Arthrobacter nitroguaiacolicus and its application on pasture

Abstract

This invention discloses a plant rhizosphere growth-promoting bacterium, *Aristolochia nitroguaiacos* (…). Paenarthrobacter nitroguajacolicus YD-2-4, deposited at the China Microbial Culture Collection Center (CGMCC) under accession number CGMCC No. 36649, possesses various growth-promoting properties, including nitrogen fixation, phosphorus solubilization, IAA production, and ACC deaminase production. It significantly promotes the growth of forage grasses such as alfalfa, wheatgrass, crested wheatgrass, red fescue, Artemisia arenaria, and Stipa purpurea. The strain promoted shoot growth by 25.98% and 14.85% in Artemisia arenaria and red fescue, respectively, and root growth by 27.98% and 19.85% in Artemisia arenaria and Stipa purpurea, respectively. It also increased biomass accumulation in Artemisia arenaria and red fescue by 36.60% and 22.91%, respectively. Regarding plant antioxidant capacity, YD-2-4 significantly enhanced peroxidase activity in Artemisia arenaria and alfalfa, and increased the total antioxidant capacity of red fescue and Stipa purpurea. Strain YD-2-4 can serve as an excellent plant rhizosphere growth promoter, and has broad application prospects in the microbial remediation of degraded grasslands in alpine regions and the development of biofertilizers.

Description

Technical Field

[0001] This invention relates to the field of research on rhizosphere growth-promoting bacteria of forage plants, specifically to a rhizosphere growth-promoting bacterium, *Arthrobacter nitroguaiacos*, and its application on different types of forage grasses. Background Technology

[0002] Alpine grassland ecosystems, as vital natural resources for maintaining the ecological balance of the Qinghai-Tibet Plateau and supporting livestock development, are facing increasingly serious degradation problems. These degradations are mainly manifested in systemic functional decline, including decreased vegetation cover, soil nutrient loss, and an increase in toxic weeds. Traditional grassland restoration measures primarily rely on physical enclosure and chemical fertilizer application, but these methods have significant limitations: enclosure measures have long restoration cycles, making it difficult to meet the needs of livestock development; long-term use of chemical fertilizers easily leads to soil compaction, a homogenized microbial community structure, and even a significant decrease in soil pH, accelerating the leaching of calcium and magnesium ions and activating toxic elements such as aluminum and manganese, which are poisonous to grass roots, thus failing to achieve a synergistic improvement in ecological and production benefits.

[0003] In recent years, microbial remediation technology based on plant rhizosphere growth-promoting bacteria (PGPR) has provided a new solution for the restoration of alpine grasslands. PGPR promotes plant growth through multiple mechanisms, including direct mechanisms such as biological nitrogen fixation, phosphorus solubilization, potassium solubilization, synthesis of plant growth hormones, and ACC deaminase production; and indirect mechanisms such as inducing systemic resistance and antagonizing pathogenic microorganisms. However, the current application of PGPR in alpine grasslands faces significant technical bottlenecks. First, most commercially available PGPR strains are isolated from low-altitude agricultural soils and have poor adaptability to adverse conditions such as extreme low temperatures, strong ultraviolet radiation, and nutrient deficiency in alpine environments, making it difficult for them to effectively colonize the rhizosphere and maintain functional activity after introduction. Second, existing strains generally have a single growth-promoting function, often only responding to specific plant species or single stresses, while the ecological restoration of alpine grasslands requires multifunctional strains capable of simultaneously addressing multiple environmental stresses.

[0004] Crucially, existing PGPR strains generally lack broad-spectrum growth-promoting properties for different forage species in alpine grasslands. Alpine grassland vegetation typically comprises complex community structures composed of various plants such as grasses and leguminous species. However, current research largely focuses on single forage species, lacking broad-spectrum PGPR resources capable of simultaneously promoting the growth of multiple forage grasses. This species-specific limitation severely restricts the practical application of PGPR technology in overall grassland restoration. Ideally, PGPR strains should be able to transcend plant family and genus boundaries, exhibiting stable growth-promoting effects on both the main constructive and dominant species in the community, thereby achieving synergistic grassland vegetation restoration.

