Application of foreign DNA fragments in improving disease resistance of wheat

Abstract

The application belongs to the technical field of crop disease prevention and treatment, and discloses application of an exogenous DNA fragment in improving the disease resistance of wheat. After extracting wheat DNA, the application carries out fragmentation treatment to obtain an exogenous DNA fragment with a size of 500-3000 bp. The exogenous DNA fragment is used for treating wheat plants, can induce the wheat to produce resistance to Puccinia striiformis Westend, effectively reduces the biomass of Puccinia striiformis Westend, and does not affect the agronomic characters of the wheat, and the optimal use concentration is 200 ng / μL, and the optimal treatment time is 2 d. The application provides a green and safe prevention and control measure for wheat stripe rust, and has contribution significance in aspects of persistent control of wheat stripe rust, improvement of wheat yield and economic benefits and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of crop disease prevention and control, and relates to the application of exogenous DNA fragments in improving the disease resistance of wheat. Background Art

[0002] The research and application of plant immunity has become a hot topic in the field of plant protection. Plants face potential threats from a variety of pathogens throughout their growth. To combat pathogens and microbial infection, plants have evolved effective defense mechanisms over the course of long-term evolution to combat pathogen invasion. These defenses primarily include physical and chemical barriers and the innate immune system. The innate immune system primarily encompasses two immune response modes: pathogen-associated molecular pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Research has shown that PTI and ETI can mutually enhance plant defenses.

[0003] Exogenous DNA is produced through active or passive excretion mechanisms and cell lysis pathways. It is produced when cells or tissues are damaged and degraded. Exogenous DNA infecting plants may represent a damage-associated molecular pattern (DAMP), which helps to enhance the specificity of plant self-recognition after damage. Therefore, studying the role of exogenous DNA in plant immune responses, elucidating the mechanism of action of exogenous DNA in regulating host disease resistance, and developing green and safe plant disease control measures have far-reaching significance for increasing crop yields and economic benefits.

[0004] In wheat cultivation, wheat stripe rust ( Puccinia striiformis f. sp. Tritici ) is a major fungal disease that affects the safety of wheat production and is devastating to wheat. The prevention and control of wheat stripe rust mainly include the cultivation of resistant varieties, chemical control and biological control. Among them, the cultivation and promotion of disease-resistant varieties has always been the most economical, effective and environmentally friendly prevention and control measure. However, due to the long breeding period and the frequent mutation of stripe rust fungi, new physiological subspecies continue to appear, which has caused wheat stripe rust-resistant varieties to lose their resistance and value. In addition, the irrational use of pesticides has not only increased the cost of chemical control, but also brought about a series of problems such as environmental pollution and food safety, and increased wheat resistance. Biological control generally has problems such as low prevention efficiency and high cost. Therefore, there is an urgent need to find economical, efficient, safe and environmentally friendly methods for the prevention and control of wheat stripe rust. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems, the present application researches the immunity of exogenous DNA of wheat to Puccinia striiformis West. The control effect of the exogenous DNA fragment on Puccinia striiformis West is explored through the changes of wheat leaf phenotype, tissue cytology detection, biomass ratio and agronomic traits. Based on the technical idea, the technical scheme is provided as follows.

[0006] The present application provides the application of the exogenous DNA fragment in improving the disease resistance of wheat. The exogenous DNA fragment is extracted from wheat leaves. The size of the exogenous DNA fragment is 500-3000 bp.

[0007] Further, in the above-mentioned application, the preparation method of the exogenous DNA fragment is as follows: extracting wheat leaf DNA, fragmenting the wheat leaf DNA into 500-3000 bp DNA fragments by ultrasonic fragmentation method, and diluting for use.

[0008] Further, the use concentration of the exogenous DNA fragment is 200 ng / μL, and the treatment time is 2 d.

[0009] Further, the ultrasonic fragmentation condition is as follows: power 24 w, ultrasonic opening 3 s, ultrasonic closing 5 s, and ultrasonic fragmentation time 30 s.

