Application of Arthrobacter plantarum ARZ1 and its compound inoculant in promoting peanut nodulation and nitrogen fixation

Abstract

This invention discloses the application of Arthrobacter oryzae and its compound microbial agent in promoting peanut nodulation and nitrogen fixation, belonging to the field of microbial technology. This invention is the first to apply a compound microbial agent composed of Arthrobacter oryzae and Sphingomonas melonis SPZ1 to peanut nodulation and nitrogen fixation. This compound microbial agent has a significant impact on the number of peanut root nodules, the fresh weight and dry weight of peanut root nodules, and especially can increase the content of leghemoglobin. When applied during peanut cultivation, it can significantly increase the number of full pods, the full pod rate, and the kernel yield.

Description

TECHNICAL FIELD

[0001] The present application relates to a plant Arthrobacter ARZ1 strain and application of a complex microbial agent of the strain in promoting peanut nodule fixation of nitrogen, and belongs to the technical field of microorganisms. BACKGROUND

[0002] Peanut (Arachis hypogaea L.) is also known as groundnut, which belongs to annual dicotyledonous plants and has root nodules. Peanut is the fifth largest oil crop in the world and is an economic crop for both consumption and oil pressing, with an oil yield of 45%-50%, which is much higher than that of other oil crops, and plays a huge role in guaranteeing national edible oil safety and promoting farmers' income.

[0003] Peanut roots can form nodules, and these nodules can directly use atmospheric nitrogen as a nitrogen source, which plays a crucial role in the supply of nitrogen to peanut. The nitrogen fixation in the root nodule can convert atmospheric nitrogen into ammonia that can be directly used by plants, which 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 root nodule nitrogen fixation and peanut yield, and root nodule nitrogen fixation is one of the main nitrogen sources for peanut, with an average nitrogen supply accounting for more than 40% of the total nitrogen, and the highest being up to 50%. Therefore, improving the ability of peanut root nodule nitrogen fixation has an important influence on the growth and yield of peanut itself, is an effective way to achieve nitrogen-saving cultivation, and is an important measure to maintain and improve soil fertility and promote the sustainable development of agriculture. Therefore, it is of great significance to take effective control measures to improve peanut nodule fixation of nitrogen in production.

[0004] Currently, there is no literature report that plant Arthrobacter has the biological activity of promoting peanut nodule fixation of nitrogen. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a plant Arthrobacter ARZ1 strain and application of a complex microbial agent of the strain in promoting peanut nodule fixation of nitrogen.

[0006] In order to achieve the above-mentioned purpose, the present inventors determined the suitable complex microbial agent for application in peanut by exploring the effects of different strains on the number of root nodules, fresh weight of root nodules, dry weight of root nodules, leghemoglobin content, number of filled fruits, filled fruit rate and kernel percentage of two peanut varieties, and finally obtained the following technical scheme:

[0007] A plant Arthrobacter (Arthrobacter oryzae) ARZ1, the strain preservation number of which is CCTCC No: M20241883. A Sphingomonas melonis (guavaculture sphingomonad) SPZ1, the strain preservation number of which is CCTCC No: M20241884.

[0008] It should be noted that the plant Arthrobacter oryzae adopted by the present application is isolated from peanut rhizosphere soil, has excellent self-nitrogen fixation ability, can survive in peanut rhizosphere and soil, grows well under the environmental conditions of pH 7.0-9.0, and survives well under the environmental conditions of pH 8.0. The strain is identified as Arthrobacter oryzae by morphological characteristics, culture characteristics and physiological and biochemical characteristics of microorganisms. The strain has been preserved in China Center for Type Culture Collection on September 2, 2024, and the preservation number is CCTCC No:M20241883.

