Coprinus radiatus and application thereof in efficient synthesis of nano-selenium

Abstract

The invention discloses coprinus radiatus and an application of the coprinus radiatus in efficient synthesis of nano-selenium. The invention provides a coprinus radians J2 strain which is preserved in the Guangdong Microbial Culture Collection Center on September 27, 2024, and the preservation number of the coprinus radians J2 strain is GDMCC No: 65225. The coprinus radians J2 strain has been preserved in the Guangdong Microbial Culture Collection Center on September 27, 2024. The research finds that the coprinus radiatus has the capability of reducing inorganic selenium into nano-selenium, can efficiently synthesize nano-selenium, can reduce toxic sodium selenite in a short time to obtain nano-selenium with small particle size, good biological activity and low toxicity, and is high in conversion rate and high in yield. And a simpler, safer and more efficient synthesis method is provided for biosynthesis of nano-selenium. Meanwhile, it is found that the coprinus radiatus selenium-rich bacterial liquid has an inhibition effect on various pathogenic fungi, can be used for preventing and treating various plant diseases, is high in prevention effect, and provides reference for development and utilization of nano-selenium synthesized by microorganisms and preparation of biocontrol products.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbial synthesis of nano-selenium. More specifically, it relates to Coprinellus radians and its application in the efficient synthesis of nano-selenium. Background Art

[0002] Selenium is an essential trace element for humans and animals. It has been found through research that selenium participates in the antioxidant process in the body, enhances immunity, prevents cancer, prevents various cardiovascular and cerebrovascular diseases, alleviates the toxicity of heavy metal ions, and also plays an important role in agriculture. It can increase crop yields, improve crop quality, reduce heavy metal toxicity, and improve the appearance and flavor of crops. Since selenium cannot be synthesized autonomously in the human body and must be ingested through diet, it is crucial to consume selenium-rich foods or selenium supplements reasonably for human health.

[0003] There are mainly two forms of selenium in nature: inorganic selenium in the form of selenide (Se 2+ ), sodium selenite (Se 4+ ), or selenate (Se 6 + ), and organic selenium in the form of a combination with amino acids through biotransformation. As for nano-selenium, it is not the main form of selenium in nature, but is obtained by reducing selenate or sodium selenite to nano-selenium through physical, chemical, or biological methods. Since the bioabsorption and utilization rate of nano-selenium is higher than that of inorganic selenium and organic selenium, there are still certain problems in its synthesis and preparation methods. For example, the synthesis and preparation cost is relatively high by physical methods, the synthesis environment is relatively dangerous, the particle size is uneven, and the biological activity is poor; the stability, biocompatibility, and biological activity of the synthesis by chemical methods will all decrease. Stabilizers or modifiers need to be added during the preparation process, and it is also prone to agglomeration. Dispersants or protectants need to be added to maintain its stable structure and physiological activity. The preparation process is complex, which is prone to secondary pollution and purification difficulties.

[0004] In contrast, using biological methods to synthesize nano-selenium through microorganisms shows obvious advantages: the synthesis of nano-selenium by microorganisms is more efficient, can be produced on a large scale, reduces costs, and is more stable, with high purity and higher biological activity. It is an environmentally friendly synthesis method. However, there are still few publicly available microbial materials that can be used to synthesize nano-selenium, and their conversion efficiency is relatively low. Since many microbial strains have low tolerance to inorganic selenium, this limits their application in nano-selenium production.

[0005] Therefore, it is necessary to provide more microbial materials that can efficiently synthesize nano-selenium, which can convert inorganic selenium into nano-selenium, provide a way to efficiently and rapidly synthesize biological nano-selenium, and provide a reference for the development and utilization of microbial synthesis of nano-selenium. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects and deficiencies of the existing microbial materials for synthesizing nano-selenium, and to provide a Coprinellus radians and its application in efficiently synthesizing nano-selenium, so as to provide a reference for the microbial synthesis and transformation into nano-selenium.

[0007] The first object of the present invention is to provide a strain of Coprinellus radians J2.

[0008] The second object of the present invention is to provide the application of the Coprinellus radians J2 strain.

