Arthrobacter plantarum ARZ1 and application of complex microbial inoculant thereof in promoting nodulation and nitrogen fixation of peanuts

Abstract

The invention discloses arthrobacter plantarum ARZ1 and application of a complex microbial inoculant thereof in promoting nodulation and nitrogen fixation of peanuts, and belongs to the technical field of microorganisms. According to the invention, the complex microbial inoculant consisting of active bacteria of arthrobacter plantarum ARZ1 and sphingomonas melonis SPZ1 is applied to peanut nodulation nitrogen fixation for the first time, and the complex microbial inoculant has obvious influence on the number of peanut root nodules, fresh weight and dry weight of the peanut root nodules, especially can increase the content of bean hemoglobin, and can be used for preparing nitrogen fixation of peanut nodules. When the fertilizer is applied to the peanut planting process, the full fruit number, the full fruit rate and the kernel rate of peanuts can be greatly increased.

Description

Technical Field

[0001] The invention relates to a plant Arthrobacter ARZ1 strain and application of a composite bacterial agent of the strain in promoting peanut nodulation and nitrogen fixation, belonging to the technical field of microorganisms. Background Art

[0002] Peanut (Arachis hypogaea L.), also known as groundnut, is an annual dicotyledonous plant with nodules on its roots. Peanut is the fifth largest oil crop in the world and an economic crop for both food and oil extraction. Its oil yield is as high as 45%-50%, much higher than other oil crops. It plays a huge role in ensuring the safety of national edible oils and fats and promoting farmers' income growth.

[0003] Peanut roots can form nodules, which can directly use nitrogen in the atmosphere as a nitrogen source, playing a vital role in the nitrogen supply of peanuts. Nitrogen fixation in nodules can convert nitrogen in the atmosphere into ammonia that can be directly used by plants. This process is of great significance for improving soil fertility and reducing the use of chemical fertilizers. There is a significant positive correlation between the amount of nitrogen fixed by nodules and peanut yield. Nodule nitrogen fixation is one of the main nitrogen sources for peanuts, and the average nitrogen supply accounts for more than 40% of the total nitrogen, and can reach up to 50%. Therefore, improving the nitrogen fixation ability of peanut nodules has an important impact on the growth and yield of peanuts themselves, is an effective way to achieve nitrogen-saving cultivation, and is also an important measure to maintain and improve soil fertility and promote the sustainable development of agriculture. It can be seen that it is of great significance to take effective regulatory measures in production to improve peanut nodulation and nitrogen fixation.

[0004] At present, there is no literature reporting that Arthrobacter has the biological activity of promoting peanut nodulation and nitrogen fixation. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a plant Arthrobacter ARZ1 strain, and the use of a composite bacterial agent of the strain in promoting peanut nodulation and nitrogen fixation.

[0006] In order to achieve the above purpose, the inventors determined the composite bacterial agent suitable for application in peanuts by exploring the effects of different strains on the number of nodules, fresh weight of nodules, dry weight of nodules, leghemoglobin content, number of full fruits, full fruit rate and kernel yield rate of two peanut varieties, and finally obtained the following technical scheme:

[0007] A plant Arthrobacter oryzae ARZ1, whose strain preservation number is CCTCCNo: M20241883. A melon sphingomonas melonis SPZ1, whose strain preservation number is CCTCCNo: M20241884.

[0008] It should be noted that the plant Arthrobacter ARZ1 (Arthrobacter oryzae) used in the present invention is isolated from the rhizosphere soil of peanuts, has excellent self-nitrogen fixation ability, can survive in the rhizosphere and soil of peanuts, grows well under pH7.0-9.0 environmental conditions, and survives well under pH 8.0. The strain was identified as Arthrobacter ARZ1 (Arthrobacter oryzae) by microbiological characteristics such as morphological characteristics, culture characteristics, and physiological and biochemical characteristics. The strain has been deposited in the China Center for Type Culture Collection, with a preservation date of September 2, 2024, and a preservation number of CCTCC No: M20241883.