[0005] Therefore, isolating and screening native PGPR strains with broad-spectrum growth-promoting properties and high environmental adaptability has become a key breakthrough in promoting the development of alpine grassland ecological restoration technology. The broad-spectrum growth-promoting properties of PGPRs should be considered one of the core indicators for evaluating their application potential. Their mechanism may stem from the combined effects of plant growth regulators, nutrient activation capabilities, and stress tolerance characteristics produced by the strains, which can activate the growth and development pathways of various forage grasses. Developing PGPR inoculants with broad-spectrum growth-promoting functions can not only significantly improve the practicality of microbial remediation technology but also provide crucial technical support for constructing stable and efficient alpine grassland ecosystems. Summary of the Invention

[0006] This invention addresses the shortcomings and defects of the prior art by proposing a strain of nitroguaiacol-type arthrobacterium and its application in forage grasses.

[0007] The purpose of this invention is to provide a strain of nitroguaiacol-type arthrobacterium ( Paenarthrobacter nitroguajacolicus YD-2-4, this strain is currently deposited at the China General Microbiological Culture Collection Center, address: No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, accession number CGMCC No. 36649, deposit date November 17, 2025.

[0008] As a preferred choice, *Arthrobacter nitroguaiacol* YD-2-4 can dissolve both organic and inorganic phosphorus.

[0009] As a preferred choice, Nitroguaiacol-type Arthrobacter YD-2-4 has nitrogen-fixing activity.

[0010] As a preferred option, *Arthrobacter nitroguaiacos* YD-2-4 is capable of producing IAA and ACC deaminases.

[0011] As a preferred choice, Nitroguaiacol-based Arthrobacter YD-2-4 can promote the growth of various forage grasses such as red fescue, purple needlegrass, crested wheatgrass, ice grass, alfalfa, and Artemisia arenaria.

[0012] The second objective of this invention is to provide the application of *Arthrobacter nitroguaiacol* YD-2-4 on pasture grasses of the Qinghai-Tibet Plateau. The bacterial solution of YD-2-4 or an inoculum agent with YD-2-4 as the core strain can be applied as a microbial fertilizer, effectively promoting the growth of pasture grasses on the Qinghai-Tibet Plateau, including *Festuca aurantium*, *Stipa purpurea*, *Leymus chinensis*, *Agrostis pilosa*, *Alfalfa*, and *Artemisia arenaria*, promoting shoot and root growth, effectively increasing pasture biomass, and significantly enhancing the peroxidase activity and total antioxidant capacity of pasture grasses. This achieves the microbial restoration of degraded grasslands in high-altitude areas.

[0013] The *Arthrobacter nitroguaiacol* YD-2-4 provided in this invention was screened from alpine grasslands of the Qinghai-Tibet Plateau. It exhibits good tolerance to the alpine climate and microecological environment of the grassland soils of the Qinghai-Tibet Plateau. Application using it as the core inoculant results in good colonization without disrupting the original microecological balance of the alpine grasslands. YD-2-4 possesses multiple life-promoting properties, including phosphorus solubilization, nitrogen fixation, IAA production, and ACC deaminase production, and shows good growth-promoting effects on various forage grasses, especially significantly promoting the growth of leguminous forage grasses *Artemisia arenaria* and *Alfalfa*. Simultaneously, *Arthrobacter nitroguaiacol* YD-2-4 significantly enhances the antioxidant capacity of six forage grasses. The peroxidase (POD) activities of *Artemisia arenaria* and *Alfalfa* increased by 28.68% and 63.81% respectively compared to the control, while the total antioxidant capacity (TAOC) of *Festuca aurantium* and *Stipa aurantium* increased by 51.43% and 27.66%, respectively. The present invention provides a multifunctional rhizosphere growth-promoting bacterium, *Arthrobacter nitroguaiacos* YD-2-4, which enriches the resource pool of PGPR forage grasses in alpine grasslands and has broad application prospects in the microbial restoration and biofertilizer development of degraded alpine grasslands.

[0014] Preservation Instructions Strain name: Nitroguaiacol-type Arthrobacter Latin name: Paenarthrobacter nitroguajacolicus . Strain number: YD-2-4 Preservation Institution: China General Microbiological Culture Collection Center, China Microbiological Culture Collection Committee Collection institution abbreviation: CGMCC Address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing Deposit date: November 17, 2025 CGMCC Registration Number: CGMCC No. 36649 Attached Figure Description

[0015] Figure 1 The results are for the detection of YD-2-4 in Example 1, where a is the colony of YD-2-4 and b is the Gram staining result.

