Resin-eating neosphingobacterium LB9 and its composite bacterial agent and application

Abstract

The present invention relates to the field of microbial technology, and in particular to a resin-eating new sphingobacterium LB9 and a composite bacterial agent and application thereof. The strain LB9 of the present invention is obtained by screening and separating from the rhizosphere of pear trees in calcareous soil by an applicant, and has the ability to produce IAA and / or iron carriers. Potted plant experiments have shown that the composite bacterial agent prepared from the strain LB9, the strain LB4 and the strain CD1 can significantly improve the root development morphology of peanut seedlings, increase the biomass of the seedlings, and has a good growth-promoting effect on plants; the composite bacterial agent also has a good iron supplementation function, can effectively promote the growth of pear tree, increase the biomass of pear tree, and significantly increase the total iron content of the root system and the active iron content of the leaves of pear tree, indicating that the strain and the corresponding composite bacterial agent both have good growth-promoting and iron supplementation functions.

Description

Technical Field

[0001] The present invention relates to the field of microbial technology, and in particular to resin-eating neosphingobacterium LB9 and a composite bacterial agent and application thereof. Background Art

[0002] Iron is the earliest essential nutrient element discovered for plants. It is abundant in nature, ranking fourth among all elements. As a component of cytochrome, ribonucleotide reductase, nitrogenase, ferroximate and other substances, iron participates in important metabolic processes in plants, such as carbon assimilation, biological fixation and assimilation of nitrogen, storage and transportation of molecular oxygen, reduction of ribonucleotides, decomposition of peroxides and electron transfer.

[0003] Iron deficiency chlorosis is a physiological disease caused by relatively low Fe content in plants, which leads to yellowing of leaves, weakened plant growth, and even endangers plant survival. According to statistics, about 40% of the world's soil is iron-deficient, and the iron deficiency is particularly prominent in arid and semi-arid calcareous soils. In recent years, as global drought has gradually worsened, the salinization area of ​​arable land in the world has gradually expanded, and plant iron deficiency chlorosis has become more serious. Iron deficiency chlorosis has seriously affected the growth and production of crops, fruit trees, flowers and other plants. Relevant researchers have developed a variety of technologies to improve this disease, such as applying nano-iron oxide solution, local soil acidification, arbuscular mycorrhizal fungal colonization, etc., but there is always a situation where the economic investment is too high and it is easy to relapse. For this reason, it is necessary to find an ecological, long-term and economical solution.

[0004] Plant rhizosphere growth-promoting bacteria are the main bacterial species of microbial fertilizers, and have multiple growth-promoting effects such as nitrogen fixation, phosphorus solubilization, phosphorus solubilization, potassium solubilization, secretion of plant hormones, production of iron carriers, improvement of soil environment, regulation of plant growth, and improvement of plant stress resistance. In the prior art, the problem of fermentation bacteria in biological fertilizers is often solved by screening corresponding rhizosphere bacteria. However, in actual work, we found that due to the huge differences in physiological characteristics between strains, a large number of effective strains are often required to be screened. However, based on the current application situation, we found that the use of a single strain is often too single in function. Therefore, in order to improve the absorption of iron by plants and promote the growth of plant roots, the combination of different functional strains, complementary functions and screening of composite bacterial agents can better alleviate the iron deficiency chlorosis of plants and promote plant growth. Summary of the invention

[0005] In view of the above, it is necessary to use a combination of strains with different functions, complement each other's functions and screen out compound bacterial agents to better alleviate the iron deficiency chlorosis of plants and promote plant growth, in order to address the problem that the physiological characteristics between strains are very different and the use of single strains is often too single in function.

[0006] In order to achieve the above purpose, the present invention screened out a new strain: Novosphingobium resinovorum The strain LB9 is classified as: Novosphingobium resinovorum LB9, Chinese classification name: New Sphingobacterium resinophilum LB9, preservation number is CCTCC NO: M20241257; the strain is deposited in China Center for Type Culture Collection, address: No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, and the preservation date is June 17, 2024.

[0007] The present invention also includes the resin-eating new sphingobacterium Novosphingobium resinovorum Inoculum of strain LB9.

