A pristerophora gigantea hhys-1, microbial inoculant and application thereof

Abstract

The present application relates to the technical field of industrial microorganisms, and particularly discloses a Priestia megaterium HHY-1, a microbial inoculant thereof and application. The Priestia megaterium HHY-1 has a preservation number of CGMCC No. 34470. The Priestia megaterium provided in the present application has multiple functions such as nitrogen fixation, phosphorus dissolution, iron carrier production, IAA production capacity and antioxidant enzyme activity, can play a comprehensive role in multiple dimensions such as nutrition supply, growth regulation and stress resistance protection, effectively helps the good growth of dry alkali wheat and barley 19 in a saline-alkali environment, and has great significance for improving the yield of dry alkali wheat and barley in a saline-alkali land and promoting sustainable agricultural development, and shows extremely high practical value in the growth promotion of dry alkali wheat and barley 19.

Description

Technical Field

[0001] This invention relates to the field of industrial microbiology, and in particular to a species of Priestella giantiflora HHY-1, its microbial agents, and their applications. Background Technology

[0002] The harmful effects of saline-alkali soil on plants are mainly manifested in three aspects: osmotic pressure stress, ion stress, and high pH stress. High soil osmotic pressure inhibits water absorption by plant roots, leading to leaf dehydration, which in turn significantly inhibits photosynthesis and growth. High concentrations of sodium (Na) in saline-alkali soils further exacerbate the problem. + Easily absorbed by roots, intracellular Na + Excessive accumulation of these substances can disrupt intracellular ion homeostasis, induce malondialdehyde accumulation and cell membrane lipid oxidation, leading to increased membrane permeability; while high pH values ​​not only inhibit root absorption of Fe... 2+ and Mg 2+ Absorption of nitrogen affects the normal functioning of photosynthesis and hinders the assimilation and transport of nitrogen, leading to impaired nitrogen metabolism in plants.

[0003] Among the various methods for improving saline-alkali land, salt-tolerant and growth-promoting bacteria, as a core component of microbial improvement technology, have demonstrated significant advantages due to their survival ability and unique role under salt stress. Currently, although some salt-tolerant microbial strains have been discovered and applied to saline-alkali land improvement, existing strains still have limitations in terms of salt tolerance, growth-promoting effect, and environmental adaptability. Some strains have a single growth-promoting function, making it difficult to comprehensively improve plant growth and soil quality. Therefore, screening and developing microbial strains with salt tolerance, excellent comprehensive growth-promoting effect, and broad adaptability is of great significance for improving the efficiency of saline-alkali land remediation and ensuring agricultural production. Summary of the Invention

[0004] To address the issues of limited functionality and poor overall growth-promoting effect of existing salt-tolerant and alkali-tolerant growth-promoting strains, this invention provides a *Priscilla megaterium* HHY-1, its microbial agent, and its applications.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0006] A species of Priestia megaterium, HHY-1, with accession number CGMCC No. 34470.

[0007] Priestia megaterium HHY-1 was screened from wheat topsoil in Huanghua County, Cangzhou City using the LB solid medium method containing 5% NaCl. It was classified and named Priestia megaterium. It was deposited on May 9, 2025, at the China General Microbiological Culture Collection Center (CGMCC), with accession number CGMCCNo. 34470. The deposit address is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0008] The biological characteristics of *Priestella giantiflora* HHY-1 provided by this invention are as follows: On LB solid medium at 28°C, single colonies are white, nearly circular, with neat edges, a relatively moist surface, and raised. Under an optical microscope, the bacteria are rod-shaped, with elliptical spores, and are Gram-positive.

[0009] The *Priestella megaterium* HHY-1 provided by this invention can rapidly multiply within a pH range of 5–9, and its OD... 600 The absorbance ranges from 2.56 to 2.80, indicating that the bacteria can adapt to soil environments with different acidity and alkalinity levels. It can maintain strong activity and reproductive capacity in both acidic and alkaline saline-alkali soils.

