Application of 3-phenyl propyl acetate in preparation of medicine for preventing and treating fungal diseases of rice

Abstract

The invention discloses an application of 3-phenyl propyl acetate in preparation of a medicine for preventing and treating fungal diseases of rice. Experiments show that the compound can effectively inhibit mycelial growth and conidia germination of magnaporthe oryzae, can interfere conidia of magnaporthe oryzae to form appressorium, has an obvious inhibition effect on magnaporthe oryzae, and also inhibits mycelial growth of rhizoctonia solani. The inventor also accidentally finds that the antibacterial effect of the pesticide can be promoted by adding a small amount of 3-phenyl propyl acetate into the pesticide, so that the small amount of 3-phenyl propyl acetate can be used as a pesticide synergist for preventing and treating the rice fungal diseases. Therefore, the 3-phenyl propyl acetate has good application value in the aspects of prevention and control of rice fungal diseases and drug development.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology, and particularly relates to application of 3-phenylpropyl acetate in preparing medicines for preventing and treating fungal diseases of rice. Background Art

[0002] Rice (Oryza sativa L.) is one of the important food crops and occupies a very important position in the world's food production. Nearly 50% of the world's population relies on it as their staple food. Its safe production is crucial to ensuring social stability and economic development. The rice planting area in my country accounts for about 1 / 4 of the country's farmland area. Like other crops, rice will inevitably be attacked by a series of pathogens during its planting, growth and development. Rice will encounter a variety of fungal diseases during its growth, mainly including rice false smut, rice blast, sheath blight, smut, etc., which seriously affect the yield and quality of rice. Among them, rice blast caused by Magnaporthe oryzae is one of the most serious diseases of rice. It is a major problem in the world's rice production and is known as "rice cancer". The occurrence of rice blast can reduce rice production by 10% to 30% each year. This disease can occur in all rice-growing areas and at different growth stages of rice. It has the characteristics of wide distribution and great harm, resulting in a serious reduction in rice production, threatening the food production security of my country and even the world. Therefore, the research on the prevention and control of rice blast has important economic value and social benefits. Rice blast is prone to occur at all stages of rice growth: seedling blast, node blast, and leaf blast. The infection process of rice blast on rice mainly includes: under suitable environmental conditions, rice blast will produce and release conidia, which will spread with wind and rain and adhere to the surface of rice leaves; conidia can form germ tubes after germination; germ tubes differentiate into attachment cells after germination and adhere to the cuticle of rice leaves; attachment cells differentiate into infection spikes; infection spikes further break through the cuticle and penetrate into the cells of rice leaves, and form infection hyphae in host cells, expand between cells, and complete the initial infection. Rice blast continues to grow, multiply and spread in mesophyll cells, causing necrotic lesions to appear on rice leaves within 5-7 days, and produces conidia on the lesions, which become the source of infection for the next round of infection. Rice blast fungus mainly infects the aboveground tissues of rice with conidia. When the conidia contact the host epidermis, they germinate to form germ tubes, which then differentiate into appressorium. The appressorium forms infection spikes that penetrate the host epidermis and then continue to enter the host cells, causing the host plant to show symptoms in about 5-7 days. Among them, the key process for the successful infection of rice by rice blast fungus is the formation of highly specialized infection structures - appressorium. The turgor pressure generated by the mature appressorium can enable the infection spikes to penetrate the rice cuticle and successfully infect rice cells. When the rice blast fungus cannot form a complete appressorium, its pathogenicity is significantly weakened. At present, the main methods for preventing and controlling rice blast are breeding resistant varieties, chemical control and field management. Among them, most of the disease-resistant varieties are vertically resistant varieties based on the "gene-to-gene" theory, and these varieties are prone to lose disease resistance. Chemical control has the advantages of economy, high efficiency, convenience and rapidity, and has always been an indispensable part of the comprehensive management system of rice blast. The prevention and control of rice blast is a hot topic in global research.Chemical control plays an important role in the integrated management of pests and diseases. It has the characteristics of rapid results, simple methods, strong emergency response, and is not restricted by geographical location and seasonality.