[0008] The present invention also includes the resin-eating new sphingobacterium Novosphingobium resinovorum A composite bacterial agent of strain LB9, wherein the composite bacterial agent is composed of resin-eating neosphingosine bacteria Novosphingobium resinovorum strain LB9, Pseudomonas jejuni Pseudomonas jessenii strain LB4 and Pseudomonas spp. Pseudomonas sp. strain CD1; the resin-eating new sphingobacterium Novosphingobium resinovorum The deposit number of strain LB9 is CCTCC NO: M20241257; the Pseudomonas jejuni Pseudomonas jessenii The strain LB4 is classified as: Pseudomonas jessenii LB4, Chinese classification name: Pseudomonas japonicus LB4, preservation number is CCTCC NO: M20241258; the strain is deposited in the China Center for Type Culture Collection, address: No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, and the preservation date is June 17, 2024.

[0009] The Pseudomonas Pseudomonas sp. Strain CD1 is classified as: Pseudomonas sp. CD1, Chinese classification name: Pseudomonas CD1, preservation number is CCTCC NO: M20231300; the strain is deposited in China Center for Type Culture Collection, address: No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, and the preservation date is July 17, 2023. The strain is a published strain, disclosed in patent document 202311758216.X.

[0010] The present invention also includes a method for preparing the composite bacterial agent, which comprises: inoculating the strains into TSB culture medium to obtain corresponding bacterial liquids, and then mixing the three bacterial liquids in equal volume ratios to obtain the composite bacterial agent.

[0011] The present invention also includes the resin-eating new sphingobacterium Novosphingobium resinovorum Application of the strain LB9, the bacterial agent or the composite bacterial agent in the preparation of biological organic fertilizer and / or foliar fertilizer.

[0012] The present invention also includes the resin-eating new sphingobacterium Novosphingobium resinovorum Application of strain LB9, the bacterial agent or the composite bacterial agent in promoting the growth of pears and / or peanuts.

[0013] The present invention also includes the resin-eating new sphingobacterium Novosphingobium resinovorum Application of strain LB9, the bacterial agent or the composite bacterial agent in producing IAA and / or siderophore.

[0014] The present invention also includes the resin-eating new sphingobacterium Novosphingobium resinovorum Application of strain LB9, the bacterial agent or the composite bacterial agent in increasing the total iron content in roots and active iron content in leaves of Pyrus betula.

[0015] Application of the resin-eating neosphingobacterium Novosphingobium resinovorum The method for planting plants using strain LB9, the bacterial agent or the composite bacterial agent is characterized in that the method comprises adding a bacterial suspension containing strain LB9, a biological organic fertilizer of the composite bacterial agent and / or a foliar fertilizer to the plants at the seedling stage.

[0016] Furthermore, the plant is pear and / or peanut.

[0017] The present invention has the following beneficial effects: the strain LB9 of the present invention is obtained by screening and separating from the rhizosphere of pear trees in calcareous soil by the applicant, and has the ability to produce IAA and / or iron carriers. Through potted plant experiments, it is found that the composite bacterial agent prepared by the strain LB9, the strain LB4 and the strain CD1 can significantly improve the root development morphology of peanut seedlings, increase the biomass of seedlings, and has a good growth-promoting effect on plants; the composite bacterial agent also has a good iron supplementation function, can effectively promote the growth of pear, increase the biomass of pear, and significantly increase the total iron content of the pear root system and the active iron content of the leaves, indicating that the strain and the corresponding composite bacterial agent both have good growth-promoting and iron supplementation functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the colony morphology of strain LB4.

[0019] Figure 2 This is the phylogenetic tree of strain LB4 constructed based on the 16S rRNA sequence.

[0020] Figure 3 This is the colony morphology of strain LB9.

[0021] Figure 4 Phylogenetic tree of strain LB9 based on 16S rRNA sequence.

[0022] Figure 5 This is the result of a potted experiment in which peanuts were inoculated with the LB9 composite bacterial agent.

[0023] Figure 6 This is a graph showing the experimental results of different bacterial agents on the aboveground dry weight of peanut seedlings.

[0024] Figure 7 This is a graph showing the experimental results of different bacterial agents on the dry weight of the underground part of peanut seedlings.

[0025] Figure 8 This is the experimental result of different bacterial agents on the total dry weight of peanut seedlings.

[0026] Fig. 9 This is a graph showing the experimental results of the effects of different bacterial agents on the root growth of peanut seedlings.

[0027] Fig.10 This is the experimental result of different bacterial agents on the total root length of peanut seedlings.