[0010] After culturing in LB liquid medium containing 3% NaCl for 24 h, its OD 600 The absorbance was 2.24; after culturing in LB liquid medium containing 5% NaCl for 24 h, its OD... 600 The absorbance of 1.83 indicates that the bacteria can still grow and reproduce well even in environments with high salt concentrations, and can tolerate a certain degree of salt stress. It can be applied to the improvement of saline-alkali land with medium to high salinity.

[0011] At 28℃, this bacterium has the ability to fix nitrogen and solubilize phosphorus, can produce siderophores and auxin (IAA), and has antioxidant capacity, thus it can efficiently promote the germination and growth of drought-resistant wheat.

[0012] In a second aspect, the present invention provides a microbial composition comprising the aforementioned Priestella megaterium HHY-1.

[0013] Thirdly, the present invention also provides a microbial inoculant containing *Priscilla megaterium* HHY-1.

[0014] The Priestella giantiflora HHY-1 provided by this invention can be widely used for soil improvement and plant growth promotion in saline-alkali areas. It can be made into a liquid microbial agent for easy use, and can be used for field spraying or seed dressing.

[0015] Specifically, the microbial agent is a liquid agent.

[0016] Furthermore, the viable count of *Priscilla megaterium* HHY-1 in the microbial agent is 2 × 10⁻⁶. 6 ~7×10 8 CFU / mL.

[0017] Fourthly, the present invention also provides a method for preparing the above-mentioned microbial inoculant, comprising the following steps:

[0018] The *Priestella giantiflora* HHY-1 was inoculated into LB liquid medium and cultured at 25℃~30℃ and 180r / min~200r / min for 1~2 days. The cultured suspension was centrifuged, the supernatant was discarded, and the suspension was washed. Then, sterile water was added until the viable cell count in the suspension reached 2×10⁻⁶. 6 ~7×10 8 CFU / mL yields microbial inoculants.

[0019] The above-mentioned method for preparing microbial agents has advantages such as simple operation, mild culture conditions, short production cycle, low cost, and stable quality of the agents. It is suitable for large-scale production and provides strong technical support for the widespread application of Priestella megaterium HHY-1 microbial agents.

[0020] Furthermore, the LB medium comprises: 10g tryptone, 5g yeast extract, 10g sodium chloride and 1000mL water, pH 7.4, sterilized at 121℃ for 20min.

[0021] Fifthly, the present invention also provides the application of the above-mentioned Priestella giantiflora HHY-1 in nitrogen fixation, iron carrier production, auxin production, promotion of nitrogen and phosphorus absorption, improvement of drought and salt stress resistance and improvement of antioxidant enzyme activity.

[0022] The *Priestella giantiflora* HHY-1 provided by this invention possesses nitrogen-fixing capabilities, converting atmospheric nitrogen into nitrogen that plants can absorb and utilize, increasing soil nitrogen content, providing sufficient nitrogen nutrition for the growth of plants such as saline-alkali wheat, and alleviating nitrogen deficiency in saline-alkali land. Its phosphorus-solubilizing ability converts phosphorus in the soil that is difficult for plants to absorb into available phosphorus, improving soil phosphorus utilization, promoting plant phosphorus absorption, and aiding plant growth and development. Simultaneously, this bacterium can produce siderophores, which can chelate iron in the soil, converting iron that is originally difficult for plants to obtain into an absorbable form, effectively solving the iron deficiency problem caused by high pH values ​​in saline-alkali land, and ensuring the normal functioning of plant photosynthesis and other physiological processes. Furthermore, the auxin (IAA) produced by this bacterium can directly promote cell division and elongation in saline-alkali wheat, which is beneficial to root growth and plant development, increasing the growth rate and biomass of saline-alkali wheat. Moreover, the antioxidant capacity of this bacterium can help dryland wheat resist oxidative stress caused by saline-alkali environment, reduce the accumulation of harmful substances such as malondialdehyde, protect the integrity of cell membrane, and maintain the normal physiological function of cells, thereby efficiently promoting the germination and growth of dryland wheat and providing strong support for the planting and yield increase of dryland wheat in saline-alkali land.