[0009] The Sphingomonas melonis adopted by the present application is also isolated from peanut rhizosphere soil, has excellent self-nitrogen fixation ability, can survive in peanut rhizosphere and soil, grows well under the environmental conditions of pH 6.0-9.0, and survives well under the environmental conditions of pH 8.0. The strain is identified as Sphingomonas melonis by morphological characteristics, culture characteristics and physiological and biochemical characteristics of microorganisms. The strain has been preserved in China Center for Type Culture Collection on September 2, 2024, and the preservation number is CCTCC No:M20241884.

[0010] The two strains above-mentioned have a significant positive promoting effect on the nodule number, nodule fresh weight, nodule dry weight, leghemoglobin content, full fruit number, full fruit rate and kernel rate of the two peanut varieties Qinghua No. 6 and Qinghua No. 22 after being used alone or in combination, and therefore the present application further provides the following applications:

[0011] (1) Application of the ARZ1 strain or the SPZ1 strain or the complex microbial agent of ARZ1 and SPZ1 in promoting peanut nodule fixation.

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

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

[0014] (4) Application of the ARZ1 strain or the SPZ1 strain or the complex microbial agent of ARZ1 and SPZ1 in promoting the increase of peanut full fruit number, full fruit rate and kernel rate.

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

[0016] Further preferably, the complex microbial agent is used in a ratio of 2:1 of the number of living Sphingomonas melonis SPZ1 and Arthrobacter oryzae ARZ1.

[0017] Still further preferably, the complex microbial agent is prepared into a microbial solution with a total number of living bacteria of (1.0-2.0)×10 10 cfu / mL; the first application is at the flowering stage of peanuts, with a dosage of 2.5-3.5 L / 667 m 2 ; the second application is at the podding stage of peanuts, with a dosage of 2.5-3.5 L / 667 m 2 .

[0018] Still further preferably, if the artificial application method is used, the microbial solution is diluted with water and sprayed on the roots of peanuts using an agricultural sprayer; if the unmanned aerial vehicle spraying method is used, the diluted microbial solution is directly placed in a pesticide tank and sprayed before rain.

[0019] Still further preferably, when the peanuts are planted in a film mulching mode, the microbial solution is drip irrigated under the film, and the water depth is 8-10 cm to wet the soil.

[0020] Still further preferably, the microbial solution and the pesticide cannot be used together, and the interval between the two is more than 2 days.

[0021] In addition, the complex microbial agent can be prepared by the following method: the Sphingomonas melonis SPZ1 and Arthrobacter oryzae ARZ1 cultured to the logarithmic growth phase are mixed, and a protective agent is added to the mixed microbial solution, so as to adjust the number of living bacteria to (1.0-2.0)×10 10 cfu / mL, pH 6-9; the protective agent comprises 90-120 g / L skimmed milk powder, 25-35 mL / L glycerol, 90-120 g / L malt dextrin, 120-180 g / L sea gall sugar, and 8-13 g / L L-glutamic acid sodium.

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

[0023] The fermentation culture method of Arthrobacter oryzae ARZ1 is as follows: Arthrobacter oryzae ARZ1 is inoculated into beef extract protein peptone culture solution at an inoculation amount of 4%-10%, and incubated at 25-27°C for 24-72 hours; after centrifugal washing, a mixed solution containing 0.5 g / L of Yeast Extract, 20 g / L of Mannitol, 0.2 g / L of K2HPO4, 0.8 g / L of KH2PO4, 0.2 g / L of MgSO4·7H2O, 0.1 g / L of CaSO4·2H2O, 0.01 g / L of FeCl3, 0.002 g / L of Na2MoO4·2H2O and 15 g / L of Agar is added to each bacterial precipitate, pH is adjusted to 6-9, and the viable bacterial count of Arthrobacter oryzae is adjusted to (1.0-2.0)×10 10 cfu / mL, and then the mixture is uniformly mixed and poured into a culture solution.

