A microbial inoculant for regulating the secondary metabolism of warm turmeric and promoting the growth of warm turmeric, a preparation method and application thereof

Abstract

The present application belongs to the field of traditional Chinese medicinal material biotechnology and microbial application technology, and particularly relates to a microbial inoculum for regulating and controlling the secondary metabolism of Curcuma wenyujin and promoting the growth of Curcuma wenyujin, and a preparation method and application thereof. The microbial inoculum of the present application comprises a Fusarium proliferatum R15 strain with a preservation number of CGMCC No.3.29813. The strain has a high indole acetic acid yield capacity, and the total terpene yield of the strain is increased by nearly 7 times under the induction of a Curcuma wenyujin host signal. Experimental results prove that the microbial inoculum can significantly increase the biomass of Curcuma wenyujin, and induce the directional accumulation of active components of sesquiterpenes of the host, and is a core means for realizing green planting and quality improvement and efficiency increase of traditional Chinese medicinal materials.

Description

Technical Field

[0001] This invention belongs to the field of biotechnology and microbial application technology of traditional Chinese medicine, specifically relating to a microbial agent for regulating the secondary metabolism of Curcuma aromatica and promoting its growth, as well as its preparation method and application. Background Technology

[0002] Curcuma wenyujin, a plant belonging to the genus Curcuma in the ginger family (Zingiberaceae), is one of the famous "Eight Zhejiang Herbs." Its dried rhizome "Wen'ezhu" and tuberous root "Yujin" are rich in sesquiterpenoids (such as β-elemene, curcumol, and curcumidine), exhibiting significant anti-tumor, hepatoprotective, and anti-inflammatory pharmacological effects. Currently, enhancing the medicinal efficacy of Curcuma wenyujin largely relies on cultivation environment control, lacking precise biological induction methods.

[0003] Endophytic fungi have developed complex chemical communication with their hosts over a long period of evolution. Studies have shown that certain endophytic fungi can not only directly promote growth by secreting plant hormones, but also act as "biological inducers" to activate the host's secondary metabolic pathways. However, how to screen functional strains with high hormone production potential that can accurately respond to host signals and induce sesquiterpene accumulation is a key problem that urgently needs to be solved in the current green and efficient cultivation of Chinese medicinal herbs. Summary of the Invention

[0004] This invention aims to provide a microbial agent for regulating the secondary metabolism and promoting the growth of Curcuma zedoaria and its preparation method. It utilizes the excellent growth-promoting and metabolic regulation potential of the Fusarium solani R15 strain, an endophytic fungus of Curcuma zedoaria, to achieve precise intervention in the growth and secondary metabolic processes of Curcuma zedoaria and apply it to regulate the secondary metabolism of Curcuma zedoaria and promote the growth of Curcuma zedoaria plants.

[0005] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution: A strain of Fusarium proliferatum R15, with accession number CGMCC No.3.29813, deposited on March 31, 2026, is deposited at the China General Microbiological Culture Collection Center, located at No.3, No.1 Beichen West Road, Chaoyang District, Beijing.

[0006] A microbial agent for regulating the secondary metabolism of Curcuma longa and promoting its growth, comprising an active ingredient, said active ingredient including a Fusarium proliferatum R15 strain as described above.

[0007] Preferably, the Fusarium proliferatum R15 strain has an indoleacetic acid secretion capacity of not less than 50 μg / mL.

[0008] The *Fusarium proliferatum* R15 strain of this invention was isolated from *Curcuma wenyujin*. It possesses an extremely strong auxin secretion capacity, producing indoleacetic acid (IAA) at a rate of 57.47 μg / mL, demonstrating significant potential for inducing root differentiation and promoting growth. Simultaneously, *Fusarium proliferatum* R15 strain exhibits host signal-responsive metabolic characteristics; under the induction of *Curcuma wenyujin* root exudates (host signal), its total terpene metabolite production can increase nearly sevenfold. Furthermore, it possesses the genetic basis for inducing the expression of key enzymes in host sesquiterpene synthesis, indicating metabolic regulatory potential.

