Use of cinnamon essential oil in prevention and control of plant diseases

Abstract

Provided is the use of a cinnamon essential oil in the prevention and control of plant diseases, wherein the plant diseases prevented and controlled by the cinnamon essential oil are root rot or anthracnose. The antifungal tests prove that at a 2000-fold dilution concentration, the antifungal rate of the cinnamon essential oil is 81.11% against Colletotrichum circinans, 80.95% against Colletotrichum spaethianum, 49.64% against Fusarium solani, 21.43% against Fusarium oxysporum and 14.98% against Fusarium redolens, while at a relatively low dilution level, the antifungal rates of the cinnamon essential oil against the five pathogenic fungi all reach 100%.

Description

Use of cinnamon essential oil in preventing and controlling plant diseases

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 18, 2023, with application number CN202311195934.0 and invention name “Use of cinnamon essential oil in preventing and controlling plant diseases”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application belongs to the technical field of plant disease prevention and control, and specifically relates to the use of cinnamon essential oil in preventing and controlling plant diseases. Background Art

[0003] Essential oils are natural antimicrobial agents, often called "liquid gold." They are primarily extracted from natural plant structures, such as petals, buds, leaves, branches, and resins. Essential oils typically possess a fragrance and are often loved for their unique flavor. Beyond their aroma, essential oils also possess numerous other beneficial properties, such as antioxidant, anti-aging, and anti-pathogenic properties. These benefits have led to their increasing popularity, attracting more and more researchers, and expanding their applications.

[0004] Studies have shown that plant essential oils can affect the cell membranes and cell walls of fungi, increasing the permeability of the fungal cell membranes, leading to a loss of cellular integrity and death. Plant essential oils can also affect the synthesis of fungal nucleic acids and proteins, and inactivate fungal cells by affecting the expression levels of mycotoxin synthesis genes.

[0005] Root rot is named for the decay of plant roots, which prevent them from properly absorbing water, minerals, and other nutrients from the soil, leading to increasing weakness and eventual death. The main symptoms of root rot are yellowing and wilting of leaves throughout the plant, followed by root rot. This plant disease is caused by the combined actions of numerous nematodes, fungi, and bacteria, resulting in a complex etiology that cannot be treated by simply suppressing a single pathogen. Affected plants can sometimes also be infected with other saprophytes, resulting in complex symptoms and exacerbating the condition.

[0006] The main pathogens causing root rot in Polygonatum sibiricum are fungi such as Fusarium oxysporum and Fusarium solani. Currently, spraying chemical fungicides is the primary method for controlling root rot in order to increase Polygonatum sibiricum yield. However, chemical fungicides are associated with toxicity and pesticide residues. Consuming Polygonatum sibiricum with pesticide residues can be highly harmful to human health, and chemical fungicides can also cause some environmental damage.

[0007] Summary of the Invention

[0008] Based on the above reasons, this application intends to use biological methods to prevent and treat Polygonatum root rot and reduce the environmental impact of chemical fungicides. Plant essential oils are natural, green, pollution-free substances extracted from various plants with good antibacterial activity. They have significant antibacterial effects. Essential oils are also biodegradable, volatile, and have low residual concentrations, making them environmentally friendly. Therefore, this application intends to seek a plant essential oil with better preventive and treatment effects on Polygonatum root rot.

[0009] Based on the above technical objectives, the present application provides a use of cinnamon essential oil in preventing and controlling plant diseases, particularly root rot and anthracnose. Antibacterial tests have demonstrated that cinnamon essential oil has a significant inhibitory effect against onion anthracnose, ash anthracnose, Fusarium solani, Fusarium oxysporum, and Fusarium odoriferum, which cause plant root rot.

[0010] The technical solutions provided in this application are as follows:

[0011] In a first aspect of the present application, a method for preparing cinnamon essential oil for preventing and treating plant diseases is provided, wherein the disease is root rot or anthracnose. The cinnamon essential oil is prepared by extracting cinnamon medicinal materials by steam distillation and collecting the essential oil.

[0012] Preferably, the cinnamon essential oil is used to inhibit onion anthracnose fungi, ash anthracnose fungi, Fusarium oxysporum, Fusarium solani or Fusarium odoriferum.

[0013] Preferably, the plant is Polygonatum sibiricum.

[0014] Preferably, the steam distillation extraction comprises: mixing the cinnamon medicinal material with distilled water and performing distillation extraction.

[0015] Preferably, the dosage ratio of the cinnamon medicinal material to water is 1 g: 20 mL.

[0016] Preferably, the cinnamon essential oil is prepared into a medicament.

[0017] Preferably, the agent further comprises an excipient that is pesticide-acceptable.