[0003] Rice sheath blight is one of the main diseases of rice and one of the three major diseases in the world. Rice sheath blight is a soil-borne fungal disease caused by Rhizoctonia solani Kühn. Rhizoctonia solani is a soil-borne fungus with a wide host range, strong saprophytic properties, and a polynucleate fungus. It lacks a stable genetic transformation system, so the prevention and control methods are limited. In recent years, with the change of climate, the increase in the use of nitrogen fertilizers, and the promotion of high-yield cultivation techniques with short stalks and dense planting, the harm of sheath blight has become increasingly serious. Pathogenic mechanism of rice sheath blight: Rhizoctonia solani can form a special infection structure during the infection process to facilitate its invasion into the host. It is generally accepted that it destroys the host cell wall by secreting cell wall degrading enzymes and toxins, changes the osmotic pressure inside and outside the cell, and affects the host's ability to survive in harsh environments. In the late stage of infection, the hyphae of Rhizoctonia solani will produce extracellular degradative enzymes, such as pectin degrading enzymes and cellulolytic enzymes, which damage rice tissues and show symptoms of yellowing of leaf sheaths or leaves. The toxins produced by the sheath blight fungus are mainly sugar substances such as glucose and galactose, which can induce plant diseases at very low concentrations. After entering the host, it will not establish new physiological and biochemical processes by itself, but will reduce the host's resistance to pathogens by affecting plant photosynthesis, water transport, and the activity of various enzymes or proteins. At present, the prevention and control of rice sheath blight mainly relies on chemical fungicides and cultivation measures.

[0004] 3-Phenylpropyl Acetate (CAS No. 122-72-5). 3-Phenylpropyl Acetate is usually a colorless to light yellow liquid at room temperature, with a special aroma, which is often used in the preparation of spices and flavors, especially in fruit and flower flavors, so it is used as a food flavor. It is also used as a solvent and an intermediate in organic synthesis. After searching, there is no report on the application of 3-Phenylpropyl Acetate in agricultural production. Summary of the invention

[0005] In view of the above technical problems, the present invention provides the use of 3-phenylpropyl acetate in the preparation of drugs for preventing and controlling fungal diseases of rice.

[0006] The invention discloses an application of protected 3-phenylpropyl acetate in preparing medicine for preventing and treating fungal diseases of rice.

[0007] Furthermore, the fungal diseases of rice are rice blast and rice sheath blight.

[0008] Furthermore, the 3-phenylpropyl acetate is used in the preparation of a drug for inhibiting the mycelial growth and spore germination of rice blast fungus.

[0009] Furthermore, the 3-phenylpropyl acetate is used in the preparation of a drug that interferes with the formation of appressorium of rice blast fungus.

[0010] Furthermore, the 3-phenylpropyl acetate is used in the preparation of a drug for inhibiting the growth of Rhizoctonia solani hyphae.

[0011] Furthermore, the concentration of the 3-phenylpropyl acetate is 50 μg / mL-200 μg / mL.

[0012] The present invention also protects the use of 3-phenylpropyl acetate in preparing a pesticide synergist for preventing and controlling fungal diseases of rice.

[0013] Further, the concentration of the 3-phenylpropyl acetate is 1-5 μg / mL

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention has found that the compound can effectively inhibit the growth of mycelium and conidia germination of rice blast fungus, interfere with the formation of appressorium of rice blast fungus conidia, have a significant inhibitory effect on rice blast fungus, and also inhibit the growth of mycelium of Rhizoctonia solani. At the same time, it is also found that adding a small amount of 3-phenylpropyl acetate to pesticides can promote the antibacterial effect of pesticides, indicating the use of a small amount of 3-phenylpropyl acetate as a synergist in the preparation of pesticides for preventing and controlling rice fungal diseases. Therefore, 3-phenylpropyl acetate has a good application value in the prevention and control of rice fungal diseases and drug development. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The effect of different concentrations of 3-phenylpropyl acetate on the mycelial growth of rice blast strain H7 and Rhizoctonia solani strain LC-Q-29;

