Disclosure of Invention
The present application has been made to solve the above-mentioned drawbacks of the prior art. An acinetobacter, a microbial inoculum, a plant growth promoter, a biological fertilizer and application are needed, and experiments prove that the acinetobacter can degrade ursolic acid generated by asparagus, prevent and treat the stem blight of the asparagus and promote plant growth and nitrogen fixation.
The application provides an Acinetobacter which is named Acinetobacter sp.11.12.7.6 and is preserved in China general microbiological culture Collection center (CGMCC) with the preservation number of 29270 in the year 2023, month 12 and 8. The preservation address is the institute of microorganisms at the national academy of sciences of the yang ward area of Beijing city.
The application also provides a microbial inoculum, and the active ingredient of the microbial inoculum comprises the acinetobacter according to the embodiment of the application.
The application also provides a plant growth promoter, which contains the acinetobacter according to the embodiment of the application.
The application also provides a biological fertilizer, which contains the acinetobacter according to the embodiment of the application.
The test proves that the acinetobacter in the application can degrade ursolic acid produced by asparagus, prevent and treat stem blight of asparagus and promote plant growth and nitrogen fixation.
In some embodiments, the microbial agents, plant growth promoters, and biofertilizers described above may be in a variety of dosage forms, such as solutions, emulsions, suspensions, powders, granules, wettable powders, or water dispersible granules.
In some embodiments, the bacterial agent contains a carrier besides the acinetobacter, wherein the carrier can be a carrier which is common in the bacterial agent field and is biologically inert. The carrier may be a solid carrier or a liquid carrier, the solid carrier may be a mineral material, a plant material or a polymer compound, the mineral material may be at least one of clay, talc, kaolin, montmorillonite, white carbon, zeolite, silica and diatomaceous earth, the plant material may be at least one of corn flour, bean flour and starch, and the polymer compound may be polyvinyl alcohol or/and polyglycol.
In some embodiments, the liquid carrier may be an organic solvent, vegetable oil, mineral oil, or water, and the organic solvent may be decane or/and dodecane.
If necessary, an adhesive, a stabilizer (such as an antioxidant) and the like may be added to the microbial inoculum, and the microbial inoculum is not particularly limited.
The application also provides application of the acinetobacter, the microbial inoculum, the plant growth promoting agent or the biological fertilizer in degrading ursolic acid generated by asparagus. The acinetobacter has better degradation rate on ursolic acid generated by asparagus in the range of 0.1-100 mg/L, and has 30% degradation effect even under the condition of high concentration ursolic acid of 500 mg/L.
The application also provides application of the acinetobacter, the microbial inoculum, the plant growth promoting agent or the biological fertilizer in asparagus disease control, preferably in asparagus stem blight control. Tests prove that after the bacteria liquid of the acinetobacter is fermented and cultured with the asparagus, the asparagus has similar effect on preventing and treating the stem blight of the asparagus as a chemical bactericide.
The application also provides application of the acinetobacter, the microbial inoculum, the plant growth promoter or the biological fertilizer in promoting the recovery of microbial communities of asparagus rhizosphere soil. Acinetobacter can influence the microbial community structure of asparagus rhizosphere, and can enable the microbial community of diseased soil to be restored to a healthy state.
The application also provides an application of the acinetobacter, the microbial inoculum, the plant growth promoter or the biofertilizer in promoting plant growth, and preferably, the plant is asparagus.
The application also provides application of the acinetobacter, the microbial inoculum, the plant growth promoting agent or the biological fertilizer in biological nitrogen fixation.
The application also provides a method for promoting the restoration of microbial communities of the rhizosphere soil of asparagus, which comprises the step of applying the acinetobacter, the microbial agents, the plant growth promoters or the biofertilizer to the rhizosphere soil of the asparagus.
The application also provides a method for promoting the growth of asparagus, which comprises the step of applying the acinetobacter, the microbial inoculum, the plant growth promoting agent or the biological fertilizer to rhizosphere soil of the asparagus.