[0009] Preferably, the active ingredient includes any one or more combinations of the fermentation products of the Fusarium R15 strain, mycelium, and conidia.

[0010] Preferably, the microbial agent further includes auxiliary components, which include at least one of Curcuma longa residue, humic acid, and peat moss.

[0011] Preferably, the total number of viable bacteria in the microbial agent is not less than 2 × 10⁻⁶. 8 CFU / g.

[0012] Preferably, the microbial agent is in solid form with a water content of 10-20%.

[0013] The preparation method of the microbial agent for regulating the secondary metabolism and promoting the growth of Curcuma zedoaria, as described above, includes the following steps: S1: Liquid fermentation of Fusarium proliferatum strain R15 to obtain seed liquid or fermentation broth; S2: Mix the seed liquid or fermentation liquid obtained in step S1 with an organic carrier, and carry out solid-state fermentation or adsorption to obtain the product. S3: The product obtained in step S2 is dried to obtain the microbial agent.

[0014] Preferably, the organic carrier in step S2 includes Curcuma aromatica residue.

[0015] Preferably, the water content of the organic carrier in step S2 is 15-20%.

[0016] Preferably, a method for preparing a microbial inoculant for regulating the secondary metabolism of Curcuma longa and promoting its growth includes the following steps: S1: Inoculate Fusarium proliferatum R15 strain into fermentation medium and culture with shaking at 25-30℃ until the logarithmic growth phase to obtain seed culture; S2: The seed liquid obtained in step S1 is inoculated into a carrier matrix for solid-state fermentation to obtain the product; the carrier matrix contains 30-60% by mass of Curcuma zedoaria residue; S3: The product obtained in step S2 is subjected to low-temperature drying to obtain the microbial agent.

[0017] The application of the microbial agent described above for regulating the secondary metabolism of Curcuma zedoaria and promoting its growth in regulating the secondary metabolism of Curcuma zedoaria and promoting the growth of Curcuma zedoaria plants.

[0018] Preferably, the promotion of Tulip Plant growth includes inducing root development, increasing biomass, enhancing the plant's antioxidant stress resistance, and / or activating rhizosphere soil nutrients.

[0019] The application of a microbial agent, as described above, used to regulate the secondary metabolism of Curcuma zedoaria and promote its growth in increasing the content of secondary metabolites in Curcuma zedoaria.

[0020] Preferably, the secondary metabolite is a sesquiterpene compound.

[0021] Preferably, the sesquiterpenoids include any one or more combinations of turmeric alcohol, turmeric dione, gemmaconazole and β-elemene.

[0022] Therefore, the present invention has the following beneficial effects: (1) This invention provides an endophytic fungus Fusarium R15 isolated from Curcuma longa, which has a high production capacity of indoleacetic acid (IAA) (not less than 50 μg / mL), which can effectively promote the root development and biomass increase of Curcuma longa; at the same time, under the induction of host signal of Curcuma longa, the total terpene production of this strain increased by nearly 7 times, showing excellent metabolic regulation potential. (2) The microbial agent prepared based on this single strain can significantly increase the biomass of Curcuma longa and induce the targeted accumulation of sesquiterpene active ingredients in the host, providing core biological resources for the green planting and quality improvement of Chinese medicinal materials. Attached Figure Description

[0023] Figure 1 This image shows the colony morphology of Fusarium strain R15 on PDA medium.

[0024] Figure 2 This is a trend diagram of total terpene content in Fusarium strain R15 induced by host signaling in Curcuma longa. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0026] Example 1: Collection, isolation and identification of Fusarium R15, an endophytic fungus of Curcuma longa. 1. Sample collection and pretreatment: The tested Curcuma wenyujin was collected from the standardized planting base of Shazhou Village Cooperative Economic Organization, Taoshan Town, Ruian City, Wenzhou, Zhejiang Province (27.82°N, 120.32°E, altitude 300~500 m). Plants that were in the rhizome swelling stage, were growing vigorously, and were free from diseases and pests were selected, and their root, stem, and leaf tissues were collected respectively.