[0009] The cucurbit sphingomonas SPZ1 (Sphingomonas melonis) used in the present invention is also isolated from the rhizosphere soil of peanuts, has excellent self-nitrogen fixation ability, can survive in the rhizosphere and soil of peanuts, grows well under pH 6.0-9.0 environmental conditions, and survives well under pH 8.0. The strain was identified as cucurbit sphingomonas melonis SPZ1 by microbiological characteristics such as morphological characteristics, culture characteristics, and physiological and biochemical characteristics. The strain was deposited in the China Center for Type Culture Collection on September 2, 2024, with the deposit number CCTCCNo: M20241884.

[0010] When the above two strains are used alone or in combination, they have a significant positive promoting effect on the number of nodules, fresh weight of nodules, dry weight of nodules, leghemoglobin content, number of full fruits, full fruit rate and kernel yield rate of two peanut varieties, Qinghua No. 6 and Qinghua No. 22. Therefore, the present invention also provides the following applications:

[0011] (1) Application of ARZ1 strain or SPZ1 strain or a composite bacterial agent of ARZ1 and SPZ1 in promoting nodulation and nitrogen fixation in peanut.

[0012] (2) Application of ARZ1 strain or SPZ1 strain or a composite bacterial agent of ARZ1 and SPZ1 in promoting the increase of peanut nodule number.

[0013] (3) Application of ARZ1 strain or SPZ1 strain or the composite bacterial agent of ARZ1 and SPZ1 in promoting the increase of peanut nodule fresh weight, nodule dry weight and leghemoglobin content.

[0014] (4) Application of ARZ1 strain or SPZ1 strain or a composite bacterial agent of ARZ1 and SPZ1 in promoting the increase of the number of full peanuts, the full peanut rate and the kernel yield rate;

[0015] In the above application, the ARZ1 strain is Arthrobacter oryzae ARZ1CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1CCTCC No: M20241884.

[0016] Further preferably, when the composite bacterial agent is used, the ratio of the number of live bacteria of Sphingomonas melonis SPZ1 and Arthrobacter oryzae ARZ1 is 2:1.

[0017] Further preferably, the composite bacterial agent is prepared to have a total viable bacterial count of (1.0-2.0)×10 10 cfu / mL of bacterial solution; the first application is in the beginning flowering stage of peanuts, the dosage is 2.5-3.5L / 667m 2 The second application is during the peanut pod-setting period, with a dosage of 2.5-3.5L / 667m 2 .

[0018] Still more preferably, if manual application is adopted, the bacterial solution is diluted with clean water and then sprayed on the roots of peanuts using an agricultural sprayer; if drone spraying is used, the bacterial solution is directly diluted with clean water and placed in a medicine barrel and sprayed before rain.

[0019] Still more preferably, when peanuts are planted in a film-covered planting method, drip irrigation with bacterial solution is adopted, and the irrigation depth moistens the soil by 8-10 cm.

[0020] Still more preferably, the bacterial solution and the pesticide cannot be used together, and the interval between their use is more than 2 days.

[0021] In addition, the composite bacterial agent of the present invention can be prepared by the following method: mixing the bacterial solution of Sphingomonas melonis SPZ1 and Arthrobacter oryzae ARZ1 cultured to the logarithmic growth phase, and adding a protective agent to the mixed bacterial solution to adjust the number of viable bacteria to (1.0-2.0)×10 10 cfu / mL, pH 6-9; the protective agent is composed of: 90-120g / L skim milk powder, 25-35mL / L glycerol, 90-120g / L maltodextrin, 120-180g / L lacquer sugar and 8-13g / L L-sodium glutamate.

