of the polygonatum sibiricum. The arthrobacter HJ1, as a beneficial biocontrol bacterium for polygonatum sibiricum root rot fungal diseases, is of great significance to healthy and green development of the polygonatum sibiricum industry.

Description

Technical Field

[0001] This invention belongs to the field of disease control technology, specifically relating to a strain of Arthrobacter HJ1 for controlling root rot in Polygonatum sibiricum and its application. Background Technology

[0002] Polygonatum ( Polygonatum sibiricum *Delar. ex Redoute* is a perennial herb belonging to the order Asparagales, family Liliaceae, and genus *Polygonatum*, including *Polygonatum multiflorum* (…). P. cyrtonema ), Chicken Head Polygonatum ( P. sibiricum ) and Yunnan Polygonatum ( P. kingianum Several varieties of Polygonatum sibiricum are produced, mainly in Guizhou, Hunan, Hubei, Sichuan, and Anhui provinces. As an important medicinal resource, its rhizome is the primary part used in traditional Chinese medicine. The rhizome is slender, yellowish-brown or yellowish-brown, and has a flexible texture. Studies have shown that Polygonatum sibiricum is rich in polysaccharides, saponins, flavonoids, and alkaloids, possessing anti-fatigue, antioxidant, and immune-enhancing effects. In recent years, due to over-harvesting, environmental damage, and continuous cropping problems, Polygonatum sibiricum plants have experienced poor growth, slow and smaller new rhizome elongation, severe root rot, and a significant decline in yield and quality, sometimes even resulting in total crop failure.

[0003] Polygonatum is susceptible to various diseases during its growth, among which fungal root rot is one of the most serious diseases affecting its production. This disease is mainly caused by various fungi, with common pathogens including Fusarium (…). Fusarium spp. ), Aspergillus awamori ( Aspergillus awamori ) and Alternaria ( Alternaria spp. This fungal root rot disease, transmitted through the soil, infects the roots of Polygonatum, causing root cortex rot and severely impairing the root system's ability to absorb water and nutrients. Above-ground symptoms include slow plant growth, yellowing and wilting leaves, and in severe cases, death of the entire plant. Polygonatum fungal root rot is characterized by a short incubation period, rapid onset, wide spread, and high severity. Once the disease occurs, field control becomes significantly more difficult. In some high-incidence areas, the incidence rate can reach 30% to 50%, or even higher, causing huge economic losses to growers. Furthermore, this disease significantly reduces the quality of Polygonatum, lowering its medicinal value and market competitiveness. Conventional chemical control methods suffer from pesticide residues and pathogen resistance, which are inconsistent with the trend of green planting. Therefore, finding a highly efficient, environmentally friendly, and non-toxic control method has become a key research focus.

[0004] Biocontrol agents are a kind of beneficial microorganisms that can inhibit the growth of pathogenic bacteria or reduce the population density of pathogenic bacteria, and achieve effective prevention and control of plant diseases through various mechanisms such as competition for ecological niche, secretion of antibacterial substances and induction of plant resistance. At present, the screening of biocontrol agents is mainly derived from natural microbial resources such as soil microbial community, plant rhizosphere microbial group and plant endophytic bacteria group. Microorganisms in these environments often have natural ecological adaptability with plants or soil and have high biocontrol potential. Therefore, screening of biocontrol agents beneficial to the root rot fungal disease of Rhizoma Polygonati has important significance for the healthy and green development of Rhizoma Polygonati industry. SUMMARY

[0005] In view of the defects in the prior art, the purpose of the present application is to provide Arthrobacter HJ1 which can be used for preventing and treating Rhizoma Polygonati root rot.

[0006] The purpose of the present application is achieved by the following technical solutions: The present application provides Arthrobacter sp. Arthrobacter HJ1, the preservation number of which is CCTCC NO: M20251843.

[0007] The present application provides a microbial preparation comprising the Arthrobacter HJ1 according to the above technical solutions.

[0008] Preferably, the viable bacterial count in the microbial preparation is greater than or equal to 1×10 6 cfu / mL.

