Use of pachysandra endogenous flavobacterium in promoting plant growth

Abstract

The application provides application of a broadleaf paloontia endophytic flavobacterium in promoting plant growth, the flavobacterium strain P1R7GS3 in the application is separated from the roots of healthy broadleaf paloontia and is preserved in the Guangdong Microbial Digital Culture Collection Center with a preservation number of GDMCC No: 66990; has the effects of ammonia production, indole acetic acid production and zinc dissolution and has a biological membrane formation capacity, which has an excellent promoting effect on the growth of plants, in particular, the growth of broadleaf paloontia. The application can significantly promote the growth of stem thickness, leaf number, fresh weight, leaf fresh weight, dry weight and leaf dry weight of broadleaf paloontia plants; meanwhile, the application promotes the synthesis of effective substances such as broadleaf paloontia alcohol and broadleaf paloontia ketone while improving the biomass of broadleaf paloontia; and can be used as a biological fertilizer for promoting the growth of field crops and effectively reducing the use of chemical fertilizers.

Description

Technical Field

[0001] This application belongs to the field of microbial technology, and in particular relates to the application of *Flavobacterium endophytum* in promoting plant growth. Background Technology

[0002] Plant endophytes are microorganisms that live within the various tissues and organs of healthy plants at certain or all stages of their life cycle, without causing disease symptoms in the host plant. Numerous studies have shown that endophytes can promote the growth and development of host plants, and some endophytes also possess the function of defending against pathogens. Their use as microbial fertilizers has attracted widespread attention from researchers across multiple disciplines. Endophytes exhibit high adaptability to various environments, rapid growth rates, and biochemical diversity. They can metabolize a wide range of natural and exogenous compounds and are an indispensable part of the plant microenvironment. When endophytes grow in conjunction with the host plant, they can stimulate the host's growth in various ways. In conclusion, plant endophytic growth-promoting bacteria have significant agricultural implications for improving crop productivity, and the discovery of new endophytic growth-promoting bacteria is crucial in agricultural production.

[0003] Previous studies have confirmed that endophytic bacteria have a direct growth-promoting effect, improving soil nutrient availability through nitrogen fixation, phosphorus solubilization, potassium solubilization, and zinc solubilization. For example, *Bacillus belye* (… Bacillus velezensis Some strains can secrete organic acids and enzymes, promoting the release of elements such as phosphorus and potassium. Some endophytic bacteria can secrete hormones such as indoleacetic acid (IAA) and gibberellin (GA) to regulate plant growth. For example, *Microbacterium rubrum*. Microbacterium testaceum B2R can efficiently synthesize IAA, significantly promoting root development in potted crops. Some endophytic bacteria help plants cope with adversity such as salinity and drought by synthesizing or indirectly regulating the synthesis of osmotic protective substances (such as proline and soluble sugars) or regulating the plant's antioxidant system; some endophytic bacteria can also promote plant growth by producing growth-promoting volatile organic compounds (VOCs), such as... Bacillus amyloliquefaciens VOCs produced by SQR9 can significantly promote the growth of Arabidopsis thaliana and its roots. On the other hand, endophytic bacteria can also play an indirect role in promoting growth, for example, by competing for nutrients and secreting antimicrobial substances (such as antibiotics and siderophores) to inhibit pathogens. For example, Bacillus subtilis... Bacillus subtilis DZSY21 can prevent corn leaf blight ( Bipolaris maydis Alternatively, it can promote growth or enhance resistance to pathogens by activating the expression of plant growth and defense genes; some endophytic bacteria can also improve the rhizosphere and plant microbial community after inoculation and enrich beneficial bacteria, thereby promoting plant growth.

[0004] Patchouli ( Pogostemon cablinPatchouli, with its aromatic and dampness-dispelling, appetite-stimulating, nausea-relieving, and heat-relieving properties, is one of the "Ten Southern Chinese Herbs" and a key ingredient in over 50 kinds of traditional Chinese medicine preparations. Research on its endophytic growth-promoting bacteria is of significant value in agriculture and medicinal plant cultivation. Discovering superior endophytic bacteria in patchouli for the development of specialized bio-fertilizers to replace chemical fertilizers and pesticides represents a novel, green, and effective method to increase crop yields, enhance pest and disease resistance, and reduce environmental damage. Summary of the Invention

[0005] This application provides the application of *Flavobacterium endophytum* from patchouli in promoting plant growth, in order to solve the problems existing in related technologies. The technical solution is as follows: In one aspect, embodiments of this application provide the application of *Patchouli endophytic flavobacterium* in promoting plant growth.

