Application of exogenous DNA fragment in improvement of wheat disease resistance

Abstract

The invention belongs to the technical field of crop disease control, and discloses application of an exogenous DNA fragment in improvement of wheat disease resistance. According to the invention, after wheat DNA is extracted, fragmentation treatment is carried out, such that an exogenous DNA fragment with a size of 500-3000 bp is obtained. When the exogenous DNA fragment is used for treating wheat plants, wheat can be induced to generate resistance against puccinia striiformis, the biomass of puccinia striiformis is effectively reduced, meanwhile, the agronomic traits of wheat are not affected, the optimal use concentration is 200 ng / mu L, and the optimal treatment time is 2 d. The invention provides a green and safe wheat stripe rust prevention and control measure, and has contribution significance in the aspects of lasting control of wheat stripe rust, improvement of wheat yield and economic benefits and the like.

Description

Technical Field

[0001] The 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] Plant immunity research and application has become a research hotspot in the field of plant protection. Plants face potential threats from a variety of pathogens during their growth. In order to resist pathogens and microbial infections, plants have evolved effective defense mechanisms to resist the invasion of pathogens during the long-term evolution process. It mainly includes two lines of defense: physical and chemical barriers and the innate immune system. The innate immune system mainly includes two immune response modes: pathogen-associated molecular pattern-triggered immune response (PAMPs triggered immunity, PTI) and effector-triggered immune response (Effector triggered immunity, ETI). Studies have found that PTI and ETI can enhance each other to achieve a stronger plant defense effect.

[0003] Exogenous DNA is DNA 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 improve the specificity of self-recognition after plants are damaged. Therefore, studying the role of exogenous DNA in plant immune response, analyzing the mechanism of action of exogenous DNA in regulating host disease resistance, and developing a green and safe plant disease prevention and control measure have far-reaching significance for improving 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 includes methods such as breeding resistant varieties, chemical control and biological control. Among them, the breeding and promotion of disease-resistant varieties has always been the most economical, effective and environmentally friendly prevention and control measures. However, due to the long breeding period and the frequent mutation of stripe rust fungi, new physiological subspecies continue to appear, which leads to the loss of resistance and utilization value of wheat stripe rust resistant varieties. In addition, the irrational use of pesticides has not only increased the cost of chemical control, but also brought a series of environmental pollution, food safety and other problems, 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 invention studies the immune effect of wheat exogenous DNA on stripe rust, and explores the control effect of exogenous DNA fragments on wheat stripe rust through changes in wheat leaf phenotype, tissue cytology detection, biomass ratio and agronomic traits. Based on this technical idea, the present invention provides the following technical solutions.

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

[0007] Furthermore, in the above application, the method for preparing the exogenous DNA fragments is: extracting wheat leaf DNA, breaking the wheat leaf DNA into DNA fragments of 500-3000 bp by ultrasonic fragmentation, and diluting them for use.

[0008] Furthermore, the exogenous DNA fragments were used at a concentration of 200 ng / μL, and the treatment time was 2 days.

[0009] Furthermore, the ultrasonic crushing conditions were as follows: power 24 W, ultrasound on for 3 s, off for 5 s, and ultrasonic crushing time of 30 s.

[0010] On the other hand, the present invention also provides a method for preventing and controlling wheat stripe rust, the method comprising: 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 500~3000bp.

[0011] Furthermore, in the above method, the preparation method of the exogenous DNA fragments is: extracting wheat leaf DNA, breaking the wheat leaf DNA into DNA fragments of 500-3000 bp by ultrasonic fragmentation, and diluting them for use.

[0012] Furthermore, in the above method, the exogenous DNA fragment is used at a concentration of 200 ng / μL, and the treatment time is 2 days.

[0013] Furthermore, in the above method, the conditions for ultrasonic fragmentation are: power 24w, ultrasound on for 3s, off for 5s, and ultrasonic fragmentation time is 30s.

[0014] Compared with the prior art, the present invention "Application of exogenous DNA fragments in improving wheat disease resistance" has the following beneficial effects: 1) The present invention extracts wheat DNA by ultrasonic fragmentation and then fragments it to obtain exogenous DNA fragments. The exogenous DNA fragments can induce wheat to produce resistance to stripe rust and enhance the immunity of wheat to stripe rust.