[0027] 2. Surface disinfection and separation: Establish differentiated disinfection protocols based on different tissue textures. Leaves (L): Soak in 75% ethanol for 0.5 min, rinse 3 times with sterile water, and soak in 2% NaClO solution for 2 min.

[0028] Underground tissue (T / R): Soak in 75% ethanol for 1 min, rinse 3 times with sterile water, and soak in 2% NaClO solution for 2 min.

[0029] After disinfection, the tissue was cut into 0.5×0.5×0.5 cm pieces and inoculated into PDA medium containing 0.01 mg / mL ampicillin (the composition of PDA medium is: 200.0 g potato, 20.0 g glucose, and 20.0 g agar), and incubated at 28°C.

[0030] 3. Strain Identification: Through morphological observation and ITS sequence amplification and alignment analysis, a core strain R15 was screened. R15 is Fusarium proliferatum, GenBank accession number MN372057.1, with a similarity of 99.035%; it is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 3.29813, and the deposit date is March 31, 2026.

[0031] Fusarium strain R15 was isolated from the tuberous roots of healthy Curcuma longa plants in the rhizome swelling stage at the standardized planting base of the Shazhou Village Cooperative Economic Organization in Taoshan Town, Ruian City, Wenzhou, Zhejiang Province (27.82°N, 120.32°E, altitude 300-500 m). The isolation was performed using the tissue block method on PDA medium at 28 °C. The strain was isolated on October 22, 2024, and deposited with CGMCC on March 31, 2026. All strains used in the following examples were derived from this strain. The colony morphology of the strain on PDA medium is as follows: Figure 1 As shown in the figure. "Front" indicates the front view morphology of colonies on PDA medium; "back" indicates the back view morphology of colonies on PDA medium.

[0032] Example 2: Verification of the growth-promoting potential and nutrient activation ability of endophytic fungi 1. Indoleacetic acid (IAA) production capacity determination: Fusarium strain R15 isolated from the roots of Curcuma longa was inoculated into PDB medium containing 0.05% L-tryptophan (PDB medium composition: 200.0 g potato (filtered liquid after boiling for 30 min), 20.0 g glucose, and distilled water to a final volume of 1000 mL), and cultured at 28 ℃ with shaking at 150 rpm for 7 days. 1 mL of the fermentation supernatant was mixed with 2 mL of Salkowski chromogenic reagent and incubated in the dark for 30 min. The absorbance was measured at 530 nm using a UV spectrophotometer. The absorbance was determined according to the standard curve y = 0.0177x + 0.0786 (R...). 2 Calculated using 0.9986, the IAA secretion concentration of Fusarium R15 strain reached 57.47 μg / mL, indicating that Fusarium R15 strain can produce IAA that promotes plant growth and has a strong potential to induce lateral root development and increase root absorption area.

[0033] Example 3: Characterization of sesquiterpene synthesis potential based on non-targeted metabolomics 1. Testing platform: A Vanquish ultra-high performance liquid chromatograph coupled with a Q Exactive HF-X mass spectrometer was used. A Waters ACQUITY Premier HSS T3 column (1.8 μm, 2.1 mm × 100 mm) was used, and the mobile phases were 0.1% formic acid aqueous solution (A) and 0.1% formic acid acetonitrile solution (B).