[0010] On the other hand, the present application also provides a method for preventing and treating wheat stripe disease. The method comprises: using a preparation containing an exogenous DNA fragment, and applying the preparation to wheat. The exogenous DNA fragment is extracted from wheat leaves. The size of the exogenous DNA fragment is 500-3000 bp.

[0011] Further, in the above-mentioned method, the preparation method of the exogenous DNA fragment is as follows: extracting wheat leaf DNA, fragmenting the wheat leaf DNA into 500-3000 bp DNA fragments by ultrasonic fragmentation method, and diluting for use.

[0012] Further, in the above-mentioned method, the use concentration of the exogenous DNA fragment is 200 ng / μL, and the treatment time is 2 d.

[0013] Further, in the above-mentioned method, the ultrasonic fragmentation condition is as follows: power 24 w, ultrasonic opening 3 s, ultrasonic closing 5 s, and ultrasonic fragmentation time 30 s.

[0014] Compared with the prior art, the application of the exogenous DNA fragment in improving the disease resistance of wheat has the following beneficial effects:

[0015] 1) The exogenous DNA fragment is obtained by fragmenting the extracted wheat DNA by ultrasonic fragmentation method. The exogenous DNA fragment can induce the resistance of wheat to Puccinia striiformis West and enhance the immunity of wheat to Puccinia striiformis West.

[0016] 2) The application uses different concentrations and different treatment times of exogenous DNA fragments to treat wheat, and then inoculates the stripe rust, so as to determine the optimal use concentration and the optimal treatment time of the exogenous DNA fragments.

[0017] 3) The application proves the performance of the exogenous DNA fragments at the tissue cell level by means of DAB staining, trypan blue staining and WGA-488 staining.

[0018] 4) The application determines the biomass change of the stripe rust in the leaf tissue after the treatment of the exogenous DNA fragments by quantitative detection.

[0019] 5) Based on the indoor test results, the application designs field control schemes of the exogenous DNA fragments used alone and mixed with tebuconazole, so as to enrich the application ways of the exogenous DNA fragments in the prevention and control of the wheat stripe rust. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the technical roadmap of the application.

[0021] Figure 2 is the gel electrophoresis diagram of the exogenous DNA fragments obtained by ultrasonic crushing.

[0022] Figure 3 is the phenotype of the water source 11 wheat leaf corresponding to different treatment times and different use concentrations of the exogenous DNA fragment solution. Figure 3 The left graph in is the leaf phenotype of different treatment times. Figure 3 The right graph in is the leaf phenotype of different use concentrations. Figure 3 In, "CK" represents a blank control group.

[0023] Figure 4 is the DAB staining result of 1d and 2d after the inoculation of the stripe rust physiological race CYR31 of the three treatment groups. SV represents the stomatal vesicle, and the scales corresponding to 1d and 2d are 10 μm and 20 μm respectively.

[0024] Figure 5 is the trypan blue staining result of 1d and 2d after the inoculation of the stripe rust physiological race CYR31 of the three treatment groups. SV represents the stomatal vesicle, and the scales corresponding to 1d and 2d are 10 μm and 20 μm respectively.

[0025] Figure 6 is the WGA-488 staining result of 1d, 2d and 5d after the inoculation of the stripe rust physiological race CYR31. SV represents the stomatal vesicle, HMC represents the haustorial mother cell, and IH represents the infection hypha. The scales corresponding to 1d, 2d and 5d are 10 μm, 10 μm and 50 μm respectively.

[0026] Figure 7 is the biomass ratio (Pst / Wheat) of different treatment groups at 8d, 12d after inoculation of Pst CYR31. Figure 7 In the figure, CK represents blank control; "50", "100", "200" represent the concentration of exogenous DNA fragment respectively; error line represents standard error; "*" represents p<0.05, "**" represents p<0.01, and ns represents not significant.

[0027] Figure 8 is the disease phenotype of groups 1-8 in the field.

[0028] Figure 9 is the percentage distribution of different disease grades of groups 1-8 at 15d after inoculation of Pst.