Experiments prove that the acinetobacter, the microbial inoculum, the plant growth promoter, the biological fertilizer and the application of the application can degrade ursolic acid generated by asparagus, inhibit toxic substances generated by harmful microorganisms at the root of the asparagus, surpass the activity of pathogenic bacteria in preventing and controlling the stem blight of the asparagus, have the effect of resisting the pathogenic bacteria, effectively reduce the content of phomopsis in diseased soil, promote the recovery of microbial communities in the diseased soil, enable the structure and the function of the microbial communities to be closer to the state of healthy soil, enable the chlorophyll content, the activity and the growth quantity of root systems of the asparagus and promote the growth of plants, and have important application value in the aspects of preventing and controlling and growing asparagus diseases.
Detailed Description
The present application will be described in detail below with reference to the drawings and detailed description to enable those skilled in the art to better understand the technical scheme of the present application. Embodiments of the present application will be described in further detail below with reference to the drawings and specific examples, but not by way of limitation.
The terms "first," "second," and the like, as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises" and the like means that elements preceding the word encompass the elements recited after the word, and not exclude the possibility of also encompassing other elements.
Example 1 acquisition of strains
(1) Selecting a plant occurrence point of a light asparagus disease in an asparagus field of a champion variety with the asparagus stem blight, scraping a sample with a sterile spoon, taking about 2 g samples in 15 mL sterile water, culturing 20min at 200 r/min and 37 ℃ to uniformly mix the samples, carrying out gradient dilution on the mixed solution by 10 3 times, coating the diluted solution on an LB culture medium for purification, and repeating the purification step for 3-4 times until all colony forms are consistent, thereby finishing the purification;
(2) And (3) picking the purified single colony obtained in the step (1), culturing overnight in a 4 mL LB liquid culture medium at 200 r/min and 37 ℃, mixing the bacterial liquid with glycerin with the concentration of 50% according to the volume ratio of 1:1, and storing in a-20 ℃ refrigerator or a-80 ℃ refrigerator.
Example 2 identification of strains
(1) Morphological identification
The purified bacteria obtained in the step (1) of example 1 were picked up and cultured in a 4 mL LB liquid medium at 200 r/min and 37 ℃ for 3 weeks, and then the morphological characteristics of the purified strain were observed and recorded, the whole colony was green, yellowish, club-shaped, arranged in clusters, and observed under an optical microscope, and the mycelia of the strain were smooth.
(2) Molecular biological identification
① Bacterial strain DNA extraction and sequencing
The purified bacteria are selected and cultured in 4 mL LB liquid medium at 200 r/min and 37 ℃ overnight, bacterial DNA is extracted by using a kit, 16S rDNA is amplified by PCR (the primer sequence of the PCR amplification comprises 27f and 1492r, the primer sequence of the 27f is 5'-TCCGTAGGTGAACCTGCGG-3', the gene sequence of the 27f is shown as SEQ ID NO.1, the primer sequence of the 1492r is 5'-TCCTCCGCTTATTGATATGC-3', the gene sequence of the 1492r is shown as SEQ ID NO. 2, the amplification system of the PCR is 50 mu L, 25 mu L of 2 xTap PCR PreMix,2 mu L of 27F,2 mu L of 1492 2R,1 mu L of bacterial DNA and 20 mu L of ddH 2 O are mixed, after the reaction, the product is checked by using 1% agarose gel electrophoresis, and the band is sent to Beijing Liuhua large gene technology Co., ltd for sequencing, and the gene sequence of Acinetobacter.11.12.7.6 is shown as SEQ ID NO. 3.