[0028] Fig.11 This is the experimental result of different bacterial agents on the root surface area of ​​peanut seedlings.

[0029] Fig.12 This is a graph showing the experimental results of different bacterial agents on the aboveground dry weight of Pyrus betulae seedlings.

[0030] Fig.13 This is a graph showing the experimental results of different bacterial agents on the underground dry weight of Pyrus betulaeformis seedlings.

[0031] Fig.14 This is a graph showing the experimental results of different bacterial agents on the total dry weight of Pyrus betulaeformis seedlings.

[0032] Fig.15 This is the SPAD experimental results of different fungal agents on Pyrus betulaeformis seedlings.

[0033] Fig.16 This is the result of different bacterial agents on the total iron content in the roots of Pyrus betulaeformis seedlings.

[0034] Fig.17 This is the result of different bacterial agents on the active iron content in the leaves of Pyrus betulaeformis seedlings.

[0035] Biomaterial Deposit Information

[0036] Three strains were used in the present application examples, and their preservation information is as follows: ① Neosphingobacterium resinophilum ( Novosphingobium resinovorum ) strain LB9, which is classified as: Novosphingobium resinovorum LB9, Chinese classification name: New Sphingobacterium resinophilum LB9, preservation number is CCTCC NO: M20241257; the strain is deposited in China Center for Type Culture Collection, address: No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, and the preservation date is June 17, 2024.

[0037] ② Pseudomonas jejuni ( Pseudomonas jessenii ) strain LB4, which is classified as: Pseudomonas jessenii LB4, Chinese classification name: Pseudomonas japonicus LB4, preservation number is CCTCC NO: M20241258; the strain is deposited in the China Center for Type Culture Collection, address: No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, and the preservation date is June 17, 2024.

[0038] ③ Pseudomonas ( Pseudomonas sp. ) strain CD1, which is classified as: Pseudomonas sp. CD1, Chinese classification name: Pseudomonas CD1, preservation number is CCTCC NO: M20231300; the strain is deposited in China Center for Type Culture Collection, address: No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, and the preservation date is July 17, 2023. The strain is a published strain, disclosed in patent document 202311758216.X. DETAILED DESCRIPTION

[0039] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0040] Any feature disclosed in this specification (including any appended claims and abstract), unless otherwise stated, is merely an example of a series of equivalent or similar features. Example 1

[0041] This example is the separation and identification of strain LB4 and strain LB9.

[0042] 1. Isolation and identification of Pseudomonas jejuni LB4.

[0043] 1. Isolation and purification of strain LB4: 1 g of rhizosphere soil from pear trees in a calcareous pear orchard in Xinxiang, Henan Province was collected and added to a 50 ml conical flask containing glass beads and 9 ml of SM buffer. The soil suspension was obtained by shaking at 30 °C and 170 °C for 30 min. Sterile water was added to gradually dilute the suspension into 10 -5 ~10 -7 The concentration suspension was spread on TSA medium and cultured at 30°C for 48 hours. Then, a single bacterium was picked out by the plate streak method to purify the strain.

[0044] 2. Identification of strain LB4: ① Morphological identification The specific operation is: inoculate the LB4 strain on TSB medium and culture it in a constant temperature incubator. After 24 hours of culture, observe until round colonies appear on the plate. Figure 1 As shown, Figure 1The colonies were milky white, opaque, with smooth edges and a smooth and moist surface. The colonies were regular circles with relatively uniform sizes, no wrinkles or protrusions on the surface, and no diffuse or flocculent edges, which were consistent with the morphological characteristics of Pseudomonas jejuni LB4; ② After the strain DNA was extracted and sequenced, molecular identification was performed to construct a phylogenetic tree. Combined with the phylogenetic tree ( Figure 2 ) and morphological identification, the strain was classified and named Pseudomonas jessenii .

[0045] 2. Isolation and identification of resin-feeding neosphingobacterium LB9.

[0046] 1. Isolation and purification of strain LB9: 1 g of rhizosphere soil from pear trees in a calcareous pear orchard in Xinxiang, Henan Province was collected and added to a 50 ml conical flask containing glass beads and 9 ml of SM buffer. The soil suspension was obtained by shaking at 30°C and 170°C for 30 min. Sterile water was added to gradually dilute the suspension into 10 -5 ~10 -7 The concentration suspension was spread on TSA medium and cultured at 30°C for 48 hours. Then, a single bacterium was picked out by the plate streak method to purify the strain.

