Application of trans, cis-2, 6-nonadienal in prevention and treatment of rice diseases

Abstract

The invention discloses application of trans, cis-2, 6-nonadienal in prevention and treatment of rice diseases, and belongs to the technical field of plant disease prevention and treatment. Research finds that the trans, cis-2, 6-nonadienal as a plant self-synthesized substance has an obvious inhibition effect on the growth of xanthomonas oryzae and pyricularia grisea, and the trans, cis-2, 6-nonadienal can be used as an effective component to be applied to prevention and treatment of field bacterial streak and rice blast and improve plant immunity. The invention provides theoretical support for developing novel pesticides for preventing and treating rice bacterial streak and rice blast, and has important significance.

Description

Technical Field

[0001] The invention relates to the technical field of plant disease prevention and control, and particularly to application of trans, cis-2,6-nonadienal in rice disease prevention and control. Background Art

[0002] Rice is the staple food for over half of the world's population and holds a vital position as a food crop. In Asia, especially in populous countries like China and India, rice consumption is extremely high. Its rich carbohydrate content provides a basic source of energy for a large population. Rice diseases, primarily caused by infections by fungi, bacteria, and other microorganisms, are a significant factor affecting rice production. These include:

[0003] Bacterial leaf streak (BLS) of rice, caused by Xanthomonas oryzae pv. oryzicola (Xoc), is a serious threat to rice production and is a subject of plant quarantine in my country. BLS was first reported in 1918 and has since rapidly spread to major rice-producing regions in Asia, Africa, and Australia. To date, BLS has spread to 421 counties (cities, and districts) across 14 provinces in China, with the most severe impacts occurring in rice-growing areas of East, South, Central, and Southwest China, making it the fourth most common rice disease in my country. Therefore, finding effective prevention and control measures is crucial for ensuring rice production safety.

[0004] Rice blast is one of the most troublesome diseases in rice-growing areas worldwide, posing a significant threat to global food security and designated as a priority for monitoring and control in many countries and regions. Due to its highly transmissible and pathogenic nature, rice blast has spread wreaking havoc in rice fields on every continent. From traditional rice-growing regions in Asia to emerging growing areas in the Americas and Africa, rice blast is a persistent threat to rice production in almost every region. In my country, rice blast is a major and long-standing problem plaguing rice production. It is widespread across rice-producing regions, particularly in key rice-producing areas such as Northeast China, the middle and lower reaches of the Yangtze River, and South China, where outbreaks are frequent and severe, making it the number one threat to rice production in my country. According to incomplete statistics, annual rice yield reductions due to rice blast are staggering. In peak years and severely affected areas, yield reductions can reach 30%-50%, resulting in devastating economic losses for countless hardworking farmers.

[0005] Therefore, exploring comprehensive, efficient and sustainable rice disease prevention and control strategies is of immeasurable significance for protecting my country's food foundation, safeguarding the vital interests of farmers and stabilizing the global food supply.

[0006] Trans-cis-2,6-nonadienal has a strong violet and cucumber-like aroma and is widely used in beverages, such as beverages, candies, baked goods, and alcoholic beverages, primarily to enhance their flavor. However, there are currently no reports on the use of trans-cis-2,6-nonadienal in rice disease control. Summary of the Invention

[0007] In view of the above-mentioned prior art, the purpose of the present invention is to provide an application of trans, cis-2,6-nonadienal in preventing and controlling rice diseases.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] The first aspect of the present invention provides the use of trans, cis-2,6-nonadienal in at least one of the following (1)-(3):

[0010] (1) Inhibit the growth of Xanthomonas;

[0011] (2) preparing antibacterial products for Xanthomonas;

[0012] (3) Prepare drugs for preventing and treating rice bacterial leaf streak disease.

[0013] In the above application, preferably, the Xanthomonas is Xanthomonas oryzae pv. oryzicola (Xoc).

[0014] The second aspect of the present invention provides the use of trans, cis-2,6-nonadienal in at least one of the following (A)-(C):

[0015] (A) inhibiting the growth of rice blast fungus;

[0016] (B) preparing an antibacterial product for rice blast fungus;

[0017] (C) preparing a medicament for preventing and treating rice blast.

[0018] In the above application, preferably, the rice blast fungus is Magnaporthe oryzae.