[0009] The third object of the present invention is to provide a method for synthesizing nano-selenium by the Coprinellus radians J2 strain.

[0010] The fourth object of the present invention is to provide a kind of nano-selenium.

[0011] The fifth object of the present invention is to provide a product.

[0012] The sixth object of the present invention is to provide a method for inhibiting phytopathogenic fungi or controlling plant diseases.

[0013] The above objects of the present invention are achieved by the following technical solutions:

[0014] The present invention provides a strain of Coprinellus radians J2, which was deposited in the Guangdong Provincial Microbial Culture Collection Center on September 27, 2024, and the deposit number is GDMCC No: 65225.

[0015] The present invention isolated a strain of Coprinellus radians J2 from Aquilaria sinensis wood. The center of the Coprinellus radians colony is yellow, the mycelium is hairy, colorless or light yellow, showing radial long strips and gradually turning yellow, and finally tawny. The spores are smooth, dark brown, oval or ovoid, 6-9um. Research shows that the Coprinellus radians J2 strain can convert inorganic selenium into red nano-selenium in the mycelium, can tolerate sodium selenite, can efficiently synthesize nano-selenium, can reduce the toxic sodium selenite in a short time, and obtain nano-selenium with small particle size, good biological activity and low toxicity, and its conversion rate is high. The nano-selenium particles are produced in the mycelium of Coprinellus radians and excreted outside the cells, and the shape is round cake-like, and the particle size range is between 200 and 500nm. The present invention provides more, efficient and rapid ways for the biosynthesis of nano-selenium.

[0016] Therefore, the present invention provides the application of the Coprinellus radians J2 strain in reducing inorganic selenium to nano-selenium.

[0017] The present invention provides the application of the Coprinellus radians J2 strain in the preparation of nano-selenium.

[0018] Coprinellus radians is an edible and medicinal fungus of the genus Coprinellus. It can be harvested in its juvenile stage, with a delicious taste and delicate texture. Using the mycelium of Coprinellus radians as a microbial transformation material for synthesizing nano-selenium not only increases the safety of the transformation but also reduces the production cost of nano-selenium, providing more ways to efficiently and rapidly synthesize bio-nano-selenium from fungi.

[0019] The method for synthesizing nano-selenium using Coprinellus radians strain J2 in the present invention is as follows: After culturing Coprinellus radians in a medium for 1 - 7 days, inorganic selenium is added, and then the culture is continued for 5 - 15 days. The resulting red precipitate is the elemental nano-selenium particles.

[0020] Preferably, the medium is PDB medium, and the culture conditions are: temperature is 25 - 28 °C, and the rotation speed is 200 r / min.

[0021] Preferably, the inorganic selenium is sodium selenite.

[0022] More preferably, the concentration of sodium selenite is 1 - 10 mM.

[0023] The present invention provides a nano-selenium prepared by the above method.

[0024] The present invention provides a product containing the nano-selenium prepared by the above method.

[0025] Meanwhile, research shows that after culturing and preparing nano-selenium using Coprinellus radians strain J2, its selenium-rich bacterial powder or bacterial liquid can also be used to prevent and control various plant fungi and their diseases, and has good inhibitory effects on the growth of Rhizoctonia solani, Fusarium solani, Sclerotium rolfsii, Alternaria alternata, Colletotrichum fructicola, Fusarium pesudograminearum, Stagonosporopsis cucurbitacearum, Botrytis cinerea. The inhibition rates are 46.05%, 78.96%, 83.54%, 72.50%, 74.79%, 70.63%, 79.33%, 86.17% respectively; it can be used to prevent and control plant diseases caused by these pathogenic fungi, such as tobacco damping-off, sweet potato black rot, peanut southern blight, tobacco brown spot, pepper anthracnose, wheat basal rot, cucurbit gummy stem blight, gray mold, etc. At the same time, when the selenium-rich bacterial powder is used for the prevention and control of tobacco diseases, the control effect on damping-off reaches 78.60%, showing a good prevention and control effect.

[0026] Therefore, the present invention also provides the application of Coprinellus radians J2 strain in inhibiting phytopathogenic fungi or in controlling plant diseases.