[0047] 2. Identification of strain LB9: ① Morphological identification The specific operation is: inoculate the LB9 strain on TSB medium and culture it in a constant temperature incubator. After 24 hours of culture, observe until round colonies appear on the plate. Figure 3 As shown, Figure 3 The colonies were light yellow, opaque, and had a relatively uniform shape. The colonies had neat edges, were round, and had a smooth surface. This was consistent with the morphological characteristics of the resin-eating neosphingobacterium LB9; ② After the strain DNA was extracted and sequenced, molecular identification was performed to construct a phylogenetic tree. Combined with the phylogenetic tree ( Figure 4 ) and morphological identification, the strain was classified and named Novosphingobium resinovorum . Example 2

[0048] This example is a growth-promoting function assay of strain LB9 and strain LB4.

[0049] 1. Determination of the growth-promoting function of strain LB9.

[0050] 1. Determination of iron-dissolving capacity of strain fermentation broth: Add 1% of the activated strain to a 50 μmol·L -1 Fe2O3 solid powder was added to TSB medium and treated with no inoculation (CK) for three replicates at 28℃ and 170r·min -1 The culture was shaken for 48 h. The fermentation supernatant was collected and digested by mixed acid (concentrated HNO3:HClO4=4:1) method, and the iron content was determined by ICP-OES.

[0051] 2. Qualitative determination of IAA function of strains: LB4 strain was added to TSB medium containing L-tryptophan at a 1% inoculum, 30℃ 170 r·min -1 After shaking for 48 hours, centrifuge at 10,000 rpm for 5 minutes to obtain the supernatant. Take 100 μL of the supernatant and mix it with an equal volume of Salkowski colorimetric solution. Mix 100 μL of uninoculated culture medium with an equal volume of Salkowski colorimetric solution as a blank control. React in dark conditions for 30 minutes. If the solution turns red, it means that the strain has IAA ability.

[0052] 3. Determination of strain growth ability: Inoculate LB9 strain seed solution and measure the OD of the bacterial solution under each treatment at 0, 4, 8, 12, 16, 20, and 24 hours 600 Value, determine its 24h growth status.

[0053] 4. Determination of iron carrier production capacity: Referring to Schwyn and Neilands, the bacterial suspension cultured in MSA medium for 48 h under iron-limited conditions was centrifuged at 3500 rpm for 10 min through a perforated filter. The supernatant was mixed with CAS detection solution in a 1:1 ratio, allowed to react for 2 h, and the OD was measured. 630 The absorbance value at nm (A); the control is sterile MSA culture medium, which is also mixed with CAS detection solution in equal proportions and the absorbance value (Ar) is measured. The relative content of iron carriers is calculated according to the formula [(Ar-As) / Ar]×100%.

[0054] The above growth-promoting properties test results are shown in Table 1.

[0055]

[0056] As shown in Table 1, the LB9 strain has good growth-promoting function and the ability to produce iron carriers and dissolve insoluble iron oxide.

[0057] 2. Determination of the growth-promoting function of strain LB4.

[0058] 1. Qualitative determination of IAA function of strains: LB4 strain was added to TSB medium containing L-tryptophan at a 1% inoculum, 30°C, 170 r·min -1 After shaking for 48 hours, centrifuge at 10,000 rpm for 5 minutes to obtain the supernatant. Take 100 μL of the supernatant and mix it with an equal volume of Salkowski colorimetric solution. Mix 100 μL of uninoculated culture medium with an equal volume of Salkowski colorimetric solution as a blank control. React in dark conditions for 30 minutes. If the solution turns red, it means that the strain has IAA ability.

[0059] 2. Determination of nitrogen fixation and phosphorus solubilization ability of strains: Add 10 μL of the activated LB4 bacterial suspension to the Axubei nitrogen fixation medium, the Montgina organophosphate medium and the PKO inorganic phosphorus medium, respectively, with three replicates each, and culture in a 28°C incubator for 5 days. Observe whether there are halos or transparent circles on the culture medium, and judge the strain's ability to fix nitrogen and solubilize organic and inorganic phosphorus based on the ratio of the halo or transparent circle (D) to the colony diameter (d).