[0009] The present application provides a preparation method of the microbial preparation according to the above technical solutions, comprising: Culturing the Arthrobacter HJ1 in a culture medium to obtain a microbial preparation.

[0010] Preferably, the culture temperature is 23-35℃ (the optimum temperature is 28℃), and the culture time is 12-36h (the optimum culture time is 24h).

[0011] The present application provides a preparation for preventing and treating Rhizoma Polygonati root rot, comprising the Arthrobacter HJ1 according to the above technical solutions, the microbial preparation according to the above technical solutions or the microbial preparation prepared by the preparation method according to the above technical solutions.

[0012] The present application provides the Arthrobacter HJ1 according to the above technical solutions, the microbial preparation according to the above technical solutions, the microbial preparation prepared by the preparation method according to the above technical solutions or the preparation according to the above technical solutions for use in inhibiting root rot pathogenic bacteria.

[0013] Preferably, the root rot pathogenic bacteria comprise Fusarium oxysporum.

[0014] This invention provides the application of the *Arthrobacter HJ1* described in the above technical solution, the microbial preparation described in the above technical solution, the microbial preparation prepared by the preparation method described in the above technical solution, or the preparation described in the above technical solution in the prevention and control of root rot of *Polygonatum sibiricum*.

[0015] This invention provides a method for preventing and controlling root rot in Polygonatum sibiricum, comprising: Apply microbial preparations or formulations containing Arthrobacter HJ1 as described in the above technical solution during the cultivation of Polygonatum sibiricum; Alternatively, a microbial preparation or formulation containing Arthrobacter HJ1 as described in the above technical solution may be applied to the collected rhizomes of Polygonatum.

[0016] The beneficial effects of this invention are: This invention provides a type of Arthrobacter ( Arthrobacter The *Arthrobacter* sp. HJ1, with preservation number CCTCC NO: M20251843, was discovered through experiments. This invention found that *Arthrobacter* HJ1, as a biocontrol bacterium, exhibits significant antagonistic effects against various pathogens. It can effectively inhibit multiple plant pathogens by producing antimicrobial substances and competing for ecological niches, demonstrating its important potential in the biological control of plant diseases. The results of the embodiments of this invention show that *Arthrobacter* HJ1 has a significant inhibitory effect on *Fusarium oxysporum*, the pathogen causing root rot in *Polygonatum sibiricum*. *Arthrobacter* HJ1 has a significant inhibitory effect on root rot in *Polygonatum sibiricum* under in vitro conditions, significantly reducing the expansion of root rot lesions caused by *Fusarium oxysporum* in detached rhizomes. In field trials, the use of *Arthrobacter* HJ1 significantly reduced the incidence of root rot in *Polygonatum sibiricum* and improved the control efficacy against it. Furthermore, the safety test results of this invention show that *Arthrobacter* HJ1 has no adverse effects on the growth of *Polygonatum sibiricum* and can be safely used for the control of fungal root rot in *Polygonatum sibiricum*. Therefore, the Arthrobacter HJ1 provided by this invention, as a beneficial biocontrol bacterium against fungal root rot in Polygonatum, is of great significance to the healthy and green development of the Polygonatum industry.

[0017] Biological Preservation Information Arthrobacter HJ1, Latin scientific name: Arthrobacter sp. was deposited on August 18, 2025 at the China Center for Type Culture Collection, Wuhan University, Wuhan, China, with accession number CCTCC NO: M20251843. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The graph shows the inhibitory effect of biocontrol bacterium HJ1 on five pathogens causing root rot in Polygonatum sibiricum. Figure 2 This is a colony morphology diagram of strain HJ1; Figure 3 This is a photograph of strain HJ1 under a microscope (1000X). Figure 4 This is a diagram showing the developmental tree of strain HJ1 constructed based on the 16S rRNA gene sequence. Figure 5 The image shows the inhibitory effect of the fermentation broth of strain HJ1 on the lesions of root rot of Polygonatum odoratum HJGF10. Figure 6 The field control efficacy of strain HJ1 fermentation broth against root rot of Polygonatum sibiricum is shown in the figure. Figure 7 The effect of biocontrol bacterium HJ1 on the growth of Polygonatum sibiricum. Detailed Implementation

[0020] This invention provides a type of Arthrobacter ( Arthrobacter sp.) HJ1, the preservation number of the Arthrobacter HJ1 is CCTCC NO: M20251843.