[0027] Preferably, the phytopathogenic fungi are one or more of Rhizoctonia solani, Fusarium solani, Sclerotium rolfsii, Alternaria alternata, Colletotrichum fructicola, Fusarium pseudograminearum, Didymella bryoniae, Botrytis cinerea; the plant diseases are one or more of tobacco damping-off, sweet potato black rot, peanut southern blight, tobacco brown spot, pepper anthracnose, wheat basal rot, cucurbit gummy stem blight, gray mold.

[0028] The present invention provides the application of Coprinellus radians J2 strain in the preparation of biocontrol products.

[0029] The present invention provides a biocontrol product containing Coprinellus radians J2 strain.

[0030] Preferably, the biocontrol product is a biocontrol agent, and more preferably a selenium-rich bacterial powder.

[0031] The present invention also provides a preparation method of the selenium-rich bacterial powder: culturing Coprinellus radians J2 strain with inorganic selenium, filtering, rinsing and drying the prepared selenium-rich bacterial liquid to obtain Coprinellus radians mycelium rich in nano-selenium, and then grinding it into powder with a mortar to obtain the selenium-rich bacterial powder.

[0032] Furthermore, the prepared selenium-rich bacterial powder is made into a bacterial liquid by adding sterile water.

[0033] In addition, the present invention also provides a method for inhibiting phytopathogenic fungi or controlling plant diseases, culturing Coprinellus radians with inorganic selenium, and then treating the sample with the prepared selenium-rich bacterial powder or bacterial liquid.

[0034] Preferably, the medium is PDB medium, and the culture conditions are: temperature is 25 - 28 °C, and rotation speed is 200 r / min.

[0035] Preferably, the inorganic selenium is sodium selenite.

[0036] More preferably, the concentration of sodium selenite is 1 - 10 mM.

[0037] The present invention has the following beneficial effects:

[0038] In the present invention, a Coprinellus radians strain J2 was isolated from the wood of Aquilaria sinensis (Lour.) Spreng. Research shows that Coprinellus radians can convert inorganic selenium into red nano-selenium in the mycelium, can tolerate sodium selenite, can efficiently synthesize nano-selenium, can reduce toxic sodium selenite in a short time, and obtain nano-selenium with small particle size, good biological activity and low toxicity, and its conversion rate is high. It provides more ways for the biosynthesis of nano-selenium, and efficiently and rapidly synthesizes bio-nano-selenium from fungi. At the same time, the Coprinellus radians provided by the present invention is a special intracellular selenium-producing fungus, and nano-selenium is produced in the mycelium of Coprinellus radians and excreted extracellularly; the method for synthesizing nano-selenium using Coprinellus radians has the characteristics of simplicity, stability, high efficiency, rapidity and intuitiveness.

[0039] The microbial material Coprinellus radians used in the present invention itself has bactericidal activity and is an edible and medicinal fungus. After being combined with selenium element to form nano-selenium, it has high biological safety. Using the mycelium of Coprinellus radians as a microbial transformation material for synthesizing nano-selenium can not only increase the safety of the transformation, but also reduce the production cost of nano-selenium. And the biocontrol agent prepared from selenium-rich Coprinellus radians has inhibitory effects on a variety of phytopathogenic fungi and can be used to control a variety of plant diseases. Its control effect is good, and it can be used to prepare more biocontrol products and can be better applied to fields such as agricultural production and animal feed. Description of the Drawings

[0040] Figure 1 It is a colony morphology diagram.

[0041] Figure 2 It is an electron micrograph of spore production of the strain.

[0042] Figure 3 It is a gel electrophoresis diagram of the colony PCR product.

[0043] Figure 4 It is a strain phylogenetic tree constructed based on ITS.

[0044] Figure 5 It is a diagram of the growth of Coprinellus radians mycelium under different culture conditions (from left to right in the figure, the concentrations of sodium selenite are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mM in turn, where A is for 24 h of culture; B is for 5 days of culture; C is for 10 days of culture).

[0045] Figure 6 It is a standard curve diagram of sodium selenite.