[0034] 2. Spatial distribution characteristics of metabolites: Fusarium R15 strain was cultured under standard PDB conditions (i.e., Fusarium R15 strain was inoculated into PDB liquid medium and placed in a constant-temperature shaking incubator at 28 ℃ and 180 rpm in the dark for 7 days. After fermentation, the fermentation broth was centrifuged (8000 rpm, 10 min), and the supernatant was collected for subsequent metabolite detection). Non-targeted metabolomics (LC-MS / MS) identified 3079 compounds. Paired differential analysis of intracellular (mycelium) and extracellular (fermentation broth) metabolites of Fusarium R15 strain revealed 1962 differentially expressed metabolites (955 significantly upregulated extracellularly and 1008 significantly upregulated intracellularly), indicating significant spatial differentiation in the intracellular and extracellular metabolomics profiles of this strain. Further targeted analysis of the core sesquiterpenoid components revealed that the detection signal intensity of curcumol in the fermentation broth of Fusarium R15 strain was more than 10 times higher than that of intracellular intermediates, and its curcumol secretion capacity was 10-40 times higher than that of other tested strains. Simultaneously, a significant concentration gradient was observed between the sesquiterpene synthesis intermediates detected within the mycelium and the extracellular secreted sesquiterpene final products (curcumol, gemcitabine, etc.). Based on the above metabolomics data, especially the extreme enrichment characteristics of curcumol in the extracellular secretory fluid (response intensity more than 10 times higher than intracellular, and 10-40 times higher than other strains), it can be concluded that Fusarium R15 strain possesses a sesquiterpene metabolic characteristic of "intracellular synthesis and extracellular secretion."

[0035] Example 4: Host signaling response and total terpene gain regulation based on OSMAC strategy 1. Preparation of the induction environment: 5% (w / v) of the crude extract of *Curcuma longa* host was added to PDB medium (PDB medium consists of: 200 g potato (washed, peeled, boiled for 30 min and then filtered), 20 g glucose, and distilled water to a final volume of 1000 mL, pH adjusted to 7.0. The medium must be autoclaved at 115℃ for 20 min before the experiment) to simulate the host microenvironment. The preparation method of the crude extract of *Curcuma longa* host is as follows: Weigh 5 g of *Curcuma longa* powder, add 100 mL of deionized water, and extract at 80℃ for 2 h; repeat the extraction twice, filter with qualitative filter paper, and combine the extracts to obtain the crude extract of *Curcuma longa* host. When using, add it to the PDB medium at a ratio of 5% (v / v) and sterilize together.

[0036] 2. Determination of metabolites: Metabolites were determined using the vanillin-perchloric acid colorimetric method, with absorbance read at 548 nm. The absorbance was calculated based on the oleanolic acid standard curve: y = 0.0089x + 0.0646 (R²). 2 =0.9948) reduction yield. The trend of total terpene content of Fusarium R15 strain under host signal induction in Curcuma longa is shown in the figure below. Figure 2 As shown.

[0037] Figure 2 The results showed that in the uninduced blank PDB (control group), the total terpene production of Fusarium R15 strain was 62.19 mg / L; under the induction of 5% Curcuma longa host crude extract (Curcuma longa crude extract group), the total terpene production of Fusarium R15 strain soared to 499.55 mg / L, an increase of nearly 7 times.

[0038] 3. Biomass response: Under the induction of 5% crude extract of Curcuma zedoaria host, the mycelial dry weight of Fusarium strain R15 increased from 5.96 g / L to 10.38 g / L (an increase of 74.2%), indicating that Fusarium strain R15 is sensitive to Curcuma zedoaria signaling molecules and has a metabolic response, providing direct evidence that it responds to host signals and exerts metabolic regulatory functions after rhizosphere colonization.

[0039] Example 5: Effects of Fusarium R15 inoculant (microbial inoculant) on the growth of Curcuma longa plants To verify the actual growth-promoting effect of the single-strain microbial agent prepared in this invention on *Curcuma longa* plants, a greenhouse pot experiment with strictly controlled variables was conducted.

[0040] 1. Experimental Design: The experiment included a blank control group (CK group, each pot was treated with 5.0 g of sterilized drug residue carrier without live bacteria) and a Fusarium R15 inoculum treatment group (each pot was treated with 5.0 g of Fusarium R15 solid inoculum (i.e., microbial inoculum) prepared according to the method in Example 7, with a live bacteria count ≥2×10⁻⁶). 8 CFU / g). Ten parallel samples were set up in each group. Each pot (25cm in diameter) was planted with one piece of healthy turmeric seed ginger of the same size and placed in an artificial climate chamber for conventional water and light management.