[0022] The fermentation culture method of Sphingomonas melonis SPZ1 is as follows: Sphingomonas melonis SPZ1 is inoculated into beef extract peptone culture medium at an inoculum amount of 4%-10%, and is cultured at a constant temperature of 25-27°C for 24-72 hours. After centrifugal washing, a mixed solution containing 0.5g / L Yeast Extract, 20g / L Mannitol, 0.2g / L K2HPO4, 0.8g / L KH2PO4, 0.2g / L MgSO4·7H2O, 0.1g / L CaSO4·2H2O, 0.01g / L FeCl3, 0.002g / L Na2MoO4·2H2O, and 15g / L Agar is added to each bacterial precipitate, and the pH is 4. 6-9, and the viable count of Sphingomonas melonis SPZ1 was adjusted to (1.0-2.0)×10 10 cfu / mL, mix well and pour into culture.

[0023] The fermentation culture method of Arthrobacter oryzae ARZ1 is as follows: oryzae ARZ1 was inoculated into beef extract peptone culture medium at an inoculum rate of 4%-10%, and cultured at a constant temperature of 25-27°C for 24-72 hours. After centrifugation and washing, a mixed solution containing 0.5 g / L Yeast Extract, 20 g / L Mannitol, 0.2 g / L K2HPO4, 0.8 g / L KH2PO4, 0.2 g / L MgSO4﹒7H2O, 0.1 g / L CaSO4﹒2H2O, 0.01 g / L FeCl3, 0.002 g / L Na2MoO4﹒2H2O, and 15 g / L Agar was added to each bacterial precipitate, and the pH was adjusted to 6-9, and the viable count of Arthrobacter oryzae ARZ1 was adjusted to (1.0-2.0)×10 10 cfu / mL, mix well and pour into culture.

[0024] In addition, the present invention also provides a method for using the composite bacterial agent to promote peanut nodulation and nitrogen fixation, the method comprising preparing the composite bacterial agent into a total number of viable bacteria of (1.0-2.0)×10 10 cfu / mL of bacterial solution, the first application is in the beginning of flowering of peanuts, the dosage is 3L / 667m 2 The second application was during the peanut pod-setting period, with a dosage of 3L / 667m 2 .

[0025] Further preferably, as described above, in the planting method for promoting nitrogen absorption and utilization of peanuts, if manual application is adopted, the solution is diluted with clean water and then sprayed on the roots of peanuts using an agricultural sprayer; if drone spraying is used, the bacterial solution is directly diluted with clean water and placed in a medicine barrel for spraying before rain.

[0026] Further preferably, in the planting method for promoting nitrogen absorption and utilization of peanuts as described above, when the peanuts are planted in a film-covered planting method, drip irrigation with bacterial solution is carried out using the sub-film drip irrigation method, and the irrigation depth is sufficient to wet the soil 8-10 cm.

[0027] Still more preferably, in the planting method for promoting nitrogen absorption and utilization of peanuts as described above, no matter which application method is used, it should be noted that the applied bacterial solution and pesticide cannot be used together, and the interval between their use is more than 2 days.

[0028] Compared with the prior art, the active bacteria in the composite bacterial agent of the present invention are composed of Arthrobacter oryzae ARZ1 and Sphingomonas melonis SPZ1. The two bacteria in the composite bacterial agent promote the increase in the number of peanut nodules through synergistic action, and the fresh weight, dry weight and leghemoglobin content of the nodules are significantly improved. In particular, the number of full fruits, the full fruit rate and the kernel yield rate of peanuts can be increased. Application in the peanut planting process can greatly improve the nodulation and nitrogen fixation ability of peanuts. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 :Plant culture and scanning electron microscopy images of Arthrobacter oryzae ARZ1;

[0030] Figure 2 :Plate culture and scanning electron microscopy images of Sphingomonas melonis SPZ1;

[0031] Figure 3 :The effect of each group of strains on the number of peanut nodules;

[0032] Figure 4 :Effects of each group of strains on the fresh weight of peanut nodules;

[0033] Figure 5 :Effects of each group of strains on the dry weight of peanut nodules;

[0034] Figure 6 :Effects of each group of strains on leghemoglobin content;

[0035] Figure 7 :The effect of each group of strains on the number of full fruits;

[0036] Figure 8 :The effect of each group of strains on the fruit-filling rate;

[0037] Fig. 9 :The effect of each group of strains on kernel yield;

[0038] Figure 3-Figure 9 Different letters in the text represent significant differences among different treatments in the same group (p<0.05). DETAILED DESCRIPTION

[0039] The above contents of the present invention are further described in detail below by way of examples, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples, and all technologies realized based on the above contents of the present invention belong to the scope of the present invention. In addition, the test methods in the following examples are conventional methods unless otherwise specified.