[0016] Figure 2 This is a graph showing the effect of different concentrations of 3-phenylpropyl acetate on the mycelial growth diameter of the rice blast fungus strain H7;

[0017] Figure 3 This is a graph showing the inhibition rate of different concentrations of 3-phenylpropyl acetate on the mycelial growth of the rice blast fungus strain H7;

[0018] Figure 4 This is a graph showing the effect of different concentrations of 3-phenylpropyl acetate on the mycelial growth diameter of Rhizoctonia solani strain LC-Q-29;

[0019] Figure 5 This is a graph showing the inhibition rate of different concentrations of 3-phenylpropyl acetate on the mycelial growth of Rhizoctonia solani strain LC-Q-29;

[0020] Figure 6 The effect of different concentrations of 3-phenylpropyl acetate on the conidia germination of Magnaporthe grisea;

[0021] Figure 7 The effect of different concentrations of 3-phenylpropyl acetate on the appressorium formation of Magnaporthe grisea;

[0022] Figure 8 The effect of different concentrations of 3-phenylpropyl acetate on the dry weight of mycelium of rice blast strain H7 and Rhizoctonia solani strain LC-Q-29;

[0023] Fig. 9 This is a graph showing the effect of different concentrations of 3-phenylpropyl acetate on the dry weight of mycelium of the rice blast strain H7;

[0024] Fig.10 This is a graph showing the effect of different concentrations of 3-phenylpropyl acetate on the dry weight of mycelium of Rhizoctonia solani strain LC-Q-29;

[0025] Fig.11 This is a graph showing the effect of the mixed treatment of 3-phenylpropyl acetate with azoxystrobin, tebuconazole and ketoconazole on the mycelial growth diameter of the rice blast strain H7;

[0026] Fig.12 This is a graph showing the effect of the mixed treatment of 3-phenylpropyl acetate and azoxystrobin on the mycelial growth diameter of the rice blast strain H7;

[0027] Fig.13 This is a graph showing the effect of the mixed treatment of 3-phenylpropyl acetate and azoxystrobin on the mycelial growth of the rice blast strain H7;

[0028] Fig.14 This is a graph showing the effect of the mixed treatment of 3-phenylpropyl acetate and tebuconazole on the mycelial growth diameter of the rice blast strain H7;

[0029] Fig.15 This is a graph showing the effect of the mixed treatment of 3-phenylpropyl acetate and tebuconazole on the mycelial growth of the rice blast strain H7;

[0030] Fig.16 This is the effect of the mixed treatment of 3-phenylpropyl acetate and ketoconazole on the mycelial growth diameter of the rice blast strain H7;

[0031] Fig.17 This is a graph showing the effect of mixed treatment of 3-phenylpropyl acetate and ketoconazole on the mycelial growth of rice blast strain H7.

[0032] Note: The same letters between the groups indicate no significant difference, different letters indicate significant difference (P<0.05), and letters a, b, c, d represent P values ​​less than 0.05, indicating significant difference. DETAILED DESCRIPTION

[0033] Source of the test strains: The rice blast fungus strain H7 and the Rhizoctonia solani strain LC-Q-29 are preserved by the applicant and can be provided by the applicant. The applicant's contact address is No. 95, Jinhei Road, Panlong District, Kunming City, Yunnan Province, Yunnan Agricultural University, Postal Code: 650100.