[0029] Figure 10 is the percentage distribution of different disease grades of groups 1-8 at 23d after inoculation of Pst.

[0030] Figure 11 is the percentage distribution of different disease grades of groups 1-8 at 31d after inoculation of Pst.

[0031] Figure 12 is the ear length of wheat after harvesting of groups 1-8.

[0032] Figure 13 is the grain number per ear of wheat after harvesting of groups 1-8.

[0033] Figure 14 is the number of ears per unit of wheat after harvesting of groups 1-8.

[0034] Figure 15 is the thousand-grain weight of wheat after harvesting of groups 1-8. DETAILED DESCRIPTION

[0035] The present application will be described in conjunction with the embodiments thereof, which are described in a manner clear and complete, and it is obvious that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0036] The experimental methods in the following examples are all conventional methods, and are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions, unless otherwise specified. The materials, reagents, etc. used in the following examples can be obtained from commercial channels, unless otherwise specified.

[0037] Figure 1The technical roadmap of the present application is shown in the following figure. The present application provides a method and results for analyzing the resistance effect and mechanism of exogenous DNA fragments on wheat stripe rust. The method comprises the following steps:

[0038] S1, extracting wheat leaf DNA, obtaining DNA fragments by ultrasonic fragmentation method (the size of the fragments after fragmentation: 500-3000 bp);

[0039] S2, treating the wheat plants with the obtained exogenous DNA fragments, and then inoculating the plants with stripe rust (affinity stripe rust physiological race CYR31) to obtain the optimal use concentration and treatment time;

[0040] S3, treating the wheat plants with the exogenous DNA fragments, and then inoculating the plants with stripe rust to determine the histological changes of the wheat plants;

[0041] S4, treating the wheat plants with the exogenous DNA fragments, and then inoculating the plants with stripe rust to obtain the biomass changes of the wheat plants and stripe rust;

[0042] S5, field test of the disease prevention and yield increase effect of the exogenous DNA fragments. The present application will be described in detail through the following examples.

[0043] Example 1

[0044] This example describes the preparation of exogenous DNA fragments.

[0045] Take the wheat leaves from water source 11, extract the leaf DNA by CTAB method, and use an ultrasonic disrupter (Fisher Scientific Company, model: FB50220) to perform ultrasonic fragmentation. The fragmentation conditions are as follows: power 24w, ultrasonic on for 3s and off for 5s, and the ultrasonic fragmentation time is 30s. After the ultrasonic fragmentation treatment is completed, the fragmented DNA with a size of 500-3000 bp is obtained, and the target band is verified by electrophoresis to obtain the exogenous DNA fragments.

[0046] Figure 2 The gel electrophoresis diagram of the exogenous DNA fragments obtained by ultrasonic fragmentation. Figure 2 As can be seen in the figure, there are obvious bands in the range of 500-3000 bp, indicating that the sample preparation is successful.

[0047] Example 2

[0048] This example describes the phenotype of wheat plants inoculated with affinity stripe rust physiological race CYR31 after being treated with exogenous DNA fragments of different treatment times and different use concentrations.

[0049] When the wheat of water source 11 grows to two leaves with one heart, the exogenous DNA fragment prepared in Example 1 is formulated into a solution with a concentration of 200 ng / μL, and the wheat leaves are treated with the solution for 2 d, 5 d and 7 d respectively, and then inoculated with the physiological race CYR31 of Puccinia striiformis f. sp. tritici with an inoculation concentration of 5 mg / mL (5 mg of Puccinia striiformis f. sp. tritici uredospores mixed with 1 mL of electronic fluorination liquid to form a spore suspension), and the phenotypes of the wheat of water source 11 in each treatment group are observed. The sterile water is used instead of the exogenous DNA fragment solution, and the rest of the experimental conditions are the same, which is used as a blank control (CK).