[0024] In addition, the application also provides a planting method for promoting peanut nodule fixation and nitrogen fixation by using the above-mentioned complex microbial agent, which comprises preparing the complex microbial agent into a bacterial solution with a total viable bacterial count of (1.0-2.0)×10 10 cfu / mL, applying the bacterial solution to peanuts for the first time at the beginning of flowering, and the amount is 3 L / 667 m 2 ; and applying the bacterial solution to peanuts for the second time at the pod setting stage, and the amount is 3 L / 667 m 2 .

[0025] Further preferably, the planting method for promoting the absorption and utilization of nitrogen in peanuts as described above, if using artificial application, after dilution with clean water, the peanuts are sprayed with an agricultural sprayer at the root; if using unmanned aerial vehicle spraying, the fungus liquid is directly diluted with clean water and placed in the pesticide tank and sprayed before the rain.

[0026] Further preferably, the planting method for promoting the absorption and utilization of nitrogen in peanuts as described above, when peanuts are planted in a mulching manner, the fungus liquid is drip irrigated under the film, and the irrigation depth is 8-10 cm to wet the soil.

[0027] Further preferably, the planting method for promoting the absorption and utilization of nitrogen in peanuts as described above, regardless of the application method, the applied fungus liquid and pesticides cannot be used together, and the interval between the two is more than 2 days.

[0028] Compared with the prior art, the active bacteria in the complex bacterial agent are composed of Arthrobacter oryzae ARZ1 and Sphingomonas melonis SPZ1, and the two bacteria in the complex bacterial agent promote the increase of peanut nodule number through synergistic effect, and the fresh weight, dry weight and leghemoglobin content of the nodule are obviously improved. Especially, the number of full fruits, the full fruit rate and the kernel rate of peanuts can be improved, and the ability of peanut nodule nitrogen fixation can be greatly improved when applied to peanut planting process. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 : Plate culture and scanning electron microscope image of Arthrobacter oryzae ARZ1;

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

[0031] Figure 3 : Effect of application of each group of strains on peanut nodule number;

[0032] Figure 4 : Effect of application of each group of strains on peanut nodule fresh weight;

[0033] Figure 5 : Effect of application of each group of strains on peanut nodule dry weight;

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

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

[0036] Figure 8 Effects of application of different strains on fruit fullness rate;

[0037] Figure 9 Effects of application of different strains on kernel yield;

[0038] Figures 3-9 Different letters in the text represent significant differences between different treatments within the same group (p<0.05). Detailed Implementation

[0039] The following embodiments further illustrate the above-described content of the present invention in detail. However, this should not be construed as limiting the scope of the present invention to the following embodiments. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Furthermore, unless otherwise specified, the experimental methods in the following embodiments are conventional methods.

[0040] Example 1: Screening and isolation of ARZ1 and SPZ1 strains

[0041] (1) Discovery, screening, isolation, and identification of bacterial strains. Based on the screening experiment of adding specific root exudates in maize-peanut intercropping, the inventors found that adding root exudates can increase the number of root nodules in peanut rhizosphere and stimulate nodulation and nitrogen fixation in peanut plants. Therefore, we speculate that the addition of root exudates reassembles the soil microbial community, thereby promoting nodulation and nitrogen fixation in peanuts. Based on this, we prepared a suspension of peanut rhizosphere soil samples treated with the above-mentioned root exudate addition, spread the bacterial suspension on bacterial culture medium, and isolated and purified the bacterial strains. The 16S rRNA sequence of the isolated strains was obtained using high-throughput sequencing technology. The 16S rRNA sequence was compared with the NCBI nr database. Sequence clustering analysis was performed based on the degree of comparison and similarity to construct a phylogenetic tree. The isolated and purified strains were compared with known strains, and comprehensive analysis of morphology, physiology, and biochemistry was performed to determine the bacterial species. To further verify the function of the strains, peanut cultivation addition experiments were carried out using the isolated and purified strains.