[0023] Furthermore, this bacterium can maintain strong activity and reproductive capacity within a pH range of 5 to 9, and can tolerate a certain degree of salt stress, exhibiting high environmental adaptability and making it widely applicable to different types of saline-alkali land.

[0024] In a sixth aspect, the present invention also provides the application of the above-mentioned Priestella giantiflora HHY-1 or the microbial composition described herein in promoting the growth of drought-resistant wheat.

[0025] In a seventh aspect, the present invention also provides the application of microbial agents in promoting the growth of drought-resistant wheat.

[0026] Specifically, the drought-resistant wheat is Jiemai 19.

[0027] The *Priestella giantiflora* HHY-1 provided by this invention is particularly suitable for the cultivation of the drought-resistant and alkaline-tolerant Maijiemai 19 variety. This bacterium is salt-tolerant and possesses multiple abilities, including phosphorus solubilization, nitrogen fixation, iron carrier production, IAA production, and antioxidant activity.

[0028] In stressful environments such as drought and salinity, plants often face the dual pressures of iron deficiency and oxidative damage. The siderophore and antioxidant mechanisms of *Priscilla megaterium* HHY-1 work synergistically: the siderophore enhances the absorption and utilization of iron from the rhizosphere, alleviating iron deficiency; while the antioxidant capacity reduces the harmful effects of oxidative damage. This synergistic effect more effectively improves plant stress resistance and promotes growth under adverse conditions.

[0029] At the same time, this bacterium can also enhance the absorption of nutrients by plants. As a nitrogen-fixing bacterium, it can fix atmospheric nitrogen and convert it into ammonium ions (NH4+). + This bacterium provides nitrogen nutrition to its host plant, with which it forms a symbiotic relationship. Furthermore, this salt-tolerant bacterium significantly improves the absorption of nitrogen and phosphorus by plants, thereby enhancing their salt tolerance and promoting the growth of saline-alkali wheat under saline-alkali conditions. This provides strong support for the cultivation and increased yield of saline-alkali wheat in saline-alkali land. Attached Figure Description

[0030] Figure 1 The growth curves of *Priestella gigantea* HHY-1 in different pH LB liquid media are shown in the figure; different letters in the figure represent the difference level of P < 0.05.

[0031] Figure 2 The colony morphology of *Priestella gigantea* HHY-1 of this invention is shown.

[0032] Figure 3 This is a Gram staining image of Priestella giantiflora HHY-1 under an optical microscope.

[0033] Figure 4 This is the phylogenetic tree of *Priestella gigantea* HHY-1 of the present invention;

[0034] Figure 5 The diagram shows the nitrogen fixation capacity of *Priestella megaterii* HHY-1 in Example 2 of this invention; where (A) is 7d and (B) is 10d.

[0035] Figure 6 This is a graph illustrating the siderophore production capacity of *Priscilla megaterium* HHY-1 in Example 2 of this invention.

[0036] Figure 7 This is a graph illustrating the phosphate-solubilizing ability of *Priscilla megaterium* HHY-1 in Example 2 of this invention.

[0037] Figure 8 This is a graph showing the seed germination and growth of *Maize 19*, a drought-resistant wheat variety, in Application Example 1 of this invention; different letters in the graph represent the difference level of P < 0.05.

[0038] Figure 9 This is a diagram showing the growth of wheat seedlings of drought-resistant wheat variety 19 in Application Example 2 of the present invention; different letters in the diagram represent the difference level of P < 0.05. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0040] Culture medium used in the examples:

[0041] LB liquid medium (1L): 10g tryptone, 5g yeast extract, 10g sodium chloride, 1000mL water, pH 7.4, sterilized at 121℃ for 20min.

[0042] LB solid medium (1L): 10g tryptone, 5g yeast extract, 10g sodium chloride, 15g agar, 1000mL water, pH adjusted to 7.4, sterilized at 121℃ for 20min.