[0015] 2) The present invention uses exogenous DNA fragments of different concentrations and different treatment times to treat wheat, and then inoculates stripe rust to clarify the optimal use concentration and optimal treatment time of the exogenous DNA fragments.

[0016] 3) The present invention uses DAB staining, trypan blue staining and WGA-488 staining to explore the manifestation of exogenous DNA fragment-induced resistance at the tissue cell level.

[0017] 4) The present invention clarifies the biomass change of stripe rust in leaf tissue after treatment with exogenous DNA fragments through quantitative detection.

[0018] 5) Based on the results of indoor tests, the present invention designed field control schemes such as using exogenous DNA fragments alone or in combination with tebuconazole, enriching the application methods of exogenous DNA fragments in the prevention and control of wheat stripe rust. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the technical roadmap of the present invention.

[0020] Figure 2 It is the gel electrophoresis diagram of exogenous DNA fragments obtained by ultrasonic fragmentation.

[0021] Figure 3 It is the phenotype of wheat leaves in Water Source 11 corresponding to different treatment times and different concentrations of exogenous DNA fragment solution. Figure 3 The left picture in the figure shows the leaf phenotypes at different treatment times; Figure 3 The right picture in the figure shows the leaf phenotypes at different concentrations. Figure 3 "CK" in the table means blank control group.

[0022] Figure 4 The DAB staining results of the three treatment groups at 1d and 2d after inoculation with stripe rust race CYR31. SV stands for substomatal capsule, and the scale bars for 1d and 2d are 10μm and 20μm, respectively.

[0023] Figure 5 The results of trypan blue staining of the three treatment groups 1d and 2d after inoculation with stripe rust race CYR31. SV stands for substomatal sac, and the scale bars for 1d and 2d are 10μm and 20μm, respectively.

[0024] Figure 6 The WGA-488 staining results at 1d, 2d and 5d after inoculation with stripe rust race CYR31. SV stands for substomatal sac, HMC stands for haustoria mother cell, and IH stands for infected hyphae. The scale bars for 1d, 2d and 5d are 10μm, 10μm and 50μm, respectively.

[0025] Figure 7It is the biomass ratio (Pst / Wheat) of different treatment groups 8d and 12d after inoculation with stripe rust physiological race CYR31. Figure 7 In the figure, CK represents blank control; "50", "100" and "200" represent the concentrations of exogenous DNA fragments, respectively; error bars represent standard errors: "*" represents p < 0.05, "**" represents p < 0.01, and ns represents not significant.

[0026] Figure 8 These are the disease phenotypes of groups 1 to 8 from field statistics.

[0027] Fig. 9 This is the percentage distribution of different disease levels on the 15th day after groups 1 to 8 were inoculated with stripe rust.

[0028] Fig.10 This is the percentage distribution of different disease levels on the 23rd day after groups 1 to 8 were inoculated with stripe rust.

[0029] Fig.11 This is the percentage distribution of different disease levels on the 31st day after groups 1 to 8 were inoculated with stripe rust.

[0030] Fig.12 This is the ear length of wheat in groups 1 to 8 after harvest.

[0031] Fig.13 It is the number of grains per ear after harvesting groups 1 to 8 of wheat.

[0032] Fig.14 It is the number of ears per unit after 1 to 8 groups of wheat are harvested.

[0033] Fig.15 It is the thousand-grain weight of wheat in groups 1 to 8 after harvest. DETAILED DESCRIPTION

[0034] The present invention is explained below in conjunction with the embodiments, and the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0036] Figure 1 The embodiment of the present invention provides a method and result of analyzing the resistance effect and mechanism of wheat stripe rust by exogenous DNA fragment treatment, including: S1, extract DNA from wheat leaves, and obtain DNA fragments by ultrasonic fragmentation (band size after fragmentation: 500-3000 bp); S2, treating wheat plants with the obtained exogenous DNA fragments, and then inoculating with stripe rust (compatible stripe rust physiological race CYR31) to obtain the optimal concentration and treatment time; S3, wheat plants were treated with exogenous DNA fragments and then inoculated with stripe rust to determine the histocytological changes of wheat; S4, treating wheat plants with exogenous DNA fragments, and then inoculating stripe rust to obtain the biomass changes of stripe rust and wheat; S5, field test of the effect of exogenous DNA fragments on wheat disease prevention and yield increase. The present invention is described in detail below through examples.