[0034] Example 1 Effect of 3-phenylpropyl acetate on mycelial growth of rice blast strain H7 and Rhizoctonia solani strain LC-Q-29 A method for inhibiting mycelial growth of rice blast fungus and Rhizoctonia solani using 3-phenylpropyl acetate comprises the following steps:

[0035] S1: 3-phenylpropyl acetate was dissolved in dimethyl sulfoxide to prepare a mother solution (10000 μg / mL), and the prepared mother solution of 3-phenylpropyl acetate was added to the PDA culture medium to make the final concentrations of 3-phenylpropyl acetate 10 μg / mL, 50 μg / mL, 100 μg / mL and 200 μg / mL, respectively, and 3-phenylpropyl acetate was added when the temperature of the PDA culture medium was cooled to 55°C; at the same time, a PDA culture medium without 3-phenylpropyl acetate was set as a blank control group.

[0036] The preparation method of the above-mentioned PDA culture medium:

[0037] (1) Use weighing paper to weigh 20 g of glucose and 15 g of agar powder on a balance;

[0038] (2) Peel and clean the potatoes, weigh 200 g of peeled potatoes and cut them into cubes of about 1 cm using a knife on a clean chopping board;

[0039] (3) Measure 1000 mL of distilled water, add the distilled water and 200 g of peeled potato pieces into a pot, cook for 20-30 min after the water boils, and then filter the potato residue through 4 layers of clean gauze in a beaker with a measuring range of 2000 mL;

[0040] (4) Add 20 g of glucose to the filtered liquid and stir with a glass rod to fully dissolve the glucose. Add 15 g of agar powder to a 2 L conical flask and use a 1000 mL measuring cylinder to adjust the volume of the potato filtrate obtained after the glucose is fully dissolved to 1000 mL. Then add it to the conical flask containing agar powder and shake it thoroughly. Then sterilize it in a high pressure steam sterilizer at 121° C. for 20 min to obtain a PDA culture medium.

[0041] The specific method for adding 3-phenylpropyl acetate to PDA culture medium is as follows: 3-phenylpropyl acetate is drawn with a pipette and added to PDA culture medium that has been cooled to 55°C, so that the final concentrations of 3-phenylpropyl acetate in the culture medium are 10 μg / mL, 50 μg / mL, 100 μg / mL and 200 μg / mL, respectively. The culture medium is mixed and poured into a sterile culture dish, and bubbles are avoided as much as possible during the pouring process to affect the experimental results, so as to obtain PDA culture medium with different concentrations of 3-phenylpropyl acetate.

[0042] S2: Cultivation of test bacteria: Magnaporthe grisea and Rhizoctonia solani;

[0043] The specific method for culturing the test bacteria rice blast fungus and Rhizoctonia solani is as follows:

[0044] 2.1 In a sterilized clean bench, light the alcohol lamp and cool the PDA culture medium sterilized by high-pressure steam to about 55°C;

[0045] 2.2 Pour about 22 mL of culture medium into each dish with a diameter of 90 mm, and try to ensure that there are no bubbles during the pouring process;

[0046] 2.3 After the culture medium is completely solidified, take out the filter paper for testing rice blast fungus and Rhizoctonia solani from the refrigerator respectively;

[0047] 2.4 Place the tweezers in the outer flame of the alcohol lamp and burn them. After the tweezers cool down, use the tweezers to pick up the filter paper pieces containing rice blast pathogen and Rhizoctonia solani and place them on the PDA culture medium;

[0048] 2.5 Finally, seal the culture dish with sealing film and place it upside down in a constant temperature incubator at 28℃ to culture the test strain.

[0049] S3: After culturing the test bacteria Magnaporthe grisea for 7 days, a sterile cork punch was used to cut a bacterial block on the test bacteria Magnaporthe grisea culture medium, with a bacterial block diameter of 6 mm, and the blocks were placed in a PDA culture medium containing 3-phenylpropyl acetate and a blank control PDA culture medium; after culturing the test bacteria Rhizoctonia solani for 3 days, a sterile cork punch was used to cut a bacterial block on the test bacteria Rhizoctonia solani culture medium, with a bacterial block diameter of 6 mm, and the blocks were placed in a PDA culture medium containing 3-phenylpropyl acetate and a blank control PDA culture medium;

[0050] S4: The PDA medium containing 3-phenylpropyl acetate and the blank control PDA medium with the bacterial blocks were placed in a constant temperature incubator for cultivation. The temperature of the constant temperature incubator was 28°C. The rice blast strain H7 was cultivated for 9 days, and the Rhizoctonia solani strain LC-Q-29 was cultivated for 2 days. The colony diameters were measured with a vernier caliper, and the mycelial growth inhibition rates of the experimental group and the blank control group were calculated.

