Application of naphthoquinone compounds in prevention and treatment of plant wilt diseases

Abstract

The invention relates to the technical field of agricultural protection, in particular to application of naphthoquinone compounds in prevention and treatment of plant wilt diseases. The naphthoquinone compound is menadione or menadione tetraenone. According to the application, the naphthoquinone compound serves as an active substance to be prepared into a medicament, and the medicament is applied to the surfaces or roots of diseased plants so as to prevent and control plant wilt diseases caused by fusarium oxysporum. The menadione tetraenone and menadione have a remarkable inhibiting effect on fusarium oxysporum which is a fusarium wilt pathogenic bacterium, and a novel natural-source and synthetic-source bactericidal active substance is provided for preventing and treating the plant fusarium wilt. The menadione tetraenone and menadione are efficient, low in toxicity and environment-friendly, and meet the development requirements of current green pesticides.

Description

Technical Field

[0001] This invention relates to the field of agricultural protection technology, and in particular to the application of naphthoquinone compounds in the prevention and control of plant wilt disease. Background Technology

[0002] Fusarium wilt is a serious disease caused by pathogens such as Fusarium oxysporum, widely affecting various crops such as tomatoes, cucumbers, and bananas, leading to reduced yields or even total crop failure. Currently, the control of Fusarium wilt mainly relies on chemical fungicides, such as benzimidazole and triazole compounds. However, long-term use of chemical fungicides can easily lead to drug resistance in pathogens, while also posing potential risks to the environment and human health. Therefore, the development of novel, highly effective, low-toxicity, and environmentally friendly fungicides is of great significance.

[0003] Menatetrenone and menadione are two biologically active quinone compounds known to have antibacterial and antioxidant effects in the pharmaceutical field. The molecular formula of menatetrenone is Ca. 31 H 40 O2, relative molecular mass 444.6 g / mol, menadione's molecular formula is C 11 H8O2 has a relative molecular mass of 172.18 g / mol. However, there are currently no reports of the use of tetraene-menadione and menadione in agriculture for the control of plant wilt disease. Summary of the Invention

[0004] The purpose of this invention is to provide the application of naphthoquinone compounds in the prevention and control of plant wilt disease, and to provide a highly efficient and low-toxicity bactericidal active substance for the prevention and control of agricultural diseases.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides the application of naphthoquinone compounds in the prevention and control of plant wilt disease, wherein the naphthoquinone compounds are menaquinone or tetraene menaquinone.

[0007] Preferably, the prevention and control of plant wilt disease involves inhibiting the growth of pathogens that cause plant wilt disease.

[0008] Preferably, the pathogen is Fusarium oxysporum.

[0009] Preferably, the application involves preparing naphthoquinone compounds as active substances into agents and applying them to the surface or roots of diseased plants to prevent and control plant wilt disease.

[0010] Preferably, the dosage form of the agent is a suspension, emulsion, microemulsion, emulsifiable concentrate, wettable powder, or water-dispersible granule.

[0011] Preferably, the concentration of the menaquinone is 100–500 mg / L.

[0012] Preferably, the concentration of the tetraene-menaquinone is 100–500 mg / L.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] Tetraene-menadione and menadione exhibit significant inhibitory effects against Fusarium oxysporum, the pathogen of Fusarium wilt, providing a novel natural and synthetic source of fungicidal active substances for the control of plant wilt disease. Tetraene-menadione and menadione are highly effective, low in toxicity, and environmentally friendly, meeting the current requirements for the development of green pesticides. Attached Figure Description

[0015] Figure 1 The chemical structure of tetraene-menaquinone is given.

[0016] Figure 2 This is the chemical structure of menaquinone.

[0017] Figure 3 Graphs showing the antagonistic effects of different concentrations of tetraene-menaquinone and menaquinone on Fusarium oxysporum.

[0018] Figure 4 The inhibition rate of different concentrations of tetraene-naphthoquinone on the mycelia of Fusarium oxysporum.