[0019] The third aspect of the present invention provides the use of trans, cis-2,6-nonadienal in the preparation of a plant immune activator.

[0020] In the above application, the trans, cis-2,6-nonadienal activates plant immunity via the following pathways (i) or (ii):

[0021] (i) increasing the expression of defense genes;

[0022] (ii) Promote the burst of reactive oxygen species.

[0023] Furthermore, the defense genes include: OsPR1a and OsPR10a.

[0024] A fourth aspect of the present invention provides a method for preventing and controlling rice diseases, comprising the following steps:

[0025] During the entire growth period of rice, trans, cis-2,6-nonadienal is sprayed on rice leaves or rhizomes.

[0026] Preferably, the rice disease is rice bacterial leaf streak and / or rice blast.

[0027] Beneficial effects of the present invention:

[0028] The present invention has discovered that trans-, cis-2,6-nonadienal, a plant-synthesized substance, significantly inhibits the growth of Xanthomonas oryzae and Rice Blast. Trans-, cis-2,6-nonadienal can be used as an active ingredient in the prevention and treatment of bacterial leaf streak and blast in the field, enhancing plant immunity. This invention provides theoretical support for the development of new pesticides for the prevention and treatment of bacterial leaf streak and blast in rice, and is of great significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 : trans, cis-2,6-nonadienal inhibits the growth of Xanthomonas sp.

[0030] Figure 2 : Trans, cis-2,6-nonadienal controls bacterial leaf streak disease of rice.

[0031] Figure 3 : Effects of trans, cis-2,6-nonadienal on the up-regulation of OsPR1a and OsPR10a gene expression.

[0032] Figure 4 : Volatile trans, cis-2,6-nonadienal inhibits the growth of rice blast fungus.

[0033] Figure 5 : trans, cis-2,6-nonadienal improves rice resistance to rice blast. DETAILED DESCRIPTION

[0034] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0035] As mentioned above, rice bacterial leaf streak and rice blast are two major diseases that affect rice production and cause rice yield reduction. Therefore, finding therapeutic substances that can simultaneously prevent and treat rice bacterial leaf streak and rice blast is of great significance to ensuring the safety of rice production.

[0036] In view of this, the present invention analyzed the volatile substance components produced by rice plants inoculated with bacterial leaf streak by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS), determined the substances corresponding to the chromatographic peaks by comparison with the NIST17 standard mass spectrum library, and then tested the inhibitory activity of various components in the volatile substances against Xanthomonas, the pathogen of rice bacterial leaf streak. It was found that trans, cis-2,6-nonadienal has an inhibitory effect on Xanthomonas and has a preventive and therapeutic effect on bacterial leaf streak. We also found that trans, cis-2,6-nonadienal has an inhibitory effect on the fungal disease rice blast pathogen, and has a preventive and therapeutic effect on rice blast. Therefore, the present invention is proposed.

[0037] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below with reference to specific embodiments.

[0038] The test materials used in the examples of the present invention are all conventional test materials in the field and can be purchased through commercial channels. Experimental methods without detailed conditions were carried out in accordance with conventional test methods or the operating instructions recommended by the supplier.

[0039] The CAS number of trans, cis-2,6-nonadienal is 557-48-2.

[0040] The rice bacterial leaf streak pathogen used in the examples of the present invention is Xanthomonas oryzae pv. oryzicola (Xoc), which is described in the journal article "The MYB transcription factor OsMYBxoc1 regulates resistance to Xoc by directly repressing transcription of the iron transport gene OsNRAMP5 in rice," Plant Communications. The rice blast fungus used in the examples of the present invention is Magnaporthe oryzae, which is described in the journal article "Recognition of the inducible, secretory small protein OsSSP1 by the membrane receptor OsSSR1 and the co-receptor OsBAK1 confers rice resistance to the blast fungus," Molecular Plant. It is known that these pathogens can be obtained from the applicant for use in repeating this experiment.

[0041] The rice variety used was "Zhonghua 11".