[0016] Figure 2 The results of YD-2-4 in Example 3, including dissolution of inorganic phosphorus, dissolution of organic phosphorus, nitrogenase, production of IAA, and production of ACC deaminase, are presented.

[0017] Figure 3 The images show the potted plant morphology of alfalfa, Artemisia arenaria, Stipa purpurea, Leymus chinensis, Festuca aurantium and Clytemnum velutipes treated with YD-2-4 in Example 4, compared with the control group.

[0018] Figure 4 This is an analytical diagram showing the difference in shoot length between the forage grasses treated with YD-2-4 microbial agent and the control group in Example 4.

[0019] Figure 5 This is an analysis diagram of the root length of each forage grass after treatment with YD-2-4 microbial agent in Example 4, compared with the control group.

[0020] Figure 6 This is an analysis chart comparing the biomass of various forage crops after treatment with YD-2-4 microbial agent in Example 4 with that of the control group.

[0021] Figure 7 The graph shows the determination of antioxidant enzymes (POD) in forage after treatment with YD-2-4 microbial agent in Example 4. Figure 8 The graph shows the total antioxidant capacity (TAOC) of forage after treatment with YD-2-4 microbial agent in Example 4. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Note: Unless otherwise specified, the experimental methods in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0024] The culture media used in the following examples are as follows: Monkina Organic Phosphorus Medium: Glucose 10 g / L, (NH4)2SO4 0.5 g / L, NaCl 0.3 g / L, MgSO4·7H2O 0.3 g / L, MnSO4·H2O 0.03 g / L, FeSO4·7H2O 0.03 g / L, lecithin 2 g / L; Assumption medium: NaCl 0.2 g / L, KH₂PO₄ 0.2 g / L, MgSO₄ 0.2 g / L, CaCO₃ 5 g / L, mannitol 10 g / L, CaSO4 0.1 g / L; Inorganic phosphorus medium: glucose 10 g / L, (NH4)2SO4 0.5 g / L, yeast extract 0.5 g / L, NaCl 0.3 g / L, KCl 0.3 g / L, MgSO4·7H2O 0.5 g / L, FeSO4·7H2O 0.03 g / L, MnSO4·H2O 0.03 g / L, tricalcium phosphate 5 g / L.

[0025] ADF medium: Na2HPO4 6 g / L, KH2PO4 4 g / L, MgSO4 0.2 g / L, glucose 2 g / L, gluconic acid 2 g / L, citric acid 2 g / L, ACC 5.0 mmol / L, H3BO3 0.01 g / L, MnSO4·H2O 0.01 g / L.

[0026] Experimental Example 1: Screening of Nitroguaiacol-based Arthrobacter YD-2-4 The sampling site was located on a natural alpine grassland surrounding Qinghai Lake (36.6803° N, 101.3115° E; 2605.6 m). Five *Stipa purpurea* plants were randomly selected from the sampling area, and rhizosphere soil samples were collected (5-10 cm deep). 10 g of the mixed soil sample was weighed and placed in an Erlenmeyer flask containing 90 mL of sterile water. The flask was incubated at 20 ℃ with shaking for 2 h, and then serially diluted to 1×10⁻⁶. -4 100 μL of soil suspensions of different gradients were spread onto inorganic phosphorus, organic phosphorus, and Assumption medium, respectively. Three replicates of different concentration dilutions were spread. The culture was carried out at 20 °C for 7 days. Single colonies were picked according to colony morphology and the formation of lysis zones. One of the strains obtained after streak purification was named YD-2-4.

[0027] Experimental Example 2: Identification of Nitroguaiacol-based Arthrobacter YD-2-4 1. Morphological identification YD-2-4 was streaked into LB medium and incubated at 28 °C for 3 days. The physiological and biochemical characteristics of the strain were then identified according to Bergey's Manual of Bacterial Identification. The assays included: Gram staining, catalase activity, glucose degradation, methyl red test, VP test, gelatin liquefaction, H2S test, citrate test, starch hydrolysis, urease test, and indole test.