[0019] Figure 5 The inhibition rate of different concentrations of menadione on Fusarium oxysporum hyphae. Detailed Implementation

[0020] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0021] In this invention, the study of tetraenemenadione and menadione as agricultural fungicidal active substances revealed, using an activity tracking method, that tetraenemenadione and menadione possess control effects against *Fusarium oxysporum*, the pathogen of plant wilt. The following experiments were used to verify the effects of tetraenemenadione and menadione in controlling *Fusarium oxysporum*, the pathogen of plant wilt. Tetraenemenadione (CAS No. 863-61-6), with a purity greater than 98%, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.; menadione (CAS No. 58-27-5), with a purity greater than 98%, was also purchased from Shanghai Maclean Biochemical Technology Co., Ltd. The chemical structures of both are shown below. Figures 1-2 .

[0022] Example 1

[0023] Determination of the antibacterial activity of tetraenylenynaphthoquinone and manaphthoquinone against Fusarium oxysporum

[0024] 1. Test strains

[0025] The application of tetraene-menaquinone and menaquinone in the control of plant wilt disease, wherein the pathogen of plant wilt disease is Fusarium oxysporum, which was extracted and identified by our laboratory from tomato plants infected with wilt disease, and the relevant strain is preserved at the China General Microbiological Culture Collection Center.

[0026] The strain name of the *Fusarium oxysporum* is FZZ-12, its classification name is *Fusarium oxysporum*, its accession number is CGMCC NO.41736, its accession date is December 30, 2024, its depositary is the China General Microbiological Culture Collection Center, and its depositary address is No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0027] 2. Test Methods

[0028] 2.1 Plate confrontation test to verify the inhibitory effect on Fusarium oxysporum.

[0029] The experimental steps for the effects of tetraene-menadione and menadione on pathogenic bacteria are as follows:

[0030] Prepare solid agar PDA medium: 6.0g potato extract powder, 20.0g glucose, 20.0g agar, 1000ml distilled water; pH: 6.0±0.2; temperature: 30℃. Heat to dissolve, then pour the cooled agar medium into round petri dishes, filling them to approximately 1 / 3 to 1 / 2 of their height, and allow it to solidify naturally.

[0031] Under aseptic conditions, a small amount of Fusarium oxysporum spore suspension was dipped into a sterilized toothpick and inoculated into the center of a petri dish. The dish was then placed in a constant temperature incubator and cultured at 30°C for 7 days to obtain Fusarium oxysporum fungal cakes.

[0032] Antagonistic tests of tetraene-menadione and menadione against the pathogen were conducted using drug susceptibility testing. In simple terms, sterile blank drug susceptibility test tablets were immersed in tetraene-menadione and menadione solutions (using DMSO as the solvent, with three concentration gradients of 100 mg / L, 200 mg / L, and 500 mg / L, and DMSO as a positive control) for 30 minutes (see [link to test method]). Figure 3Subsequently, the cultured *Fusarium oxysporum* mycelial discs were divided into 5 mm diameter discs and further inoculated into the center of PDA solid medium, with antimicrobial susceptibility testing tablets of different concentration gradients of tetraene-menadione and menadione solutions placed around them. After incubation at 30°C for 5 days, the diameter of *Fusarium oxysporum* was measured, and the inhibition rate of these treatments on *Fusarium oxysporum* mycelia was calculated to analyze their inhibitory activity against *Fusarium oxysporum*. Each treatment was performed in triplicate. Mycelial inhibition rate (%) = (normal colony diameter - treated colony diameter) / normal colony diameter × 100.

[0033] Experiments revealed that tetraenylmenaquinone and menaquinone exhibited significant inhibitory effects against *Fusarium oxysporum*. Tetraenylmenaquinone showed average hyphal inhibition rates of 55.42% and 80.59% at concentration gradients of 200 mg / L and 500 mg / L, respectively. Menaquinone also showed significant inhibitory effects against *Fusarium oxysporum*, with average inhibition rates of 56.57%, 79.54%, and 85.54% at three concentration gradients of 100 mg / L, 200 mg / L, and 500 mg / L, respectively (see...). Figures 4-5 ).