[0006] Application of Flavobacterium endophytum in promoting plant growth; the strain is Flavobacterium strain P1R7GS3, Latin name: Flavobacterium endoglycinae It was deposited at the Guangdong Provincial Center for Microbial Culture Collection on September 18, 2025, with accession number GDMCC No: 66990.

[0007] In one embodiment, the Flavobacterium strain P1R7GS3 promotes plant growth by producing ammonia.

[0008] In one embodiment, the Flavobacterium strain P1R7GS3 promotes plant growth by producing indoleacetic acid.

[0009] In one embodiment, the Flavobacterium strain P1R7GS3 promotes plant growth by dissolving zinc.

[0010] In one embodiment, the Flavobacterium strain P1R7GS3 promotes plant growth by producing biofilm.

[0011] In one embodiment, the plant is patchouli.

[0012] In one implementation, promoting plant growth includes increasing plant height, stem diameter, number of leaves, plant fresh weight, and plant dry weight.

[0013] In one embodiment, a bacterial suspension containing the strain Flavobacterium strain P1R7GS3 is prepared and used for root irrigation treatment of patchouli in pots.

[0014] In one embodiment, the OD of live Flavobacterium strain P1R7GS3 in the bacterial suspension 600 =1.0.

[0015] Secondly, embodiments of this application provide the application of Flavobacterium endophytum in promoting the growth of patchouli active ingredients in patchouli, wherein the patchouli active ingredients are at least one of patchouli alcohol, patchouli ketone, patchouli olefin, seychelles olefin or norpatouli alcohol.

[0016] The advantages or beneficial effects of the above technical solutions include at least the following: This application provides the application of *Flavobacterium endophyte* in promoting plant growth. The *Flavobacterium* strain P1R7GS3 of this application was isolated from the roots of healthy patchouli and exhibits ammonia production, indoleacetic acid production, zinc solubilization, and biofilm formation capabilities. This demonstrates excellent growth-promoting effects, particularly on patchouli. It significantly promotes the growth of patchouli plant stem diameter, leaf number, fresh weight, leaf fresh weight, dry weight, and leaf dry weight. Simultaneously, the application of this bacterium increases patchouli biomass and promotes the synthesis of its effective substances such as patchouli alcohol and patchouli ketone. It can replace chemical fertilizers as a bio-fertilizer for promoting crop growth in the field, effectively reducing the use of chemical fertilizers.

[0017] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of this application will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0018] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0019] Figure 1 The colony morphology of Flavobacterium P1R7GS3; Figure 2 A phylogenetic tree for Flavobacterium P1R7GS3 constructed based on the 16S rRNA sequence; Figure 3 The results of ammonium ion production by Flavobacterium P1R7GS3; Figure 4 The results of the zinc-solubilizing ability test of Flavobacterium P1R7GS3; Figure 5 The result of crystal violet staining of the biofilm formed by Flavobacterium P1R7GS3 in a 48-well plate. Figure 6 The image shows the growth-promoting effect of Flavobacterium P1R7GS3 on potted patchouli. Figure 7The figure shows the comparison results of plant height, stem diameter, number of leaves, plant fresh weight, leaf fresh weight, root fresh weight, plant dry weight, leaf dry weight, and root dry weight of potted patchouli in the experimental group and control group of Flavobacterium P1R7GS3. * P <0.05; ** P <0.01; ns, P >0.05); Figure 8 Images showing the plant condition of patchouli eight weeks after inoculation with different Flavobacterium species; Figure 9 Inoculation with Flavobacterium P1R7GS3 and three other Flavobacterium species Flavobacterium endoglycinae BB8 (BB8) Flavobacterium soyae ( F. soyae ), Flavobacterium oryzae ( F. oryzae A comparison of plant height, stem diameter, main stem branches, number of leaves, fresh weight, and dry weight after eight weeks of potted cultivation (Figure 1). * P <0.05; ** P <0.01). Detailed Implementation

[0020] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0021] Patchouli ( Pogostemon cablin Patchouli is an important medicinal plant, and research on its endophytic growth-promoting bacteria is of great value in agriculture and medicinal plant cultivation. As a medicinal plant, it is more sensitive to the use of fertilizers and pesticides. Therefore, researching green biological agents that can improve crop yield and resist pests and diseases while reducing environmental damage is of great significance. Discovering superior patchouli growth-promoting endophytic bacteria for the development of patchouli-specific bio-fertilizers may be a new, green, and effective method.