[0018] Preferably, the medicament is a 250-2000-fold dilution of cinnamon essential oil.

[0019] Preferably, the medicament is a 250-1000-fold dilution of cinnamon essential oil.

[0020] Preferably, the medicament is a 250-fold, 500-fold or 1000-fold dilution of cinnamon essential oil.

[0021] Preferably, the diluent solvent is Tween-20.

[0022] Compared with the prior art, the beneficial effects of this application are:

[0023] This application provides the use of cinnamon essential oil in preventing and controlling plant diseases. Cinnamon essential oil is used to prevent and control root rot and anthracnose. Antibacterial tests have shown that at a 2000-fold dilution, cinnamon essential oil has an inhibition rate of 81.11% against onion anthracnose and 80.95% against ash anthracnose, respectively. It also has an inhibition rate of 49.64% against Fusarium solani, 21.43% against Fusarium oxysporum, and 14.98% against Fusarium odoratum. At lower dilutions, cinnamon essential oil achieves 100% inhibition against all five pathogens. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1 shows the inhibitory effect of cinnamon essential oil on onion anthracnose; Note: a to e in the figure are CK, 2000-fold dilution, 1000-fold dilution, 500-fold dilution, and 250-fold dilution, respectively;

[0026] Figure 2 shows the inhibitory effect of cinnamon essential oil on ash anthracnose fungus; Note: a to e in the figure are CK, 2000-fold dilution, 1000-fold dilution, 500-fold dilution, and 250-fold dilution, respectively;

[0027] Figure 3 shows the inhibitory effect of cinnamon essential oil on Fusarium oxysporum; Note: a to e in the figure are CK, 2000-fold dilution, 1000-fold dilution, 500-fold dilution, and 250-fold dilution, respectively;

[0028] Figure 4 shows the inhibitory effect of cinnamon essential oil on Fusarium solani; Note: a to e in the figure are CK, 2000-fold dilution, 1000-fold dilution, 500-fold dilution, and 250-fold dilution, respectively;

[0029] Figure 5 shows the inhibitory effect of cinnamon essential oil on Fusarium odoratum; Note: a to e in the figure are CK, 2000-fold dilution, 1000-fold dilution, 500-fold dilution, and 250-fold dilution, respectively;

[0030] FIG6 is a diagram showing the inhibitory effect of cinnamon essential oil on different pathogens. DETAILED DESCRIPTION

[0031] The present application will be further described below with reference to specific embodiments. The present application includes but is not limited to the following embodiments.

[0032] 1. Materials

[0033] 1.1 Test plants and strains

[0034] Cinnamon bark was purchased from the Anguo Chinese herbal medicine market in Hebei Province.

[0035] Colletotrichum circinans, C. spaethianum, Fusarium oxysporum, F. solani, and F. redolens were isolated from the root rot of Polygonatum sibiricum and stored in the Traditional Chinese Medicine Quality Testing Laboratory of Taishan University.

[0036] 1.2 Experimental instruments and reagents

[0037] GI54T vertical automatic pressure steam autoclave (Zhiwei Xiamen Instrument Co., Ltd.); VA214 electronic balance (Shanghai Jingtian Electronic Instrument Co., Ltd.); BHC-1300IIA2 clean bench (Altai Laboratory Equipment Beijing Co., Ltd.); water bath; electric heating mantle (Shanghai Shuli Instrument Co., Ltd.); essential oil extractor (Leigu Co., Ltd.).

[0038] Potato dextrose agar (PDA) and Tween-20 were both domestically produced and of analytical grade.

[0039] 2. Methods

[0040] 2.1 Extraction of cinnamon essential oil

[0041] Weigh 100g of cinnamon bark and extract its essential oil in four batches. Place 25g of the herb into a 1000mL round-bottom flask. Add 500mL of distilled water at a 1:20 ratio and stir with a glass rod until the water covers the material. Connect the rubber tubing at the bottom of the condenser to a tap, allowing the water to fill the entire condenser and flow out from the top outlet. Connect the condenser to the essential oil extractor and secure it with an iron stand. Place the round-bottom flask in an electric heating mantle and slowly heat it. Adjust the voltage to 220V. Once the essential oil begins to drip out, maintain a gentle boil for 2 hours, or until the amount of essential oil stops increasing. After the apparatus has cooled, open the stopcock at the bottom of the essential oil extractor to slowly release the essential oil. Collect the essential oil in the extractor into a centrifuge tube and record the volume of the essential oil. Repeat this process to extract the essential oil from the remaining 75g of cinnamon bark. Combine the essential oils extracted four times to obtain cinnamon essential oil stock solution, and store it in a cool place.