GCGGAGAGAGGTAGCTTGCTACTGATCTTAGCGGCGGACGGGTGAGTAATGCTTAGGAATCTGCCTATTAGTGGGGGACAACATTTCGAAAGGAATGCTAATACCGCATACGTCCTACGGGAGAAAGCAGGGGATCTTCGGACCTTGCGCTAATAGATGAGCCTAAGTCGGATTAGCTAGTTGGTGGGGTAAAGGCCTACCAAGGCGACGATCTGTAGCGGGTCTGAGAGGATGATCCGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTGGGGAATATTGGACAATGGGCGCAAGCCTGATCCAGCCATGCCGCGTGTGTGAAGAAGGCCTTATGGTTGTAAAGCACTTTAAGCGAGGAGGAGGCTACTTTAGTTAATACCTAGAGATAGTGGACGTTACTCGCAGAATAAGCACCGGCTAACTCTGTGCCAGCAGCCGCGGTAATACAGAGGGTGCAAGCGTTAATCGGATTTACTGGGCGTAAAGCGCGCGTAGGCGGCTAATTAAGTCAAATGTGAAATCCCCGAGCTTAACTTGGGAATTGCATTCGATACTGGTTAGCTAGAGTGTGGGAGAGGATGGTAGAATTCCAGGTGTAGCGGTGAAATGCGTAGAGATCTGGAGGAATACCGATGGCGAAGGCAGCCATCTGGCCTAACACTGACGCTGAGGTGCGAAAGCATGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCATGCCGTAAACGATGTCTACTAGCCGTTGGGGCCTTTGAGGCTTTAGTGGCGCAGCTAACGCGATAAGTAGACCGCCTGGGGAGTACGGTCGCAAGACTAAAACTCAAATGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGATGCAACGCGAAGAACCTTACCTGGCCTTGACATAGTAAGAACTTTCCAGAGATGGATTGGTGCCTTCGGGAACTTACATACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTTTCCTTATTTGCCAGCGAGTAATGTCGGGAACTTTAAGGATACTGCCAGTGACAACTGGAGGAAGGCGGGGACGACGTCAAGTCATCATGGCCCTTACGGCCAGGGCTACACACGTGCTACAATGGTCGGTACAAAGGGTTGCTACCTAGCGATAGGATGCTAATCTCAAAAAGCCGATCGTAGTCCGGATTGGAGTCTGCAACTCGACTCCATGAAGTCGGAATCGCTAGTAATCGCGGATCAGAATGCCGCGGTGAATACGTTCCCGGGCCTTGTACACACCGCCCGTCACACCATGGGAGTTT.
② BLAST alignment
BLAST comparison of the Acinetobacter sp.11.12.7.6 sequence obtained in the step ① in a GenBank database shows that the similarity with Acinetobacter rhizobium and Acinetobacter picocell is 100%, the same genus is tentatively determined, and the combination morphological identification result finally determines that the Acinetobacter sp.11.12.7.6 is Acinetobacter.
③ Preservation of bacterial species
Acinetobacter sp.11.12.7.6 strain is preserved in China general microbiological culture Collection center (CGMCC) at 20.12.8 of 2023, and the address is North Star Xway No. 1,3 of the Korean area of Beijing city, and the preservation number is CGMCC No.29270.
EXAMPLE 3 application of Ursolic acid degradation
(1) Picking the purified bacteria obtained in the step (1) of the example 1, and culturing the bacteria in a 4 mL LB liquid culture medium at 200 r/min and 37 ℃ overnight to obtain bacterial liquid;
preparing a culture medium 1, a culture medium 2, a culture medium 3, a culture medium 4 and a culture medium 5;
Culture medium 1 comprises 0.1mg of ursolic acid, 5g of peptone, 0.5g of ammonium sulfate, 20g of compound inorganic salt (NaCl: KCl: mgCl 2 =10:1:1) and 1000ml,pH 6.8~7.2 g of water.
1Mg of ursolic acid, 5g of peptone, 0.5 g of ammonium sulfate, 20g of compound inorganic salt (NaCl: KCl: mgCl 2 =10:1:1), 1000ml of water and pH 6.8-7.2.
Culture medium 3 comprises 10mg of ursolic acid, 5g of peptone, 0.5 g of ammonium sulfate, 20g of compound inorganic salt (NaCl: KCl: mgCl 2 =10:1:1), 1000ml of water and pH of 6.8-7.2.
Culture medium 4 comprises 100mg of ursolic acid, 5g of peptone, 0.5 g of ammonium sulfate, 20g of compound inorganic salt (NaCl: KCl: mgCl2=10:1:1) and water 1000ml,pH 6.8~7.2.
Culture medium 5 comprises 500mg of ursolic acid, 5g of peptone, 0.5 g of ammonium sulfate, 20g of compound inorganic salt (NaCl: KCl: mgCl2=10:1:1) and water 1000ml,pH 6.8~7.2.
Acinetobacter was inoculated into the above five media and cultured with shaking at 35℃and 180rpm for 7d. The culture broth was taken 10mL, centrifuged at 3500r/min for 15min, the precipitate was discarded, and the supernatant was extracted with 10mL of methylene chloride. The extract phase was evaporated to dryness using a vacuum rotary evaporator and the residue was dissolved in 1mL of methanol for further use.