[0051] The calculation formula is as follows

[0052] Inhibition rate = (control strain growth diameter - 0.7) - (treated strain growth diameter - 0.7)) / (control strain growth diameter - 0.7) (Note: 0.7 represents the inoculated bacterial block diameter)

[0053] The experimental group prepared different concentrations of 3-phenylpropyl acetate PDA culture medium, which were 10μg / mL, 50μg / mL, 100μg / mL and 200μg / mL, respectively, and inoculated with rice blast fungus blocks, and counted the colony diameters after 9 days, and calculated the mycelial growth inhibition rates of the experimental group and the blank control group. The experimental group prepared different concentrations of 3-phenylpropyl acetate PDA culture medium, which were 10μg / mL, 50μg / mL, 100μg / mL and 200μg / mL, respectively, and inoculated with rice blast fungus blocks, and counted the colony diameters after 2 days, and calculated the mycelial growth inhibition rates of the experimental group and the blank control group. The results are as follows Figure 1-5 shown.

[0054] Results: By inoculating rice blast fungus and Rhizoctonia solani in the culture medium containing 3-phenylpropyl acetate, the results showed that different concentrations of 3-phenylpropyl acetate had an effect on the growth of both rice blast fungus and Rhizoctonia solani hyphae, and as the concentration of 3-phenylpropyl acetate increased, the inhibitory effect became more obvious ( Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 ). The Duncan method in SPSS data analysis software was used to analyze the difference in mycelial growth diameter and mycelial growth inhibition rate data. The same letters between the groups indicate no significant difference, and different letters indicate significant difference (P<0.05). Letters a, b, c, and d represent P values ​​less than 0.05, indicating significant differences. The inhibition rate of 100-200 μg / mL 3-phenylpropyl acetate on the mycelium of Magnaporthe oryzae reached more than 40%, while the inhibition rate of 50-200 μg / mL 3-phenylpropyl acetate on Rhizoctonia solani reached more than 40%.

[0055] Example 2 Effect of 3-phenylpropyl acetate on spore formation and appressorium formation of rice blast strain H7

[0056] Implementation steps:

[0057] S1 placed the PDA medium with the bacterial blocks in a constant temperature incubator for 7 days, and then used a sterile punch to cut the bacterial blocks on the PDA medium where the rice blast fungus grew. The diameter of the bacterial blocks was 6 mm, and 6 bacterial blocks were selected and placed in the PDB medium.

[0058] The preparation method of the PDB culture medium:

[0059] (1) Take a weighing paper and weigh 20 g of glucose on a balance;

[0060] (2) Peel and clean the potatoes, weigh 200 g of peeled potatoes, and cut them into cubes of about 1 cm on a clean chopping board with a knife;

[0061] (3) Measure 1000 mL of distilled water and add it to a pot together with 200 g of peeled potato pieces. After the water boils, cook for another 20-30 minutes. Then, filter the potato residue through 4 layers of clean gauze in a 1 L beaker.

[0062] (4) Add 20 g of glucose to the filtered liquid, stir evenly with a glass rod, pour into a 1 L measuring cylinder, add distilled water to make up to 1000 mL, adjust the pH to natural, and dispense into conical flasks, not exceeding one-third of the volume of the conical flask. Then sterilize in a high pressure steam sterilizer at 121 °C for 20 min to obtain PDB medium.

