Application of natural unsaturated aldehyde in prevention and treatment of plant parasitic nematodes

Abstract

The application discloses application of natural unsaturated aliphatic aldehyde in prevention and treatment of plant parasitic nematodes. The natural unsaturated aliphatic aldehyde is trans, trans-2,4-heptadienal and trans-2-heptenal. The plant parasitic nematodes are root-knot nematodes, cyst nematodes and pine wood nematodes. Both the trans, trans-2,4-heptadienal and the trans-2-heptenal can exhibit excellent nematocidal activity through contact killing and fumigation, which provides a basis for development of green and environmentally-friendly nematocidal agents, and has a good application prospect for replacing traditional chemical nematocidal agents.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biological control, and particularly relates to application of natural unsaturated aliphatic aldehyde in prevention and treatment of plant parasitic nematodes. BACKGROUND

[0002] Plant parasitic nematodes cause about 157 billion US dollars of economic loss in the world every year. Among them, root-knot nematodes, cyst nematodes and pine wood nematodes are the three groups with the greatest economic impact. The host range of root-knot nematodes is extremely wide, and can parasitize more than 3000 plant species. Most species of cyst nematodes have host specificity, and usually parasitize specific or limited host plants. Pine wood nematodes have the characteristics of multiple host species, fast transmission, high mortality rate of diseased pine trees and difficult prevention and treatment.

[0003] Chemical control is the most common management strategy for preventing and treating plant parasitic nematode diseases. However, long-term and large-scale application of chemical nematicides has caused great threat to the safety of the ecological environment. Long-term use of chemical pesticides can make pests develop resistance, leading to reduced efficacy. And with the increase of resistance, higher doses of chemical pesticides need to be used, which further aggravates environmental pollution and health risks. Therefore, developing environmentally friendly and efficient biological nematicides is an important goal of researchers.

[0004] Natural unsaturated aliphatic aldehydes widely exist in plant volatile essential oils, and play an important role in the defense response of plants in response to pathogenic microorganisms and insect invasions. Natural unsaturated aliphatic aldehydes usually have aroma and are natural spices. Trans, trans-2,4-heptadienal and trans-2-heptenal are natural unsaturated aliphatic aldehydes produced in plants. Trans, trans-2,4-heptadienal and trans-2-heptenal are food spices (GB2760) allowed to be used in China, and are also food spices and food preservatives allowed to be used by the US Food and Drug Administration (FDA). The present application explores the prevention and treatment effect of trans, trans-2,4-heptadienal and trans-2-heptenal on plant parasitic nematodes, and both contact killing and fumigation show excellent nematicidal activity, which has potential application value in nematicide and is worthy of further development and utilization. SUMMARY

[0005] In view of this, the purpose of the present application is to provide application of natural unsaturated aliphatic aldehyde in prevention and treatment of plant parasitic nematodes, wherein the natural unsaturated aliphatic aldehyde is any one of trans, trans-2,4-heptadienal and trans-2-heptenal. Natural unsaturated aliphatic aldehyde also has strong volatility in a natural state, and can be directly used as a nematode fumigant.

[0006] Preferably, the natural unsaturated aliphatic aldehyde is trans, trans-2,4-heptadienal and / or trans-2-heptenal.

[0007] Preferably, the natural unsaturated aliphatic aldehyde is mixed with the synergist to form a nematode contact agent for controlling plant parasitic nematodes.

[0008] Preferably, the synergist is a solution of 0.05%-5% Tween, and the solute of the solution is Tween 20 or / and Tween 80, and the volume fraction of methanol in the solution is 1%.

[0009] Preferably, the 0.05%-5% Tween solution is a 0.2% Tween 80 solution. Tween 20 has a lower dispersing effect on trans, trans-2,4-heptadienal and trans-2-heptenal than Tween 80, so Tween 80 is preferred.

[0010] Preferably, the plant parasitic nematodes are root-knot nematodes, cyst nematodes or pine wood nematodes. Root-knot nematodes, cyst nematodes and pine wood nematodes are the three most harmful groups of plant parasitic nematodes.

[0011] Preferably, the natural unsaturated aliphatic aldehyde controls plant parasitic nematodes through contact and / or fumigation.

[0012] Preferably, the concentration of the natural unsaturated aliphatic aldehyde used in contact is 1-1000 μg / mL, and the concentration of the natural unsaturated aliphatic aldehyde used in fumigation is 0.1-100 μL / L.