[0042] Example 1: Analysis of Volatile Organic Compounds by Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry (SPME-GC-MS)

[0043] 1. Test method:

[0044] Solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) was used to analyze the volatile compounds produced by rice plants inoculated with Xanthomonas spp. The following steps were used: Rice leaves inoculated with Xanthomonas spp. were cut into small sections and placed in sealed headspace vials. After 24 hours, a solid-phase microextraction (SPME) column was inserted into the headspace vial to collect volatile compounds for 60 minutes at 40°C. The column was then inserted into the GC-MS inlet for analysis. The column was programmed to heat at 50°C for 3 minutes, then increase the temperature to 300°C (10°C / min), and maintain the column at 300°C for 20 minutes. Using rice leaves not inoculated with Xanthomonas spp. as a control, SPME-GC-MS was used to analyze the VOCs produced by rice plants inoculated with bacterial leaf streak. The resulting mass spectra were compared with the NIST17 (National Institute of Standards and Technology) standard mass spectral library to determine the corresponding components of each chromatographic peak.

[0045] 2. Test results:

[0046] The results of the volatile component analysis of rice leaves inoculated with Xanthomonas are shown in Table 1.

[0047] Table 1: Volatile gas composition

[0048]

[0049] The results showed that the nine volatile substances were (Z)-hept-4-enal (RT=22.761), hexyl acetate (RT=24.087), hexyl butyrate (RT=30.691), ethyl octanoate (RT=31.597), (2E,4E)-2,4-heptadienal (RT=34.304), trans, cis-2,6-nonadienal (RT=38.397), cis-2,6-nonadien-1-ol (RT=45.248), (2E,4E)-2,4-decadienal (RT=47.208), and ethyl dodecanoate (RT=47.886).

[0050] Based on the content of the above-mentioned volatile substances and the difficulty of obtaining them, trans, cis-2,6-nonadienal was selected as the research object to investigate its effect on rice diseases.

[0051] Example 2: Effect of trans, cis-2,6-nonadienal on Xanthomonas growth

[0052] 1. Test method:

[0053] Pour the PSA medium mixed with Xanthomonas into a culture dish, and after solidification, use a sterilized puncher to punch a round hole in the center of the medium. Prepare trans, cis-2,6-nonadienal solutions with different concentrations using anhydrous ethanol as the solvent. Drop 20 μL of 0 μM, 0.1 μM, 1 μM, and 10 μM trans, cis-2,6-nonadienal solutions into the center of the round hole, respectively, and use anhydrous ethanol as the control (CK). Each concentration is repeated three times. Seal the culture dish with a sealing film to block the flow of air between the culture dish and the outside environment. Place the culture dish in a 28°C incubator and incubate for 72 hours. Then observe the formation of the inhibition zone.

[0054] 2. Test results:

[0055] The results are shown in Table 2. Figure 1 It was found that as the concentration of the volatile substance trans, cis-2,6-nonadienal increased, the inhibition zone gradually expanded, indicating that the volatile organic compound trans, cis-2,6-nonadienal had a certain inhibitory effect on Xanthomonas.

[0056] Example 3: Preventive effect of trans, cis-2,6-nonadienal on bacterial leaf blight of rice

[0057] 1. Test method:

[0058] Prepare a solution of trans, cis-2,6-nonadienal with a concentration of 10 μM using sterilized water. Spray 30-day-old rice leaves with 10 μM trans, cis-2,6-nonadienal solution, with a spraying amount of 1 ml per plant. Use the same amount of sterilized water as the control. After 24 hours, inoculate the same amount of Xanthomonas, and then incubate in a greenhouse at 28°C with 16 hours of light and 8 hours of darkness. After 7 days, count the length of the lesion. Each treatment is repeated three times.

[0059] 2. Test results:

[0060] The results are shown in Table 3. Figure 2 It was found that the length of the lesion caused by bacterial leaf blight of rice was significantly shorter in the group sprayed with 10 μM trans, cis-2,6-nonadienal than in the control group. This proves that trans, cis-2,6-nonadienal can improve the resistance of rice to bacterial leaf blight.

[0061] Example 4: Activation effect of trans, cis-2,6-nonadienal on plant immunity

[0062] 1. Test method:

[0063] The trans, cis-2, 6-nonadienal was prepared into a solution with a concentration of 10 μM with sterilized water. After spraying the 30-day-old rice leaves with the 10 μM trans, cis-2, 6-nonadienal solution, samples were taken at 0 hour, 12 hours and 24 hours respectively, and the expression of the defense genes OsPR1a and OsPR10a was detected.