[0050] In addition, the wheat of water source 11 is treated with the exogenous DNA fragment solution with a concentration of 50 ng / μL, 100 ng / μL and 200 ng / μL respectively for 2 d, and then inoculated with the physiological race CYR31 of Puccinia striiformis f. sp. tritici with an inoculation concentration of 5 mg / mL (5 mg of Puccinia striiformis f. sp. tritici uredospores mixed with 1 mL of electronic fluorination liquid to form a spore suspension), and the phenotypes of the wheat of water source 11 in each treatment group are observed. The sterile water is used instead of the exogenous DNA fragment solution, and the rest of the experimental conditions are the same, which is used as a blank control.

[0051] Figure 3 The left graph in FIG. 1 is the leaf phenotype at different treatment times, and the right graph in FIG. 1 is the leaf phenotype at different use concentrations. Figure 3 The left graph in FIG. 1 is the leaf phenotype at different treatment times, and the right graph in FIG. 1 is the leaf phenotype at different use concentrations. Figure 3 The left graph in FIG. 1 is the leaf phenotype at different treatment times, and the right graph in FIG. 1 is the leaf phenotype at different use concentrations. Figure 3 “CK” in FIG. 1 represents a blank control.

[0052] It can be known from the left graph in FIG. 1 that the effect of treating for 2 d is better, and it can be known from the right graph in FIG. 1 that the effect of treating with the exogenous DNA fragment at a concentration of 200 ng / μL is better. Figure 3 Figure 3 The left graph in FIG. 1 is the leaf phenotype at different treatment times, and the right graph in FIG. 1 is the leaf phenotype at different use concentrations. Figure 3 The results shown in FIG. 1 show that the best treatment time for treating the wheat leaves with the exogenous DNA fragment is 2 d, and the best treatment concentration is 200 ng / μL.

[0053] Example 3

[0054] This example describes the histocytological changes of the physiological race CYR31 of Puccinia striiformis f. sp. tritici after being treated with the exogenous DNA fragment.

[0055] ​The water source 11 wheat was treated with 50 ng / μL of exogenous DNA fragment solution for 2 d, and the water source 11 wheat was treated with 200 ng / μL of exogenous DNA fragment solution for 2 d and 5 d, and then the three treatment groups were inoculated with the affinity Puccinia striiformis f. sp. CYR31 at a concentration of 5 mg / mL. The samples were taken at 1 d and 2 d after inoculation, and the samples were subjected to DAB staining (for determining the generation of active oxygen in wheat) and trypan blue staining (for determining the cell necrosis). The treatment method of the CK group was that the water source 11 wheat was treated with water instead of the exogenous DNA fragment solution, and the remaining treatment steps were the same.

[0056] The same test method was used to take samples at 1 d, 2 d and 5 d after inoculation with the affinity Puccinia striiformis f. sp. CYR31, and WGA-488 staining was performed (for determining the change of Puccinia striiformis colony). The treatment method of the CK group was that the water source 11 wheat was treated with water instead of the exogenous DNA fragment solution, and the remaining treatment steps were the same. The results of DAB staining, trypan blue staining and WGA-488 staining were observed and recorded, the generation of active oxygen in wheat, the cell necrosis and the change of Puccinia striiformis colony after different treatment times were compared, and the performance of exogenous DNA fragment-induced resistance at the tissue cell level was preliminarily determined.

[0057] Figure 4 is the DAB staining result of the three treatment groups at 1 d and 2 d after inoculation with Puccinia striiformis f. sp. CYR31. SV represents the sub-stoma sac, and the scales corresponding to 1 d and 2 d are 10 μm and 20 μm, respectively. It can be seen from Figure 4 that the area of active oxygen generated by Puccinia striiformis in the wheat plant treated with 200 ng / μL of exogenous DNA fragment for 2 d is significantly more than that of the control.

[0058] Figure 5 is the trypan blue staining result of the three treatment groups at 1 d and 2 d after inoculation with Puccinia striiformis f. sp. CYR31. SV represents the sub-stoma sac, and the scales corresponding to 1 d and 2 d are 10 μm and 20 μm, respectively. It can be seen from Figure 5 that the necrosis area generated by Puccinia striiformis in the wheat plant treated with 200 ng / μL of exogenous DNA fragment for 2 d is significantly more than that of the control.