[0060] 3. Determination of iron carrier production capacity: Referring to Schwyn and Neilands, the bacterial suspension cultured in MSA medium for 48 h under iron-limited conditions was centrifuged at 3500 rpm for 10 min through a perforated filter. The supernatant was mixed with CAS detection solution at a ratio of 1:1, allowed to react for 2 h, and the OD was measured. 630 The absorbance value at nm (A); the control is sterile MSA culture medium, which is also mixed with CAS detection solution in equal proportions and the absorbance value (Ar) is measured. The relative content of iron carriers is calculated according to the formula [(Ar-As) / Ar]×100%.

[0061] The above growth-promoting properties test results are shown in Table 2.

[0062]

[0063] As can be seen from Table 2, strain LB4 also has good growth-promoting function and good siderophore production ability. Example 3

[0064] This embodiment is a composite bacterial agent and a preparation method thereof.

[0065] This example uses the strains applied for on the same day: Pseudomonas jejuni ( Pseudomonas jessenii )LB4, Neosphingobacterium resiniferum ( Novosphingobium resinovorum )LB9 and Pseudomonas ( Pseudomonas sp. )CD1 (the corresponding function is disclosed in patent application 202311758216.X), and the specific preparation method of the composite bacterial agent is: Pseudomonas jejuni ( Pseudomonas jessenii )LB4, Neosphingobacterium resiniferum ( Novosphingobium resinovorum )LB9 and Pseudomonas ( Pseudomonas sp. )CD1 were inoculated into TSB medium, cultured at 22-30°C under aerobic conditions for 48-72 hours to obtain the corresponding bacterial solution, and then the three bacterial solutions were mixed in equal volume ratios to obtain a composite bacterial agent; Pseudomonas jejuni ( Pseudomonas jessenii ) The effective viable count of LB4 is 1.4×10 9 CFU / mL, Neosphingobacterium resinophilum ( Novosphingobium resinovorum ) The effective viable count of LB9 is 1.5×10 9 CFU / mL, effective viable count of Pseudomonas CD1 was 1.7×10 9 CFU / mL. Example 4

[0066] Study on the growth-promoting effect of composite fungal agents on peanut seedlings.

[0067] (1) Peanut seedlings: Soak the peanut seeds in sterile water for 12 hours, add 1% hydrogen peroxide to disinfect for 20 minutes, and finally wash with sterile water. Spread the sterilized seeds on a culture medium covered with filter paper soaked in sterile water, place in a 28°C constant temperature incubator for germination for 3-5 days, select white peanut seeds and sow them in sterilized substrate for seedling cultivation. When the peanut seedlings have 2-3 true leaves, select healthy and consistent seedlings and transplant them into a sterilized mixed soil with a ratio of 3:2 of calcareous soil: quartz sand.

[0068] (2) Inoculation: The composite bacterial suspension prepared in Example 3 and the bacterial suspensions of LB9, LB4, and CD1 single strains (final concentration of 10 7 CFU / g soil) was inoculated into the rhizosphere of peanut seedlings, and the uninoculated treatment was used as the control. Each treatment was repeated 12 times, and samples were collected after 30 days of cultivation to determine the phenotypic traits of peanut.

[0069] The test results are as follows Figure 5-Figure 13 As shown, Figure 5 This is the result of the composite fungicide on the growth of peanut plants. It can be seen from the figure that: Figure 5 ②The growth rate was significantly better than that of the plants not inoculated with any fungus. Figure 5 ①; The experimental results of the effects of composite bacterial agent, LB9 single strain, LB4 single strain and CD1 single strain on the dry weight of peanut seedlings are as follows Figure 6-Figure 8 As shown, from Figure 6-Figure 8 It can be seen that the aboveground dry weight, root dry weight and total dry weight of peanut seedlings in the experimental groups inoculated with single strains of LB9, LB4 and CD1 were significantly higher than those in the control group (CK); and after the combination of several strains, the aboveground dry weight, root dry weight and total dry weight of peanut seedlings treated with the composite bacterial agent (Mix) were better than those of single strains, and even reached significant differences. Among them, compared with the control group (CK), the aboveground dry weight, root dry weight and total dry weight of peanut seedlings in the composite bacterial agent treatment (Mix) were significantly increased by 78.42%, 155.4% and 84.32%, respectively. From the observation of the root system, it can also be seen that both the single strain experimental group and the composite bacterial agent have improved the root system of peanuts. Specifically, Figure 9-13 shown; from Fig. 9It can be seen that the root systems of the experimental groups inoculated with single strain LB9, single strain LB4 and single strain CD1 are more developed than those of CK, while the root system of the peanut seedlings inoculated with the composite microbial agent (Mix) is significantly more developed than that of the peanut seedlings not inoculated with any microbial agent (CK), with little difference compared with the root system of the single strain LB9, and significantly better than the root system inoculated with the single strain LB4; in addition, from Figure 10-11 The experimental results also showed that the root length and root surface area of ​​the peanut seedlings in the experimental groups inoculated with single strains LB9, LB4 and CD1 were higher than those in the control group (CK), and reached a significant level. After the combination of several strains, the root length and root surface area of ​​the peanut seedlings treated with the composite bacterial agent (Mix) were equivalent to the promoting effect of single strains CD1 and LB9 on root length, and significantly higher than those of the single strain LB4. Compared with the control group (CK), the root length and root surface area of ​​the peanut seedlings treated with the composite bacterial agent (Mix) were increased by 147.0% and 121.0% respectively compared with the control group (CK). Example 5