[0042] (2) Microbiological properties of the microorganisms. Arthrobacter oryzae ARZ1 colonies are white, round, and moist. Figure 1 It can grow on nitrogen-fixing medium, with an optimal growth pH of 6-9 and a temperature of 25-27℃. *Sphingomonas melonis* SPZ1 colonies are yellow, round, with small, moist, smooth, opaque mycelial growths, regular edges, and no halo. Figure 2 It can grow on nitrogen-fixing medium, with a suitable pH of 6-9 and a temperature of 25-27℃.

[0043] Example 2: Preparation of ARZ1, SPZ1 inoculants and complex inoculants

[0044] (1) Arthrobacter oryzae ARZ1 was inoculated into beef extract peptone culture solution (beef extract 3 g / L, peptone 10 g / L, Nacl 5 g / L, agar 15 g / L) at an inoculation amount of 4%-10%, and incubated at 25-27°C for 24-72 hours. After centrifugal washing, 0.5 g / L of Yeast Extract, 20 g / L of Mannitol, 0.2 g / L of K2HPO4, 0.8 g / L of KH2PO4, 0.2 g / L of MgSO4·7H2O, 0.1 g / L of CaSO4·2H2O, 0.01 g / L of FeCl3, 0.002 g / L of Na2MoO4·2H2O, and 15 g / L of Agar were added to the bacterial precipitate, and the pH was adjusted to 6-9. The viable count of Arthrobacter oryzae ARZ1 was adjusted to about 1.0 x 10 10 cfu / mL, and mixed uniformly. The suspension was then poured into the culture solution. The specific operation method for pouring culture was as follows: the Arthrobacter oryzae ARZ1 suspension was diluted and added to sterile nitrogen-fixing culture medium. After solidification, the culture was incubated upside down. Single strains were proliferated to form colonies. A single colony was taken to prepare a suspension, and the process was repeated multiple times to obtain a pure culture.

[0045] (2) Sphingomonas melonis SPZ1 was inoculated into beef extract peptone culture solution (beef extract 3 g / L, peptone 10 g / L, Nacl 5 g / L, agar 15 g / L) at an inoculation amount of 4%-10%, and incubated at 25-27°C for 24-72 hours. After centrifugal washing, 0.5 g / L of Yeast Extract, 20 g / L of Mannitol, 0.2 g / L of K2HPO4, 0.8 g / L of KH2PO4, 0.2 g / L of MgSO4·7H2O, 0.1 g / L of CaSO4·2H2O, 0.01 g / L of FeCl3, 0.002 g / L of Na2MoO4·2H2O, and 15 g / L of Agar were added to the bacterial precipitate, and the pH was adjusted to 6-9. The viable count of Sphingomonas melonis SPZ1 was adjusted to about 1.0 x 10 10cfu / mL, mixed and then poured into culture; the specific operation method of pouring culture is: after dilution, the Sphingomonas melonis SPZ1 suspension is added into sterile nitrogen fixation medium, and after solidification, it is cultured upside down, a single strain proliferates to form a colony, a single colony is made into a suspension, and the process is repeated multiple times to obtain a pure culture.

[0046] (3) Preparation of protective agent: 100 g / L skimmed milk powder, 30 mL / L glycerol, 100 g / L malt dextrin, 150 g / L jambu sugar, and 10 g / L L-glutamic acid sodium, pH 6-9.

[0047] (4) Add the protective agent prepared in step (3) to the Arthrobacter plantarum ARZ1 bacterial solution obtained in step (1), and adjust the viable bacterial count to about 1.0 x 10 10 cfu / mL ARZ1 bacterial agent Add the protective agent prepared in step (3) to the Sphingomonas melonis SPZ1 bacterial solution obtained in step (2), and adjust the viable bacterial count to about 1.0 x 10 10 cfu / mL SPZ1 bacterial agent .

[0048] Mix the bacterial solutions obtained in steps (1) and (2) according to the viable bacterial count ratio of Sphingomonas melonis SPZ1:Arthrobacter plantarum ARZ1 as 2:1, and add the protective agent prepared in step (3) to the mixed bacterial solution, and adjust the viable bacterial count to about (1.0-2.0) x 10 10 cfu / mL Complex bacterial agent .