[0041] 2. Index Measurement: After 60 days of routine management, the entire plant was removed, the substrate attached to the roots was rinsed with deionized water, and the surface moisture was absorbed. The growth indicators of individual plants were then measured. The experimental results are presented as average values ​​for each group, as detailed in Table 1 below.

[0042] Table 1: Effects of Fusarium R15 inoculum (microbial inoculum) on the growth indicators of individual Curcuma longa plants Blank control group (CK group) 25.3 12.1 18.4 22.6 Fusarium R15 inoculum treatment group 34.8 17.6 29.7 38.5 .

[0043] 3. Results Analysis: As shown in Table 1, the application of Fusarium R15 inoculant (i.e., microbial inoculant) significantly improved all growth indicators of Curcuma zedoaria, with the most significant increase in the fresh weight of the underground tubers, which is directly related to yield, reaching 70.4%. This growth-promoting result highly corresponds to the physiological characteristics of high IAA production (57.47 μg / mL) of Fusarium R15 strain in Example 2: after colonization in the rhizosphere, Fusarium R15 strain continuously releases exogenous IAA, promoting lateral root differentiation and root elongation (root length increased by 45.5%) in Curcuma zedoaria. The improved root structure enhances the plant's absorption efficiency of water and mineral nutrients, thereby driving the accumulation of photosynthetic biomass in the aboveground parts (aboveground fresh weight increased by 61.4%) and ultimately efficient translocation to the underground tubers. This result indicates that the Fusarium R15 inoculant (i.e., microbial inoculant) of this invention can significantly increase the underground biomass of individual Curcuma zedoaria plants.

[0044] Example 6: Effect of Fusarium R15 inoculum (i.e., microbial inoculum) on the accumulation of sesquiterpenoids in Curcuma longa. To further clarify the regulatory effect of Fusarium R15 inoculant (i.e., microbial inoculant) on the core quality components of Curcuma longa, quantitative analysis of the core medicinal components was performed on the Curcuma longa tuberous roots harvested in Example 5.

[0045] 1. Sample processing and detection: Curcuma longa rhizomes from the blank control group (CK group) and the Fusarium R15 inoculum treatment group were dried at 60 ℃ to constant weight, pulverized, and passed through a 60-mesh sieve. The content of the core characteristic sesquiterpenoid components (curcumol and gemmaconone) was quantitatively determined (in mg / g dry weight) by high performance liquid chromatography (HPLC).

[0046] 2. Chromatographic conditions: An Agilent Zorbax SB-C18 column (4.6 mm × 250 mm, 5 μm) was used. The mobile phase was acetonitrile-water with gradient elution. The gradient elution program was as follows: 0–15 min, acetonitrile linearly increased from 50% to 75%; 15–20 min, maintained at 75% acetonitrile; 20–21 min, acetonitrile decreased from 75% to 50%; 21–25 min, maintained at 50% acetonitrile. The flow rate was 1.0 mL / min, the detection wavelength was set to 210 nm, and the column temperature was maintained at 30 ℃. The quantitative results of each component in the rhizome of *Curcuma longa* are shown in Table 2 below.

[0047] Table 2: Effect of Fusarium R15 inoculum (microbial inoculum) on the content of characteristic sesquiterpenes in Curcuma longa tuberous roots (mg / g dry weight) Blank control group (CK group) 1.28 0.42 Fusarium R15 inoculum treatment group 2.67 0.89 .