And detecting the residual quantity of the ursolic acid in the sample by adopting a high performance liquid chromatography method, and calculating the degradation rate. The parameters are that acetonitrile and water (pH is regulated to 2.8 by acetic acid) are used as mobile phases, the flow rate is 1.0mL/min, the column temperature is 30 ℃, and the detection wavelength is 280nm. Gradient elution is adopted, acetonitrile is increased from 5% to 40% for 0-30min, acetonitrile is maintained for 40% for 30-40min, acetonitrile is maintained for 40% to 45min, and acetonitrile is reduced from 40% to 5%.
The growth of Acinetobacter sp.11.12.7.6 in the presence of ursolic acid autotoxic substances of different concentrations was analyzed by high performance liquid chromatography. Acinetobacter shows remarkable concentration dependence on degradation efficiency of ursolic acid in a 7-day culture period. Specifically, when the concentration of ursolic acid is 0.1 mg/L, the acinetobacter shows extremely high degradation efficiency, and the degradation rate is as high as 95.4%. As the concentration of ursolic acid increases to 1 mg/L, the degradation efficiency is slightly reduced, but still remains at a high level of 90.8%. Further increasing the concentration of ursolic acid to 10 mg/L and reducing the degradation efficiency to 81.7%. When the concentration of ursolic acid reaches 100 mg/L, the degradation efficiency of Acinetobacter is obviously reduced to 70.4%. And under the condition of high concentration ursolic acid of 500 mg/L, the degradation efficiency of the acinetobacter is further reduced to 32.6%.
Example 4 prevention and treatment of asparagus stem blight and Nitrogen fixation and growth promotion effects
The test site is set in the city of the coastal region of the coastal state of Shandong province, and the prevention and treatment target is 4-year old champion asparagus, and the past incidence rate is about 23%. The treatment time is half a month before picking up the bamboo shoot (2023, 4, 20 days) and half a month after picking up the bamboo shoot (6, 20 days). The treatment method and concentration are that the purified bacteria obtained in the step (1) of the example 1 are selected and cultured in a4 mL LB liquid culture medium at 200 r/min and 37 ℃ overnight to obtain bacterial liquid, the bacterial liquid fermentation liquid of Acinetobacter with 300 times of dilution is used for root irrigation, 500mL of each hole is irrigated, and the control medicament is 800 times of 50% compound carbendazim and blank treatment. The cell area is 70m 2, and each process is repeated 3 times. The investigation method is that 10 plants are investigated in each district by random sampling, the total stem number, the diseased stem number, the fresh weight of asparagus plant height and the nitrogen content are counted, and the control effect is calculated compared with the control.
TABLE 1 application effects of asparagus stem blight and nitrogen fixation and growth promotion
Proved by 20 days of study in 7 of 2023, as shown in table 1, the stem blight is obviously reduced after the Acinetobacter is treated, the average stem disease rate is 6.5%, the carbendazim is 6.3%, the treatment is similar to that of carbendazim, and the control effect is 70.35%. This result reveals that the acinetobacter bacteria liquid has a potential comparable to that of the chemical bactericide in preventing and controlling the stem blight of asparagus, and although the incidence rate is slightly high, in practical application, the small difference may not have statistical significance. In addition, the growth promoting effect of the acinetobacter bacteria liquid on the asparagus is very obvious, and the field visual effect is shown in the figure, namely the asparagus plants in the acinetobacter treatment area are thick, and the asparagus plants in the control area are short and sparse. The nitrogen content of the acinetobacter inoculated asparagus sample is significantly higher than that of the control group (untreated) and the carbendazim treated group. Specifically, the nitrogen content of the asparagus sample inoculated with the acinetobacter is 37.64 mg/g, which is higher than that of an asparagus sample which is not subjected to any treatment and that of an asparagus sample which is subjected to carbendazim treatment, and the nitrogen content and the incidence rate of the asparagus sample are measured on 5 indexes of plant height, stem number per plant, fresh weight per stem, nitrogen content of the plant and incidence rate. Acinetobacter had a greater improvement than the control.
The asparagus which is not ill and has no need of applying Acinetobacter and carbendazim in advance is withered after being ill, and has no fresh branches and leaves basically, and the asparagus added with the carbendazim is good in growth after being ill and the asparagus added with the Acinetobacter is good in growth of the branches and leaves.