[0049] Example 3: Test of ARZ1 strain in pot-grown peanut planting

[0050] Test type: pot test

[0051] Test site: Qingdao Agricultural University (Qingdao, China)

[0052] Test time: May 2023-September 2023

[0053] Test crop: peanuts (variety Qinghua No. 6, Qinghua No. 22)

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

[0055] Test groups: CK is blank control, ARZ1-F and ARZ1-T are both Arthrobacter ARZ1 inoculant treatment, each treatment has 3 replicates, and they are arranged in random blocks.

[0056] Test design: PVC pots were used for potting, with an inner diameter of 16 cm and a pot height of 23.5 cm. The bacterial solution was added 25 days after peanut seeding, and sampling was performed at the harvest period after the addition of the bacterial solution.

[0057] Amount and method: ARZ1-F was applied with 0.05 mL of ARZ1 bacterial agent prepared in Example 2 per pot, and ARZ1-T was applied with 0.1 mL of ARZ1 bacterial agent prepared in Example 2 per pot. The bacterial solution was diluted to 200 mL, respectively, and poured onto the roots of peanuts. The CK was 200 mL of blank water solution.

[0058] Table 1 Number of nodule of peanut plant under treatment of ARZ1

[0059]

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

[0061] From the test results in Table 1, the number of nodules of Qinghua No. 6 was significantly increased by 53.84% and 33.82% under ARZ1-F treatment compared with CK and ARZ1-T, respectively. The number of nodules of Qinghua No. 22 was significantly increased by 163.73% and 42.00% under ARZ1-F and ARZ1-T treatments compared with CK, respectively, and there was a significant difference between the two concentrations of ARZ1. In summary, the ARZ1-F treatment of ARZ1 had a significant effect on the increase of nodule number of peanut plants, and could significantly increase the number of peanut nodules.

[0062] Example 4: Test of SPZ1 strain in pot-grown peanut planting

[0063] Test type: potting test

[0064] Test site: Qingdao Agricultural University (Qingdao, China)

[0065] Test time: May 2023-September 2023

[0066] Test crop: peanuts (varieties Qinghua No. 6 and Qinghua No. 22)

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

[0068] Test groups: CK was the blank control, SPZ1-F and SPZ1-T were both treated with bacterial agent of cucurbita sp1, with 3 replicates per treatment, and were arranged in random blocks.

[0069] Test design: PVC pots were used for potting, with an inner diameter of 16 cm and a pot height of 23.5 cm. The fungicide was added 25 days after peanut seeding (mix the bacterial solution with 200 ml water and pour it into the peanut roots), and sampling was carried out at the harvest period after the addition of the bacterial solution.

[0070] Usage and method: SPZ1-F was applied with 0.05 mL of SPZ1 bacterial agent prepared in Example 2 per pot, and SPZ1-T was applied with 0.1 mL of SPZ1 bacterial agent prepared in Example 2 per pot. The bacterial solution was diluted to 200 mL, respectively, and poured into the peanut roots. The CK was 200 mL of blank water solution.

[0071] Table 2 Number of root nodules of plants treated with Sphingomonas sp. SPZ1

[0072]

[0073]

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

[0075] Example 5: Test of compound microbial agent in field peanut planting

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

[0077] Test time: May 2024-September 2024

[0078] Test crop: peanuts (varieties Qinghua No. 6 and Qinghua No. 22)

[0079] Test soil: The soil is sand slurry black soil (soil pH is 7.06, organic matter is 16.18 g / kg, alkali hydrolysis nitrogen is 77.76 mg / kg, available phosphorus is 45.58 mg / kg, and available potassium is 78.69 mg / kg).