[0037] Example 1 This example describes the preparation of exogenous DNA fragments.

[0038] Wheat leaves from water source 11 were taken, and leaf DNA was extracted by CTAB method, and ultrasonic disruption was performed using an ultrasonic disruptor (Fisher Scientific, model: FB50220). Disruption conditions: power 24w, ultrasound on 3s, off 5s, and ultrasonic disruption time of 30s. After the ultrasonic disruption treatment, fragmented DNA with a band size of 500-3000bp was obtained, and the target band was verified by electrophoresis running, that is, the exogenous DNA fragment was obtained.

[0039] Figure 2 It is the gel electrophoresis diagram of exogenous DNA fragments obtained by ultrasonic fragmentation. Figure 2 As can be seen in the figure, there are obvious bands in the range of 500~3000bp, indicating that the sample preparation was successful.

[0040] Example 2 This example describes the phenotype of wheat inoculated with the compatible stripe rust race CYR31 after being treated with exogenous DNA fragments at different treatment times and different concentrations.

[0041] When the wheat of water source 11 grew to two leaves and one heart, the exogenous DNA fragments prepared in Example 1 were prepared into a solution with a concentration of 200 ng / μL, and the wheat leaves were treated for 2d, 5d and 7d respectively, and then inoculated with the physiological subspecies of the stripe rust fungus CYR31 at a concentration of 5 mg / mL (5 mg of wheat stripe rust summer spores were mixed with 1 mL of electronic fluoride solution to form a spore suspension), and the phenotype of the wheat of water source 11 in each treatment group was observed. Sterile water was used to replace the exogenous DNA fragment solution, and the other experimental conditions were the same as the blank control (CK).

[0042] In addition, the wheat from water source 11 was treated with exogenous DNA fragment solutions at concentrations of 50, 100 and 200 ng / μL for 2 days, and then inoculated with the physiological race CYR31 of stripe rust at a concentration of 5 mg / mL (5 mg of wheat stripe rust summer spores were mixed with 1 mL of electronic fluoride solution to form a spore suspension), and the phenotype of wheat from water source 11 in each treatment group was observed. Sterile water was used instead of the exogenous DNA fragment solution, and the other experimental conditions were the same as the blank control.

[0043] Figure 3 It is the phenotype of wheat leaves in Water Source 11 corresponding to different treatment times and different concentrations of exogenous DNA fragment solution. Figure 3 The left picture in the figure shows the leaf phenotypes at different treatment times; Figure 3 The right picture in the figure shows the leaf phenotypes at different concentrations. Figure 3 "CK" in the table means blank control.

[0044] Depend on Figure 3 From the left figure, we can see that the effect of exogenous DNA fragment treatment for 2 days is better; Figure 3 As shown in the right figure, after the treatment with 200ng / μL of exogenous DNA fragments, the wheat leaves did not produce spores and only showed a small amount of necrosis. This concentration has a better treatment effect. Figure 3 The results presented showed that the optimal treatment time for treating wheat leaves with exogenous DNA fragments was 2 days, and the optimal treatment concentration was 200 ng / μL.

[0045] Example 3 This example describes the histological cytological changes of the inoculated compatible stripe rust race CYR31 after treatment with exogenous DNA fragments.

[0046] The water source 11 wheat was treated with 50ng / μL exogenous DNA fragment solution for 2 days, and 200ng / μL exogenous DNA fragment solution was used for 2 days and 5 days. After that, the three treatment groups were inoculated with the physiological subspecies CYR31 of stripe rust at a concentration of 5mg / mL. Samples were taken 1d and 2d after inoculation, and the samples were stained with DAB (for determining the production of wheat reactive oxygen species) and trypan blue (for determining cell necrosis). The treatment method of the CK group was: the water source 11 wheat was treated with clean water instead of the exogenous DNA fragment solution, and the other treatment steps were the same.