[0040] Example 1: Screening and Isolation of ARZ1 and SPZ1 Strains

[0041] (1) The process of discovering, screening, isolating and identifying strains. Based on the test of adding specific root secretions of corn and peanut intercropping, the inventors found that the addition of root secretions can increase the number of peanut rhizosphere nodules and stimulate the nodulation and nitrogen fixation of peanut plants. Therefore, we speculate that the addition of root secretions reassembles the soil microbial community, thereby promoting the nodulation and nitrogen fixation of peanuts. On this basis, we prepared the peanut rhizosphere soil samples treated with the above-mentioned root secretion addition into a suspension, applied the bacterial solution to the bacterial culture medium, and isolated and purified the strains. The 16S rRNA sequence of the isolated strains was obtained using high-throughput sequencing technology, and the 16S rRNA sequence was compared with the nr database of NCBI. The sequence clustering analysis was performed by comparing the degree and similarity, and a phylogenetic tree was constructed. The isolated and purified strains were compared with known strains, and a comprehensive analysis was performed in terms of morphology, physiology and biochemistry to determine the bacterial species. In order to further verify the function of the strains, the isolated and purified strains were used to carry out peanut cultivation addition experiments.

[0042] (2) Mycological properties of microorganisms. The colonies of Arthrobacter oryzae ARZ1 are white, round, and moist. Figure 1 ), can grow on nitrogen-fixing medium, with a suitable pH of 6-9 and a temperature of 25-27°C. The colonies of Sphingomonas melonis SPZ1 are yellow, round, small, moist and smooth, opaque, with neat edges and no halos ( Figure 2 ), can grow on nitrogen-fixing medium, suitable growth pH is 6-9, temperature is 25-27℃.

[0043] Example 2: Preparation of ARZ1, SPZ1 and composite bacterial agents

[0044] (1) Arthrobacter oryzae ARZ1 was inoculated at a rate of 4% to 10% in a beef extract peptone culture medium (beef extract 3 g / L, peptone 10 g / L, NaCl 5 g / L, agar 15 g / L), pH 7.4-7.6, culture at a constant temperature of 25-27°C for 24-72 hours, and after centrifugation and washing, add a nitrogen-fixing medium containing 0.5 g / L Yeast Extract, 20 g / L Mannitol, 0.2 g / L K2HPO4, 0.8 g / L KH2PO4, 0.2 g / L MgSO4·7H2O, 0.1 g / L CaSO4·2H2O, 0.01 g / L FeCl3, 0.002 g / L Na2MoO4·2H2O, and 15 g / L Agar to the bacterial precipitate, pH 6-9, and adjust the viable count of Arthrobacter oryzae ARZ1 to about 1.0×10 10 cfu / mL, mix well and then pour culture; the specific operation method of pour culture is: dilute the plant Arthrobacter oryzae (Arthrobacter oryzae) ARZ1 suspension and add it to the sterile nitrogen-fixing medium, invert and culture after solidification, a single strain proliferates to form colonies, take a single colony to make a suspension, repeat several times to obtain a pure culture.