[0064] After spraying the 30-day-old rice leaves with the 10 μM trans, cis-2, 6-nonadienal solution, samples were taken at 24 hours, and the active oxygen burst of the rice leaves was detected by DAB staining. The same amount of sterilized water (0 μM) was sprayed as a control.

[0065] 2. Test results:

[0066] The results are shown in Figure 3 It was found that, compared with 0 hour, the expression of OsPR1a and OsPR10a in the rice leaves was significantly increased at 12 hours after treatment and 24 hours after treatment.

[0067] Compared with the control treatment, the active oxygen in the rice leaves treated with trans, cis-2, 6-nonadienal was significantly accumulated at 24 hours after treatment.

[0068] Therefore, it is proved that trans, cis-2, 6-nonadienal can activate the immune response of plants.

[0069] Example 5: Effect of trans, cis-2, 6-nonadienal on the growth of Magnaporthe grisea

[0070] 1. Test method:

[0071] Magnaporthe grisea cakes were inoculated in the center of a CM culture dish, and 10 μM trans, cis-2, 6-nonadienal was added at the edge of the culture dish. Ethanol or trans, cis-2, 6-nonadienal was added as a control. Each treatment was repeated 3 times. The culture dish was sealed with sealing film to block the air circulation inside and outside the culture dish, and was placed in a 28°C incubator for culture. The mycelial diameter was measured after 96 hours to calculate the growth inhibition rate.

[0072] Growth inhibition rate (%) = (control colony diameter - treatment colony diameter) / (control colony diameter - cake diameter) x 100.

[0073] In the calculation formula of the above growth inhibition rate, "control colony diameter" refers to the CM medium without the addition of trans, cis-2, 6-nonadienal.

[0074] 2. Test results:

[0075] The results are shown in Figure 4The results showed that the inhibition rate was 30.1% when 10 μM of trans, cis-2,6-nonadienal was added at the edge of the culture dish, and the ethanol volatiles did not inhibit the growth of the rice blast fungus on the CM medium.

[0076] Example 6: Trans, cis-2,6-nonadienal for the prevention and treatment of rice blast

[0077] 1. Test method:

[0078] The 14-day-old rice leaves were sprayed with 10 μM of trans, cis-2,6-nonadienal; sterilized water was used as a control (Control). After one day, the conidia suspension of the rice blast fungus was sprayed on the rice seedlings. The plants were kept in complete darkness for the first 24 hours after inoculation, and then moved to a growth chamber with 28°C, 12 hours light / 12 hours darkness. The growth of the fungus was detected after 7 days.

[0079] 2. Test results:

[0080] The results are shown in Figure 5 The results showed that the area of the rice blast disease on the rice plants treated with trans, cis-2,6-nonadienal was significantly smaller than that of the control. This proved that trans, cis-2,6-nonadienal can improve the resistance of rice to the rice blast fungus.

[0081] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. Use of trans, cis-2,6-nonadienal in at least one of the following (1)-(3): (1) Inhibit the growth of Xanthomonas; (2) preparing antibacterial products for Xanthomonas; (3) Prepare drugs for preventing and treating rice bacterial leaf streak disease.

2. The use according to claim 1, characterized in that The Xanthomonas is Xanthomonas oryzae pv. oryzicola (Xoc).

3. Use of trans, cis-2,6-nonadienal in at least one of the following (A) to (C): (A) inhibiting the growth of rice blast fungus; (B) preparing an antibacterial product for rice blast fungus; (C) preparing a medicament for preventing and treating rice blast.

4. The use according to claim 3, characterized in that The rice blast fungus is Magnaporthe oryzae.

5. Application of trans, cis-2,6-nonadienal in the preparation of plant immune activators.

6. The use according to claim 5, characterized in that The trans, cis-2,6-nonadienal activates plant immunity through the following pathways (i) or (ii): (i) increasing the expression of defense genes; (ii) Promote the burst of reactive oxygen species.

7. The use according to claim 6, characterized in that The defense genes include: OsPR1a and OsPR10a.

8. A method for preventing and controlling rice diseases, characterized in that: The following steps are involved: During the entire growth period of rice, trans, cis-2,6-nonadienal is sprayed on rice leaves or rhizomes.

9. The method according to claim 8, characterized in that The rice disease is rice bacterial leaf streak and / or rice blast.

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