[0042] 2.2. Antibacterial experiment of plant essential oils against root rot pathogens

[0043] 2.2.1. Activation of fungi

[0044] Weigh 5.7744g of PDA culture medium into a conical flask, add 144mL of distilled water, seal the flask, and place it in a sterilizer. Adjust the system and sterilize at 121°C for 20 minutes. In a clean bench, pour the sterilized PDA culture medium evenly into the culture dish near the sterile area of ​​the flame. Place the sterilized inoculation needle in the outer flame of the alcohol lamp and burn it repeatedly. After it cools, use the inoculation needle to pick up a piece of the prepared bacterial slice and place it in the center of the PDA culture medium. After sealing, place it in an incubator at 26°C for inverted culture for 7 days.

[0045] 2.2.2 Preparation of culture medium

[0046] PDA medium formula: Add 40.1 g of PDA medium powder to every 1000 mL of distilled water, place in an autoclave, and sterilize at 121°C for 20 minutes.

[0047] The cinnamon essential oil stock solution was emulsified by adding 0.5% Tween-20 and diluted to four concentration gradients of 10 times, 20 times, 40 times and 80 times.

[0048] 10-fold dilution process: Take 1.5 mL of cinnamon essential oil stock solution and add it to 50 mL centrifuge tube No. 1, add 1 mL of Tween-20, and then add 12.5 mL of double distilled water to prepare 15 mL of mother solution 1.

[0049] 20-fold dilution process: Take 7 mL of mother solution 1 and add it to 50 mL centrifuge tube No. 2. Add 7 mL of double-distilled water to make 14 mL of mother solution 2.

[0050] 40-fold dilution process: Take 7 mL of mother solution 2 and add it to 50 mL centrifuge tube No. 3. Add 7 mL of double-distilled water to make 14 mL of mother solution 3.

[0051] 80-fold dilution process: Take 7 mL of mother solution 3 and add it to 50 mL centrifuge tube No. 4. Add 7 mL of double-distilled water to make 14 mL of mother solution 4.

[0052] The sterilized PDA culture medium was cooled to about 50°C, and the diluted essential oil mother liquors of each gradient were added thereto and mixed thoroughly to dilute the essential oil concentrations to 250 times, 500 times, 1000 times, and 2000 times.

[0053] 250-fold dilution process: Take 6 mL of stock solution 1 and add it to 144 mL of PDA medium to make 150 mL.

[0054] 500-fold dilution process: Take 6 mL of mother solution 2 and add it to 144 mL of PDA medium to make 150 mL.

[0055] 1000-fold dilution process: Take 6 mL of mother solution 3 and add it to 144 mL of PDA medium to make 150 mL.

[0056] 2000-fold dilution process: Take 6 mL of mother solution 4 and add it to 144 mL of PDA medium to make 150 mL.

[0057] Pour the prepared PDA culture medium containing essential oil into a 90mm culture dish. The height of the poured culture medium should be about one-third of the height of the culture dish.

[0058] 2.2.3 Antibacterial operation steps

[0059] Heat a sterilized punch over an alcohol lamp for a short time. Once the temperature has cooled, punch a sufficient number of bacterial discs onto the activated culture dish. Use an inoculating needle to pick up a bacterial disc and place it in the center of the dish. Repeat each gradient three times. Seal the plate and place it in an incubator, inverted, for 5–7 days. When the colonies reach two-thirds of the dish, measure their diameter.

[0060] 3. Data processing

[0061] When the colonies reach two-thirds of the plate, measure their diameters using the cross-hatch method, photograph, and record the data. Use Excel to calculate the average colony diameters at each concentration and determine the inhibition rate. Inhibition rate (%) = [(average diameter of control colonies - 6 mm) - (average diameter of treated colonies - 6 mm)] / (average diameter of control colonies - 6 mm) × 100%.

[0062] EC 50 : half-maximal inhibitory concentration, also known as half-maximal effect concentration, EC 50 Often used as an indicator of drug safety, it refers to the drug concentration that produces a significant effect on 50% of the tested bacterial species. For this test, it refers to the essential oil concentration that inhibits 50% of the tested bacterial species.

[0063] The colony diameters of each bacterial species at each concentration were recorded in a table, and the average colony diameters at different concentrations were calculated, and the inhibition rate was calculated using the values.