[0080] Test groups:

[0081] CK is a blank water solution control;

[0082] The ARZ1-F group was applied with ARZ1 bacterial agent prepared in Example 2, with an application amount of 1.5 L / 667 m2 ;

[0083] ARZ1-T group ARZ1 inoculant prepared in Example 2 was applied at a dosage of 3 L / 667 m 2 ;

[0084] SPZ1-F group SPZ1 inoculant prepared in Example 2 was applied at a dosage of 1.5 L / 667 m 2 ;

[0085] SPZ1-T group SPZ1 inoculant prepared in Example 2 was applied at a dosage of 3 L / 667 m 2 ;

[0086] ST+AF group composite inoculant prepared in Example 2 was applied at a dosage of 3 L / 667 m 2 ;

[0087] Method of use: the first application, at the beginning of flowering of peanuts, the amount of each inoculant designed in the above test groups mentioned in the above treatments was diluted to 15 L with clean water, and then sprayed on the roots of peanuts using a manual application method with an agricultural sprayer; the second application, at the podding stage of peanuts, the amount and application method were the same as the first time. It should be noted that the inoculant should not be used with pesticides, and the two should be used more than 2 days apart.

[0088] Planting management: peanuts were planted using the method of mulching and ridging, with a ridge distance of 90 cm, 2 rows per ridge, a small row distance of 35 cm on the ridge, and a hole distance of 11 cm (2 seeds per hole). 50 kg of compound fertilizer (N-P2O5-K2O: 15-15-15) was applied per mu, and no additional fertilizer was applied in the later period.

[0089] Test results:

[0090] 1) Effect on peanut nodule number

[0091] Through the comparison of the test results of Figure 3 , it was found that compared with CK and the four single strain groups, the composite inoculant ST+AF group significantly increased the number of peanut nodules. The number of nodules of Qinghua No. 6 in the composite inoculant ST+AF group was significantly increased by 84.85% compared with the blank control group, and the number of nodules of Qinghua No. 22 was significantly increased by 235.53%. Through statistical comparison, in terms of nodule number of the two peanut varieties, the ST+AF group had a significant increase in peanut nodule number compared with the SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0092] 2) Effect on peanut nodule fresh weight

[0093] Through the comparison of the test results ofFigure 4 The experimental results of the comparison showed that, compared with CK and four single strain groups, the complex inoculant ST+AF group significantly improved the peanut nodule fresh weight. The complex inoculant ST+AF group significantly improved the nodule fresh weight of Qinghua No. 6 by 253.33% and Qinghua No. 22 by 131.03% compared with the blank control group. Through statistical comparison, the nodule fresh weight of the two peanut varieties in the complex inoculant ST+AF group was significantly higher than that in the single strain SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0094] 3) Effect on peanut nodule dry weight

[0095] Through the comparison of the experimental results, it was found that, compared with CK and four single strain groups, the complex inoculant ST+AF group significantly improved the peanut nodule dry weight. The complex inoculant ST+AF group significantly improved the nodule dry weight of Qinghua No. 6 by 168.12% and Qinghua No. 22 by 78.08% compared with the CK group. Through statistical comparison, the nodule dry weight of the two peanut varieties in the complex inoculant ST+AF group was significantly higher than that in the single strain SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups. Figure 5 4) Effect on leghemoglobin content

[0096] Through the comparison of the experimental results, it was found that, compared with CK and four single strain groups, the complex inoculant ST+AF group significantly improved the peanut leghemoglobin content. Compared with the CK group, the complex inoculant ST+AF group significantly improved the leghemoglobin content of Qinghua No. 6 by 46.38% and Qinghua No. 22 by 21.12%. Through statistical comparison, the leghemoglobin content of the two peanut varieties in the complex inoculant ST+AF group was significantly higher than that in the single strain SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0097] Figure 6 5) Effect on the number of filled fruits

[0098] Through the comparison of the experimental results, it was found that, compared with CK and four single strain groups, the complex inoculant ST+AF group significantly improved the peanut filled fruit number. Compared with the CK group, the complex inoculant ST+AF group significantly improved the filled fruit number of Qinghua No. 6 by 71.43% and Qinghua No. 22 by 118.18%. Through statistical comparison, the filled fruit number of the two peanut varieties in the complex inoculant ST+AF group was significantly higher than that in the single strain SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0099] 6) Effect on peanut filled fruit rate Figure 7