[0043] Assumption medium (1L) for nitrogen-fixing bacteria: KH2PO4 0.2g, MgSO4 0.2g, NaCl 0.2g, CaCO3 5.0g, mannitol 10.0g, CaSO4 0.1g, agar 15.0g, pH 7.0, sterilized at 121℃ for 15min.

[0044] YMA (Yeast Mannitol Agar) liquid culture medium (1L): yeast extract 1.0g, mannitol 10.0g, dipotassium hydrogen phosphate 0.5g, magnesium sulfate 0.2g, sodium chloride 0.1g; calcium carbonate 5g, pH 6.8~7.2, sterilize at 121℃ for 15min.

[0045] Inorganic phosphorus solid culture medium (1L): glucose 10.0g, (NH4)2SO4 0.5g, NaCl 0.3g, MgSO4 0.3g, MnSO4 0.03g, K2SO4 0.3g, FeSO4 0.03g, Ca3(PO4)2 5.0g, agar 15.0g, pH 7.0, sterilized at 116℃ for 30min.

[0046] Inorganic phosphorus liquid culture medium (1L): glucose 10.0g, (NH4)2SO4 0.5g, NaCl 0.3g, MgSO4 0.3g, MnSO4 0.03g, K2SO4 0.3g, FeSO4 0.03g, Ca3(PO4)2 5.0g, pH 7.0, sterilized at 116℃ for 30min.

[0047] CAS medium (1L): Chromium azurite S 60.5mg, cetyltrimethylammonium bromide 72.9mg, FeCl3·6H2O 2.645mg, Na2H2PO4·2H2O 295.25mg, disodium hydrogen phosphate dodecahydrate 1213.5mg, NH4Cl 125mg, KH2PO4 37.5mg, NaCl 62.5mg, agar 9000mg, pH 6.8, sterilized at 115℃ for 30min.

[0048] MSA (Modified Sucrose-Aspartate) medium (1L): sucrose 20.0g, L-asparagine 2.0g, K2HPO4 1.0g, MgSO4·7H2O 0.5g.

[0049] Example 1

[0050] 1. Initial screening of Priestella megaterium

[0051] Soil samples were collected from the wheat topsoil layer of Houxianzhuang Village, Huanghua City. Using the dilution plating method, bacterial strains were isolated on LB medium containing 5% NaCl. A total of 50 strains with different colony morphologies were obtained. The isolated bacteria were purified by multiple streak plating to obtain pure cultures, which were then preserved. The purified strains were inoculated into shake tubes containing 2 mL of liquid LB medium and cultured overnight. After the culture became turbid, the strains were preserved with 50% (v / v) glycerol, with three replicates for each strain. The cultures were stored at -80℃.

[0052] 2. Secondary screening of Priestella megaterium

[0053] 2.1 Alkali resistance test

[0054] The salt-tolerant strains obtained from the initial screening were inoculated into LB liquid medium (pH 3.0–11.0) at a 1% inoculation rate and cultured at 28°C with shaking at 180 rpm. After 24 hours, the absorbance of the bacterial solution was measured, including the OD value. 600 The strain with the highest value is designated HHY-1, and its growth curve is shown below. Figure 1 As shown, the results demonstrate that this strain grows well at pH 5–9, and its OD... 600 The value is 2.56 to 2.80, indicating that the strain has strong alkali resistance.

[0055] 2.2 Identification of strain HHY-1

[0056] 2.2.1 Morphological observation

[0057] At 28°C, on LB solid medium, a single colony is white, nearly round, with neat edges, a relatively moist surface, and is raised. Figure 2 As shown. Under an optical microscope, the bacterium appears as a rod-shaped organism, Gram-positive, as indicated. Figure 3 As shown.

[0058] The physiological and biochemical identification results of this strain were as follows: negative for VP test, L-arabinose utilization test, D-mannitol utilization test, nitrate reduction test, and starch hydrolysis test; positive for citrate utilization test, propionate utilization test, D-xylose utilization test, and gelatin liquefaction test.

[0059] Based on colony morphology, Gram staining, and physiological and biochemical identification results, and referring to Bergey's Manual of Bacterial Systematics, strain HHY-1 can be preliminarily identified as Priestella megaterium.