[0064] Then, based on the obtained inhibition rate, find the corresponding probability value in the probability value conversion table. Finally, use the logarithm of the essential oil concentration LogC as the X-axis and the probability value at each concentration as the Y-axis. Select the numerical range corresponding to the X-axis and the Y-axis, and use Excel to insert a scatter plot so that the resulting chart shows the toxicity regression equation Y=aX+b formula, the straight line direction and R 2 Value. 2The closer it is to 1, the stronger the correlation between the values. The anti-value of the X value obtained by substituting y = 5.0 into the toxicity regression equation is the EC 50 Value. By EC 50 It is worth to know the antibacterial ability of essential oils.

[0065] 4. Results and Analysis

[0066] 4.1 Essential Oil Extraction

[0067] The extraction rate of cinnamon essential oil in this experiment was about 1%, and 6 mL of cinnamon essential oil was extracted. The color of cinnamon essential oil was yellow, and the essential oil had a strong plant smell.

[0068] 4.2 Inhibitory effect of cinnamon essential oil on five bacteria

[0069] The average colony diameters in the control group indicate that, under the same culture conditions, the colonies of Colletotrichum fraxinus, Fusarium oxysporum, and Fusarium solani were larger, with average diameters of 62 mm, 48 mm, and 56.3 mm, respectively. The colonies of Colletotrichum cepacia and Fusarium odoratum were similar in size, with an average diameter of 30.7 mm in the control group. Figures 1-6 show that cinnamon essential oil exhibited a particularly significant inhibitory effect against both anthracnose pathogens. The inhibitory effects on Colletotrichum cepacia and Colletotrichum fraxinus differed only when the essential oil was diluted 2000-fold, with inhibition rates of 81.11% and 80.95%, respectively. The inhibitory effect on Fusarium solani is moderate, and the inhibitory effect on Fusarium oxysporum and Fusarium odoratum is not obvious, but the inhibition rate reaches 100% at three concentration gradients of 250 times, 500 times and 1000 times. At a dilution gradient of 2000 times, the inhibition rates of cinnamon essential oil on Fusarium solani, Fusarium oxysporum and Fusarium odoratum are 49.64%, 21.43% and 14.98% respectively.

[0070] According to the obtained EC 50 The inhibitory effect of cinnamon essential oil on the five fungi is ranked from best to worst as follows: onion anthracnose fungus > ash tree anthracnose fungus > Fusarium solani > Fusarium oxysporum > Fusarium odoriferum, and the corresponding EC 50 The values ​​were 0.000121960 mL / L (diluted 8199 times), 0.000122951 mL / L (diluted 8133 times), 0.000251550 mL / L (diluted 3975 times), 0.000375161 mL / L (diluted 2665 times), and 0.000414386 mL / L (diluted 2413 times), respectively, Table 1.

[0071] Table 1 EC of various bacteria under cinnamon essential oil 50 value

[0072] Cinnamon essential oil's overall inhibitory effect against anthracnose pathogens was greater than its inhibitory effect against Fusarium spp. It had the least inhibitory effect against Fusarium odoriferum and the best inhibitory effect against Colletotrichum cepacia. Cinnamon essential oil achieved 100% inhibition against all five pathogens at 250-, 500-, and 1000-fold dilutions, with only a difference in inhibition observed at a 2000-fold dilution.

[0073] Although the above embodiment provides a detailed description of the present application, it is only a part of the embodiments of the present application, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present application.

Claims

1. A use of cinnamon essential oil in preventing and treating plant diseases, characterized in that: The disease is root rot or anthracnose, and the preparation steps of the cinnamon essential oil are: extracting cinnamon medicinal materials by steam distillation and collecting essential oil.

2. The use according to claim 1, characterized in that The cinnamon essential oil is used for inhibiting onion anthracnose fungi, ash tree anthracnose fungi, Fusarium oxysporum, Fusarium solani or Fusarium aromaticum.

3. The use according to claim 1, characterized in that The plant is Polygonatum sibiricum.

4. The use according to claim 1, characterized in that The steam distillation extraction comprises: mixing cinnamon medicinal materials with distilled water and performing distillation extraction.

5. The use according to claim 4, characterized in that The dosage ratio of the cinnamon medicinal material to water is 1g:20mL.

6. The use according to claim 1, characterized in that: The cinnamon essential oil is prepared into a medicament.

7. The use according to claim 6, characterized in that The medicament also includes pesticide-acceptable adjuvants.

8. The use according to claim 6 or 7, characterized in that The medicament is a 250-2000 times dilution of cinnamon essential oil.

9. The use according to claim 8, characterized in that The medicament is a 250-1000 times dilution of cinnamon essential oil.

10. The use according to claim 9, characterized in that The medicament is a 250-fold, 500-fold or 1000-fold dilution of cinnamon essential oil.

11. The use according to claim 10, characterized in that The diluent solvent of the diluent is Tween-20.

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