[0063] S2: Place the bacterial block in PDB medium and place it in a shaker at 120rpm and 28℃ for 3-4 days, then take 400μL of mycelial suspension into prune juice medium to make the bacterial liquid evenly distributed. Place it in a 28℃ incubator for about 4 days, and then place it in a light incubator for about 7 days, wash the spores with 0.1% Tween water, and prepare conidia suspension; add 3-phenylpropyl acetate mother solution to the conidia suspension to a final concentration of 10μg / mL, 50μg / mL, 100μg / mL and 200μg / mL, respectively, drop the conidia suspension mixed with 3-phenylpropyl acetate onto a hydrophobic glass slide, keep it moist in the dark at 28℃ for 4h and 8h, and observe the spore germination and appressorium formation of rice blast strain H7 under a microscope.

[0064] The preparation method of the prune juice culture medium:

[0065] (1) Use weighing paper to weigh 5 g of lactose, 5 g of yeast extract, and 15 g of agar powder on a balance;

[0066] (2) Use a 100-mL measuring cylinder to measure 40 mL of prune juice for later use;

[0067] (3) Pour lactose, yeast extract and prune juice into a 2 L beaker, add distilled water to make up to 1000 mL and stir thoroughly to fully dissolve lactose and yeast extract;

[0068] (4) adding 0.8 mL of 1 mM sodium hydroxide solution to adjust the pH, and packaging the solution in blue-capped bottles. Add an appropriate amount of agar powder in advance according to the dosage of 15-20 g / L to the blue-capped bottles. The volume of the solution to be packaged should not exceed one-third of the volume of the blue-capped bottles. Then, sterilize the solution in a high-pressure steam sterilizer at 121° C. for 20 min to obtain prune juice culture medium.

[0069] Results: The results of spore germination and appressorium formation were as follows Figure 6 and Figure 7 After adding different concentrations of 3-phenylpropyl acetate to the conidia suspension, the results showed that 100 μg / mL 3-phenylpropyl acetate had an inhibitory effect on the conidia germination and appressorium formation of Magnaporthe oryzae. At 200 μg / mL, both conidia germination and appressorium formation were significantly inhibited (e.g. Figure 6 and Figure 7 The Duncan method in SPSS data analysis software was used to analyze the significance of the conidia germination rate and appressorium formation rate. The same letters between the groups indicate no significant difference, and different letters indicate significant difference (P<0.05). Letters a, b, c, and d represent P values ​​less than 0.05, indicating significant difference.

[0070] Example 3 Effect of 3-phenylpropyl acetate on dry weight of mycelium of rice blast strain H7 and Rhizoctonia solani strain LC-Q-29

[0071] The experimental steps are as follows:

[0072] S1: After the PDA medium containing the rice blast strain H7 bacteria block was placed in a constant temperature incubator and cultured for 7 days, a sterile punch was used to cut the bacteria block on the PDA medium where the rice blast pathogen grew, and the bacteria block diameter was 6 mm. Four bacteria blocks were picked and placed in YEG liquid medium. After the PDA medium containing the LC-Q-29 bacteria block of the solani was placed in a constant temperature incubator and cultured for 3 days, a sterile punch was used to cut the bacteria block on the PDA medium where the solani bacteria grew, and the bacteria block diameter was 6 mm. Four bacteria blocks were picked and placed in YEG liquid medium.

[0073] S2: Add the 3-phenylpropyl acetate mother solution to the YEG liquid medium containing the bacterial block to a final concentration of 10 μg / mL, 50 μg / mL, 100 μg / mL and 200 μg / mL of 3-phenylpropyl acetate. After the bacterial block in the YEG liquid medium was shaken and cultured at 28 degrees Celsius and 60 r / min for 7 days, the bacterial block was taken out of the YEG liquid medium and dried in an oven at 55 degrees Celsius for 48 hours to measure the dry weight of the mycelium.