[0021] The *Arthrobacter* HJ1 provided by this invention was isolated from the soil of a *Polygonatum sibiricum* planting base under forest cover in Pingbaying State-owned Forest Farm, Xianfeng County, Hubei Province. *Arthrobacter* HJ1 was cultured on LB medium at 28℃ for 24 hours. The colonies were milky white, small, and smooth. Gram staining confirmed it to be Gram-positive. Microscopic observation showed the strain to be short rod-shaped. Physiological and biochemical characterization results showed that *Arthrobacter* HJ1 was positive for aesculin, cellobiose, maltose, melibiose, sucrose, trehalose, inulin, pinoside, raffinose, geraniol, and D-pinoside. The 16S rRNA gene sequence of *Arthrobacter* HJ1 is shown in SEQ ID NO.3. Morphological, physiological, biochemical, and molecular biological identifications confirmed that the biocontrol bacterium HJ1 belongs to the genus *Arthrobacter* (…). Arthrobacter This strain is deposited at the China Center for Type Culture Collection (CCTCC), accession number: CCTCC NO: M20251843.

[0022] The Arthrobacter HJ1 provided by the present application can efficiently inhibit the growth of the root rot pathogen Fusarium oxysporum of polygonatum sibiricum, and can be used for preventing and treating the root rot of polygonatum sibiricum, and can significantly improve the prevention and treatment effect of the root rot of polygonatum sibiricum under the in vitro condition of polygonatum sibiricum rhizome and during planting.

[0023] The present application provides a microbial preparation, comprising the Arthrobacter HJ1 described in the above technical solution. As an optional embodiment of the present application, the viable bacterial count in the microbial preparation is greater than or equal to 1×10 6 cfu / mL, and can also be 1×10 6 ~1×10 8 cfu / mL.

[0024] The present application provides a preparation method of the microbial preparation described in the above technical solution, comprising: culturing the Arthrobacter HJ1 in a culture medium to obtain a microbial preparation. The present application does not have special limitations on the type of the culture medium, as long as the Arthrobacter HJ1 can grow normally. As an optional embodiment of the present application, the culture medium can be LB culture medium. As an optional embodiment of the present application, the culture temperature can be 23~35℃, and can also be 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 or 35℃, and the optimum temperature is 28℃; the culture time can be 12~36 h, and can also be 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 or 36 h, and the optimum culture time is 24 h. After the culture is completed, the obtained culture solution can be directly used as a microbial preparation. Alternatively, the viable bacterial count of the culture solution can be adjusted to the required concentration, and then the bacterial solution with adjusted viable bacterial count is used as a microbial preparation.

[0025] The present application provides a preparation for preventing and treating the root rot of polygonatum sibiricum, comprising the Arthrobacter HJ1 described in the above technical solution, the microbial preparation described in the above technical solution, or the microbial preparation prepared by the preparation method described in the above technical solution.

[0026] The present application provides the application of the Arthrobacter HJ1 described in the above technical solution, the microbial preparation described in the above technical solution, the microbial preparation prepared by the preparation method described in the above technical solution, or the preparation described in the above technical solution in inhibiting the root rot pathogen. As an optional embodiment of the present application, the root rot pathogen comprises Fusarium oxysporum. The present application shows through the results of the examples that the Arthrobacter HJ1 has a high inhibition effect on different sources of the root rot pathogen Fusarium oxysporum of polygonatum sibiricum, Fusarium oxysporum and the inhibition rate reaches 60%~75.3%.