[0046] Figure 7 It is a diagram of the growth of Coprinellus radians mycelium (the growth of Coprinellus radians mycelium is on the left in the figure, and the growth of Coprinellus radians mycelium after adding 3 mM sodium selenite is on the right in the figure).

[0047] Figure 8SEM scanning electron micrograph of Coprinellus radians mycelium (in the figure, A is the control mycelium; B is the selenium-enriched mycelium induced by 3 mM; C is the cross-sectional view of the broken mycelium).

[0048] Figure 9 SEM scanning electron micrograph of elemental selenium nanoparticles.

[0049] Figure 10 EDS energy spectrum of elemental selenium nanoparticles (in the figure, A is the elemental analysis of selenium nanoparticles in the selenium-enriched mycelium induced by 3 mM; B is the elemental analysis of elemental selenium nanoparticles).

[0050] Figure 11 Picture of selenium-enriched bacteria powder.

[0051] Figure 12 Control effect of selenium-enriched bacteria solution of Coprinellus radians on various phytopathogenic fungi (in the figure, the first row of each is the blank control group, where A is Rhizoctonia solani of tobacco; B is Ceratocystis fimbriata of sweet potato; C is Sclerotium rolfsii of peanut; D is Alternaria alternata of tobacco; E is Colletotrichum capsici of pepper; F is Fusarium graminearum of wheat; G is Didymella bryoniae of cucurbit; H is Botrytis cinerea).

[0052] Figure 13 Statistical results of lesion area of tobacco inoculated with Rhizoctonia solani by selenium-enriched bacteria solution of Coprinellus radians (in the figure, A is the control group, only inoculated with the pathogen; B is the treatment group, sprayed with selenium-enriched bacteria solution first and then inoculated with the pathogen). Specific implementation mode

[0053] The present invention will be further described below in conjunction with the attached drawings of the specification and specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

[0054] Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0055] The culture medium formula used in the examples is as follows:

[0056] PDA medium: 200 g of potato, 20 g of glucose, 17 g of agar, 1 L of distilled water.

[0057] MA medium: 2.8 g of glucose, 1.22 g of MgSO4·7H2O, 2.72 g of KH2PO4, 2.18 g of fungal peptone, 30 g of agar, 1 L of distilled water.

[0058] PDB medium: 200 g of potato, 20 g of glucose, 1 L of distilled water.

[0059] Example 1 Isolation and purification of strains

[0060] The sample was taken from the moldy part of Aquilaria sinensis (Lour.) Gilg wood. First, under a laminar flow hood, the moldy tissue was peeled off with a sterilized scalpel and cut into 4 - 5 small squares of 5×5 mm with scissors. It was first washed 2 - 3 times with sterile water to remove the surface stains of the diseased tissue. The diseased tissue was soaked in 75% ethanol for 1 min for disinfection, then soaked in 10% sodium hypochlorite solution for 5 min, and finally rinsed repeatedly with sterile water until the medicament on the tissue surface was washed clean. The moisture on the tissue surface was blotted dry with sterilized filter paper, and the diseased tissue was clamped into a PDA medium with forceps and placed in an incubator at 24°C for cultivation. When the colony grew to a diameter of 1 cm, according to the colony morphology, color, etc., different agar plugs were implanted into a new PDA medium with a sterilized borer and continued to be cultivated. The above steps were repeated until a single colony was formed in the PDA medium.

[0061] Identification of the strain in Example 2

[0062] 1. Morphological identification

[0063] It was cultivated in a PDA medium for 7 days, and the colony morphological characteristics, color, etc. were observed. Then, an agar plug was taken and 1 mL of water was added to a MA medium and cultivated at 28°C for 7 days. Then 5 mL of water was added and shaken well. After filtration with filter paper, a clean glass slide was taken, and a drop of the filtrate was dropped in the center of the frosted surface with a dropper. Then the cover glass was covered, and the moisture was blotted dry with absorbent paper. The spore morphology was observed under a microscope.

[0064] The colony morphology was as Figure 1 shown. The center of the colony was yellow, the hyphae were woolly, colorless or light yellow, showing radial long edges, gradually turning yellow, and finally tan. The electron micrograph under the microscope was as Figure 2 shown. The spores were smooth, dark brown, oval or ovoid, 6 - 9 μm.