[0028] 2. Molecular identification Genomic DNA was extracted from bacterial strains using the TIAN amp Bacteria DNA Kit (China) from Tiangen Biotech Co., Ltd., following the kit's instructions. PCR amplification was performed using universal primers 27F and 1492R. After passing 1% agarose gel electrophoresis, the amplified products were sent to Sangon Biotech (Shanghai) Co., Ltd. for sequencing. The sequence data of all strains were compared for homology in the NCBI GenBank sequence database.

[0029] 3. Results YD-2-4 appears as pale yellow, round colonies on LB medium. The surface is smooth, moist, and glossy, and the colonies are opaque with a viscous texture, easily picked up with an inoculation loop. Figure 1 a). Gram staining produces a blue-purple color, indicating Gram-positive bacteria (a). Figure 1 (b) This strain can utilize glucose to produce acid (glucose decomposition +), and can hydrolyze starch and liquefy gelatin, indicating that it has the corresponding extracellular hydrolytic enzyme activity. Regarding nitrogen source utilization, the strain can reduce sulfate to produce hydrogen sulfide (H2S test +) and hydrolyze urea (urease test +), but cannot utilize citrate (citrate test -). Furthermore, this strain does not produce catalase (H2O2 enzyme -), indole, or acetylmethylethanol (VP test -), and the methyl red test is negative (Table 1). These physiological and biochemical characteristics are consistent with the typical characteristics of Arthroblasts.

[0030] Table 1. Physiological and biochemical analysis results of YD-2-4 Test Category result Test Category result <![CDATA[H2O2 enzyme]]> - <![CDATA[H2S test]]> + Glucose breakdown + Citrate test - Methyl red test - Starch hydrolysis + Acetylmethylethanol (VP) test - Indole test - Gelatin liquefaction + Urease test + Note: (+) indicates a positive result, and (-) indicates a negative result.

[0031] PCR amplification yielded a 1354 bp 16S rDNA fragment of strain YD-2-4, the specific sequence of which is shown in Sequence 1. Homology comparison between the obtained sequence and publicly available 16S rDNA sequences in the EzBioCloud database showed that YD-2-4 is similar to *Arthrobacter nitroguaiacol* (…). Paenarthrobacter nitroguajacolicus The homology was the highest, reaching 99.93%.

[0032] Example 3: Analysis of the growth-promoting characteristics of *Arthrobacter nitroguaiacol* YD-2-4 Strain YD-2-4 was inoculated into 100 mL of inorganic phosphorus and organophosphorus culture medium and cultured in a shaker at 28 ℃ for 7 days. After centrifugation (5000 r / min, 10 min), 5 mL of the supernatant was mixed with 45 mL of 0.5 mol / L NaHCO3 solution. 5 mL of this mixture was then reacted with 4 mL of ammonium molybdate-sulfuric acid reagent, and the volume was adjusted to 50 mL. Using uninoculated medium as a control, the absorbance was measured at 700 nm. Based on OD... 700 The actual amount of phosphorus dissolved by the strain is calculated.

[0033] Strain YD-2-4 was inoculated into a gas collecting bottle containing 10 mL of Assumption semi-solid medium and cultured at 20 °C for 2 days. Then, 10% (v / v) acetylene gas was injected, and the mixture was incubated at 20 °C for 2 days. The ethylene production content was quantitatively determined using an Agilent GC 7890B network gas chromatograph. The nitrogenase activity of the strain was evaluated by quantifying the N2 fixation rate through the determination of ethylene accumulation.

[0034] Strain YD-2-4 was inoculated into LB medium containing 0.05% L-tryptophan and cultured at 20 ℃ and 180 r / min for 7 days. After centrifugation at 10000 r / min for 10 min, 500 µL of the supernatant was dropped onto a white ceramic plate, and an equal volume of S2 colorimetric solution was added simultaneously. After standing in the dark at room temperature for 30 min, the color change was observed. A pink color indicates the secretion of IAA, while no color change indicates a negative result, i.e., no IAA secretion. The absorbance was measured at 530 nm, and the results were analyzed based on the OD value. 530 The value is used to calculate the amount of IAA secreted by the strain.