[0074] The preparation method of the YEG liquid culture medium:

[0075] (1) Use weighing paper to weigh 25 g of glucose and 5 g of yeast extract on a balance and place them in a 2000 mL beaker;

[0076] (2) Accurately measure 1000 mL of distilled water using a measuring cylinder and add it to the beaker and stir thoroughly to fully dissolve the glucose and yeast extract;

[0077] (3) Packaging: Use a measuring cylinder to accurately measure 100 mL of fully dissolved culture medium and add it to a 250 mL conical flask.

[0078] (4) After the subpackaging is completed, seal the mouth of the conical bottle with two culture medium sealing films and sterilize it in a high-pressure steam sterilizer at 121°C for 20 min to obtain YEG liquid culture medium.

[0079] Results: The mycelia of the rice blast strain H7 and the Rhizoctonia solani strain LC-Q-29 were cultured in YEG liquid medium containing 3-phenylpropyl acetate. After 7 days of shaking culture, the mushroom blocks were taken out and dried, and the dry weight of the mycelia was measured. The results showed that the addition of 50 μg / mL of 3-phenylpropyl acetate could significantly inhibit the growth of the mycelia of the rice blast strain H7 and the Rhizoctonia solani strain LC-Q-29. When 100 μg / mL of 3-phenylpropyl acetate was added, the mycelia growth of the rice blast strain H7 and the Rhizoctonia solani strain LC-Q-29 was completely inhibited ( Figure 8 ). By measuring the dry weight of mycelium, it was found that with the increase of the concentration of 3-phenylpropyl acetate treatment, the dry weight of mycelium of rice blast strain H7 and Rhizoctonia solani strain LC-Q-29 decreased significantly ( Fig. 9 , Fig.10 The Duncan method in SPSS data analysis software was used to analyze the significance of mycelium dry weight data. The same letters between the groups indicated no significant difference, and different letters indicated significant difference (P<0.05). Letters a, b, c, and d represented P values ​​less than 0.05, indicating significant differences.

[0080] Example 4 Use of 3-phenylpropyl acetate as a synergist for pesticide control of rice fungal diseases

[0081] The three pesticides used in this experiment are azoxystrobin (Shanghai McLean Biochemical Technology Co., Ltd., CAS No.: 131860-33-8), tebuconazole (Beijing Solaibao Technology Co., Ltd., CAS No.: 107534-96-3) and ketoconazole (TCI Shanghai Chemical Industry Development Co., Ltd., CAS No.: 65277-42-1). Azoxystrobin is a methoxyacrylate fungicide pesticide with high efficiency and broad spectrum, and has good activity against almost all fungal diseases. Tebuconazole is an organic compound, a high-efficiency, broad-spectrum, systemic triazole fungicide pesticide with three functions of protection, treatment and eradication, a broad fungicide spectrum and a long lasting effect. Ketoconazole is an imidazole broad-spectrum antifungal drug. The three pesticides were mixed with 3-phenylpropyl acetate to treat rice blast strain H7 in order to explore the effect of 3-phenylpropyl acetate on the antibacterial function of these three pesticides.

[0082] The experimental steps are as follows:

[0083] After the PDA medium containing the rice blast strain H7 bacterial block was placed in a constant temperature incubator for 7 days, a sterile punch was used to cut bacterial blocks on the PDA medium where the rice blast fungus grew, and the bacterial blocks had a diameter of 6 mm, and were placed in a PDA medium containing 3-phenylpropyl acetate, a PDA medium containing 3-phenylpropyl acetate and a mixture of different pesticides, and a blank control PDA medium. The specific method of adding 3-phenylpropyl acetate to the PDA medium is as follows: 3-phenylpropyl acetate is drawn with a pipette and added to the PDA medium that has been cooled to 55°C, so that the concentration of 3-phenylpropyl acetate in the final medium is 5 μg / mL, the medium is mixed and poured into a sterile culture dish, and bubbles that appear during the pouring process are avoided as much as possible to affect the experimental results, and PDA culture media with different concentrations of 3-phenylpropyl acetate are obtained.