[0045] (2) Sphingomonas melonis SPZ1 was inoculated at an inoculum amount of 4% to 10% in a beef extract peptone culture medium (beef extract 3 g / L, peptone 10 g / L, NaCl 5 g / L, agar 15 g / L), and cultured at a constant temperature of 25-27° C. for 24-72 hours. After centrifugation and washing, a mixed solution containing 0.5 g / L Yeast Extract, 20 g / L Mannitol, 0.2 g / L K2HPO4, 0.8 g / L KH2PO4, 0.2 g / L MgSO4·7H2O, 0.1 g / L CaSO4·2H2O, 0.01 g / L FeCl3, 0.002 g / L Na2MoO4·2H2O, and 15 g / L Agar was added to each bacterial precipitate, and the pH was adjusted to 8. 6-9, and the number of live bacteria of Sphingomonas melonis SPZ1 was adjusted to about 1.0×10 10cfu / mL, mix well and then pour culture; the specific operation method of pour culture is: dilute the Sphingomonas melonis SPZ1 suspension and add it to the sterile nitrogen-fixing medium, invert and culture after solidification, a single strain proliferates to form colonies, take a single colony to make a suspension, repeat several times to obtain a pure culture.

[0046] (3) Prepare a protective agent, the composition of which is: 100 g / L skim milk powder, 30 mL / L glycerol, 100 g / L maltodextrin, 150 g / L lacquer sugar and 10 g / L sodium L-glutamate, pH 6-9.

[0047] (4) Add the protective agent prepared in step (3) to the Arthrobacter ARZ1 bacterial solution obtained in step (1) to adjust the viable bacterial count to about 1.0×10 10 cfu / mL , and obtain ARZ1 bacterial agent The protective agent prepared in step (3) was added to the bacterial solution of Sphingomonas cucurbitae SPZ1 obtained in step (2) to adjust the number of viable bacteria to about 1.0×10 10 cfu / mL , and obtain SPZ1 bacterial agent .

[0048] The bacterial liquid obtained in steps (1) and (2) was mixed at a live bacterial count ratio of 2:1 between Sphingomonas cucurbitae SPZ1 and Arthrobacter plantum ARZ1, and the protective agent prepared in step (3) was added to the mixed bacterial liquid to adjust the live bacterial count to about (1.0-2.0)×10 10 cfu / mL , and obtain the composite bacterial agent .

[0049] Example 3: Experiment on the ARZ1 strain in potted peanut cultivation

[0050] Test type: Pot test

[0051] Experimental location: Qingdao Agricultural University (Qingdao, China)

[0052] Test time: 2023.05-2023.09

[0053] Test crops: Peanuts (variety: Qinghua No. 6, Qinghua No. 22)

[0054] Test soil: sterilized soil (soil pH 6.70, organic matter 11.92 g / kg, alkaline nitrogen 99.86 mg / kg, available phosphorus 35.22 mg / kg, available potassium 89.79 mg / kg).

[0055] Experimental groups: CK was the blank control, ARZ1-F and ARZ1-T were treated with plant bacterium ARZ1, and each treatment was repeated 3 times in random blocks.

[0056] Experimental design: PVC pots were used for potting, with an inner diameter of 16 cm and a height of 23.5 cm. Bacterial solution was added 25 days after peanut sowing, and samples were taken at the harvest time after the bacterial solution was added.

[0057] Dosage and method: ARZ1-F was treated with 0.05 mL / pot of the ARZ1 inoculant prepared in Example 2, and ARZ1-T was treated with 0.1 mL / pot of the ARZ1 inoculant prepared in Example 2. The bacterial solutions were diluted to 200 mL respectively and poured to the roots of peanuts. CK was 200 mL of blank aqueous solution.

[0058] Table 1 Number of nodules in plants treated with Arthrobacterium arz1

[0059]

[0060] Note: Different letters represent significant differences among different treatments in the same group (p<0.05).

[0061] From the experimental results in Table 1, it can be seen that the number of nodules of Qinghua No. 6 under ARZ1-F treatment was significantly increased by 53.84% and 33.82% compared with CK and ARZ1-T, respectively. The number of nodules of Qinghua No. 22 under ARZ1-F and ARZ1-T treatments was significantly increased by 163.73% and 42.00% compared with CK treatment, respectively. There was a significant difference between the two concentration treatments of Arthrobacterium plantarum ARZ1. In summary, the ARZ1-F treatment of Arthrobacterium plantarum ARZ1 has a significant effect on the increase in the number of nodules of peanut plants and can significantly increase the number of peanut nodules.