[0035] Strain YD-2-4 was inoculated into a test tube containing 7.5 mL of ADF medium and cultured at 20 °C with shaking at 180 r / min for 72 h. After centrifugation at 4 °C and 8000 r / min for 10 min, 1 mL of the supernatant was taken and mixed with 800 μL of 0.56 mol / L HCl solution. Then, 300 μL of 2,4-dinitrophenylhydrazine (2,4-DNPH) solution was added and mixed again. The mixture was then incubated at 30 °C for 30 min. Finally, 2 mL of 2 mol / L NaOH solution was added, and the absorbance was measured at 540 nm. The OD value was then calculated. 540 The ACC deaminase activity of the strain was calculated.

[0036] The results showed that *Arthrobacter nitroguaiacol* YD-2-4 could produce clear zones on inorganic phosphorus, organic phosphorus (Monkina) medium, and Assumption medium. The solubility index was 1.21 on inorganic phosphorus medium, 1.26 on organic phosphorus (Monkina) medium, and 2.14 on Assumption medium (Table 2). This preliminarily indicates that *Arthrobacter nitroguaiacol* YD-2-4 possesses both phosphorus-solubilizing and nitrogen-fixing activities, with nitrogen-fixing activity being superior to phosphorus-solubilizing activity.

[0037] Table 2. Determination of the clear zone size of *Arthrobacter nitroguaiacol* YD-2-4 on different culture media. culture medium d (mm) D (mm) D / d solubility Inorganic phosphorus culture medium 3.61 4.38 1.21 weak Monkina Organic Phosphorus Medium 3.56 4.49 1.26 weak Assumption medium 3.24 6.94 2.14 powerful Note: d, colony diameter (mm); D, lysis zone diameter (mm); D / d, solubility index.

[0038] Quantitative analysis of the growth-promoting characteristics of *Arthrobacter nitroguaiacos* YD-2-4 showed that the activities of this strain in dissolving inorganic phosphorus, dissolving organic phosphorus, nitrogenase, producing IAA, and producing ACC deaminase were 76.41 μg / mL, 42.13 μg / mL, 157.31 μg / mL, 59.09 μg / mL, and 12.24 μg / mL, respectively. Figure 2 Among the various indicators, nitrogenase activity was significantly higher than other indicators, while ACC deaminase activity was the lowest. In conclusion, YD-2-4 is a multifunctional PGPR strain capable of efficiently solubilizing phosphorus, fixing nitrogen, and secreting IAA and ACC deaminases. It can provide a theoretical basis for the next step of potted plant growth-promoting experiments and also provide strain resources for the development of microbial agents.

[0039] Experiment Example 4: Effects of Nitroguaiacol-based Arthrobacter YD-2-4 on the growth of seedlings of different forage grasses 1. Preparation of fermentation broth of Nitroguaiacol-type Arthrobacter YD-2-4 Strain YD-2-4 was transferred to LB liquid medium and incubated at 20 °C and 180 r / min for 1 day. After centrifugation at 5000 r / min for 20 min, the bacterial pellet was adjusted to OD using sterile LB medium. 600 The value was 1.0, and the bacterial concentration was then diluted with sterile water to a final concentration of 1×10⁻⁶. 7 CFU / mL.

[0040] 2. Soaking treatment with *Arthrobacter nitroguaiacol* YD-2-4. Select plump and uniformly sized forage seeds, sterilize them with 3% NaClO for 5 min, then sterilize them with 75% ethanol for 10 min, and finally rinse them three times with sterile water. Place the sterilized Stipa purpurea seeds in a 1×10 7 The strain YD-2-4 was soaked in a CFU / mL culture medium for 6 h, while sterile water soaking served as a blank control.

[0041] 3. Pot experiment setup The soil for the potted plants was taken from the alpine grassland of Xihai Town, Haibei Prefecture (36.6803 °N, 101.3115 °E, 3033.8 m). The soil was brownish-yellow, with a pH of 8.19, an electrical conductivity of 549.33 μs / cm, an organic matter content of 30.83 g / kg, and a available nitrogen content of 30.34 mg / kg. It was classified as brown calcareous soil.

[0042] After removing impurities, the potting soil was sieved through a 100-mesh sieve. The fine soil was then mixed thoroughly and filled into pots, with each pot containing 230 ± 1 g of soil. Seeds soaked in bacterial solutions of different concentrations were transferred to the potting soil, with 12 seeds per pot and 6 replicates per treatment. The pots were then incubated in a light incubator under the following conditions: 20 ℃, 12 h light / 12 h dark, light intensity of 900 µmol / m / s, and humidity of 40% RH.