[0065] 2. Molecular biological identification

[0066] The DNA of the colony was extracted according to the SK8259 kit, and the fungal rDNA-ITS universal primers ITS1 and ITS4 (ITS1: 5'-TCCGTAGGTGAACCTGCGC-3'; ITS4: 5'-TCCTCCGCTTATTGATATGC-3') were used for amplification and sequencing. The PCR amplification system was 20 μL, DNA template 1 μL, primers 0.5 μL each, Green Taq Mix 10 μL, ddH2O 8 μL; reaction conditions: 95℃ pre-denaturation for 3 min, 95℃ denaturation for 15 s, 58℃ annealing for 15 s, 72℃ extension for 1 min, 35 cycles, 72℃ extension for another 5 min, and storage at 4℃. The amplified product was detected in 1.0% agarose gel electrophoresis, and the gel imaging was observed. The PCR product was then sent to Sangon for sequencing, and the sequencing results were submitted to NCBI for Blast comparison analysis.

[0067] Gel electrophoresis of colony PCR products is shown in Figure 3 As shown in Figure 1, the size of the amplified fragment is about 600 bp. DNA sequence alignment results show that the sequence homology with Coprinellus radians reaches 99.69%. The constructed phylogenetic tree is shown in Figure 1. Figure 4 As shown, the strain is clustered with Coprinellus radians (OP3PP715424.1) into one branch. Combined with the above morphological identification results, the taxonomy of the strain isolated in Example 1 is attributed to Coprinellus radians, and it is named J2 strain, and it was deposited in Guangdong Microbiological Culture Collection Center on September 27, 2024, with a deposit number of GDMCC No: 65225, and the deposit address is: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou.

[0068] Example 3 Synthesis of Nano-Selenium from Mycelium of Agaricus radiatus

[0069] Prepare several 250mL triangular flasks, fill them with 150mL PDB culture medium, add the cake of Coprinus radiata, and culture them at 200r / min and 25-28℃ for 7 days. Then add different amounts of sodium selenite (Na2SeO3) solution filtered by 0.22μM filter membrane to each triangular flask at the same time, so that the final concentration in PDB culture medium is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10mM, set 3 groups of replicates for each concentration gradient, culture them in a shaker at 25-28℃ and 200r / min for 10 days, and observe the growth of Coprinus radiata mycelium in each triangular flask during the culture process.

[0070] The results are as follows Figure 5As shown in the figure, after adding sodium selenite solution to the Coprinellus radians mycelium under the same culture conditions and then culturing, except for the blank control group, the color of the Coprinellus radians mycelium in the culture medium with a sodium selenite solution concentration of 1 - 10 mM all changed to red, indicating that the Coprinellus radians mycelium has the ability to transform sodium selenite into nano-selenium, and its ability to reduce inorganic selenium to nano-selenium is strong and fast. When the mycelium was continuously cultured until the 5th day, the color changes in the culture media with different concentrations could be clearly seen. The Coprinellus radians mycelium was white-pink at 1 mM, dark red at 2 and 3 mM, and the color was darker at 3 mM, bright red at 4, 5, 6, 7, 8 mM, and orange-red at 9 and 10 mM. When the mycelium was continuously cultured until the 10th day, the color distinction was more obvious, but the color change pattern from 0 to 10 mM was the same as that on the 5th day, and it could be visually observed that the color at 3 mM was dark red and the darkest.

[0071] Example 4 Conversion rate of selenium-enriched Coprinellus radians mycelium to Na2SeO3

[0072] After the conversion tended to be stable, PDB culture medium with 0 - 10 mM was taken into a 50 mL centrifuge tube. After centrifuging at 10000 r / min for 10 min, the selenium-enriched Coprinellus radians mycelium precipitate was washed 3 times with sterile water, and the fresh mycelium was first dried at 105 °C and then at 60 °C to constant weight. The dried Coprinellus radians mycelium was repeatedly ground into selenium powder (i.e., selenium-enriched bacterial powder) in a mortar.