[0100] 6) Effect on peanut filled fruit rate​​

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

[0102] 7) Effect on peanut kernel rate

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

[0104] In summary, through statistical comparison, the compound microbial agent ST+AF had significant differences compared with the blank control and single microbial agent addition in many aspects of peanut nodule nitrogen fixation indicators. This shows that the compound microbial agent prepared by Sphingomonas melonis SPZ1 and Arthrobacter oryzae ARZ1 at a ratio of 2:1 (total effective viable bacteria number is (1.0-2.0) x 10 10 cfu / mL) and applied at a dose of 3 L / 667m 2 at the beginning of flowering and pod setting of peanuts can promote plant growth, increase nodule number, nodule fresh weight, nodule dry weight, leghemoglobin content, filled fruit number, filled fruit rate and kernel rate, and is beneficial to improve peanut plant nodule nitrogen fixation.

Claims

1. A plant Arthrobacter sp. Arthrobacter oryzae ARZ1, with the strain preservation number CCTCC No: M20241883.

2. Application of ARZ1 strain or SPZ1 strain or complex inoculant of ARZ1 and SPZ1 in promoting peanut nodule fixation of nitrogen, wherein the ARZ1 strain is plant Arthrobacter Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Pseudomonas sp. Sphingomonas melonis SPZ1 CCTCC No: M20241884.

3. The use of ARZ1 strain or SPZ1 strain or the complex inoculant of ARZ1 and SPZ1 in promoting the increase of peanut nodule number, wherein the ARZ1 strain is Arthrobacter sp. Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas sp. Sphingomonas melonis SPZ1 CCTCC No: M20241884.

4. Application of ARZ1 strain or SPZ1 strain or complex inoculant of ARZ1 and SPZ1 in promoting increase of peanut nodule fresh weight, nodule dry weight and leghemoglobin content, wherein the ARZ1 strain is Arthrobacter sp. Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas sp. Sphingomonas melonis SPZ1 CCTCC No: M20241884.

5. Application of ARZ1 strain or SPZ1 strain or complex inoculant of ARZ1 and SPZ1 in promoting the increase of peanut full fruit number, full fruit rate and kernel rate, wherein the ARZ1 strain is Arthrobacter sp. Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas sp. Sphingomonas melonis SPZ1 CCTCC No: M20241884.

6. Use according to any one of claims 2 to 5, characterized in that, The compound microbial agent is used to treat Sphingosine monocytogenes of cucurbits ( Sphingomonas melonis SPZ1 and Plantar Arthrobacter Sphingomonas melonis The live bacteria ratio of ARZ1 is 2:

1.

7. Use according to claim 6, characterized in that, The complex microbial agent is prepared into a microbial solution with a total number of viable bacteria of (1.0-2.0)×10 10 cfu / mL; the complex microbial agent is applied to peanuts at a flowering stage for the first time, with a dosage of 2.5-3.5 L / 667 m 2 ; and the complex microbial agent is applied to peanuts at a podding stage for the second time, with a dosage of 2.5-3.5 L / 667 m 2 .

8. Use according to claim 7, characterized in that, Arthrobacter oryzae 9. Use according to claim 7, characterized in that, If the artificial application mode is adopted, after dilution with clean water, the peanut root is sprayed by using an agricultural sprayer; if unmanned aerial vehicle spraying is used, the bacterial liquid is directly diluted with clean water and placed in a pesticide tank for spraying before rain.

10. Use according to claim 7, characterized in that, When the peanut is planted in a film mulching mode, the bacterial liquid is drip irrigated by using a drip irrigation method under the film, and the irrigation depth is 8-10 cm to wet the soil. The bacterial liquid and the pesticide cannot be used together, and the interval between the two uses is more than 2 days.

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