[0013] Preferably, the concentration used in contact is 200 μg / mL, and the concentration used in fumigation is 0.25 μL / L.

[0014] The natural unsaturated aliphatic aldehydes trans, trans-2,4-heptadienal and trans-2-heptenal have broad-spectrum nematocidal effects, and can be used to control the three most harmful groups of plant parasitic nematodes, root-knot nematodes, cyst nematodes and pine wood nematodes. Natural unsaturated aliphatic aldehydes are widely present in plants, green, environmentally friendly, and friendly to the environment, have strong volatility, and can kill plant parasitic nematodes through contact and fumigation. The nematode contact agent has a strong effect in a local space, while the nematode fumigant has a wider effective range in a three-dimensional space, and the dual action mode can enhance the nematocidal effect. The natural unsaturated aliphatic aldehydes trans, trans-2,4-heptadienal and trans-2-heptenal have excellent nematocidal activity, can replace traditional chemical nematocidal agents or chemical nematode fumigants, and have broad application prospects in the field of biological control. DETAILED DESCRIPTION

[0015] The application will be described in detail below with reference to the embodiments, which are only illustrative and not restrictive to the application. The application is not limited to the following embodiments or examples, and any modification and variation made without departing from the spirit of the application shall be included in the scope of the application. The experimental reagents used in the following examples can be purchased commercially unless otherwise specified. The natural unsaturated aliphatic aldehydes, trans, trans-2,4-heptadienal and trans-2-heptenal used in the following examples were purchased from Shanghai Aldrin Biochemical Technology Co., Ltd.

[0016] Example 1: Contact toxicity of natural unsaturated aliphatic aldehydes against plant parasitic nematodes

[0017] 1) Test plant parasitic nematodes

[0018] Root-knot nematode, the root-knot nematode egg mass was isolated from the roots of diseased tobacco, and the second instar larvae (J2) after hatching for 24 h were used for testing.

[0019] Cyst nematode, the mixed age cyst nematodes within 24 h were isolated from the rhizosphere soil of diseased soybean using the Bellman funnel method for testing.

[0020] Pine wood nematode, the mixed age pine wood nematodes within 24 h were isolated from the diseased pine wood using the Bellman funnel method for testing.

[0021] 2) Contacting agent

[0022] Trans, trans-2,4-heptadienal and trans-2-heptenal were respectively increased in solubility with an appropriate amount of methanol, and then diluted with 0.2% Tween 80 solution to prepare aldehyde solutions with concentrations of 50 μg / mL, 100 μg / mL, 200 μg / mL and 400 μg / mL. It should be noted that the volume fraction of methanol in the final prepared aldehyde solution is not more than 1%. The methanol and Tween 80 in the aldehyde solution prepared by the method of this embodiment will not affect the nematodes, and if the concentration is too high, it will affect the nematodes. In addition, Tween 80 has better dispersion effect on trans, trans-2,4-heptadienal and trans-2-heptenal than Tween 20. The same steps were used to prepare a solution with an equal amount of ddH2O instead of natural unsaturated aliphatic aldehydes as a control.

[0023] 3) Contacting test

[0024] The nematode suspension was adjusted to contain about 50 nematodes per 40 μL with ddH2O, and the nematode suspension was added to single wells in a 96-well cell culture plate in a ratio of 1:1 (40 μL to 40 μL) with the above different concentrations of aldehyde solution to prepare test aldehyde solutions with final concentrations of 25 μg / mL, 50 μg / mL, 100 μg / mL and 200 μg / mL, 5 wells were repeated for each concentration, and the mortality rate was calculated after treatment in a 16°C incubator for 24 h, and the corrected mortality rate was calculated according to the following formula:

[0025] Corrected mortality rate = (treatment group mortality rate - control group mortality rate) / (1 - control group mortality rate) x 100%.

[0026] 4) Result analysis

[0027] The 24 h contact killing activity of different concentrations of trans, trans-2,4-heptadienal and trans-2-heptenal on plant parasitic nematodes Meloidogyne incognita, Heterodera glycines and Bursaphelenchus xylophilus is shown in Table 1. The results show that the natural unsaturated aldehyde solution described in the present application has excellent contact killing activity on the three major types of plant parasitic nematodes that cause the most damage within 24 h at a low concentration, and the corrected mortality rate is 100% at a concentration of 200 μg / mL, which can be used to control plant parasitic nematodes at different stages, including the most invasive second instar larvae and other instar larvae and adults, and has broad-spectrum contact killing activity on plant parasitic nematodes.