[0073] At the same time, the conversion rate of Coprinellus radians mycelium to Na2SeO3 was measured. The concentration of sodium selenite was measured by the ascorbic acid reduction method, and a standard curve of Na2SeO3 was made. For the centrifuged Coprinellus radians mycelium, the supernatant sample was taken, 0.5 mL of 4 mol / L hydrochloric acid and 1 mL of 1 mol / L ascorbic acid were added, shaken and mixed evenly, and left to stand at room temperature for 10 min. The absorbance value of the reaction solution at 500 nm was measured, and the conversion rate of sodium selenite was calculated according to the following formula:

[0074] Conversion rate (%) = (C1 - C2) / C1 × 100%

[0075] In the formula: C1 is the concentration of selenium in the original culture solution, and C2 is the concentration of selenium in the supernatant.

[0076] The standard curve of Na2SeO3 is as Figure 6 shown, indicating that the standard curve equation of sodium selenite is y = 0.5766x + 0.0060, R 2 = 0.9990, and this standard curve has a good linear relationship.

[0077] The determination results of the conversion rate of Coprinellus radians mycelium to sodium selenite after culturing for 10 days under different concentrations of Na2SeO3 are shown in Table 1. It can be seen that with the increase of the final concentration of Na2SeO3 in the culture medium, its conversion rate also increases significantly. When the Coprinellus radians strain is at a selenium concentration of 3 mM, the conversion rate of selenium in the environment reaches the highest at 91.62%. When the concentration is 4 - 7 mM, the conversion rate decreases significantly, and all are above 70%. The conversion rate at 10 mM is the lowest, only 56.55%. In summary, the optimal conversion rate of Coprinellus radians mycelium to Na2SeO3 under this condition should be around 3 mM.

[0078] Table 1 Determination results of the conversion rate of Coprinellus radians mycelium to Na2SeO3

[0079]

[0080] Example 5 Determination of the tolerance of Coprinellus radians mycelium and the biomass of the mycelium

[0081] After culturing Coprinellus radians mycelium in PDB medium at a culture temperature of 25 - 28 °C and a rotation speed of 200 r / min for 7 days, sodium selenite was added to make its final concentration 3 mM, and it was statically cultured at 25 °C for 24 h. Three replicates were set, and the growth of Coprinellus radians mycelium in each Erlenmeyer flask was observed.

[0082] The results are as Figure 7 shown. The Coprinellus radians mycelium turns red under static conditions, indicating that Coprinellus radians has the ability to stably and rapidly reduce inorganic selenium to nano-selenium.

[0083] Subsequently, 150 mL of PDB medium was added to a 200 mL Erlenmeyer flask, and then 4 Coprinellus radians mushroom cakes (diameter 5 mm) were added, and they were cultured at 200 r / min and 25 - 28 °C for 4 days. At the same time, different amounts of sodium selenite solution filtered through a 0.22 μM filter membrane were added to make the final concentration of the PDB medium 0, 3, 6, 9 mM. Three replicates were set for each concentration gradient, and they were cultured in a shaker at 25 - 28 °C and 200 r / min for 10 days. The growth of Coprinellus radians mycelium was observed during the culture process. After centrifuging the PDB medium at 10000 r / min for 10 min, the Coprinellus radians mycelium precipitate was washed 3 times with sterile water, and the fresh mycelium was placed in an oven and dried to a constant weight at 60 °C, and its dry weight was measured.

[0084] The results are shown in Table 2. It can be seen from Table 2 that when Na2SeO3 is added before the mycelium has grown completely, the growth of Coprinellus radians mycelium is restricted to a certain extent at 3 mM, and with the continuous increase of the concentration, the biomass of Coprinellus radians mycelium shows a downward trend. This indicates that Coprinellus radians can tolerate a certain concentration of Na2SeO3.

[0085] Table 2 Biomass of mycelia after 10 days of cultivation under different concentrations of Na2SeO3

[0086]

[0087] Characterization and analysis of nano-selenium synthesized by Coprinellus radians in Example 6

[0088] 1. SEM characterization of Coprinellus radians mycelia

[0089] Take the Coprinellus radians mycelia samples synthesized under the conditions of sodium selenite concentrations of 0 and 3 mM in Example 4, rinse the mycelia repeatedly with distilled water to obtain control mycelia and selenium-rich mycelia. After critical point drying, observe the two groups of samples by SEM scanning electron microscopy.