[0047] Using the same test method, samples were taken 1d, 2d, and 5d after inoculation with the compatible stripe rust physiological race CYR31, and WGA-488 staining was performed (for determining the changes in the stripe rust colonies). The treatment method of the CK group was: water was used instead of the exogenous DNA fragment solution to treat the water source 11 wheat, and the other treatment steps were the same. The results of DAB staining, trypan blue staining, and WGA-488 staining were observed and recorded, and the production of active oxygen in wheat, cell necrosis, and changes in the stripe rust colonies after different treatment times were compared, preliminarily clarifying the manifestation of exogenous DNA fragment-induced resistance at the tissue cell level.

[0048] Figure 4 The following are the DAB staining results of the three treatment groups 1 day and 2 days after inoculation with stripe rust race CYR31. SV stands for substomatal capsule, and the scale bars for 1 day and 2 days are 10 μm and 20 μm, respectively. Figure 4 It can be seen that after being treated with 200 ng / μL of exogenous DNA fragments for 2 days, the area of ​​active oxygen produced by wheat plants against stripe rust was significantly larger than that of the control.

[0049] Figure 5 The results of trypan blue staining of the three treatment groups 1d and 2d after inoculation with stripe rust race CYR31. SV stands for substomatal sac, and the scale bars for 1d and 2d are 10μm and 20μm, respectively. Figure 5 It can be seen that after being treated with 200 ng / μL of exogenous DNA fragments for 2 days, the necrotic area of ​​wheat plants resistant to stripe rust was significantly larger than that of the control.

[0050] Figure 6 The WGA-488 staining results are shown in Figure 1, 2, and 5 days after inoculation with the stripe rust race CYR31. SV stands for substomatal vesicle, HMC stands for haustorium mother cell, and IH stands for infected hyphae. The scale bars for 1, 2, and 5 days are 10 μm, 10 μm, and 50 μm, respectively. Figure 6 It can be seen that after 2 days of treatment with 200 ng / μL of exogenous DNA fragments, the growth of stripe rust in wheat plants was significantly inhibited, and the colony area was also significantly reduced. Figures 4 to 6 The results presented show that after treatment with exogenous DNA fragments, wheat plants had a significant inhibitory effect on the occurrence and development of stripe rust.

[0051] Example 4 This example describes the changes in biomass of stripe rust in leaf tissues of Shuiyuan 11 wheat leaves treated with exogenous DNA fragments at different concentrations for 2 days and inoculated with the compatible stripe rust physiological race CYR31.

[0052] The exogenous DNA fragments were prepared into solutions with concentrations of 50 ng / μL, 100 ng / μL and 200 ng / μL, respectively, and treated the water source 11 wheat for 2 days. Sterile water was used to replace the exogenous DNA fragment solution, and the other experimental conditions were the same as the blank control. After the treatment, the physiological race CYR31 of the stripe rust fungus was inoculated at a concentration of 5 mg / mL (5 mg of wheat stripe rust summer spores were mixed with 1 mL of electronic fluoride solution to form a spore suspension). Samples were taken 8 days and 12 days after inoculation for biomass detection, and the biomass ratio was calculated.

[0053] Biomass determination method: using stripe rust gene PcqI and wheat genes T E They represent the biomass of the two respectively, and the corresponding biomass is calculated according to the standard curve through the amplification cycle value of fluorescent quantitative PCR.

[0054] Figure 7 It is the biomass ratio (Pst / Wheat) of different treatment groups 8d and 12d after inoculation with the physiological race CYR31 of stripe rust. Figure 7 In the figure, CK represents blank control; "50", "100" and "200" represent the concentrations of exogenous DNA fragments, respectively; error bars represent standard errors: "*" represents p < 0.05, "**" represents p < 0.01, and ns represents not significant.

[0055] Depend on Figure 7 It can be seen that after treatment with 200ng / μL of exogenous DNA fragments, the growth of stripe rust in wheat plants was significantly inhibited and the biomass decreased; and after treatment with 50ng / μL and 100ng / μL of exogenous DNA fragments, the biomass also showed a downward trend compared with CK. This result shows that treatment with 200ng / μL of exogenous DNA fragments for 2 days can achieve good control effect.

