Application of monensin sodium in prevention and treatment of agricultural fungal diseases

Abstract

The application discloses a new use of a feed additive monensin sodium in preventing and treating postharvest fruit rot fungi and agricultural plant pathogenic fungi, and belongs to the field of agricultural fungicides. The monensin sodium has significant bacteriostatic or bactericidal activity on postharvest fruit rot fungi such as Botrytis cinerea, Penicillium expansum ACCC30898, Rhizopus stolonifer CICC40327, Monilinia fructicola ACCC36263, Aspergillus flavus ACCC32601, and various plant pathogenic fungi such as Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium graminearum, Magnaporthe oryzae, Phytophthora capsici, Phytophthora infestans and potato late blight, and can be further developed and applied in the field of agricultural fungal disease prevention.

Description

Technical Field

[0001] This invention relates to a novel antibacterial use of monensin sodium, belonging to the field of agricultural fungicides. Background Technology

[0002] Plant fungal diseases seriously threaten the healthy development of agriculture and food safety, with annual grain losses exceeding 11%. For example, rice sheath blight in my country causes a loss of 6 million tons of grain annually; wheat scab causes a 10%–30% yield reduction annually; in developed countries, approximately 10%–20% of fresh fruits and vegetables rot after harvest due to post-harvest putrefactive fungi, while the proportion is even higher in developing countries, reaching 40%–50%. In my country, the total output of easily perishable specialty fruits reaches 116 million tons, with post-harvest losses of 25%–30%, amounting to approximately 70 billion yuan. Grains and fruits and vegetables rotting after infection by pathogenic microorganisms experience a significant drop in yield, deterioration in sensory quality, and a decline in nutritional value. Therefore, researching and developing new, highly effective, low-toxicity, and low-residue pesticides that can effectively control plant pathogens has become one of the primary goals of pesticide development.

[0003] Monensin, also known as rumenin, was first isolated from the fermentation broth of *Streptomyces cinnamonensis* by Haney et al. in 1967. It is one of the most widely used polyether ionocarrier antibiotics. It can improve feed utilization and weight gain in cattle, while reducing feed intake. Currently, it is commercially produced in more than 40 countries and widely used as a weight gain agent for beef cattle and sheep, and a growth promoter for pigs. The United States and Japan officially approved monensin as a feed additive in 1976 and 1977, respectively. In my country, it first passed expert technical evaluation and was applied to production in 1985. Existing research shows that monensin has strong antibacterial activity against Gram-positive bacteria such as *Staphylococcus aureus*, bacilli, clostridium, and streptococci, as well as fungi (Penicillium, Candida), and *Treponema pallidum*, but it is ineffective against Gram-negative bacteria. Based on the confirmed safety profile and existing antibacterial spectrum and activity of monensin sodium through comparative toxicology, and with the research approach of developing new uses for existing drugs, this study screened widely used polyether antibiotics for pathogenic fungal activity. The results showed that monensin sodium exhibited significant activity against plant pathogenic fungi and molds. We hope that this will reduce the R&D costs of agricultural fungicides, save time, and increase pesticide innovation output. Summary of the Invention

[0004] The purpose of this invention is to provide the application of monensin sodium in the prevention and control of agricultural fungal diseases.

[0005] This application provides the antibacterial activity of monensin sodium.

[0006] The antibacterial strains described in this application include plant pathogenic fungi: Rhizoctonia solani, Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium graminearum, Rice blast fungus, Phytophthora capsici, Potato late blight, Aspergillus flavus ACCC32601, Penicillium expansum ACCC30898, Rhizopus stolonifer CICC 40327, and Brown rot fungus of stone fruit ACCC 36263. Detailed Implementation

[0007] To better understand the essence of the present invention, the following specific embodiments are provided, but the present invention is not limited to these embodiments.

[0008] Example 1: Indoor antifungal activity assay of monensin sodium against fungi

[0009] The plant pathogenic fungi used in this experiment were strains preserved in the laboratory at 4℃. The mycelial growth rate method was adopted. All plant pathogenic fungi used in the laboratory were cultured on potato agar-dextrose medium (PDA). PDA medium formula: 200g potato (peeled), 20g glucose, 15g agar, 1000mL distilled water.

[0010] PDA culture medium preparation method: Wash and peel potatoes, weigh 200g and cut into small pieces, add water and boil until soft (boil for 20-30 minutes, until it can be pierced by a glass rod), filter through four layers of gauze into a beaker and add distilled water to 1000 mL, add 15-20g agar according to experimental needs, add 20g glucose, stir to dissolve fully, dispense into Erlenmeyer flasks, sterilize at 121℃ for 20 minutes, cool and use for later use.

[0011] Experimental methods

[0012] 1) Mycelial growth rate method.

[0013] 1. First, activate the plant pathogens by culturing them on a PDA plate at 25°C for 3-6 days.

[0014] 2. Melt the PDA culture medium by heating, cool it to 45-50℃, and add different concentrations of bactericidal composition to prepare drug-loaded plates.

[0015] 3. Using aseptic techniques, use a punch to make round mycelial cakes (5 mm in diameter) at the edge of the mycelium of each strain after 3-6 days of culture (with the growth conditions as uniform as possible). Then, use an inoculation needle to pick them up and transfer them to the center of the drug-containing plate. Finally, invert the petri dish and incubate it in an incubator (25°C).

[0016] 4. After the blank control group has fully grown, observe and measure the growth of mycelia, and use the cross-cross method to measure the diameter and process the data to calculate the percentages of growth inhibition (PGI).

[0017] 5. Mycelial growth inhibition rate (%) = (Control mycelial diameter - Treated mycelial diameter) / (Control mycelial diameter - Mycelial cake diameter) × 100

[0018] 6. Repeat each treatment 3 times.

[0019] Table 1. Antimicrobial activity of monensin sodium against agricultural pathogenic fungi.

[0020]

[0021] Table 2. Antimicrobial activity of monensin sodium against postharvest saprophytic fungi.

[0022]

[0023] The feed additive monensin sodium described in this invention exhibits excellent antibacterial activity against various agricultural plant pathogenic fungi and postharvest rot fungi of fruits, and its in vitro activity against Sclerotinia sclerotiorum and Botrytis cinerea is EC 100%. 50 The concentrations can reach 0.076 and 0.11 μg / mL, and the compound has good safety as a widely used feed additive, which can be further developed and applied in the field of agricultural fungal disease control.

Claims

1. The use of monensin sodium in the prevention and control of crop diseases caused by Sclerotinia sclerotiorum, characterized in that... The monensin sodium has the following molecular structure: 。

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