EXAMPLE 5 application of microbial community restoration of asparagus rhizosphere soil
Selecting a plant occurrence point with light asparagus diseases, scraping a sample with a sterile spoon, taking about 2 g samples in 15 mL sterile water, culturing 20 min at 200 r/min and 37 ℃ to uniformly mix the samples, carrying out gradient dilution on the mixed solution by 10 3 times, coating the diluted solution on an LB culture medium for purification, repeating the purification step for 3-4 times until all colony forms are consistent, and finishing the purification;
The purified bacteria were picked up and cultured overnight at 37℃at 200 r/min in 4mL LB liquid medium to give a bacterial solution, which was applied to the above-mentioned asparagus rhizosphere soil and after 72 hours of application, the soil after the acinetobacter pretreatment was obtained. The soil pretreated by the Acinetobacter and the healthy soil are respectively subjected to the purification method to obtain a colony sample of the disease-causing soil pretreated by the Acinetobacter and a colony sample of the healthy soil, and the colony sample of the disease-causing soil are respectively sent to the Optimago, and 16S rDNA (bacteria) in the soil is detected by a high-throughput sequencing method to obtain a result shown in figure 2. And detecting ITS (fungi) in the soil by a high throughput sequencing method to obtain the result shown in FIG. 3. As can be seen from fig. 2 and 3, the acinetobacter treatment significantly affected the composition of the soil microbial community, and in particular the relative abundance of the pathogenic fungus phomopsis was reduced to a level similar to that of healthy soil.
Wherein, FIG. 2 includes Cladosporaceae (cladosporiaceae), saccharopolysporaceae (SPHAERIACEAE), saccharopolysporaceae (eremomycetaceae), chaetomiaceae (lasiosphaeriaceae), cong Chike (nectriaceae), novel (rhizophlyctidaceae), aspergillus (ASPERIGILLACEAE), and Gemcornidae (pleosporaceae). In FIG. 3, the order of Bacillus (vicinamibacterales), the order of Bacillus (gemmatimonadales), the order of Bacillus (Bacillales), the order of chitin-binding bacteria (Chitinophagales), the order of Rhizobium (Rhizobiales), the order of Saccharomonas (saccharimonadales), the order of Burkholderiales (burkholderiales), the order of Xanthomonas (xanthomonadales), and the order of Sphingomonas (sphingomonadales) are included.
The content ratio of the diseased soil microbial community to healthy soil after the addition of the acinetobacter shows remarkable similarity. In particular, the introduction of Acinetobacter significantly promotes the recovery of the microbial community of diseased soil, making its structure and function closer to that of healthy soil. Analysis of soil microflora by high throughput sequencing technology we observed that in the soil samples after acinetobacter treatment, the relative abundance of dominant microbial phylum such as budomonas (Gemmatimonadales), bacillus (Bacillales) did not differ significantly from the relative abundance in healthy soil. In addition, the functional structure of the microbial community in the soil after the Acinetobacter treatment is similar to that of healthy soil, which shows that the introduction of the Acinetobacter has limited influence on the function and stability of the microbial community in the soil and is beneficial to restoring the soil health.
The strain of Acinetobacter sp.11.12.7.6 and pathogenic bacteria have competitive action, and the strain of Acinetobacter sp.11.12.7.6 can quickly and massively reproduce and colonise in the soil environment where asparagus grows, can prevent pathogenic microorganisms and reproduce, and destroy colonisation of the pathogenic microorganisms on the asparagus, and interfere infection of the asparagus by the pathogenic microorganisms, thereby playing a role in preventing and controlling diseases.
Furthermore, although exemplary embodiments have been described herein, the scope thereof includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of the various embodiments across), adaptations or alterations as pertains to the present application. The elements in the claims are to be construed broadly based on the language employed in the claims and are not limited to examples described in the present specification or during the practice of the application, which examples are to be construed as non-exclusive. It is intended, therefore, that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following claims and their full scope of equivalents.
The above description is intended to be illustrative and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. For example, other embodiments may be used by those of ordinary skill in the art upon reading the above description. In addition, in the above detailed description, various features may be grouped together to streamline the application. This is not to be interpreted as an intention that the features of the non-claimed application are essential to any claim. Rather, the inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that these embodiments may be combined with one another in various combinations or permutations. The scope of the application should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application, the scope of which is defined by the claims. Various modifications and equivalent arrangements of this application will occur to those skilled in the art, and are intended to be within the spirit and scope of the application.