Application of oligosaccharide in prevention and treatment of corn southern leaf blight

Abstract

The invention belongs to the technical field of agricultural science, and particularly provides application of oligosaccharide in prevention and treatment of corn southern leaf blight. The oligosaccharide has an inhibiting effect on the bipolaris maydis and can be used as an inhibitor of the bipolaris maydis. Meanwhile, the oligosaccharide can be used as a plant immune resistance inducer for preventing and treating the corn southern leaf blight, and the occurrence and development of the corn southern leaf blight are prevented and controlled by inducing basic resistance and enhancing the plant immunity. The oligosaccharide application method is simple and convenient to operate, green and environment-friendly, green prevention and control are facilitated, and grain loss caused by diseases is reduced more economically and more environmentally.

Description

Technical Field

[0001] The invention belongs to the technical field of agriculture, and particularly relates to application of oligosaccharides in preventing and treating corn leaf blight. Background Art

[0002] Corn leaf spot is caused by Helicoverpa maydis ( Bipolaris maydis ) has become a global foliar disease. The pathogen primarily infects corn leaves, sheaths, bracts, stems, and ears. In the early stages of the disease, small, water-soaked spots appear on leaves, later developing into oval or square shapes with darker, reddish-brown edges. In severe cases, multiple lesions connect, causing the leaves to wither and die. Lesions on sheaths and bracts are similar to those on leaves, but their shape is irregular, and a layer of black mold often forms on the affected areas. Ears rot and kernels mold, affecting yield and quality. It can also severely infect the stems, causing complex tissue rot. Corn leaf blight can cause a 10–20% yield reduction, resulting in significant economic losses to corn production. In recent years, corn leaf blight has become prevalent in some areas, resulting in yield losses exceeding 50% and kernel mold rates exceeding 30%. Due to its widespread occurrence and severe damage, corn leaf blight has become a major target for control and prevention of corn pests and diseases.

[0003] Currently, control measures for southern corn leaf blight primarily rely on planting resistant varieties and employing chemical and biological control measures. However, the availability of resistant varieties on the market is very limited, and available resistance genes are relatively rare, making chemical control the primary approach. However, the extensive use of conventional organic chemical pesticides poses multiple risks, including environmental pollution, ecological damage, and pesticide residues. Plant immune inducers, also known as plant immunity inducers or plant vaccines, can induce systemic acquired resistance in plants when applied to them, improving their disease resistance and thus reducing the use of chemical pesticides, meeting the needs of green plant protection. Currently, plant immune inducers such as chitosan, amino oligosaccharides, and lentinan are already in use in production. For example, chitosan can control rice black streaked dwarf, cucumber powdery mildew, and tomato virus disease. However, immune inducers for southern corn leaf blight remain to be discovered, and further research and exploration is needed to determine whether oligosaccharides have inhibitory effects against southern corn leaf blight. Summary of the Invention

[0004] The development of plant immune inducers that inhibit and control the disease is of great significance to corn production. To provide a greener and safer agent for controlling corn leaf spot, the inventors, through extensive screening, discovered an oligosaccharide that can be used to control corn leaf spot, leading to the development of the present invention.

[0005] The present invention provides the following technical solutions: In one aspect, the present invention provides the use of oligosaccharides in preventing and treating corn leaf spot disease. Preferably, the oligosaccharide is an oligosaccharide. The oligosaccharide of the present invention has a good preventive and control effect on corn leaf spot disease as a plant immune inducer.

[0006] In one aspect of the present invention, the present invention discloses the use of an oligosaccharide in the preparation of an agent for preventing and treating corn leaf blight.

[0007] One aspect of the present invention provides a use of an agent for preventing and controlling corn leaf blight, wherein the agent comprises oligosaccharides; preferably, the agent comprises 6% oligosaccharides.

[0008] In one aspect of the present invention, a method for controlling corn leaf blight is disclosed, comprising applying an agent containing oligosaccharides to corn.

[0009] In one embodiment, the present invention discloses a method for controlling corn leaf spot, comprising spraying corn leaves with a reagent containing 6% oligosaccharide as an active ingredient diluted 500-1000 times.

[0010] In one aspect of the present invention, the present invention discloses the use of oligosaccharides in inhibiting corn leaf blight pathogens. Preferably, the oligosaccharides are oligosaccharides. The corn leaf blight pathogen is Helminthosporium maydis ( Bipolaris maydis ).

[0011] In one aspect of the present invention, the present invention discloses the use of oligosaccharides in the preparation of reagents for inhibiting corn leaf blight pathogens.

[0012] In one aspect of the present invention, a method for inhibiting the bacterial blight of corn is disclosed. The method comprises applying an agent containing oligosaccharides to the bacterial blight of corn. Compared with the prior art, the advantages of the present invention are as follows:

[0013] The present invention provides a novel oligosaccharide for use in preventing and controlling southern corn leaf blight. The oligosaccharide can be used as a plant immune inducer, demonstrating excellent control effects against southern corn leaf blight. Furthermore, the present invention also discovered that the oligosaccharide has an inhibitory effect against southern corn leaf blight, making it useful as an inhibitor of southern corn leaf blight. The oligosaccharide application method is simple to operate, environmentally friendly, and conducive to green prevention and control, reducing food losses caused by the disease in a more economical and environmentally friendly manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 , are the results on the 7th day after the treatment of corn leaf blight pathogen with different concentrations of oligosaccharides; Figure 2 , is the lesion area of ​​corn leaf blight pathogen on the 7th day after being treated with oligosaccharides at different concentrations; Figure 3 , are the inhibition rates of corn leaf blight pathogens on the 7th day after treatment with oligosaccharides at different concentrations; Figure 4 , Observation of phenotype of corn leaves inoculated with southern leaf spot pathogen by oligosaccharide treatment; DETAILED DESCRIPTION

[0015] The methods used in the embodiments of the present invention, unless otherwise specified, all adopt conventional methods in the art. The reagents or materials described, unless otherwise specified, are all derived from commercial sources. Modifications or improvements made by those skilled in the art based on the disclosure of the present invention should all fall within the scope of protection claimed in the present invention.