[0059] Figure 6 is the WGA-488 staining result at 1 d, 2 d and 5 d after inoculation with Puccinia striiformis f. sp. CYR31. SV represents the sub-stoma sac, HMC represents the haustorial mother cell, and IH represents the infection hypha. The scales corresponding to 1 d, 2 d and 5 d are 10 μm, 10 μm and 50 μm, respectively. It can be seen from Figure 6 that the growth of Puccinia striiformis in the wheat plant treated with 200 ng / μL of exogenous DNA fragment for 2 d is significantly inhibited, and the colony area is also significantly reduced. In combination with Figures 4-6The results show that the exogenous DNA fragment can significantly inhibit the development of Puccinia striiformis in wheat plants.

[0060] Example 4

[0061] This example describes the biomass changes of Puccinia striiformis in the leaves of wheat Triticum aestivum L. cv. 11 treated with different concentrations of exogenous DNA fragments for 2 days after inoculation with Puccinia striiformis race CYR31.

[0062] The exogenous DNA fragments were prepared into solutions with concentrations of 50 ng / μL, 100 ng / μL and 200 ng / μL, respectively, and were used to treat wheat Triticum aestivum L. cv. 11 for 2 days. Sterile water was used instead of the exogenous DNA fragment solution as a blank control. The inoculation concentration of Puccinia striiformis race CYR31 was 5 mg / mL (5 mg of Puccinia striiformis spores mixed with 1 mL of electronic fluorination solution to form a spore suspension). The samples were taken for biomass detection at 8 days and 12 days after inoculation, and the biomass ratio was calculated.

[0063] Biomass determination method: The Puccinia striiformis gene PsEF and the wheat gene TaEF represent the biomass of Puccinia striiformis and wheat, respectively. The corresponding biomass was calculated according to the standard curve based on the amplification cycle value of the fluorescence quantitative PCR.

[0064] Figure 7 is the biomass ratio (Pst / Wheat) at 8 days and 12 days after inoculation of Puccinia striiformis race CYR31 in different treatment groups. Figure 7 In the table, CK represents the blank control; "50", "100" and "200" represent the concentrations of the exogenous DNA fragments, respectively; the error bar represents the standard error; "*" represents p<0.05, "**" represents p<0.01, and ns represents not significant.

[0065] It can be seen from Figure 7 that the growth of Puccinia striiformis in wheat plants is significantly inhibited after treatment with the exogenous DNA fragment at a concentration of 200 ng / μL, and the biomass decreases. The biomass also shows a decreasing trend compared with CK after treatment with the exogenous DNA fragments at concentrations of 50 ng / μL and 100 ng / μL. The results show that treatment with the exogenous DNA fragment at a concentration of 200 ng / μL for 2 days can achieve good control effect.

[0066] Example 5

[0067] This example describes the field test of the disease prevention and yield increase effect of the exogenous DNA fragment on wheat.

[0068] Based on the indoor experiment, eight groups were set up in the field, with three replicates in each group, for a total of 24 plots, each measuring 2 m x 2 m. Groups 1, 2, and 3 were compared with Group 4, which received clean water; Groups 5, 6, and 7 were compared with Group 8, which received clean water.

[0069] Treatment methods for 8 groups:

[0070] Group 1: After being treated with exogenous DNA fragments for 7 days, the cells were inoculated with the compatible stripe rust race CYR31.

[0071] Group 2: The exogenous DNA fragments were mixed with tebuconazole and treated for 7 days before inoculation with the compatible stripe rust race CYR31.

[0072] Group 3: After being treated with tebuconazole for 7 days, the plants were inoculated with the compatible stripe rust race CYR31.

[0073] Group 4: After being treated with clean water for 7 days, the plants were inoculated with the compatible stripe rust race CYR31.

[0074] Group 5: After being treated with exogenous DNA fragments for 2 days, the cells were inoculated with the compatible stripe rust race CYR31.

