Molecular marker related to leukoderma resistance on corn chromosome 2 and application of molecular marker

Abstract

The invention belongs to the technical field of molecular marker assisted breeding, and particularly discloses a molecular marker related to white spot resistance on corn chromosome 2 and application, and provides a molecular marker gene related to corn white spot resistance, and the gene sequence is shown as SEQ ID NO: 1 and / or SEQ ID NO: 2. According to the present invention, the molecular marker is commonly localized to SNP: 2-212792117 and the downstream gene Zm00001eb107230 on the corn chromosome 2, the SNP can be localized in a plurality of different environments, 20.39% of phenotypic variation can be explained, and the related candidate functional gene mainly codes the Remorin family protein, has been proved to be related to corn resistance, and can be used as the corn leukoderma resistance molecular marker;

Description

Technical Field

[0001] The invention belongs to the technical field of molecular marker-assisted breeding, and specifically relates to an application of a molecular marker site SNP: 2-212792117 related to white spot disease resistance on corn chromosome 2 and a candidate functional gene Zm00001eb107230 associated therewith in improving corn white spot disease resistance. Background Art

[0002] As one of the important food crops, corn (Zea mays L.) directly affects the world's food security and the development of animal husbandry. In recent years, corn white spot disease caused by Pantoea ananatis is a leaf disease that seriously affects corn production. The disease was first reported in India in 1965 and was prevalent in Brazil and the United States from the 1980s to the 1990s. According to reports, severe white spot disease can cause a more than 60% reduction in corn production in Brazil. Since mid-July 2020, white spot disease has broken out in the southwestern corn ecological zone of my country, especially in Yunnan, resulting in a large-scale reduction in corn production in some areas, with losses of 10% to 50%, seriously endangering corn production and causing a sharp drop in farmers' income. Since 2023, the disease has spread to the main corn producing areas in the north and has now become a national corn disease. In the early stage of corn white spot disease, lesions appear on the leaves at the base, and then quickly spread to the upper part of the plant. In the later stages of the disease, a chlorotic appearance appears, which affects the plant carbon cycle and photosynthesis. If some leaves are infected before the corn filling stage, the net photosynthetic rate can drop sharply by 40%, which will cause the reproductive maturity stage to end prematurely, and ultimately lead to deformed corn ears and low seed yield, seriously reducing the yield and quality of corn.

[0003] At present, the prevention and control of white spot disease mainly focuses on measures such as optimizing field farming systems and the use of agricultural chemicals. Studies in recent years have shown that white spot disease resistance depends largely on its genetic factors. Therefore, breeding genetically resistant white spot disease varieties is the most economical and effective way to control the disease. However, since white spot disease is a newly outbreak corn disease in my country, the functional genes related to white spot disease resistance have not yet been cloned. Summary of the invention

[0004] The main purpose of the present invention is to provide a molecular marker related to white spot disease resistance on corn chromosome 2 and its application, so as to provide a new method for breeding new corn varieties resistant to white spot disease using modern molecular breeding technology.

[0005] The present invention specifically provides the following technical solutions:

[0006] On the one hand, the present invention provides a molecular marker related to corn white spot resistance, and the molecular marker gene sequence is shown in SEQ ID NO:1 and / or SEQ ID NO:2; as shown in SEQ ID NO:1, the sequence presents A / T polymorphism at the 201st base from the 5′ end; as shown in SEQ ID NO:2, the sequence corresponds to the corn Chr2:212799375-212800757 sequence, and the bases at the 212800221, 212800219 or 212800217 positions from the 5′ end present C / G, A / G, C / G polymorphism.

[0007] On the other hand, the molecular markers associated with corn white spot resistance of the present invention are characterized in that the molecular markers are SNP sites, including at least one of the sites 212792117, 212800397, 212800429, 212800459, 212800221, 212800219 or 212800217 located on chromosome 2 of corn, and the reference genome version where the SNP sites are located is Zm-B73-REFERENCE-NAM-5.0.