[0027] The application provides application of the above-mentioned Arthrobacter HJ1, the above-mentioned microbial preparation, the microbial preparation prepared by the above-mentioned preparation method or the above-mentioned preparation in preventing and treating rhizoctonia root rot. The Arthrobacter HJ1 can be used for preventing and treating rhizoctonia root rot, and can significantly improve the prevention and treatment effect of rhizoctonia root rot under the condition of in vitro rhizome of Polygonatum and during planting. The results of the examples show that the Arthrobacter HJ1 can significantly improve the prevention and treatment effect of rhizoctonia root rot caused by Fusarium oxysporum on Polygonatum under the condition of in vitro rhizome of Polygonatum, effectively reduces the expansion of the lesion, and the prevention and treatment efficiency is as high as 76% to 84.48%. The Arthrobacter HJ1 can significantly reduce the incidence of rhizoctonia root rot of Polygonatum in the field, and the prevention and treatment efficiency is as high as 57.01%.

[0028] The application provides a method for preventing and treating rhizoctonia root rot, which comprises: applying the microbial preparation or the preparation containing the above-mentioned Arthrobacter HJ1 during planting of Polygonatum; or applying the microbial preparation or the preparation containing the above-mentioned Arthrobacter HJ1 to the collected rhizome of Polygonatum. The application is not limited to the application method, and the application method in the art can be used.

[0029] In order to further illustrate the application, the technical solutions provided by the application are described in detail below in combination with the drawings and examples, but they should not be understood as limiting the protection scope of the application.

[0030] Example 1 1. Isolation and screening The soil sample collection site is the understory Polygonatum planting base of Pingba Camp State-owned Forest Farm in Xianfeng County, Hubei Province. Five-point sampling method is used to collect soil, and 5 g of the collected soil sample is put into a centrifuge tube containing 45 mL of sterile water to shake thoroughly, to prepare a soil suspension with a concentration of 10 -1 The soil suspension is diluted by stages to 10 -2 -10 -5 to obtain soil suspensions with different concentrations. 20 μL of the soil suspensions with concentrations of 10 -3 , 10 -4 , 10 -5 are respectively taken by a pipette gun, and are coated on R2A, NA, LB and BHI medium plates, and are respectively placed in a culture box at 23, 25, 28, 30 and 35℃ for 12, 24 and 36 h to obtain isolated strains with different morphologies. The single colonies with different morphologies are picked and inoculated into centrifuge tubes containing 1 mL of LB medium, and are placed in a shaking bed at 28℃ and 180 r / min for 24 h. All the isolated strains are stored in a refrigerator at 4℃ for standby.

[0031] 2. Antagonistic test The antagonistic bacteria with inhibitory effect on the pathogen of rhizome rot of Polygonatum were screened by plate confrontation culture method. The bacteria liquid stored at 4℃ in step 1 was inoculated into liquid LB medium, and cultured at 28℃ in a constant temperature shaker at 180 r / min for 24 h. Meanwhile, the pathogen of rhizome rot of Polygonatum (as shown in Table 1) was placed on PDA medium plate and cultured at 28℃ in a constant temperature incubator for 3 d. Then, a 5 mm diameter puncher was used to punch the fungus cake and place it in the center of a new PDA plate with the mycelium facing down. 2 μL of the reactivated bacterial liquid was inoculated 2.5 cm away from the mycelium block, and no bacterial liquid was added as a control group. Each treatment was repeated 3 times and placed in a 28℃ incubator for culture. When the blank control grew up to cover the culture dish, the antagonistic effect of the isolated strains on the pathogen of rhizome rot of Polygonatum was observed, and the strains with inhibitory effect were screened out.

[0032] The inhibitory effect of the screened antagonistic bacteria on the pathogen of rhizome rot of Polygonatum (as shown in Table 1) was determined by plate confrontation method, and the inhibition rate was calculated according to the formula, to ensure that the pathogen would not inhibit the growth of the antagonistic bacteria during application. Finally, the antagonistic bacterial strains that could effectively inhibit the growth of the pathogen and had no antagonistic effect on the pathogen were screened out.

[0033] Inhibition rate = (colony diameter of control group - colony diameter of treatment group) / colony diameter of control group × 100%.