[0075] Group 6: The exogenous DNA fragments were mixed with tebuconazole and treated for 2 days before inoculation with the compatible stripe rust race CYR31.

[0076] Group 7: After being treated with tebuconazole for 2 days, the plants were inoculated with the compatible stripe rust race CYR31.

[0077] Group 8: After being treated with clean water for 2 days, the samples were inoculated with the compatible stripe rust race CYR31.

[0078] In the above groups, the concentration of the exogenous DNA fragment solution was 200 ng / μL, and the dosage was 50 mL / mL. 2 For tebuconazole, 10 mL of 43% tebuconazole was diluted with 45 kg of water, for a dosage of 45 kg per mu. Both the inoculation concentration of the CYR31 race of the wheat stripe rust fungus and the CYR31 fungus were 5 mg / mL (5 mg of wheat stripe rust uredospores were mixed with 1 mL of electronic fluoride solution to form a spore suspension). The plant phenotype, disease grade percentage, and post-harvest spike length, number of grains per spike, number of grains per spike, and 1000-grain weight were analyzed for each group. Disease grade classification was based on the NY / T 1443.1-2007 standard.

[0079] Figure 8 The disease phenotypes of different treatment groups are statistically analyzed in the field. Figure 8It can be seen that, in general, the phenotype of treatment 7d (groups 1-3) has no significant difference compared with treatment 2d (groups 5-7), indicating that the treatment with exogenous DNA fragments, the treatment with exogenous DNA fragments and tebuconazole mixture, and the treatment with tebuconazole all produce persistent resistance to Puccinia striiformis in wheat plants. In addition, the disease condition of exogenous DNA fragment treatment for 7d compared with water treatment for 7d, and the disease condition of exogenous DNA fragment treatment for 2d compared with water treatment for 2d is lighter, indicating that the exogenous DNA fragment produces obvious resistance to Puccinia striiformis. It is worth noting that the exogenous DNA fragment and tebuconazole mixture treatment, tebuconazole treatment have significant effect under the condition of treatment for 7d and treatment for 2d, significantly inhibit the growth of Puccinia striiformis, and the sporulation is also obviously reduced, indicating that in practical application, the exogenous DNA fragment and tebuconazole can be used together.

[0080] Figure 9 The percentage distribution of different disease grades of groups 1-8 in this example on the 15th day after inoculation with Puccinia striiformis is shown in the following table. Figure 9 It can be seen that, under the condition of treatment for 7d, the disease condition of exogenous DNA fragment and tebuconazole mixture treatment, tebuconazole treatment is lighter than that of exogenous DNA fragment treatment; under the condition of treatment for 2d, the disease condition of exogenous DNA fragment and tebuconazole mixture treatment, tebuconazole treatment is lighter than that of exogenous DNA fragment treatment, indicating that the effect of exogenous DNA fragment and tebuconazole mixture treatment is better than that of only using exogenous DNA fragment treatment. At the same time, under the condition of treatment for 7d and treatment for 2d, the disease condition of exogenous DNA fragment is lighter than that of water treatment, indicating that the resistance of wheat to Puccinia striiformis is improved after exogenous DNA fragment treatment.

[0081] Figure 10 The percentage distribution of different disease grades of groups 1-8 in this example on the 23rd day after inoculation with Puccinia striiformis is shown in the following table. Figure 11 The percentage distribution of different disease grades of groups 1-8 in this example on the 31st day after inoculation with Puccinia striiformis is shown in the following table. Figure 10 、 11 It can be seen that the disease condition of exogenous DNA fragment treatment for 7d compared with water treatment for 7d, and the disease condition of exogenous DNA fragment treatment for 2d compared with water treatment for 2d is lighter, indicating that compared with water treatment, the resistance of wheat to Puccinia striiformis has a certain persistence after exogenous DNA fragment treatment. In addition, under the condition of treatment for 7d and treatment for 2d, the disease condition of exogenous DNA fragment and tebuconazole mixture treatment is lighter than that of exogenous DNA fragment treatment, indicating that the effect of exogenous DNA fragment and tebuconazole mixture treatment is better than that of only using exogenous DNA fragment treatment. Figure 10 、 11 It can be seen that the disease condition of exogenous DNA fragment and tebuconazole mixture treatment for 7d is lighter than that of exogenous DNA fragment treatment for 7d, and the disease condition of exogenous DNA fragment and tebuconazole mixture treatment for 2d is lighter than that of exogenous DNA fragment treatment for 2d, indicating that the effect of exogenous DNA fragment and tebuconazole mixture treatment is better than that of only using exogenous DNA fragment treatment, and the two can be prepared into a composite preparation for subsequent use, which is consistent with the foregoing conclusion.