[0022] This application provides the application of Flavobacterium endophytum in promoting plant growth, wherein Flavobacterium endophytum is a Flavobacterium strain ( Flavobacterium endoglycinae P1R7GS3 was deposited at the Guangdong Provincial Center for Microbial Culture Collection on September 18, 2025, with accession number GDMCC No: 66990.

[0023] This strain was isolated from the roots of healthy patchouli plants in the Shizhenshan research area of ​​Guangzhou University of Chinese Medicine, Panyu District, Guangzhou, Guangdong Province, China. On LB agar plates, it appears yellow to brownish-yellow, with a smooth surface, round or nearly round raised sections, neat edges, uniform color, and a certain degree of gloss. Morphological characteristics: Gram-negative bacteria, rod-shaped. It was deposited on September 18, 2025, at the Guangdong Provincial Microbial Culture Collection Center, located at 5th Floor, Building 59, Institute of Microbiology, Guangdong Academy of Sciences, No. 100 Xianlie Middle Road, Guangzhou, Guangdong Province, with accession number GDMCC No: 66990.

[0024] Flavobacterium strain P1R7GS3 possesses growth-promoting properties including ammonia production, indoleacetic acid production, zinc dissolution, and biofilm formation. Therefore, in one embodiment, the Flavobacterium strain P1R7GS3 promotes plant growth through ammonia production, indoleacetic acid production, zinc dissolution, or biofilm formation. In another embodiment, the Flavobacterium strain P1R7GS3 promotes plant growth through at least two of these synergistic mechanisms: ammonia production, indoleacetic acid production, zinc dissolution, and biofilm formation. In one embodiment, the plant is patchouli.

[0025] One implementation method for promoting plant growth includes increasing plant height, stem diameter, number of leaves, fresh plant weight, and dry plant weight.

[0026] As one embodiment, a bacterial suspension containing the strain is Flavobacterium strain P1R7GS3, which is then used for root irrigation treatment of patchouli in pots.

[0027] In one embodiment, the OD of live Flavobacterium strain P1R7GS3 in the bacterial suspension... 600 =1.0.

[0028] This application also provides the application of Flavobacterium endophytum in promoting the growth of patchouli active ingredients in patchouli, wherein the patchouli active ingredients are at least one of patchouli alcohol, patchouli ketone, patchouli olefin, seychelles olefin or norpatouli alcohol.

[0029] Example 1 Isolation, preservation and identification of strain P1R7GS3 1. Isolation and preservation of strain P1R7GS3 Root samples of healthy patchouli were collected from the patchouli planting area of ​​Shizhenshan Research Site of Guangzhou University of Chinese Medicine in Panyu District, Guangzhou. The samples were quickly placed in ice boxes and transported back to the laboratory. The soil and other impurities on the surface of the roots were first washed off with running water, and then dried with absorbent paper before being placed in sterilized tissue culture bottles. The samples were then placed in a clean bench with other materials such as sterile scissors and tweezers for 30 minutes of ultraviolet sterilization.

[0030] The surface disinfection procedure for patchouli roots is as follows: disinfect with 75% ethanol for 1 min, rinse once with sterile water, disinfect with 5% available chlorine NaClO for 5 min, rinse again with sterile water, disinfect with 75% ethanol for 30 s, and finally rinse 3 times with sterile water. Take 400 μL of the last rinse solution and spread it on a solid culture medium plate to check whether the surface disinfection is complete.

[0031] Place the surface-sterilized roots in a sterile mortar, cut them into small pieces, and grind them thoroughly. Add 8 mL of sterile water, mix well, and spread 400 μL of each onto a piece of LB, PDA, YM, YPD, or GS solid medium. Incubate at 28°C. After bacterial growth, select single colonies based on their color, shape, size, elevation, edge condition, surface condition, and transparency. Repeat the purification process 3-5 times until a pure strain is obtained.