[0062] Example 4: Experiment of SPZ1 strain in potted peanut cultivation

[0063] Test type: Pot test

[0064] Experimental location: Qingdao Agricultural University (Qingdao, China)

[0065] Test time: 2023.05-2023.09

[0066] Test crops: Peanuts (variety: Qinghua No. 6, Qinghua No. 22)

[0067] Test soil: sterilized soil (soil pH 6.70, organic matter 11.92 g / kg, alkaline nitrogen 99.86 mg / kg, available phosphorus 35.22 mg / kg, available potassium 89.79 mg / kg).

[0068] Experimental groups: CK was the blank control, SPZ1-F and SPZ1-T were treated with Sphingomonas cucurbitae SPZ1, each treatment was repeated 3 times and arranged in random blocks.

[0069] Experimental design: PVC pots were used for potting, with an inner diameter of 16 cm and a height of 23.5 cm. The inoculant was added 25 days after peanut sowing (mix the inoculant with 200 ml of water and pour it on the roots of peanuts), and samples were taken at the harvest time after the inoculant was added.

[0070] Dosage and method: SPZ1-F was treated with 0.05 mL / pot of the SPZ1 inoculant prepared in Example 2, and SPZ1-T was treated with 0.1 mL / pot of the SPZ1 inoculant prepared in Example 2. The bacterial solutions were diluted to 200 mL respectively and poured to the roots of peanuts. CK was 200 mL of blank aqueous solution.

[0071] Table 2 Number of nodules in plants treated with Sphingomonas cucurbitae SPZ1

[0072]

[0073]

[0074] From the test results in Table 2, it can be seen that the SPZ1-T treatment has a significant effect on increasing the number of nodules of the two varieties. The number of nodules of Qinghua No. 6 under SPZ1-T treatment was significantly increased by 66.63% and 5.00% compared with CK and SPZ1-F, respectively; the number of nodules of Qinghua No. 22 under SPZ1-T treatment was significantly increased by 101.93% and 29.50% compared with CK and SPZ1-F, respectively. In summary, the SPZ1-T treatment of Sphingomonas cucurbitae SPZ1 has a significant effect on the increase in the number of nodules of peanut plants and can significantly increase the number of peanut nodules.

[0075] Example 5: Experiment of composite bacterial agent in field peanut planting

[0076] Test location: Pingdu City, Qingdao City, Shandong Province

[0077] Test time: 2024.05-2024.09

[0078] Test crops: Peanuts (varieties: Qinghua No. 6 and Qinghua No. 22)

[0079] Experimental soil: The soil is mortar black soil (soil pH is 7.06, organic matter is 16.18g / kg, alkaline nitrogen is 77.76mg / kg, available phosphorus is 45.58mg / kg, and available potassium is 78.69mg / kg).

[0080] Test groups:

[0081] CK is blank aqueous solution control;

[0082] The ARZ1-F group was treated with the ARZ1 bacterial agent prepared in Example 2 at a dosage of 1.5 L / 667 m2 ;

[0083] The ARZ1-T group was treated with the ARZ1 bacterial agent prepared in Example 2 at a dosage of 3 L / 667 m 2 ;

[0084] The SPZ1-F group was treated with the SPZ1 bacterial agent prepared in Example 2 at a dosage of 1.5 L / 667 m 2 ;

[0085] The SPZ1-T group was treated with the SPZ1 bacterial agent prepared in Example 2 at a dosage of 3 L / 667 m 2 ;

[0086] The ST+AF group was administered with the composite bacterial agent prepared in Example 2 at a dosage of 3 L / 667 m 2 ;

[0087] Usage: The first application is at the beginning of flowering of peanuts. Dilute the amount of microbial agent per mu in the above test group mentioned in the above treatment to 15L with clean water, and then use an agricultural sprayer to spray it on the roots of peanuts manually; the second application is at the pod-setting stage of peanuts, and the amount and application method are the same as the first application. It should be noted that microbial agents should not be used together with pesticides, and the use time of the two should be at least 2 days apart.