[0090] The results are as Figure 8 shown. It shows that the surface and interior of the control mycelia are smooth and no granular substances are produced, while there are many disc-shaped granular substances inside the selenium-rich mycelia. These granular substances are red elemental nano-selenium particles, which cause the Coprinellus radians mycelia to show red. The cross-sectional diagram of the broken mycelia proves that Coprinellus radians is a special intracellular selenium-producing fungus.

[0091] 2. SEM and EDS characterization of elemental nano-selenium particles

[0092] For the nano-selenium synthesized under the condition of 3 mM in Example 5, red precipitate substances can be observed at the bottom. This precipitate is elemental nano-selenium particles, and it is characterized by scanning electron microscopy and EDS energy spectrum.

[0093] The results of the scanning electron microscopy are as Figure 9 shown. Most of the synthesized nano-selenium is in the shape of discs, and a small amount shows irregular shapes. The size of the nano-selenium particles is between 200 and 500 nm. The EDS energy spectrum is as Figure 10 shown, showing that the highest peak is the Se element, further confirming that the synthesized granular substances are nano-selenium.

[0094] Control effect of Coprinellus radians selenium-rich bacterial liquid on various diseases in Example 7

[0095] In this example, the inhibitory effects of the selenium-enriched mycelial suspension of Coprinellus radians on a variety of common phytopathogenic fungi were determined. The phytopathogenic fungi tested were: Rhizoctonia solani, Fusarium solani, Sclerotium rolfsii, Alternaria alternata, Colletotrichum fructicola, Fusarium pseudograminearum, Stagonosporopsis cucurbitacearum, Botrytis cinerea. The plant diseases caused by the infection of these fungi were tobacco damping-off, sweet potato black rot, peanut southern blight, tobacco brown spot, pepper anthracnose, wheat basal rot, cucurbit gummy stem blight, and gray mold.

[0096] The preparation method of the selenium-enriched mycelial suspension of Coprinellus radians was the same as that in Example 4. Selenium-enriched mycelial powder was prepared using 3 mM Na2SeO3. As Figure 11 shown, sterile water was added to prepare a selenium-enriched mycelial suspension with a concentration of 6 g / L, and it was diluted 10 times before use.

[0097] Inhibitory activity of phytopathogenic fungi growth: Using the plate confrontation culture method, a 5-mm mycelial disc of the corresponding pathogenic fungus was inoculated in the center of a PDA plate. Then, 20 μL of the selenium-enriched mycelial suspension was pipetted and dropped at 4 points 2.5 cm away from the mycelial disc. The culture plate inoculated with only the pathogenic fungus was used as a control. It was incubated at a constant temperature of 28°C. After 2 - 7 days, the colony diameter was measured and the inhibition rate was calculated.

[0098] Inhibition rate = (control colony diameter - treated colony diameter) / (control colony diameter - mycelial disc diameter) × 100%.

[0099] The measurement results showed that the selenium-enriched mycelial suspension had good inhibitory effects on the growth of the fungi causing the 8 diseases of tobacco damping-off, sweet potato black rot, peanut southern blight, tobacco brown spot, pepper anthracnose, wheat basal rot, cucurbit gummy stem blight, and gray mold. The specific measurement results are shown in Table 3, and the inhibition rates were 46.05%, 78.96%, 83.54%, 72.50%, 74.79%, 70.63%, 79.33%, and 86.17% respectively. The plate inhibition results are as Figure 12 shown, indicating that the selenium-enriched mycelial suspension of Coprinellus radians can be used to control a variety of plant diseases caused by these pathogenic fungi.