[0016] The culture medium involved in the present invention is as follows: Spore formation medium for B. maydis: This medium consists of 10 g / L potato extract, 10 g / L mannitol, 14 g / L agar, and water. Sterilization conditions during preparation of the spore formation medium are: 121°C for 25 min. Example 1: Oligosaccharide treatment of corn leaf spot fungus

[0017] 1) Prepare a spore-forming medium, place a conidia of B. maydis in the middle of the medium, and incubate in the dark at 28°C for 7 days.

[0018] 2) Oligosaccharide aqueous solution containing 6% oligosaccharide as the effective ingredient was used to treat corn leaf blight pathogen. This was based on preliminary experiments that found that not all oligosaccharides have inhibitory activity against corn leaf blight pathogen. The present invention further used a 5 mm diameter puncher to cut bacterial blocks of the same age at the edge of the colony, and used an inoculation needle to inoculate the bacterial blocks into the center of the solid culture medium with the mycelium facing down. Oligosaccharides (oligosaccharides) were added to the culture medium in different proportions, and the volume ratios of oligosaccharides to spore-forming culture medium were 1:1000, 2:1000, 3:1000, and 4:1000, respectively. The oligosaccharides used in the experimental group were filtered and sterilized in advance, and the same proportion of sterile water was added to the control group. The culture medium was placed in a 28°C incubator for dark culture for 7 days. After 7 days, the growth of the colonies was observed, and the colony growth was measured by the cross-cross method. The inhibition rate was calculated and repeated 3 times for each group. Observe the growth of the pathogen (such as Figure 1 ) found that oligosaccharides have an inhibitory effect on the growth of corn leaf blight; the area where the pathogen grows (such as Figure 2 ) found that compared with the control, the growth area of ​​the pathogens treated with oligosaccharides was significantly reduced; the inhibition rate (such as Figure 3 ) found that the inhibitory effect of oligosaccharides on pathogens increased with the increase of oligosaccharide concentration; the above results show that oligosaccharides have an inhibitory effect on corn leaf blight. Example 2: Application of oligosaccharides in preventing and controlling corn leaf spot

[0019] 1) Spray oligosaccharides (oligosaccharins) on the corn leaves before inoculation. When the corn leaves are 5-6, dilute an oligosaccharide solution containing 6% oligosaccharins by 1000-fold and spray evenly on the corn plants. The control group is sprayed with sterile water. Twenty-four hours after spraying, inoculate with the southern leaf spot pathogen.

[0020] 2) Prepare a spore suspension before inoculation. Use an inoculating needle to inoculate the activated corn leaf spot fungus cake into the center of the culture medium plate, with the mycelium side facing down. Incubate in the dark at 28°C for 7 days (repeat this operation for subculture). After obtaining a large number of conidia, inject an appropriate amount of sterile water onto the surface of the culture medium. Use the end of a sterile glass slide to scrape the spores off the surface of the culture medium. Filter through a double layer of sterile gauze. Dilute the spore suspension with sterile water to a final conidia concentration of 1×10 5 pieces / mL.

[0021] 3) Inoculate corn leaf spot. Spray the spore suspension evenly on the leaves of the corn plants. Cover the inoculated plants with plastic film to keep them moist for 2 days (ambient temperature 20-26°C). Observe the disease status of the corn leaves 7-10 days after inoculation. Figure 4 ) found that the disease incidence of corn leaves treated with oligosaccharides was suppressed compared with the control group. The corn not treated with oligosaccharides had serious disease, while the treated plants were only slightly diseased, indicating that direct spraying of oligosaccharides can enhance the resistance of corn plants to corn leaf blight.

Claims

1. Application of oligosaccharides in the prevention and control of corn leaf spot.

2. Oligosaccharides are used in the preparation of reagents for preventing and controlling corn leaf spot.

3. Use of an agent in preventing and treating corn leaf spot, characterized in that: The reagent comprises oligosaccharides; preferably, the reagent comprises 6% oligosaccharides.

4. A method for preventing and controlling corn leaf spot, characterized in that: The method comprises administering an agent comprising oligosaccharides to corn.

5. A method for controlling corn leaf blight according to claim 4, characterized in that: The method comprises the steps of diluting a reagent containing 6% oligosaccharides as an effective ingredient at a ratio of 500-1000 times and spraying the reagent on the corn leaves.

6. The application of oligosaccharides in inhibiting corn leaf spot pathogens is characterized in that: The corn leaf spot pathogen is Helminthosporium maydis ( Bipolaris maydis ).

7. The application of oligosaccharides in the preparation of reagents for inhibiting corn leaf blight pathogens.

8. A method for inhibiting corn leaf blight pathogen, characterized in that: The method comprises applying an agent containing oligosaccharides to the bacterial blight pathogen of corn.

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