[0034] Table 1 Information of pathogen of rhizome rot of Polygonatum

[0035] [1] Shang R, Mao J, He S Q, et al. Isolation and identification of the pathogen of rhizome rot of Polygonatum involucratum in Xishuangbanna[J]. Tropical Agricultural Science, 2025, 48(03): 53-57. [2] Li HM, Peng BW, Hu J, et al. Isolation and identification of pathogen of rhizome rot of Polygonatum cyathopetalum in Hubei and study on the inhibition of Bacillus karlinskyi on it[J / OL]. Chinese Traditional Patent Medicine, 2025, (03): 553-560. [3] Wu Y T, Yao C W, Deng B X, et al. Identification of pathogen of rhizome rot of Polygonatum and its antagonistic endophytic bacteria[J]. Zhejiang Journal of Agricultural Sciences, 2018, 30(12): 2087-2093. [4] Gong Z K. Identification of pathogen of rhizome rot of Polygonatum cyathopetalum in Tonggu, Jiangxi and characteristics of rhizosphere soil fungal community[D]. Jiangxi Agricultural University, 2024. [5] Zheng M Q, Jiang R Q, Fang W, et al. Inhibition of three strains of biocontrol bacteria on the pathogen of rhizome rot of Polygonatum cyathopetalum[J]. Chinese Journal of Chinese Materia Medica, 2023, 48(05): 1212-1217. 3. Results Biocontrol bacteria screening A total of 159 strains of bacteria were isolated from the rhizosphere soil of Polygonatum sibiricum, and strain HJ1 with inhibitory effect on the pathogenic bacteria of root rot of Polygonatum sibiricum was screened by plate confrontation culture, as shown in Table 1. Figure 1 As shown in Table 1, strain HJ1 had obvious inhibitory effect on the pathogenic bacteria HJGF29-3, 887, HF2, HJGF2 and HJ4 of root rot of Polygonatum sibiricum, and the inhibition rates were 60%, 69.4%, 75.3%, 67.1% and 70.6%, respectively, indicating that the biocontrol bacteria HJ1 had good inhibitory effect on the pathogenic bacteria of root rot of Polygonatum sibiricum, and was used for the following tests.

[0036] Example 2 Strain HJ1 identification 1. Morphological identification The screened biocontrol bacteria HJ1 were inoculated on LB medium plates by three-zone streaking method, and incubated at 28°C for 24 h, and the growth of colonies on the plates was observed and recorded.

[0037] 2. Physiological and biochemical identification The physiological and biochemical identification of the biocontrol bacteria HJ1 was carried out by API50CH system, and identification experiments were carried out in terms of gluconate utilization, glucose utilization, escin utilization, maltose utilization, cellobiose utilization, sucrose utilization, lactose utilization, sorbitol utilization, trehalose utilization, xylitol utilization and arabinose utilization.

[0038] 3. Molecular biology identification The genomic DNA of the biocontrol bacteria HJ1 was extracted by using a new type of DNAsecure plant genomic DNA extraction kit, and the 16S rRNA gene sequence thereof was amplified by using primers 27F and 1492R, and the primer sequences are shown in Table 2. The PCR amplification system was as follows: Mix 25 μL, genomic DNA 2 μL, upper and lower primers 2 μL each, and ddH2O 19 μL. The PCR reaction program of 16S rRNA was as follows: 98°C for 3 min; 98°C for 10 s, 57°C for 10 s, 72°C for 30 s, 35 cycles; 72°C for 5 min. After the PCR product was detected by 1% agarose gel electrophoresis, it was sent to Oukedengsheng Biological Technology Co., Ltd. for sequencing. The sequencing results were uploaded to the GenBank database of NCBI, and BLAST comparison was carried out, and sequences with high homology to the target strain were selected, and a phylogenetic tree was constructed by using MEGA6 software.