[0070] Study on the effect of composite bacterial agent on improving iron nutrition of Pyrus betula.

[0071] (1) Seedling cultivation of Pyrus betulus: Soak the seeds in sterile water for 24 hours, then soak them in 75% alcohol for 30 seconds, rinse them with sterile water for 3-5 times, add 2% sodium hypochlorite and soak them for 20 minutes, and finally clean them with sterile water. Spread the sterilized seeds on a culture medium covered with filter paper soaked in sterile water, place them in a 28℃ constant temperature incubator for germination for 3-5 days, select the germinated seeds and sow them in a sterilized substrate for seedling cultivation. When the Pyrus betulus seedlings in the seedling substrate have 2-3 true leaves, select healthy and consistent seedlings and transplant them into sterilized substrate pots.

[0072] (2) Inoculation: The composite bacterial suspension prepared in Example 3 and the bacterial suspensions of LB9, LB4, and CD1 single strains (final concentration of 10 7 CFU / g soil) was inoculated into the rhizosphere of Pyrus betulaeformis seedlings, and the uninoculated treatment was used as the control. Each treatment was repeated 12 times, and samples were collected after 30 days of culture to determine the phenotypic traits of Pyrus betulaeformis.

[0073] The test results are as follows Figure 12-Figure 17 As shown in the figure: The growth of Pyrus betulata seedlings is as follows Figure 12-14As shown in the figure, it can be seen that the aboveground dry weight and total dry weight of the Pyrus betulaeformis seedlings in the experimental groups inoculated with LB9 single strain, LB4 single strain and CD1 single strain were significantly increased; the underground dry weight of the Pyrus betulaeformis seedlings in the experimental groups inoculated with LB9 single strain and LB4 single strain was also significantly increased, but the underground dry weight of the Pyrus betulaeformis seedlings in the experimental group inoculated with CD1 single strain was not significantly increased; however, the aboveground dry weight, underground dry weight and total dry weight of the Pyrus betulaeformis seedlings in the composite bacterial agent treatment (Mix) were higher than those in the experimental groups inoculated with LB9 single strain, LB4 single strain and CD1 single strain, and reached a significant difference; compared with the control group (CK), the aboveground dry weight, underground dry weight and total dry weight of the Pyrus betulaeformis seedlings in the composite bacterial agent treatment (Mix) were significantly increased by 110.1%, 210.3% and 133.1%, respectively.

[0074] The experimental results of SPAD content in Pyrus betulaeformis seedlings are as follows Fig.15 As shown, from Fig.15 It can be seen that the SPAD content of Pyrus betulaeformis seedlings inoculated with single strain LB9, single strain LB4, single strain CD1 and compound bacterial agent treatment (Mix) was significantly improved, among which the best improvement effect was inoculated with single strain LB9, single strain CD1 and compound bacterial agent treatment (Mix) experimental group.