[0048] 3. Results Analysis: As shown in Table 2, after applying Fusarium R15 inoculant (microbial inoculant), the contents of two characteristic sesquiterpenoid components, curcumol and gemcitabine, in the tuberous roots of Curcuma longa were more than doubled compared with the blank control group (CK group). Among them, the content of curcumol increased from 1.28 mg / g to 2.67 mg / g (an increase of 108.6%). Based on the approximately 7-fold increase in total terpene production (62.19 → 499.55 mg / L) of Fusarium R15 strain in Example 4 under host signal induction, and the "intracellular synthesis and extracellular secretion" metabolic characteristics of this strain in Example 3, it can be reasonably inferred that after colonization in the rhizosphere, the Fusarium R15 inoculant (microbial inoculant) promotes root growth and expands the root absorption area through IAA, and specifically responds to the signals from Curcuma longa root exudates, activating its own sesquiterpene synthesis gene cluster and secreting related signaling molecules. This may then cross-border activate the expression of key enzyme genes in the host mevalonic acid (MVA) pathway, inducing the targeted accumulation of host sesquiterpene active components. These results indicate that the Fusarium R15 inoculant (microbial inoculant) of the present invention can induce the targeted accumulation of host sesquiterpene active components.

[0049] Example 7: Preparation and Application Scheme of Functional Microbial Agents 1. Fermentation process: The functionally validated Fusarium R15 strain was subjected to submerged liquid fermentation (28 °C, 5–7 days). After fermentation, the mycelium and fermentation broth were treated with low-temperature spray drying or vacuum freeze-drying techniques to prepare a product containing ≥2 × 10⁻⁶ viable cells. 8 The original bacterial powder contains CFU / g. The liquid submerged fermentation process is as follows: 1.1 Primary seed culture: (1) Inoculate the strain preserved in slant culture medium or glycerol tubes onto activated PDA medium and incubate at 28 °C for 5 days; (2) Use an inoculation knife to pick up 3-5 pieces of mycelium cake with a diameter of 5 mm and transfer them into a 250 mL Erlenmeyer flask containing 100 mL of PDB liquid culture medium; (3) Place it in a constant temperature shaking incubator and culture it in the dark at 28 ℃ and 180 rpm for 48~72 h to obtain a first-grade seed liquid with uniform mycelial ball size and strong vitality.

[0050] 1.2 Liquid submerged fermentation: (1) Inoculation ratio: Inoculate the primary seed culture into a 500 mL Erlenmeyer flask (containing 200 mL PDB liquid culture medium) at an inoculation rate of 5%~10% (v / v). (2) Parameter control: Set the fermentation temperature to 28 ℃±0.5 ℃ and the stirring speed to 180~220 rpm; (3) Fermentation cycle: Continuous culture for 5-7 days. During this period, samples are taken every 24 hours to test the pH value, reducing sugar content, and mycelial dry weight of the fermentation broth; (4) Determination of fermentation endpoint: When the reducing sugar in the fermentation broth drops below 0.5% and the dry weight of the mycelium no longer increases significantly, fermentation is stopped.

[0051] 2. Microbial agent formulation and preparation: The *Fusarium* R15 strain powder prepared above was directly used as the active ingredient. To improve the colonization effect of the strain in the rhizosphere of *Curcuma longa*, *Curcuma longa* residue that had been sterilized and dried at high temperature was selected as the organic carrier. The R15 strain powder and *Curcuma longa* residue were uniformly mixed at a mass ratio of 1:10 to obtain a microbial inoculum. The microbial inoculum was then diluted to obtain a diluted microbial inoculum solution. The preparation method of the diluted microbial inoculum solution is as follows: 2.1 Weighing and mixing: Weigh the above R15 bacterial powder at a mass ratio of 1:50 and add it to sterile water; 2.2 Mechanical stirring: Under normal temperature conditions, stir at a speed of 150~200 rpm for 20~30 min using a magnetic stirrer or electric stirring paddle; 2.3 Filtration and use: After stirring, let stand for 5-10 minutes. The diluted solution should be prepared and used immediately. It is recommended to apply it within 12 hours after preparation.