[0039] Table 2 Primer sequences required for amplification of 16S rRNA gene

[0040] 4. Results (1) After the biocontrol bacteria HJ1 was incubated at 28°C for 24 h, it grew well on LB medium, and the colonies were milky white, small and smooth, and were identified as gram-positive bacteria by gram staining (as shown in FIG. 1). Figure 2 As shown in FIG. 2, the colonies were short rod-shaped under a microscope. Figure 3

[0041] (2) The physiological and biochemical results of the strain HJ1 are shown in Table 3.

[0042] Table 3 Physiological and biochemical characteristics of the strain HJ1

[0043] Note: +: positive reaction; -: negative reaction.

[0044] (3) The 16S rRNA gene sequence of the biocontrol bacteria HJ1 is shown in SEQ ID NO. 3, and specifically is as follows: ​

[0045] The phylogenetic tree constructed based on 16S rRNA gene sequence of the strain HJ1 is shown in Fig. 1. The constructed phylogenetic tree by sequencing analysis shows that the biocontrol strain HJ1 is clustered with Arthrobacter sp. The results of morphological identification, physiological and biochemical identification and molecular biology identification show that the biocontrol strain HJ1 is Arthrobacter sp. Figure 4 Arthrobacter sp. The biocontrol strain HJ1 is preserved in China Center for Type Culture Collection, and the preservation number is CCTCC NO: M20251843.

[0046] Example 3 Extracorporeal control effect test 1. Preparation of fermentation broth: 1 mL of HJ1 bacterial liquid was added to a triangular flask containing LB liquid medium, and then the flask was placed in a constant temperature incubator at 28°C and 180 r / min for 24 h. After that, the concentration of the fermentation broth was adjusted to 10 8 cfu / mL with sterile water.

[0047] 2. The control effect of the strain HJ1 on the pathogen of rhizome rot of Polygonatum was determined by the method of wound inoculation. The rhizomes of Polygonatum with the same size were selected, washed with tap water, then washed with sterile water and dried, and then placed in a sterile glass dish covered with sterile filter paper and moistened with sterile water. The rhizomes were aseptically wounded in a clean bench, and the prepared HJ1 fermentation broth (10 8 cfu / mL) was diluted 10 times and sprayed on the rhizomes, about 5 mL per rhizome. The rhizomes were inoculated with 5 mm diameter rhizome rot pathogen HJGF2 at the wounded site, and the control group was inoculated with 5 mm diameter rhizome rot pathogen HJGF2 after being sprayed with sterile water. Each treatment was repeated twice, and the lesion area was measured and recorded after incubation at 28°C for 6 days. The control effect was calculated.

[0048] Lesion area = 1 / 4 x π x long diameter of lesion x short diameter of lesion; Control effect = (lesion area of control - lesion area of treatment) / lesion area of control x 100%.

[0049] 3. Results The results of the extracorporeal control effect of the strain HJ1 on the rhizome rot HJGF2 are shown in Table 4 and Fig. 2. Figure 5

[0050] Table 4 Control effect of the fermentation broth of the strain HJ1 on the rhizome rot HJGF2

[0051] Table 4 and Fig. 2 show that the strain HJ1 has a good control effect on the rhizome rot HJGF2. Figure 5 ​​As shown, the average in vitro control effect of strain HJ1 on HJGF2 caused by rhizome rot of Polygonatum reached 80.10% compared with the control group (CK). Therefore, the growth of the biocontrol bacteria on the pathogen HJGF2 of rhizome rot of Polygonatum has a significant inhibitory effect, can effectively reduce the expansion of disease spots, and has potential biocontrol application value.

[0052] Example 4 Field efficacy test 1. Preparation of fermentation broth: Take 1 mL of HJ1 bacterial liquid and add it to a triangular flask containing LB liquid medium. Place it in a constant temperature shaker at 28°C and 180 r / min for 24 h. Then adjust the concentration of the fermentation broth to 10 8 cfu / mL with sterile water.