[0088] Planting management: Peanuts are planted in a ridge-covered manner, with a ridge spacing of 90 cm, 2 rows per ridge, a small row spacing of 35 cm on the ridge, and a hole spacing of 11 cm (2 seeds per hole). 50 kg of compound fertilizer (N-P2O5-K2O: 15-15-15) is applied per mu, and no additional fertilizer is required in the later stage.

[0089] Test results:

[0090] 1) Effect on the number of peanut nodules

[0091] pass Figure 3 The results of the experiment were compared and found that compared with CK and four single strain groups, the compound fungus ST+AF group significantly increased the number of peanut nodules. Compared with the blank control group, the number of nodules of Qinghua No. 6 in the compound fungus ST+AF group increased significantly by 84.85%; the number of nodules of Qinghua No. 22 increased significantly by 235.53%. Through statistical comparison, in terms of the number of nodules of the two peanut varieties, the number of peanut nodules in the ST+AF group was significantly improved compared with the SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0092] 2) Effect on fresh weight of peanut nodules

[0093] pass Figure 4 The results of the experiment were compared and found that compared with CK and four single strain groups, the compound fungus ST+AF group significantly increased the fresh weight of peanut nodules. Compared with the blank control group, the fresh weight of nodules of Qinghua No. 6 in the compound fungus ST+AF group increased significantly by 253.33%; the fresh weight of nodules of Qinghua No. 22 increased by 131.03%. Through statistical comparison, the fresh weight of nodules of the two peanut varieties in the compound fungus ST+AF group was significantly higher than that of the single strain SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0094] 3) Effect on dry weight of peanut nodules

[0095] pass Figure 5 The results of the experiment were compared and found that compared with CK and four single strain groups, the compound fungus ST+AF group significantly increased the dry weight of peanut nodules. The dry weight of nodules of Qinghua No. 6 in the compound fungus ST+AF group was significantly increased by 168.12% compared with the CK group, and the dry weight of nodules of Qinghua No. 22 was significantly increased by 78.08% compared with the CK group; through statistical comparison, the dry weight of nodules of the two peanut varieties in the compound fungus ST+AF group was significantly higher than that of the single strain SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0096] 4) Effect on leghemoglobin content

[0097] pass Figure 6 The results of the experiment were compared and found that compared with CK and four single strain groups, the compound bacterial agent ST+AF group significantly increased the leghemoglobin content of peanuts. Compared with the CK group, the leghemoglobin content of Qinghua No. 6 in the compound bacterial agent ST+AF group was significantly increased by 46.38% compared with the CK group, and the leghemoglobin content of Qinghua No. 22 was significantly increased by 21.12% compared with the CK group. Through statistical comparison, the leghemoglobin content of the two peanut varieties in the compound bacterial agent ST+AF group was significantly higher than that of the single strain SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0098] 5) Impact on the number of full fruits

[0099] pass Figure 7 The results of the experiment were compared and found that compared with CK and four single strain groups, the compound fungus ST+AF group significantly increased the number of full fruits of peanuts. Compared with the CK group, the number of full fruits of Qinghua No. 6 in the compound fungus ST+AF group increased significantly by 71.43%, and the number of full fruits of Qinghua No. 22 increased significantly by 118.18%. Through statistical comparison, the number of full fruits of the two peanut varieties in the compound fungus ST+AF group was significantly higher than that of the single strain SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0100] 6) Impact on peanut fruit fullness rate

[0101] pass Figure 8 The results of the experiment were compared and found that compared with CK and four single strain groups, the compound fungus ST+AF group significantly increased the full fruit rate of peanuts. Compared with the CK group, the full fruit rate of Qinghua No. 6 in the compound fungus ST+AF group increased significantly by 43.42%, and the full fruit rate of Qinghua No. 22 increased significantly by 39.90%. Through statistical comparison, the full fruit rate of the two peanut varieties in the compound fungus ST+AF group was significantly higher than that of the single strain SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0102] 7) Impact on peanut kernel yield