[0060] 2.2.2 Molecular biological identification

[0061] The genome of bacterial strain HHY-1 was extracted using a bacterial genomic DNA extraction kit (Beijing Solarbio Science & Technology Co., Ltd.) as a template for PCR amplification. The 16S rRNA sequence of the strain was amplified using universal bacterial primers 27F (5′-AGT TTGATCCTGGCTCAG-3′) and 1492R (5′-GCTTA CCTTGTTACGACTT-3′). The 16S rRNA sequence was amplified under the following reaction conditions (94℃ for 5 min, 94℃ for 30 s, 55℃ for 30 s, 72℃ for 90 s, 35 cycles, 72℃ for 10 min), yielding a 1457 bp amplified product, as shown below:

[0062]

[0063] The determined sequences were analyzed using BLAST comparison in the National Center for Biotechnology (NCBI) database. Finally, a phylogenetic tree was constructed using the Neighbor-Joining method in MEGA 5.1. Figure 4 As shown, the phylogenetic position of this strain was determined, and based on its morphological characteristics, it was identified as *Priestia megaterium* HHY-1.

[0064] The strain HHY-1 was deposited on May 9, 2025, at the China General Microbiological Culture Collection Center (CGMCC), with accession number CGMCC No. 34470. The deposit address is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing.

[0065] Example 2

[0066] Growth-promoting properties of Priestella megaterium HHY-1

[0067] 1. Identification of nitrogen fixation capacity of strains:

[0068] Priestella giantiflora HHY-1, stored at -80℃, was inoculated into LB liquid medium at a 5% inoculum size and cultured at 28℃ and 180 rpm for 12 h. 20 μL of a 10% concentration was then added to the medium. 9 CFU / mL bacterial suspension was inoculated onto Assab medium for nitrogen-fixing bacteria. The medium was placed in an inverted incubator at 28°C, and the size of the clear zone was observed. The diameter of the clear zone (D) and the diameter of the bacterial cell (d) were measured, and the D / d value was calculated. Figure 5 As shown, the D / d value was 2 at 7 days. As the culture time of the strain increased, its transparent zone gradually expanded, and the D / d value increased to 2.5 at 10 days.

[0069] The strain was inoculated into YMA liquid medium and cultured at 28℃ and 150 r / min for 4 days. The nitrogenase activity in the supernatant was detected using a microbial nitrogenase (NITS) ELISA kit (Jiangsu Enzyme Immunoassay Co., Ltd.). The nitrogenase activity of the strain was 113.2 ng / L.

[0070] Nitrogenase is a key enzyme in the microbial nitrogen fixation process, and its activity directly determines the efficiency of nitrogen fixation. This detection result confirms at the molecular level that *Priscilla megaterium* HHY-1 possesses a strong nitrogen-fixing ability, capable of converting atmospheric nitrogen into plant-available nitrogen through the synthesis of nitrogenase. This lays a solid experimental foundation for its application in providing nitrogen nutrition to plants and improving soil nitrogen status in agricultural production.

[0071] 2. Assessment of iron production capacity:

[0072] Priestella giantiforme HHY-1, stored at -80℃, was inoculated into LB liquid medium at a 5% inoculum size and cultured at 28℃ and 180 rpm for 12 h. 20 μL of a 10% concentration was then added to the medium. 9 CFU / mL bacterial suspension was inoculated onto CAS solid medium. The medium was placed in a 28℃ biochemical incubator and inverted for incubation. The orange-red halo was observed, and the diameter of the orange-red halo (D) and the diameter of the bacterial cell (d) were measured. The D / d value was calculated. Figure 6 As shown, the D / d value is 7 at 7d.