[0032] The strain was inoculated into LB liquid medium and cultured on a shaker (30℃, 225rpm) for 24h. The bacterial culture was then mixed with 30% glycerol in a cryovial at a volume ratio of 1:1, and after being flash-frozen in liquid nitrogen, it was stored at -80℃.

[0033] 2. Identification of strain P1R7GS3 2.1. Observation of morphological characteristics Colony morphology characteristics: such as Figure 1 As shown, the colonies of strain P1R7GS3 on LB solid medium plates are yellow to brownish-yellow, with a smooth surface, round or nearly round raised edges, neat edges, uniform color, and a certain gloss. The morphological characteristics of the bacteria are: Gram-negative bacteria, rod-shaped.

[0034] 2.2. 16S rRNA sequence analysis PCR amplification was performed using primers 27F (SEQ ID NO.1: 5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (SEQ ID NO.2: 5'-GGTTACCTTGTTACGACTT-3'), and the 16S rRNA sequence was determined. PCR system (40μL): 2×Taq Master Mix Plus II 20μL, 27F 1.5μL, 1492R 1.5μL, template 1μL, add water to make up to 40μL; Amplification conditions: 98℃ for 3 min; 98℃ for 15 s, 56℃ for 30 s, 72℃ for 2 min, 35 cycles; 72℃ for 7 min; PCR amplification products were detected by 1% agarose gel electrophoresis and sequenced by Beijing Qingke Biotechnology Co., Ltd. The sequencing results were submitted to the NCBI database for BLAST analysis and comparison, revealing a strain with high homology to strain P1R7GS3. Flavobacterium endoglycinae (99.13%), a phylogenetic tree of NJ was constructed using 16S rRNA sequences, such as Figure 2 As shown, strain P1R7GS3 and Flavobacterium endoglycinae On the same branch.

[0035] 2.3. Determination of physiological and biochemical characteristics Physiological and biochemical characteristics of strain P1R7GS3 were determined according to the methods in Bergey's Manual of Bacterial Identification and the Manual of Systematic Identification of Common Bacteria. The main physiological and biochemical characteristics included contact enzymes, oxidases, and motility. The results are shown in Table 1.

[0036] Table 1. Physiological and biochemical characteristics of strain P1R7GS3

[0037] Note: "+" indicates a positive reaction, and "-" indicates a negative reaction.

[0038] Based on the above morphological characteristics, 16S rRNA phylogenetic tree, and physiological and biochemical characteristics, strain P1R7GS3 was identified as... Flavobacterium endoglycinae .

[0039] Example 2 Analysis of growth-promoting characteristics of strain P1R7GS3 1. Ammonia production activity determination A single colony of P1R7GS3 was picked and cultured in LB medium until OD200. 600 =1.0, centrifuged at 12000 rpm for 5 min, collected the precipitate, and resuspended it in an equal volume of sterile water. Endophytic bacteria were inoculated at a 1% inoculation rate into sterile shake tubes containing 3 mL of peptone-water (10 g / L peptone) liquid culture medium. The tubes were incubated at 30°C with shaking at 225 rpm for 72 h. After centrifugation at 12000 rpm for 2 min, 1.5 mL of the supernatant was collected. 0.5 mL of Nessler's reagent was added to each tube. A pale yellow precipitate indicated a small amount of ammonia, a deep yellow to brown precipitate indicated a high concentration of ammonia, and no yellow-brown precipitate indicated the absence of ammonium ion production activity. Results were as follows: Figure 3 As shown in Table 2, strain P1R7GS3 exhibits strong ammonia-producing activity.