[0056] Example 5 This example describes a field experiment on the effect of exogenous DNA fragments on preventing diseases and increasing yield of wheat.

[0057] Based on the indoor experiment, 8 groups were set up in the field, with 3 replicates in each group, a total of 24 plots, each plot was 2m×2m in size. Groups 1, 2, and 3 were compared with Group 4 with clean water; Groups 5, 6, and 7 were compared with Group 8 with clean water.

[0058] Treatment methods for 8 groups: Group 1: After being treated with exogenous DNA fragments for 7 days, the cells were inoculated with the compatible stripe rust race CYR31.

[0059] Group 2: The exogenous DNA fragments were mixed with tebuconazole, and after treatment for 7 days, the compatible stripe rust physiological race CYR31 was inoculated.

[0060] Group 3: After being treated with tebuconazole for 7 days, the plants were inoculated with the compatible stripe rust race CYR31.

[0061] Group 4: After being treated with clean water for 7 days, the plants were inoculated with the compatible stripe rust race CYR31.

[0062] Group 5: After being treated with exogenous DNA fragments for 2 days, the cells were inoculated with the compatible stripe rust race CYR31.

[0063] Group 6: The exogenous DNA fragments were mixed with tebuconazole, treated for 2 days, and then inoculated with the compatible stripe rust physiological race CYR31.

[0064] Group 7: After being treated with tebuconazole for 2 days, the plants were inoculated with the physiological race CYR31 of stripe rust.

[0065] Group 8: After being treated with clean water for 2 days, the plants were inoculated with the compatible stripe rust race CYR31.

[0066] 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, use 10mL of tebuconazole with a concentration of 43%, add 45kg of water, and the dosage is 45kg / acre. The concentration of the inoculated affinity stripe rust physiological race CYR31 is 5mg / mL (5mg of wheat stripe rust summer spores are mixed with 1mL of electronic fluoride liquid to form a spore suspension). The plant phenotype, the proportion of disease level, and the ear length, number of grains per ear, number of units per ear, and thousand-grain weight of each group were counted. The classification of disease levels refers to the NY / T 1443.1-2007 standard.

[0067] Figure 8 The disease phenotypes of different treatment groups are statistically analyzed in the field. Figure 8 It can be seen that, in general, there is no significant difference between the phenotypes of the treatment for 7 days (groups 1 to 3) and the treatment for 2 days (groups 5 to 7), indicating that the treatment with exogenous DNA fragments, the mixed treatment with exogenous DNA fragments and tebuconazole, and the treatment with tebuconazole all produced persistent stripe rust resistance in wheat plants. In addition, the disease incidence of the treatment with exogenous DNA fragments for 7 days was lighter than that of the treatment with clean water for 7 days, and that of the treatment with exogenous DNA fragments for 2 days was lighter than that of the treatment with clean water for 2 days, indicating that the exogenous DNA fragments produced significant resistance to stripe rust. It is worth noting that the mixed treatment with exogenous DNA fragments and tebuconazole and the tebuconazole treatment had significant protective effects under the conditions of treatment for 7 days and treatment for 2 days, significantly inhibiting the growth of stripe rust and significantly reducing spore production, indicating that in practical applications, the exogenous DNA fragments can be considered to be used in combination with tebuconazole.

[0068] Fig. 9 The percentage distribution of different disease levels of groups 1 to 8 in this example on the 15th day after inoculation with stripe rust. Fig. 9It can be seen that under the treatment of 7 days, the disease incidence of the mixed treatment of exogenous DNA fragments and tebuconazole and the tebuconazole treatment was lighter than that of the exogenous DNA fragment treatment; under the treatment of 2 days, the disease incidence of the mixed treatment of exogenous DNA fragments and tebuconazole and the tebuconazole treatment was lighter than that of the exogenous DNA fragment treatment, indicating that the mixed treatment of exogenous DNA fragments and tebuconazole was better than that of the exogenous DNA fragment treatment alone. At the same time, under the treatment of 7 days and 2 days, the disease incidence of the exogenous DNA fragments was lighter than that of the clean water treatment, indicating that after the treatment of exogenous DNA fragments, the resistance of wheat to stripe rust was improved.