[0103] pass Fig. 9 The results of the experiment were compared and found that compared with CK and four single strain groups, the compound fungus ST+AF group significantly increased the kernel yield of peanuts. Compared with the CK group, the kernel yield of Qinghua No. 6 in the compound fungus ST+AF group increased significantly by 23.25%, and the kernel yield of Qinghua No. 22 increased significantly by 16.22%. Through statistical comparison, the kernel yield of the two peanut varieties in the compound fungus ST+AF group was significantly higher than that of the single strain SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0104] In conclusion, statistical comparison showed that the composite agent ST+AF had significant differences in many aspects of peanut nodulation and nitrogen fixation indicators compared with the blank control and single agent addition. This indicates that the composite agent prepared by Sphingomonas melonis SPZ1 (Sphingomonas melonis) and Arthrobacter oryzae ARZ1 (Arthrobacter oryzae) in a ratio of 2:1 (the total number of effective viable bacteria was (1.0-2.0)×10 10 cfu / mL), 3L / 667m 2 Applying appropriate amount of fertilizer at the initial flowering and podding stages of peanut can promote plant growth, increase the number of peanut nodules, fresh weight of nodules, dry weight of nodules, leghemoglobin content, number of full fruits, full fruit rate and kernel yield rate, which is beneficial to improving the nodulation and nitrogen fixation of peanut plants.

Claims

1. A plant Arthrobacter oryzae (Arthrobacter oryzae) ARZ1, whose strain collection number is CCTCCNo:M20241883.

2. Application of ARZ1 strain or SPZ1 strain or a composite bacterial agent of ARZ1 and SPZ1 in promoting nodulation and nitrogen fixation in peanut, wherein the ARZ1 strain is Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1 CCTCC No:M20241884.

3. The use of ARZ1 strain or SPZ1 strain or a composite bacterial agent of ARZ1 and SPZ1 in promoting the increase in the number of peanut nodules, wherein the ARZ1 strain is Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1 CCTCC No: M20241884.

4. The use of ARZ1 strain or SPZ1 strain or a composite bacterial agent of ARZ1 and SPZ1 in promoting the fresh weight, dry weight and leghemoglobin content of peanut nodules, wherein the ARZ1 strain is Arthrobacter oryzae ARZ1CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1CCTCC No: M20241884.

5. Application of ARZ1 strain or SPZ1 strain or a composite bacterial agent of ARZ1 and SPZ1 in promoting the number of full peanut fruits, full fruit rate and kernel yield rate, wherein the ARZ1 strain is Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1 CCTCC No: M20241884.

6. The use according to any one of claims 2 to 5, characterized in that: When the composite strain is used, the ratio of the number of live bacteria of Sphingomonas melonis SPZ1 and Arthrobacter oryzae ARZ1 is 2:

1.

7. The use according to claim 6, characterized in that: The composite bacterial agent is prepared to have a total number of viable bacteria of (1.0-2.0)×10 10 cfu / mL of bacterial solution; the first application is in the beginning flowering stage of peanuts, the dosage is 2.5-3.5L / 667m 2 The second application is during the peanut pod-setting period, with a dosage of 2.5-3.5L / 667m 2 .

8. The use according to claim 7, characterized in that: If manual application is adopted, the solution will be diluted with clean water and sprayed on the roots of peanuts with an agricultural sprayer; if drone spraying is used, the bacterial solution will be directly diluted with clean water and placed in a medicine barrel and sprayed before rain.

9. The use according to claim 7, characterized in that: When peanuts are planted in a film-covered planting method, the bacterial solution is dripped under the film, and the irrigation depth is 8-10cm to moisten the soil.

10. The use according to claim 7, characterized in that: The bacterial solution and pesticides cannot be used together, and the interval between their use should be more than 2 days.

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