[0075] The experimental results on the iron content of Pyrus betulaeformis seedlings are as follows Figure 16-17 As shown, from Fig.16 It can be seen that the root total iron content of the Pyrus betulae seedlings in the experimental group inoculated with the LB9 single strain and the LB4 single strain was lower than that of the control group, and the difference was significant. The root total iron content of the Pyrus betulae seedlings in the experimental group inoculated with the CD1 single strain was higher than that of the control group, and the difference was significant. The root total iron content of the experimental group inoculated with the composite bacterial agent treatment (Mix) reached the highest, and the difference was significant. Fig.17 As shown in the figure, the active iron content of the leaves of the experimental groups inoculated with LB9 single strain, LB4 single strain, CD1 single strain and composite bacterial agent treatment (Mix) was significantly improved, among which the best improvement effect was in the experimental group inoculated with LB9 single strain; this shows that LB9 has a strong iron activation ability when used alone, and can significantly improve the active iron level per unit mass. In addition, under the Mix treatment, although the active iron content decreased slightly, it did not reach a significant difference, and its biomass increased by 133.1%. This shows that the Mix treatment can maintain a high iron activation ability while significantly promoting the growth of Pyrus betula seedlings, reflecting its comprehensive advantages in improving plant iron nutrition and growth performance.

[0076] In summary, the resin-eating new sphingobacterium LB9 screened by the applicant of the present invention has the ability to produce IAA, dissolve phosphorus, fix nitrogen and produce iron carriers. The applicant mixed the strain with strains with the same activity: Pseudomonas jejuni LB4 and Pseudomonas CD1 to prepare a composite bacterial agent, and used the composite bacterial agent in potted experiments of peanuts and pears. The potted experiments proved that the composite bacterial agent has a good effect on promoting plant growth, and can also increase the iron content of plants, effectively prevent the occurrence of plant chlorosis, and has good growth-promoting and iron-supplementing functions.

[0077] The above-described embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. Neosphingobacterium resiniferum Novosphingobium resinovorum The strain LB9 has a deposit number of CCTCCNO: M20241257.

2. A resin-eating sphingobacterium according to claim 1 Novosphingobium resinovorum Inoculum of strain LB9.

3. A resin-eating sphingobacterium according to claim 1 Novosphingobium resinovorum The composite bacterial agent of strain LB9 is characterized in that: The composite bacterial agent is made from resin-feeding neosphingosine bacteria Novosphingobium resinovorum strain LB9, Pseudomonas jejuni Pseudomonas jessenii strain LB4 and Pseudomonas spp. Pseudomonas sp. strain CD1 composition; Neosphingobacterium resiniferum Novosphingobium resinovorum The deposit number of strain LB9 is CCTCCNO: M20241257; Pseudomonas jejuni Pseudomonas jessenii The deposit number of strain LB4 is CCTCC NO: M20241258; The Pseudomonas Pseudomonas sp. The deposit number of strain CD1 is CCTCC NO: M20231300.

4. A method for preparing the composite bacterial agent as claimed in claim 3, characterized in that: The method comprises: inoculating the strains into TSB culture medium respectively to obtain corresponding bacterial liquids, and then mixing the three bacterial liquids in equal volume ratio to obtain the composite bacterial agent.

5. The resin-eating neosphingosine bacteria according to claim 1 Novosphingobium resinovorum Use of the strain LB9, the bacterial agent as claimed in claim 2 or the composite bacterial agent as claimed in claim 3 in the preparation of biological organic fertilizer and / or foliar fertilizer.

6. The resin-eating neosphingobacterium according to claim 1 Novosphingobium resinovorum Use of strain LB9, the bacterial agent as claimed in claim 2 or the composite bacterial agent as claimed in claim 3 in promoting the growth of pears and / or peanuts.

7. The resin-eating neosphingobacterium according to claim 1 Novosphingobium resinovorum Use of strain LB9, the bacterial agent as described in claim 2 or the composite bacterial agent as described in claim 3 in producing IAA and / or siderophore.

8. The resin-eating neosphingobacterium according to claim 1 Novosphingobium resinovorum Use of the strain LB9, the bacterial agent as claimed in claim 2 or the composite bacterial agent as claimed in claim 3 in increasing the active iron content in leaves of Pyrus betulaeformis.

9. Use of the resin-eating neosphingosine bacteria as claimed in claim 1 Novosphingobium resinovorum The method for planting plants using the strain LB9, the bacterial agent according to claim 2 or the composite bacterial agent according to claim 3 is characterized in that: The method comprises the following steps: adding a bacterial suspension containing the strain LB9, a composite bacterial agent, a biological organic fertilizer and / or a foliar fertilizer to the plants during the seedling stage.

10. The method according to claim 9, characterized in that The plants are pear and / or peanut.

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