[0040] 2. Determination of IAA (indoleacetic acid) production capacity A single colony of P1R7GS3 was picked and cultured in LB medium until OD200. 600=1.0, centrifuged at 12000 rpm for 5 min, collected the precipitate, and resuspended it in an equal volume of sterile water. Endophytic bacteria were inoculated at a 1% inoculation rate into 50 mL shake flasks (containing 10 mL LB liquid medium with 5 mmol tryptophan added), and this inoculation was repeated for 4 flasks. The flasks were incubated at 30℃ for 72 h. After centrifugation (12000 rpm, 2 min), 500 μL of the supernatant was mixed with 500 μL of Salkowski reagent and incubated in the dark at room temperature for 30 min. The color change was observed; if the color turned red, it indicated that the strain had the ability to produce IAA. After pink development, the absorbance was measured at 530 nm. LB medium with tryptophan added was used as a negative control. A standard curve was plotted using the absorbance corresponding to pure IAA (with IAA standard concentration gradients of 3.125, 6.25, 12.5, 25, and 50 μg / mL). The equation of the IAA standard curve was y = 0.0068x + 0.0108 (R²). 2 =0.9929), and the IAA production amount (μg / mL) was calculated. The results are shown in Table 2. The strain P1R7GS3 has the ability to produce IAA. The amount of IAA that the strain P1R7GS3 can secrete is calculated to be 6.87±1.86μg / mL using the linear formula of absorbance value.

[0041] Table 2 Results of IAA (indoleacetic acid) production capacity assay of strain P1R7GS3

[0042] 3. Zinc dissolving capacity test A single colony of P1R7GS3 was picked and cultured in LB medium until OD200. 600 =1.0, centrifuged at 12000 rpm for 5 min, collected the precipitate, and resuspended it in an equal volume of sterile water. 5 μL was inoculated onto zinc-dissolving medium. Each culture plate was inoculated three times at different locations, and each endophytic bacterium was inoculated three times. The culture plates were incubated at 30°C for 7 days. The appearance of a clear area around the colony indicated zinc-dissolving ability. Results are as follows. Figure 4 As shown, the strain has a certain ability to dissolve zinc.

[0043] 4. Determination of biofilm formation capacity Each endophytic bacterium was cultured in LB medium until OD. 600 =1.0, inoculated at a 1% inoculum volume into 3 mL of 1 / 10 LB culture medium, then transferred to a 48-well plate (500 μL per well) using a pipette, and incubated at 30°C for 72 h. Subsequently, carefully aspirate with a 1 mL syringe to remove unbound bacteria from the plate, add 500 μL of methanol for fixation for 15 min. Remove the fixative, air dry in a ventilated area (until no flowing liquid is visible), add 500 μL of 0.1% crystal violet solution, stain at room temperature for 30 min, aspirate the crystal violet solution, and wash three times with sterile water. After air drying in a laminar flow hood, photograph the results as shown. Figure 5 as shown. Then add 500 μL of 95% ethanol, gently shake the plate, and dissolve at room temperature for 3-5 min to fully dissolve the biofilm color. Pipette 200 μL of the dissolved solution into a 96-well plate, measure the absorbance at 570 nm, with the blank control (CK) being 1 / 10 LB culture medium without inoculation, and each sample is repeated 5 times. The biofilm formation ability is characterized according to the following formula: DC = 2 × the absorbance value of the control group; D = the absorbance value of the treatment group; Strong biofilm: D > 2 × DC; Weak biofilm: DC < D < 2 × DC; No biofilm formation: D < DC. The results are shown in Table 3: DC < D < 2DC, indicating that the strain P1R7GS3 has a weak biofilm formation ability.

[0044] Table 3 Determination of the biofilm formation ability of strain P1R7GS3 (n=5)

[0045] Example 3 Effect of inoculating strain P1R7GS3 on the growth of Pogostemon cablin Plant materials: Pogostemon cablin seedlings with a plant height of about 25 cm (nursery pot size: bottom diameter 10.2 cm, height 12.5 cm, outer caliber and inner caliber are 14.5 cm and 13.5 cm respectively; one plant per pot).

[0046] Inoculum bacterial solution: First prepare P1R7GS3 seed solution (pick a single colony of P1R7GS3, inoculate it into 3 mL of LB culture medium, and culture overnight on a shaker (30°C, 225 r / min)), then pipette 2 mL of the seed solution (1% inoculum amount) into a 500 mL Erlenmeyer flask containing 200 mL of LB culture medium, and culture on a shaker (30°C, 225 r / min) until OD 600 =1.0.

[0047] Experimental method: Take 30 mL of P1R7GS3 culture solution and pour it into the soil around the roots of Pogostemon cablin, the control group is poured with an equal amount of sterile LB culture solution, after pouring the endophytic bacteria culture solution and the sterile culture solution, cover with a layer of soil, and there are 4 replicates for each treatment. The second bacterial solution is poured after an interval of four weeks (28 days), and agronomic traits are measured after 16 weeks of planting. The growth effect of Pogostemon cablin plants is as Figure 6 shown; the comparison diagram of changes in plant height, stem diameter, leaf number, plant fresh weight, leaf fresh weight, root fresh weight, plant dry weight, leaf dry weight, and root dry weight is as Figure 7 shown.