[0069] Fig.10 The percentage distribution of different disease levels on the 23rd day after the stripe rust was inoculated in Groups 1 to 8 of this Example. Fig.11 The percentage distribution of different disease levels in groups 1 to 8 of this example on the 31st day after inoculation with stripe rust. Fig.10 , 11 It can be seen that the disease incidence of wheat treated with exogenous DNA fragments for 7 days was lighter than that of wheat treated with clean water for 7 days, and that of wheat treated with exogenous DNA fragments for 2 days was lighter than that of wheat treated with clean water for 2 days, indicating that wheat resistance to stripe rust was more persistent after treatment with exogenous DNA fragments than that of wheat treated with clean water. Fig.10 , 11 It can be seen that the disease incidence rate when the mixed treatment of exogenous DNA fragments and tebuconazole for 7 days is lighter than that when the exogenous DNA fragments are used for 7 days, and the disease incidence rate when the mixed treatment of exogenous DNA fragments and tebuconazole for 2 days is lighter than that when the exogenous DNA fragments are used for 2 days, indicating that the mixed treatment of exogenous DNA fragments and tebuconazole is more effective than the treatment with exogenous DNA fragments alone. In the future, it can be considered to prepare the two into a composite preparation for use, which is consistent with the above conclusion.

[0070] Fig.12 , Fig.13 , Fig.14 , Fig.15 The statistical results of wheat ear length, number of grains per ear, number of ears per unit and thousand-grain weight after harvest in different treatment groups are shown. The blank control is marked as a, and those with significant difference compared with a are marked as b, and those without significant difference are marked as a. Similarly, those with significant difference compared with b are marked as c, and those without significant difference are marked as b. If the difference is between a and b, it is marked as ab. Figures 12 to 15 It can be seen that compared with the clean water treatment (blank control), the wheat ear length, number of grains per ear, number of ears per unit and thousand-grain weight were improved after treatment with exogenous DNA fragments, indicating that the exogenous DNA fragments can not only play a role in resisting stripe rust, but also do not affect the agronomic traits of wheat.

[0071] In summary, the present invention uses exogenous DNA fragments to treat wheat leaves, conducts research on inducing wheat immunity to stripe rust, analyzes the mechanism of action of exogenous DNA fragments in regulating wheat disease resistance, and verifies that treatment with exogenous DNA fragments can induce wheat to produce resistance to stripe rust and inhibit the growth of stripe rust. It is a green and safe measure for the prevention and control of wheat stripe rust, and provides new ways and solutions for the long-term control of wheat stripe rust, improving wheat yield and economic benefits, etc.

[0072] The embodiments described above are only some embodiments of the present invention, not all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. All other embodiments obtained without creative work and related deductions and substitutions made by ordinary technicians in the field under the conditions of the concept of the present invention belong to the scope of protection of the present invention.

Claims

1. The application of exogenous DNA fragments in improving disease resistance of wheat, characterized in that: The exogenous DNA fragments are extracted from wheat leaves; the size of the exogenous DNA fragments is 500-3000 bp.

2. The use according to claim 1, characterized in that: The method for preparing the exogenous DNA fragments is as follows: extracting wheat leaf DNA, breaking the wheat leaf DNA into DNA fragments of 500-3000 bp by ultrasonic breaking method, and diluting them for use.

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

4. The use according to claim 2, characterized in that: The ultrasonic crushing conditions were as follows: power 24 W, ultrasound on for 3 s, off for 5 s, and ultrasonic crushing time of 30 s.

5. 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; and the size of the exogenous DNA fragments is 500-3000 bp.

6. The method according to claim 5, characterized in that The method for preparing the exogenous DNA fragments is as follows: extracting wheat leaf DNA, breaking the wheat leaf DNA into DNA fragments of 500-3000 bp by ultrasonic breaking method, and diluting them for use.

7. The method according to claim 6, characterized in that The exogenous DNA fragments were used at a concentration of 200 ng / μL and the treatment time was 2 days.

8. The method according to claim 6, characterized in that The conditions of ultrasonic crushing are: power 24W, ultrasound on for 3s, off for 5s, and ultrasonic crushing time is 30s.

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