[0073] The strain was inoculated into MSA liquid medium and incubated at 28°C and 150 rpm for 2 days. The bacterial culture was then centrifuged at 10000 rpm for 10 minutes. 1 mL of the supernatant was collected, and 1 mL of CAS detection solution was added. The culture was allowed to stand for 60 minutes, and the OD200 was then analyzed. 630 The absorbance (As) was measured using a blank culture medium without inoculation as a control. OD 630 The absorbance (Ar) of the strain was measured, and the siderophore activity of the strain was calculated according to the formula SU=[(Ar-As) / Ar]×100%. The SU value was found to be 17.11%.

[0074] The SU value is an important indicator for measuring siderophore activity. A higher SU value indicates a stronger binding capacity between the siderophore and iron ions, meaning higher siderophore activity. The SU value of 17.11% in this strain further confirms that it has a certain siderophore-producing capacity, and can effectively bind iron ions in the environment by producing siderophores, creating favorable conditions for plant absorption and utilization of iron.

[0075] 3. Phosphorus solubility assessment:

[0076] Priestella giantiforme HHY-1, stored at -80℃, was inoculated into LB liquid medium at a 5% inoculum size and cultured at 28℃ and 180 rpm for 12 h. 20 μL of a 10% concentration was then added to the medium. 9 CFU / mL bacterial suspension was inoculated onto inorganic phosphorus solid medium. The medium was then incubated upside down in a 28°C biochemical incubator. After 7 days, the size of the clear zone was observed. Figure 7As shown, its D / d value is 2.0 at 7d, indicating a significant phosphorus-dissolving effect.

[0077] Priestella giantiflora HHY-1, stored at -80℃, was inoculated into inorganic phosphorus liquid medium at a 1% inoculum size. After culturing for 7 days, the supernatant was collected by centrifugation. The phosphorus content in the culture supernatant was determined by the molybdenum antimony colorimetric method, and the dissolved phosphorus content was found to be 357.01 mg / L.

[0078] The above experimental results show that Priestella megaterium HHY-1 has excellent phosphorus solubilization performance. This characteristic enables it to convert the large amount of insoluble phosphorus in the soil into soluble phosphorus that can be absorbed by plants, effectively improving the utilization rate of soil phosphorus and providing sufficient phosphorus nutrition for plant growth. Especially in phosphorus-deficient saline-alkali environments, the phosphorus solubilization ability of this strain will play an important role in improving soil fertility and promoting plant growth.

[0079] 4. IAA production capacity

[0080] Using an indoleacetic acid oxidase (IAA) activity assay kit, *Priscilla gigantea* HHY-1, stored at -80℃, was inoculated into LB liquid medium at a 5% inoculum size and cultured at 28℃ and 180 rpm for 12 h. After collecting the bacterial culture and centrifuging to discard the supernatant, 1 mL of extraction buffer was added for every 5 million bacteria. The bacteria were then sonicated (200W for 3 seconds, 30-second intervals, repeated 30 times). The mixture was then centrifuged at 12000g and 4℃ for 15 min, and the supernatant was collected. The IAA enzyme activity was then determined according to the manufacturer's instructions.

[0081] The standard curve equation for the detection of indoleacetic acid oxidase activity is y = 0.1434x + 0.0408 (R²). 2 =0.9997), and according to this standard curve equation, the IAA enzyme activity of strain HHY1 was calculated to be 0.242 U / 10. 4 cell.

[0082] The above results demonstrate that *Priestella megaterium* HHY-1 possesses the ability to produce IAA (inhibitory activity esters). In saline-alkali environments, the IAA produced by this strain can effectively alleviate the inhibitory effects of abiotic stress on plant growth and promote better plant growth and development.

[0083] 5. Antioxidant enzyme activity

[0084] Priestella giantiflora HHY-1, stored at -80℃, was inoculated into LB liquid medium at a 5% inoculum and cultured at 28℃ and 180 rpm for 12 h. The antioxidant capacity of strain HHY-1 was determined using a catalase (CAT) kit and a superoxide dismutase (SOD) kit. The results showed that the catalase activity of strain HHY-1 was 0.071 nmol / min / 10⁻¹⁰.4 The superoxide dismutase activity in the cell was 0.033 U / 10. 4 cell.