[0048] From Figure 6-7 it can be seen that after the bacterial solution prepared from strain P1R7GS3 is applied, the growth-promoting effect on Pogostemon cablin is obvious, which significantly promotes the stem diameter of Pogostemon cablin ( Figure 7 b in), leaf number ( Figure 7 c) Fresh weight of the plant ( Figure 7 d) Fresh weight of leaves Figure 7 e), plant dry weight ( Figure 7 g) and leaf dry weight ( Figure 7 The growth of h) indicates that this strain has a good plant growth-promoting effect. This bacterium can be used to develop microbial agents and bio-fertilizers for promoting crop growth in the field.

[0049] Example 4 Effects of different Flavobacterium species on the growth of patchouli Plant material: Patchouli seedlings with a height of about 25cm (seedling pot size: bottom diameter 10.2cm, height 12.5cm, outer diameter and inner diameter are 14.5cm and 13.5cm respectively; one seedling per pot).

[0050] Inoculated strain: P1R7GS3, Flavobacterium endoglycinae BB8 (BB8) Flavobacterium soyae ( F. soyae ), Flavobacterium oryzae ( F. oryzae ). Among them BB8, F. soyae, F. oryzae The Flavobacterium species with growth-promoting effects, which belong to the same genus as strain P1R7GS3, were all purchased from Wuhan Gray Algae Biotechnology Co., Ltd., with serial numbers HZB136713, HZB123886 and HZB195848, respectively.

[0051] Inoculation: First, prepare seed cultures of four types of Flavobacterium (pick a single colony, inoculate it into 3 mL of LB broth, and incubate overnight on a shaker (30℃, 225 r / min)). Then, add 2 mL of the seed culture (1% inoculum) to a 500 mL Erlenmeyer flask containing 200 mL of LB broth and incubate on a shaker (30℃, 225 r / min) until OD. 600 =1.0.

[0052] Experimental Methods: 30 mL of Flavobacterium culture solution was applied to the soil surrounding the roots of patchouli, while the control group was treated with an equal volume of sterile LB culture solution. After applying the endophytic bacterial culture solution and the sterile culture solution, a layer of soil was added. Each treatment was replicated four times. A second application of bacterial solution was performed four weeks (28 days) later. Agronomic traits were measured 8 weeks after planting. The growth effects of patchouli plants were as follows: Figure 8 As shown, the changes in plant height, stem diameter, number of main stem branches, number of leaves, plant fresh weight, and plant dry weight are compared. Figure 9 As shown.

[0053] from Figure 8-9 It can be seen that after applying bacterial solutions made from different Flavobacterium species, except... F. oryzaeAll of these treatments showed growth-promoting effects on patchouli, with the application of Flavobacterium P1R7GS3 showing the most significant growth-promoting effect, noticeably increasing the number of leaves. Figure 9 d) plant fresh weight ( Figure 9 e), plant dry weight ( Figure 9 The growth of f) in [the sample / sample]. This indicates a relative increase compared to Flavobacterium BB8. F. soyae as well as F. oryzae This strain has a more significant growth-promoting effect on patchouli and has greater application potential. It can be used to develop microbial agents and bio-fertilizers for promoting crop growth in the field.

[0054] Example 5 Effect of inoculation strain P1R7GS3 on the content of active ingredients in patchouli Plant material: Patchouli seedlings with a height of about 25cm (seedling pot size: bottom diameter 10.2cm, height 12.5cm, outer diameter and inner diameter are 14.5cm and 13.5cm respectively; one seedling per pot).