[0082] Figure 12 ,Figure 13 , Figure 14 , Figure 15 Statistical results of ear length, grain number per ear, number of ears per unit and thousand-grain weight of different treatment groups of wheat after harvesting, respectively. Among them, the blank control is used as the standard to mark a, and if there is a significant difference compared with a, it is marked b, and if there is no significant difference, it is marked a, and similarly, if there is a significant difference compared with b, it is marked c, and if there is no significant difference, it is marked b, and if the difference is between a and b, it is marked ab. Figures 12-15 It can be known from the above that compared with the water treatment (blank control), the ear length, grain number per ear, number of ears per unit and thousand-grain weight of the wheat treated by the exogenous DNA fragment are improved, which indicates that the exogenous DNA fragment can not only play a role in resisting the stripe rust, but also does not affect the agronomic traits of the wheat.

[0083] In summary, the present application uses the exogenous DNA fragment to treat the wheat leaves, and studies the immune effect of the wheat on the stripe rust, analyzes the action mechanism of the exogenous DNA fragment in the process of regulating the disease resistance of the wheat, verifies that the treatment by the exogenous DNA fragment can induce the wheat to produce the resistance to the stripe rust and inhibit the growth of the stripe rust, and is a green and safe prevention and control measure for the wheat stripe rust, which provides a new way and a new scheme for the persistent control of the wheat stripe rust, the improvement of the wheat yield and the economic benefits and the like.

[0084] The above-described embodiments are only some of the embodiments of the present application, not all the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. All other embodiments obtained by related deduction and replacement of those skilled in the art under the condition of the concept of the present application, without making creative labor, belong to the scope of protection of the present application.

Claims

1. The application of exogenous DNA fragments in improving wheat stripe rust resistance, characterized in that: The exogenous DNA fragment is extracted from wheat leaves; the size of the exogenous DNA fragment is 500-3000 bp; The method for preparing the exogenous DNA fragments comprises the following steps: extracting wheat leaf DNA, breaking the wheat leaf DNA into DNA fragments of 500-3000 bp by ultrasonic fragmentation, and diluting the DNA fragments for use.

2. The use according to claim 1, characterized in that The exogenous DNA fragments were used at a concentration of 200 ng / μL, and the treatment time was 2 days.

3. The use according to claim 1, characterized in that The ultrasonic fragmentation conditions were as follows: power 24 W, ultrasound on for 3 s, off for 5 s, and ultrasonic fragmentation duration for 30 s.

4. A method for preventing and controlling wheat stripe rust, characterized in that: The method comprises: using a preparation containing exogenous DNA fragments and applying the preparation to wheat; the exogenous DNA fragments are extracted from wheat leaves; the size of the exogenous DNA fragments is 500 to 3000 bp; The method for preparing the exogenous DNA fragments comprises the following steps: extracting wheat leaf DNA, breaking the wheat leaf DNA into DNA fragments of 500-3000 bp by ultrasonic fragmentation, and diluting the DNA fragments for use.

5. The method according to claim 4, characterized in that The exogenous DNA fragments were used at a concentration of 200 ng / μL, and the treatment time was 2 days.

6. The method according to claim 4, characterized in that The ultrasonic fragmentation conditions were as follows: power 24 W, ultrasound on for 3 s, off for 5 s, and ultrasonic fragmentation duration for 30 s.

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