[0053] 2. Select the Polygonatum planting base in Pingba Camp Forest Farm in Xianfeng County, which has been planted for 2 years. Carry out field efficacy test, and divide the test field into 6 plots with a width of 1.5 m and a length of 20 m. Randomly select 3 plots as the experimental group and the other 3 plots as the control group. On May 21, 2024, spray 100 times diluted liquid of HJ1 fermentation broth, according to the dosage of 100 L per mu, calculate 4.5 L per plot, and spray 4.5 L of 100 times diluted liquid of blank LB liquid medium per plot in the control group. Spray continuously for 3 times with an interval of 7 days, and delay one day if it rains. On September 25, 2024, investigate the number of plants with root rot in each plot during the high incidence period of root rot of Polygonatum, and calculate the incidence rate and control efficiency.

[0054] 3. Results In 2024, the biocontrol test of HJ1 on rhizome rot of Polygonatum was carried out in the Polygonatum planting base in Pingba Camp Forest Farm in Xianfeng County, as shown in Figure 6 the table, the incidence of rhizome rot of Polygonatum in the control group was about 11.14% in the second year, while the incidence of rhizome rot of Polygonatum in the Polygonatum treated with HJ1 was about 4.62%, and the control efficiency was about 57.01%.

[0055] Example 5 Safety test Select the Polygonatum seedlings with consistent growth and transplant them into the greenhouse for culture, transplant one seedling per planting box. After the Polygonatum seedlings in the planting box grow stably, irrigate 100 mL of HJ1 fermentation broth (1×10 8 cfu / mL) on the 1st, 3rd and 7th days, and pure water as blank control, 3 repeats for each treatment, observe the growth on the 15th day, record and take photos, and the results are shown in Figure 7 .

[0056] As can be seen from Figure 7 , after 15 days of irrigation with biocontrol bacteria HJ1, compared with the blank control, there is no adverse effect on the growth of Polygonatum, so it can be safely used for the prevention and control of fungal root rot of Polygonatum.

[0057] Although the above embodiments have been described in detail, they are only some embodiments of the present application, not all embodiments. Other embodiments can be obtained on the basis of the above embodiments without creativity, which are within the protection scope of the present application.

Claims

1. A strain of Arthrobacter ( Arthrobacter sp.) HJ1, the preservation number of the Arthrobacter HJ1 is CCTCC NO:M20251843.

2. A microbial preparation, characterized in that, The Arthrobacter HJ1 according to claim 1.

3. The microbial preparation according to claim 2, characterized in that, The viable cell count in the microbial preparation is ≥ 1 x 10 6 cfu / mL.

4. A method for preparing the microbial preparation according to claim 2 or 3, characterized in that, The Arthrobacter HJ1 according to claim 1. The Arthrobacter HJ1 according to claim 1 is cultured in a culture medium to obtain a microbial preparation.

5. The preparation method according to claim 4, characterized in that, The temperature of the culture is 23-35℃; and the time of the culture is 12-36 h.

6. A preparation for controlling rhizoctonia root rot of polygonatum, characterized by, The microbial preparation obtained by the Arthrobacter HJ1 according to claim 1, the microbial preparation according to claim 2 or 3, or the preparation method according to claim 4 or 5.

7. The Arthrobacter HJ1 according to claim 1, the microbial preparation according to claim 2 or 3, the microbial preparation obtained by the preparation method according to claim 4 or 5, or the preparation according to claim 6, are used for inhibiting the pathogenic fungi of root rot.

8. Use according to claim 7, characterized in that, The pathogenic fungi of root rot include Fusarium oxysporum.

9. The Arthrobacter HJ1 according to claim 1, the microbial preparation according to claim 2 or 3, the microbial preparation obtained by the preparation method according to claim 4 or 5, or the preparation according to claim 6, are used for preventing and treating the root rot of Polygonatum sibiricum.

10. A method for preventing and controlling root rot in Polygonatum sibiricum, characterized in that, The Arthrobacter HJ1 according to claim 1. The microbial preparation or preparation containing the Arthrobacter HJ1 according to claim 1 is applied during the planting of Polygonatum sibiricum; Or, the microbial preparation or preparation containing the Arthrobacter HJ1 according to claim 1 is applied on the collected rhizome of Polygonatum sibiricum.

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