[0055] Experimental Methods: Patchouli from Example 4, inoculated with blank LB (CK group) and P1R7GS3 (P1R7GS3 group) for eight weeks, was dried to constant weight at 40℃. The whole plant was powdered and passed through a 40-mesh sieve. 0.2g of patchouli powder was weighed into sample vials, with each sample weighed twice. Then, 20μL of DL-camphor (source leaf 21368-68-3) internal standard solution with a concentration of 0.999mg / mL was added to each sample vial. The vials were dried in an oven at 40℃ for 15min, and then capped. After incubating the sample vials at 90℃ for 20min, volatile substances of patchouli were extracted from the headspace vial using a solid-phase microextraction (SPME) head coated with 65μm polydimethylsiloxane / divinylbenzene (PDMS / DVB) under stirring at 300rpm for 20min. After injection, the extraction head was desorbed for 5 min at a split injection port (split ratio 10:1) at 250℃. The column oven temperature was initially maintained at 40℃ for 3.5 min, then increased to 120℃ at 20℃ / min, followed by 200℃ / min at 5℃ / min, and finally increased to 280℃ at 25℃ / min and held for 5 min. Helium was used as the carrier gas at a constant flow rate of 1.2 mL / min. The MS transfer tube temperature and ion source temperature were set to 280℃ and 300℃, respectively; the ionization mode was electron impact ionization (EI), the scanning mode was full scan, and the mass range was 40-600 m / z. Semi-quantitative analysis was performed using internal standards and compound peak areas, and the compound content (mg / g) was calculated using the following formula: ; In the formula, C x The concentration of the target compound is expressed in mg / g; A x C represents the chromatographic peak area of ​​the target compound.y V represents the mass concentration of the internal standard solution, in mg / mL. y A is the volume of the internal standard solution, in μL; y M is the peak area of ​​the internal standard; i The sample mass is in g. The content of active ingredients in patchouli under the two treatment conditions is shown in Table 4.

[0056] Table 4. Content of effective components in patchouli under two treatments (n=4, mg / g)

[0057] As shown in Table 4, compared with the blank LB liquid treatment group (CK), the content of the main active ingredients in patchouli, patchouli alcohol, patchouli ketone, and other active ingredients such as patchoulene, seychellesene, and norpatouli alcohol increased after the application of P1R7GS3 bacterial solution. Among them, the content of patchouli ketone increased by 28.13%.

[0058] In summary, the strain P1R7GS3 of this application exhibits ammonia production, indoleacetic acid production, and zinc solubility, and possesses biofilm formation capabilities. These properties provide excellent growth promotion for plants, particularly patchouli. It not only significantly promotes the growth of biomass indicators such as stem diameter, leaf number, fresh weight, leaf fresh weight, dry weight, and leaf dry weight in patchouli plants, but also increases the content of patchouli alcohol and patchouli ketone, the most effective substances in patchouli. Therefore, it can be used as a bio-fertilizer for promoting crop growth in the field, effectively reducing the use of chemical fertilizers.

[0059] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0061] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this application, and these should all be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. The application of *Patchouli* endophytic *Flavobacterium* in promoting plant growth; characterized in that, The endophytic Flavobacterium is Flavobacterium strain P1R7GS3, whose Latin name is... Flavobacterium endoglycinae It was deposited at the Guangdong Provincial Center for Microbial Culture Collection on September 18, 2025, with accession number GDMCC No: 66990. The plant in question is patchouli.

2. The application according to claim 1, characterized in that, The Flavobacterium strain P1R7GS3 promotes plant growth by producing ammonia.

3. The application according to claim 1, characterized in that, The Flavobacterium strain P1R7GS3 promotes plant growth by producing indoleacetic acid.

4. The application according to claim 1, characterized in that, The Flavobacterium strain P1R7GS3 promotes plant growth by dissolving zinc.

5. The application according to claim 1, characterized in that, The Flavobacterium strain P1R7GS3 promotes plant growth by producing biofilm.

6. The application according to claim 1, characterized in that, Promoting plant growth includes increasing plant height, stem diameter, number of leaves, fresh plant weight, and dry plant weight.

7. The application according to claim 1, characterized in that, The Flavobacterium strain P1R7GS3 was prepared into a bacterial suspension and used for root irrigation treatment of patchouli in pots.

8. The application according to claim 7, characterized in that, The OD of live Flavobacterium strain P1R7GS3 in the bacterial suspension 600 =1.

0.

9. The application according to claim 1, characterized in that, Patchouli growth includes the growth of active ingredients in patchouli; the active ingredients of patchouli are at least one of patchouli alcohol, patchouli ketone, patchouli olefin, seychelles olefin or norpatouli alcohol.

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