[0034] Example 2

[0035] Potted plant experiments to verify the inhibitory effect on Fusarium wilt caused by Fusarium oxysporum

[0036] Test crop: Tomato (variety: Da Hong).

[0037] Test method:

[0038] A suspension of Fusarium oxysporum spores was prepared and counted using a hemocytometer. Sterilized soil was used in plastic flowerpots (17.3 cm in diameter, 12.5 cm in height, and 13.5 cm in bottom diameter), with 4 kg of soil per pot.

[0039] Multiple treatments were set up: a control group (only pathogenic bacteria were added), and three concentration gradients of tetraene-menaquinone: high concentration (500 mg / L), medium concentration (200 mg / L), and low concentration (100 mg / L); three concentration gradients of menaquinone were also set up: high concentration (500 mg / L), medium concentration (200 mg / L), and low concentration (100 mg / L). Each treatment had three replicates. Tomato seedlings were cultivated, and the different concentrations of the pesticide solution were irrigated into the root zone of the plants to ensure that the solution quickly and thoroughly reached the diseased parts. Do not water immediately for several days after irrigating the roots to avoid affecting the efficacy of the pesticide. Additionally, a 1×10⁻⁶ Fusarium oxysporum spore suspension was applied to the tomato roots. 6 CFU / gram of soil was used for irrigation, and disease incidence was investigated after 60 days. Disease index and relative control efficacy were calculated (see Table 1).

[0040] Disease index = ∑(number of diseased leaves at each level × relative disease level value) / (total number of leaves surveyed × highest disease level value) × 100 Relative control effect (%) = (control disease index - treatment disease index) / control disease index × 100.

[0041] The disease levels are as follows:

[0042] Grade 0: No lesions;

[0043] Grade 1: The lesion area accounts for less than 5% of the total leaf area;

[0044] Grade 3: Lesions cover 6-10% of the total leaf area;

[0045] Level 5: Lesions cover 11-20% of the total leaf area;

[0046] Level 7: Lesions cover 21-50% of the total leaf area;

[0047] Level 9: Lesions cover more than 51% of the total leaf area.

[0048] Table 1. Control effects of tetraenylnaphthoquinone and manaphthoquinone on Fusarium oxysporum wilt disease.

[0049]

[0050]

[0051] Experiments revealed that tetraenidin and menadione exhibited significant inhibitory effects against Fusarium oxysporum. Tetraenidin showed average relative efficacy of 67.90% and 80.95% at concentration gradients of 200 mg / L and 500 mg / L, respectively. Menadione demonstrated even more significant inhibitory effects against Fusarium oxysporum, with average relative efficacy of 69.85%, 84.81%, and 90.56% at three concentration gradients of 100 mg / L, 200 mg / L, and 500 mg / L, respectively.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of naphthoquinone compounds in the control of plant wilt disease, characterized in that, The naphthoquinone compounds are menaquinone or tetraene menaquinone.

2. The application according to claim 1, characterized in that, The prevention and control of plant wilt disease involves inhibiting the growth of pathogens that cause plant wilt disease.

3. The application according to claim 2, characterized in that, The pathogen is Fusarium oxysporum.

4. The application according to claim 3, characterized in that, The application involves preparing naphthoquinone compounds as active substances into agents and applying them to the surface or roots of diseased plants to prevent and control plant wilt diseases.

5. The application according to claim 4, characterized in that, The dosage form of the drug is a suspension, emulsion, microemulsion, emulsifiable concentrate, wettable powder, or water-dispersible granule.

6. The application according to claim 5, characterized in that, The concentration of the menaquinone is 100–500 mg / L.

7. The application according to claim 5, characterized in that, The concentration of the tetraene-menaquinone is 100–500 mg / L.

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