[0043] 4. Indicator Measurement During the cultivation period, appropriate amounts of sterile water were added to maintain a constant weight in the flowerpots. The pot experiment was completed after 30 days, and morphological indicators such as seedling bud length, root length, and biomass were measured.

[0044] 5. Results Through soaking culture, strain YD-2-4 showed different effects on the growth of different types of forage grasses. Figure 3 It can be found that the height of the aboveground parts of Artemisia annua treated with strain YD-2-4 was significantly better than that of CK, and the number of tillers and plant height of Stipa purpurea and Festuca purpurea were also significantly better than those of CK.

[0045] exist Figure 4 In this study, the treatment with strain YD-2-4 significantly improved the shoot length of alfalfa, red fescue, Artemisia argyi, and Stipa purpurea, increasing them by 12.14%, 14.85%, 25.98%, and 7.61% respectively compared to the control. The effect on the shoot length of Artemisia argyi was the most significant, increasing it by 25.98%.

[0046] Treatment with strain YD-2-4 significantly promoted root growth in alfalfa, crested wheatgrass, red fescue, Artemisia arenaria, and purple needlegrass, increasing the growth rates by 15.37%, 14.05%, 19.85%, 27.98%, and 19.25% respectively compared to the control. Figure 5 Among them, the effect on promoting root growth of Artemisia annua was the most significant, increasing it by 27.98%.

[0047] Regarding forage biomass accumulation, treatment with strain YD-2-4 significantly increased the biomass accumulation of alfalfa, crested wheatgrass, red fescue, Artemisia arenaria, and purple needlegrass, by 17.38%, 14.28%, 22.91%, 36.60%, and 19.80% respectively compared to the control. Figure 6 Among them, the promoting effect on the accumulation of Artemisia annua biomass was the most significant.

[0048] Experiment Example 5: Effects of Nitroguaiacol-based Arthrobacter YD-2-4 on the antioxidant capacity of different forage seedlings 1. Determination of antioxidant capacity of forage grass After the pot experiment ended in 30 days, the peroxidase (POD) and total antioxidant (TAOC) activities of seedlings in the YD-2-4 treatment group and the blank group were determined using an enzyme activity kit (Jiangsu Keming Biotechnology Co., Ltd., China).

[0049] 2. Analysis of the antioxidant capacity of forage grasses According to the same morphological index analysis results, soaking seeds with strain YD-2-4 significantly increased the POD (Potential Occurrence Disorder) of alfalfa, red fescue, Artemisia arenaria, and Stipa purpurea. Figure 7 ) and TAOC activity ( Figure 8 The POD and TAOC activities of alfalfa increased by 63.81% and 22.77% respectively compared with the control group; the POD and TAOC activities of red fescue increased by 12.52% and 51.43% respectively; the POD and TAOC activities of Artemisia annua increased by 28.68% and 18.51% respectively; and the POD and TAOC activities of Stipa purpurea increased by 9.87% and 27.66% respectively.

[0050] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A strain of Nitroguaiacol-based Arthrobacter YD-2-4, with the accession number CGMCC No.36649 at the China General Microbiological Culture Collection Center.

2. The Nitroguaiacol-based Arthrobacter YD-2-4 according to claim 1, characterized in that... The strain is capable of dissolving both organic and inorganic phosphorus.

3. The Nitroguaiacol-based Arthrobacter YD-2-4 according to claim 1, characterized in that... The strain exhibits nitrogen-fixing activity.

4. The Nitroguaiacol-based Arthrobacter YD-2-4 according to claim 1, characterized in that... The enzyme is capable of producing IAA and ACC deaminases.

5. The use of the nitroguaiacol-based Arthrobacter YD-2-4 according to claim 1, characterized in that... The stated purpose is that strain YD-2-4 can promote pasture growth.

6. The use of the nitroguaiacol-based Arthrobacter YD-2-4 according to claim 5, characterized in that... The stated purpose is that YD-2-4 can improve the total antioxidant capacity of forage grass.

7. The use of any of the nitroguaiacol-based Arthrobacter YD-2-4 according to claim 5 or 6, characterized in that... The forage grasses are purple fescue, purple needlegrass, crested wheatgrass, ice grass, purple alfalfa, and sand wormwood.

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