[0100] Table 3 Control effects of selenium-enriched mycelial suspension on various diseases

[0101]

[0102] Example 8 Control Effect of Selenium-Rich Bacterial Liquid on Tobacco Diseases

[0103] Prepare the selenium-rich bacterial liquid of Coprinellus radians in the same way as in Example 7. A total of 2 treatment groups were designed. Spraying sterile water was used as the control group, and spraying the selenium-rich bacterial liquid on the tobacco leaves was used as the treatment group. Each treatment was repeated 3 times, and each group was repeated with 4 tobacco leaves. Tobacco leaves of the same size were selected, cleaned, wiped and disinfected with 75% alcohol, and dried for later use. The leaves were pricked with a sterile needle to create wounds, and fresh Rhizoctonia solani blocks (5 mm in diameter) were inoculated at the pricked positions, and then placed in an incubator at 28 °C and a humidity of 85%. By measuring the lesion area of the tobacco leaves, the occurrence of lesions and the control effect were recorded.

[0104] The control effect is as Figure 13 shown. The average lesion area of the control group of tobacco leaves was statistically measured by ImageJ to be 11.97 cm 2 , and the average lesion area of the treatment group was 2.56 cm 2 . The results show that the selenium-rich bacterial liquid of Coprinellus radians has a good control effect on tobacco Rhizoctonia disease, and its control efficiency reaches 78.60%.

[0105] In summary, a strain of Coprinellus radians J2 was isolated from Aquilaria sinensis wood in the present invention. The research shows that Coprinellus radians can convert inorganic selenium into red nano-selenium in the mycelium, can efficiently synthesize nano-selenium, can reduce toxic sodium selenite in a short time, and obtain nano-selenium with small particle size, good biological activity and low toxicity. Its conversion rate is high, which provides more fungal-synthesized, efficient and rapid synthetic biological nano-selenium pathways for the biosynthesis of nano-selenium, and provides a reference for the development and utilization of microbial synthesis of nano-selenium.

[0106] Since Coprinellus radians is an edible and medicinal fungus with good safety, using the mycelium of Coprinellus radians as a microbial transformation material for synthesizing nano-selenium can not only increase the safety of the transformation, but also reduce the production cost of nano-selenium. At the same time, the selenium-rich bacterial liquid of Coprinellus radians has a good inhibitory effect on a variety of plant pathogenic fungi, can be used to control a variety of plant diseases, has a good control effect, can be used to prepare more biocontrol products, and is better applied to agricultural production, animal feed and other fields.

[0107] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A strain of Coprinellus radians J2, characterized in that, The strain was deposited at the Guangdong Provincial Culture Collection of Microorganisms on September 27, 2024, with the deposit number GDMCC No: 65225.

2. Use of the Coprinellus radians J2 strain according to claim 1 in reducing inorganic selenium to nano-selenium.

3. Use of the Coprinellus radians J2 strain according to claim 1 in the preparation of nano-selenium.

4. A method for synthesizing nano-selenium using the Coprinellus radians J2 strain described in claim 1, characterized in that, After adding Coprinellus radians to the culture medium and culturing for 1 - 7 days, then adding inorganic selenium and continuing to culture for 5 - 15 days, the obtained red precipitate is the elemental nano-selenium particles.

5. The method according to claim 4, characterized in that, The culture medium used is PDB medium, and the culture conditions are: temperature is 25 - 28 °C, and the rotation speed is 100 - 200 r / min.

6. A nano-selenium, characterized in that, Prepared by the method according to claim 4 or 5.

7. A product, characterized in that, Containing the nano-selenium according to claim 6.

8. Use of the Coprinellus radians J2 strain according to claim 1 in inhibiting phytopathogenic fungi or in controlling plant diseases, characterized in that, The plant pathogenic fungi are one or more of Rhizoctonia solani, Fusarium solani, Sclerotium rolfsii, Alternaria alternata, Colletotrichum fructicola, Fusarium pesudograminearum, Stagonosporopsis cucurbitacearum, Botrytis cinerea, and the plant diseases are one or more of tobacco damping-off, sweet potato black rot, peanut southern blight, tobacco brown spot, pepper anthracnose, wheat basal rot, melon gummy stem blight, gray mold.

9. Use of the Coprinellus radians J2 strain according to claim 1 in the preparation of biocontrol products.

10. A method for inhibiting phytopathogenic fungi or controlling plant diseases, characterized in that, After culturing the Coprinellus radians according to claim 1 with inorganic selenium, prepare selenium-rich bacterial powder or bacterial liquid to treat the sample.

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