[0052] 3. Application method: a. Seed ginger treatment: Before planting *Curcuma aromatica* seed ginger, soak or mix the seeds with the diluted microbial agent prepared above to establish an endophytic symbiotic system in advance.

[0053] b. Rhizosphere application: During the vigorous growth period of Curcuma zedoaria (e.g., June to August), the microbial inoculant prepared above is applied to the rhizosphere of individual Curcuma zedoaria plants using a hole application method (application rate of 5.0-10.0 g / plant, with 8.0 g / plant being the most preferred in this embodiment). Metabolic targeted regulation is triggered through chemical signal communication within the symbiotic system. Evaluation of the application effect shows that after applying the Fusarium R15 inoculant (microbial inoculant) of this invention under potted conditions, the fresh weight of the underground tubers of a single Curcuma zedoaria plant can be increased by approximately 70% (see Example 5 for details), and the content of turmeric alcohol and gemcitabine in the Curcuma zedoaria tubers is increased by more than 100% (see Example 6 for details), indicating that the Fusarium R15 inoculant (microbial inoculant) of this invention can achieve a synergistic improvement in the yield and quality of Curcuma zedoaria.

[0054] The above description is merely a detailed explanation of preferred embodiments and principles of the present invention. For those skilled in the art, there may be changes in specific implementation methods based on the ideas provided by the present invention, and these changes should also be considered within the scope of protection of the present invention.

Claims

1. A type of Fusarium Fusarium proliferatum strain R15, characterized in that, Its accession number is CGMCCNo. 3.29813, the accession date is March 31, 2026, and it is deposited at the China General Microbiological Culture Collection Center.

2. A microbial agent for regulating the secondary metabolism of Curcuma longa and promoting its growth, characterized in that, Includes an active ingredient, said active ingredient including a Fusarium as described in claim 1. Fusarium proliferatum R15 strain.

3. A microbial agent for regulating the secondary metabolism and promoting the growth of Curcuma aromatica according to claim 2, characterized in that, The active ingredient includes any one or more combinations of the fermentation products of the Fusarium R15 strain, mycelium, and conidia.

4. A microbial agent for regulating the secondary metabolism and promoting the growth of Curcuma aromatica according to claim 2, characterized in that, The microbial agent also includes auxiliary components, which include at least one of Curcuma longa residue, humic acid, and peat moss.

5. A microbial inoculant for regulating the secondary metabolism and promoting the growth of Curcuma aromatica according to claim 2, characterized in that, The total number of viable bacteria in the microbial agent is not less than 2×10⁻⁶. 8 CFU / g.

6. A microbial agent for regulating the secondary metabolism and promoting the growth of Curcuma aromatica according to claim 2, characterized in that, The microbial agent is a solid dosage form with a water content of 10-20%.

7. A method for preparing a microbial inoculant for regulating the secondary metabolism and promoting the growth of Curcuma aromatica as described in any one of claims 2 to 6, characterized in that, Includes the following steps: S1: Fusarium Fusarium proliferatum The R15 strain was subjected to liquid fermentation to obtain seed liquid or fermentation broth. S2: Mix the seed liquid or fermentation liquid obtained in step S1 with an organic carrier, and carry out solid-state fermentation or adsorption to obtain the product. S3: The product obtained in step S2 is dried to obtain the microbial agent.

8. A method for preparing a microbial inoculant for regulating the secondary metabolism and promoting the growth of Curcuma aromatica according to claim 7, characterized in that, The organic carrier in step S2 includes the residue of Curcuma longa.

9. A method for preparing a microbial inoculant for regulating the secondary metabolism and promoting the growth of Curcuma longa according to claim 7, characterized in that, The water content of the organic carrier in step S2 is 15-20%.

10. The application of any one of the microbial agents for regulating the secondary metabolism and promoting the growth of Curcuma zedoaria as described in any one of claims 2 to 6 in promoting the growth of Curcuma zedoaria plants or the secretion of sesquiterpenoid compounds.

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