[0028] Table 1 Contact killing activity of natural unsaturated aldehyde solution on plant parasitic nematodes within 24 h

[0029]

[0030]

[0031] Example 2: Fumigation activity of natural unsaturated aldehyde on plant parasitic nematodes

[0032] 1) Test plant parasitic nematodes

[0033] Meloidogyne incognita The egg mass of Meloidogyne incognita was isolated from the roots of diseased tomato, and the second instar larvae (J2) after hatching for 24 h were used for testing.

[0034] Heterodera glycines and Bursaphelenchus xylophilus were isolated according to Example 1.

[0035] 2) Fumigant

[0036] Trans, trans-2,4-heptadienal and trans-2-heptenal were tested at concentrations of 0.25 μL / L, 0.50 μL / L, 0.75 μL / L and 1.00 μL / L respectively. Note: 0.25 μL / L means 0.25 μL of trans, trans-2,4-heptadienal or trans-2-heptenal stock solution was used per cubic decimeter of space volume, and the rest is similar.

[0037] 3) Fumigation test

[0038] The nematode suspension was adjusted to contain about 50 nematodes per 100 μL with ddH2O, and 100 μL of the nematode suspension was added to each of three concave slides, respectively. The three concave slides were then placed in a 1 L cubic decimeter acryl box, and 3 cm x 3 cm filter paper was pasted on the inner wall of the box. 0.25 μL, 0.50 μL, 0.75 μL and 1.00 μL of trans, trans-2,4-heptadienal and trans-2-heptenal were added to the filter paper of each treatment, respectively, and an equal amount of ddH2O was used as a control. The lid of the cubic decimeter acryl box was covered and sealed with PARAFILM film. Then, the box was placed in a 16 °C incubator for 24 h, and the corrected mortality rate was calculated according to the method of Example 1.

[0039] 4) Result analysis

[0040] The 24 h fumigation activity of different concentrations of trans, trans-2,4-heptadienal and trans-2-heptenal on root-knot nematodes, cyst nematodes and pine wood nematodes is shown in Table 2. The corrected mortality rate was 100%, indicating that the natural unsaturated aliphatic aldehyde described in the present application has excellent broad-spectrum fumigation activity against plant parasitic nematodes at a low dose.

[0041] Table 2 Fumigation activity of natural unsaturated aliphatic aldehyde against plant parasitic nematodes within 24 h

[0042]

[0043] In summary, the natural unsaturated aliphatic aldehydes trans, trans-2,4-heptadienal and trans-2-heptenal described in the present application have excellent contact and fumigation dual activity against various plant parasitic nematodes, and can be used for the prevention and control of plant parasitic nematodes.

[0044] The conventional techniques and schemes not described in detail in the above examples are well known in the art, and therefore will not be described in detail here. The above examples and / or experimental examples describe the preferred embodiments of the present application in detail, however, the present application is not limited to the specific details in the above embodiments, and various simple modifications can be made to the technical solutions of the present application within the scope of the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

Claims

1. The application of natural unsaturated fatty aldehydes in the control of plant parasitic nematodes, characterized in that, The natural unsaturated fatty aldehyde is trans, trans-2,4-heptadienal and / or trans-2-heptenal; the plant parasitic nematode is root-knot nematode, cyst nematode, or pine wood nematode; the natural unsaturated fatty aldehyde controls plant parasitic nematodes through contact killing and / or fumigation; the concentration of the natural unsaturated fatty aldehyde used for contact killing is 50-1000 µg / mL, and the concentration of the natural unsaturated fatty aldehyde used for fumigation is 0.25-100 µL / L.

2. The application as described in claim 1, characterized in that, The natural unsaturated fatty aldehydes are mixed with synergists to form a nematode contact insecticide for the control of plant parasitic nematodes.

3. The application as described in claim 2, characterized in that, The synergist is methanol and a 0.05%-5% Tween solution, wherein the solute in the Tween solution is Tween 80 or / and Tween 20, and the methanol accounts for 1% of the volume fraction of the nematode contact agent.

4. The application as described in claim 3, characterized in that, The Tween solution is 0.2% Tween 80.

5. The application as described in claim 1, characterized in that, The concentration used for contact killing is 200 µg / mL, and the concentration used for fumigation is 0.25 µL / L.

Images