[0084] The three pesticides used in this experiment are azoxystrobin, tebuconazole and ketoconazole. The three pesticides were dissolved in dimethyl sulfoxide to prepare mother solutions (10000 μg / mL), and the mother solutions were added to the sterilized PDA medium cooled to 55°C to make the final concentrations of the three pesticides 0.1 μg / mL. The 3-phenylpropyl acetate and pesticide mixed treatment group was to add the mother solutions of the three pesticides to the sterilized PDA medium cooled to 55°C to make the final concentration of the pesticides in the medium 0.1 μg / mL, and then add the mother solution of 3-phenylpropyl acetate to the medium with pesticides added to make the final concentration of 3-phenylpropyl acetate in the medium 5 μg / mL. At the same time, the PDA medium without 3-phenylpropyl acetate and pesticides was set as a blank control group, the PDA medium with only 3-phenylpropyl acetate added, and the PDA medium with only pesticides added were set as control groups. The PDA medium containing 3-phenylpropyl acetate, the PDA medium containing 3-phenylpropyl acetate and a pesticide mixture, and the blank control PDA medium were placed in a constant temperature incubator for culture. The temperature of the constant temperature incubator was 28°C. The rice blast strain H7 was cultured for 9 days. The colony diameters were measured with a vernier caliper, and the mycelium growth inhibition rates of the experimental group and the blank control group were calculated.

[0085] The calculation formula is as follows

[0086] Inhibition rate = (control strain growth diameter - 0.7) - (treated strain growth diameter - 0.7)) / (control strain growth diameter - 0.7) (Note: 0.7 represents the inoculated bacterial block diameter)

[0087] Results: Figure 11-17 As shown in the figure, the antibacterial effect of 5 μg / mL 3-phenylpropyl acetate was consistent with that of the control group. The inhibitory effect of a small amount of 3-phenylpropyl acetate mixed with pesticides on the mycelial growth of rice blast strain H7 was more obvious than that of 3-phenylpropyl acetate alone or pesticide alone ( Fig.11 , Fig.12, Fig.13 , Fig.14 , Fig.15 , Fig.16 , Fig.17 ). This indicates that the mixed treatment of 3-phenylpropyl acetate and pesticides can promote the antibacterial effect of pesticides, thereby further inhibiting the growth of mycelium of rice blast strain H7. It proves that 3-phenylpropyl acetate has the use of a synergist for pesticides to control rice fungal diseases. The Duncan method in SPSS data analysis software was used to analyze the difference in mycelium growth diameter and mycelium growth inhibition rate data. The same letters between the groups indicate no significant difference, and different letters indicate significant difference (P<0.05). Letters a, b, c, and d represent P values ​​less than 0.05, indicating significant differences.

Claims

1. Application of 3-phenylpropyl acetate in the preparation of drugs for preventing and treating fungal diseases of rice.

2. The use according to claim 1, characterized in that: The rice fungal diseases are rice blast and rice sheath blight.

3. The use according to claim 1, characterized in that: The 3-phenylpropyl acetate is used in the preparation of a drug for inhibiting the mycelial growth and spore germination of rice blast fungus.

4. The use according to claim 1, characterized in that: The 3-phenylpropyl acetate is used in the preparation of a drug for interfering with the formation of appressorium of rice blast fungus.

5. The use according to claim 1, characterized in that: The application of the 3-phenylpropyl acetate in the preparation of a medicine for inhibiting the hyphae growth of Rhizoctonia solani.

6. The use according to any one of claims 1 to 5, characterized in that: The concentration of the 3-phenylpropyl acetate is 50 μg / mL-200 μg / mL.

7. Use of 3-phenylpropyl acetate in the preparation of pesticide synergists for preventing and controlling fungal diseases of rice.

8. The use according to claim 7, characterized in that: The concentration of the 3-phenylpropyl acetate is 1-5 μg / mL.

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