[0085] In adverse environments such as saline-alkali land, plants and microorganisms produce large amounts of reactive oxygen free radicals due to environmental stress, which adversely affects their growth and metabolism. However, the antioxidant capacity of *Priscilla megaterium* HHY-1 not only protects its normal growth and reproduction under adverse conditions, allowing it to continuously perform functions such as nitrogen fixation, phosphorus solubilization, iron carrier production, and IAA production, but also helps plants reduce oxidative damage and enhance their resistance to adverse conditions such as saline-alkali soil through interaction, thereby promoting plant growth and development.

[0086] Example 3

[0087] This embodiment provides a liquid bacterial agent of *Priestella megaterium* HHY-1, the preparation method of which includes the following steps:

[0088] Priestiamegaterium HHY-1, preserved at -80℃ with accession number CGMCC No. 34470, was inoculated into LB liquid medium and cultured overnight at 28℃ and 180 rpm. The cultured bacterial suspension was centrifuged at 5000 rpm for 10 min, the supernatant was discarded, and the precipitate was washed with sterile water. This process was repeated three times to remove culture medium components. Then, bacterial suspensions of different concentrations were prepared with sterile water, which were then used as liquid bacterial agents. The viable counts in the microbial agents were 10-1. 8 CFU / mL, 10 7 CFU / mL, 10 6 CFU / mL.

[0089] Application Example 1

[0090] This application example is an experiment using the microbial inoculant prepared in Example 3 to promote the germination of seeds of the drought-resistant Maijiemai 19 variety.

[0091] Fifteen seeds of Jiemai 19 wheat were placed in each sterile agar plate containing sterile filter paper. Four treatments were set up: CK group (sterile water soaking); T1 group (1.0 × 10⁻⁶ seeds); and T2 group (1.0 × 10⁻⁶ seeds). 6 CFU / mL liquid inoculum incubation); T2 group (1.0×10 7 CFU / mL liquid inoculum incubation); T3 group (1.0×10 8 (CFU / mL liquid inoculant soaking), with 4 mL of liquid inoculant added to each treatment, and each group was repeated twice. The wheat was incubated in a 25℃ incubator for 2.5 days, and the sprout length and root length were measured. Figure 8 As shown.

[0092] The sprout length and root length of wheat in the control group were 3.36 cm and 4.49 cm, respectively. The concentration of the liquid inoculant was 1.0 × 10⁻⁶. 7 The effect was most significant at a concentration of CFU / mL, with a concentration of 1.0 × 10⁻⁶. 7 After soaking in CFU / mL liquid bacterial agent, the wheat sprout length was 3.93 cm, which was 16.96% higher than that of the control group; the wheat root length was 5.57 cm, which was 24.05% higher than that of the control group.

[0093] Application Example 2

[0094] This example is a pot experiment of drought-resistant and alkaline wheat variety 19. The soil used in the experiment was taken from the wheat-corn rotation topsoil of Houxianzhuang Village, Huanghua City, Hebei Province. The soil physicochemical properties are shown in Table 1.

[0095] Table 1 Soil physicochemical properties

[0096]

[0097] The test soil was placed into flowerpots with an outer diameter of 9 cm, an inner diameter of 8 cm, and a height of 8 cm, with 110 g of soil in each pot. 2.5 mL of the liquid inoculant from Example 3 was added, followed by sowing 7 seeds of *Mammillaria elegans* 19 into each pot. Four treatments were set up: CK group (2.5 mL sterile water); T1 group (1.0 × 10⁻⁶ seeds); and T2 group (1.0 × 10⁻⁶ seeds). 6 CFU / mL liquid bacterial agent); T2 group (1.0×10 7 CFU / mL liquid bacterial agent); T3 group (1.0×10 8 The bacterial culture was carried out in a CFU / mL liquid inoculum. Each treatment was repeated 4 times. After 30 days of cultivation in a greenhouse at 20℃, 14h light, and 65% air humidity, the wheat plant height, total nitrogen (digested by sulfuric acid-hydrogen peroxide, distillation method), total potassium (digested by sulfuric acid-hydrogen peroxide, flame photometry method), and total phosphorus (digested by sulfuric acid-hydrogen peroxide, vanadium molybdenum yellow colorimetric method) in wheat plants and roots were measured.

[0098] like Figure 9 As shown, application of HHY-1 liquid inoculant promoted wheat growth. The plant height of wheat in the T1–T3 treatment groups (40.16 cm–43.98 cm) was significantly higher than that of the control group (34.14 cm). Measurements of total nitrogen, total phosphorus, and total potassium content in the aboveground parts and roots of wheat revealed that application of HHY-1 liquid inoculant increased these contents. Nitrogen and phosphorus promote root growth and development in wheat, while potassium enhances photosynthetic efficiency (Tables 2 and 3). Total nitrogen, total potassium, and total phosphorus are crucial for wheat growth and development, affecting not only yield but also quality.

[0099] Table 2. Total nitrogen, total potassium, and total phosphorus content in wheat aboveground plants

[0100]

[0101] Note: Different letters indicate differences at the P<0.05 level.

[0102] Table 3. Total nitrogen, total potassium, and total phosphorus content in wheat roots

[0103]

[0104] Note: Different letters indicate differences at the P<0.05 level.

[0105] In summary, the *Priestella giantiflora* strain with accession number CGMCC No. 34470 provided by this invention possesses multiple functions, including nitrogen fixation, phosphorus solubilization, siderophore production, IAA production, and antioxidant enzyme activity. This strain can effectively solve many problems faced by *Maizenia glutinosa* 19 when growing in saline-alkali land. Through nitrogen fixation to supplement nitrogen, phosphorus solubilization to enhance phosphorus availability, siderophore production to improve iron absorption, IAA production to promote growth and development, and antioxidant enzyme activity to synergistically address oxidative stress, it plays a comprehensive role from multiple dimensions, including nutrient supply, growth regulation, and stress resistance protection. This effectively promotes the healthy growth of *Maizenia glutinosa* 19 in saline-alkali environments, and is of great significance for increasing the yield of *Maizenia glutinosa* in saline-alkali land and promoting sustainable agricultural development. It demonstrates extremely high practical value in promoting the growth of *Maizenia glutinosa* 19.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A species of Priestella gianti ( Priestia megaterium The application of HHY-1 in nitrogen fixation, iron production, auxin production, promotion of nitrogen and phosphorus absorption, improvement of drought and saline-alkali stress resistance, and enhancement of antioxidant enzyme activity is characterized by, Its accession number is CGMCC No.34470.

2. A microbial composition, characterized in that, Includes *Priestella giantiformis* HHY-1 as described in claim 1.

3. A microbial inoculant, characterized in that, Includes *Priestella giantiformis* HHY-1 as described in claim 1.

4. The microbial agent as described in claim 3, characterized in that, The microbial agent is a liquid agent.

5. The microbial agent as described in claim 4, characterized in that, The viable count of *Priscilla megaterium* HHY-1 in the microbial agent was 2. 10 6 ~7 10 8 CFU / mL.

6. The method for preparing the microbial inoculant according to any one of claims 3 to 5, characterized in that, Includes the following steps: The *Priestella giantiflora* HHY-1 was inoculated into LB liquid medium and cultured at 25℃~30℃ and 180r / min~200r / min for 1~2 days. After centrifugation, the supernatant was discarded, the cultured bacterial suspension was washed, and then sterile water was added until the viable count in the bacterial suspension was 2. 10 6 ~7 10 8 CFU / mL yields microbial inoculants.

7. The method for preparing the microbial inoculant as described in claim 6, characterized in that, The LB liquid culture medium comprises: 10g tryptone, 5g yeast extract, 10g sodium chloride and 1000mL water, pH 7.4, sterilized at 121℃ for 20min.

8. The use of *Priestella giantiflora* HHY-1 as described in claim 1 or the microbial composition as described in claim 2 in promoting the growth of drought-resistant wheat.

9. The application of the microbial inoculant according to any one of claims 3 to 5 in promoting the growth of drought-resistant wheat.

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