[0008] Furthermore, the present invention provides any of the following applications of the molecular marker:

[0009] a) Genetic diversity analysis of maize resistant to white spot disease; b) Construction of molecular genetic map of maize resistant to white spot disease; c) Whole genome association analysis of maize resistant to white spot disease; d) Identification of maize varieties resistant to white spot disease; e) Molecular marker-assisted selection breeding of maize resistant to white spot disease; f) Whole genome selection breeding of maize resistant to white spot disease.

[0010] In another aspect, the present invention provides a product for detecting the molecular marker, the product comprising a reagent, a kit or a gene chip, and the product detects the genotype of the molecular marker. In some embodiments, the gene chip comprises a liquid chip or a solid chip; in some more specific embodiments, the kit comprises a nucleic acid extraction and purification reagent: used to extract DNA from a sample, such as a lysis solution, a deproteinization solution, a rinse solution, etc.; a PCR reaction reagent: including primers, probes, dNTPs (deoxynucleotide triphosphates), DNA polymerase, etc. for amplifying a specific gene; a fluorescently labeled probe: in fluorescent PCR technology, a fluorescently labeled probe used for real-time detection of gene mutations, etc.

[0011] On the other hand, the present invention provides products for detecting the molecular markers, including products prepared by PCR, qPCR, Sanger sequencing, high-throughput sequencing, fluorescence in situ hybridization, TaqMan probe method, ARMS-PCR method or KASP method, and the products detect the genotype of the molecular markers.

[0012] Furthermore, the present invention provides any of the following applications of the product:

[0013] a) Genetic diversity analysis of white spot disease resistant maize; b) Construction of molecular genetic map of white spot disease resistant maize; c) Whole genome association analysis of white spot disease resistant maize; d) Identification or auxiliary identification of white spot disease resistant maize varieties; e) Molecular marker-assisted selection breeding of white spot disease resistant maize; f) Whole genome selection breeding of white spot disease resistant maize.

[0014] On the other hand, the present invention provides a method for screening corn with resistance to white spot disease. A corn sample to be tested is taken, and the gene sequence shown in SEQ ID NO:1 is detected. If the base at the 201bp position from the 5′ end of the sequence shown in SEQ ID NO:1 is T, it is judged to be a corn variety with resistance to white spot disease.

[0015] On the other hand, the present invention provides a method for screening corn with resistance to white spot disease. A corn sample to be tested is taken, and the gene sequence shown in SEQ ID NO:2 is detected. If the sequence shown in SEQ ID NO:2 corresponds to the corn Chr2:212799375-212800757 sequence, and the bases at positions 212800221, 212800219 or 212800217 from the 5′ end are all G, it is judged to be a corn variety with resistance to white spot disease.

[0016] On the other hand, the present invention provides a method for screening corn with white spot disease resistance, taking a corn sample to be tested, detecting SNP sites, the SNP sites include at least one of 212792117, 212800397, 212800429, 212800459, 212800221, 12800219 or 212800217 sites on corn chromosome 2, the reference genome version of the SNP site is Zm-B73-REFERENCE-NAM-5.0, and when the bases of the SNP site are T, A, G, T, G, G and G, respectively, the corn variety is judged to have white spot disease resistance. In some embodiments, the SNP sites provided by the present invention are used to prepare a liquid gene chip, and multiple site detections are performed by high-throughput genotype detection technology to identify or assist in identifying corn white spot disease resistance.

[0017] The present invention verifies through research that SNP: 2-212792117 of corn chromosome 2 (i.e., the 201 bp position from the 5′ end of the sequence shown in SEQ ID NO: 1) and its downstream gene Zm00001eb107230 (SEQ ID NO: 2) have strong resistance to corn white spot disease. Corn white spot disease resistance is a quantitative trait regulated by multiple genes. The technical scheme provided by the present invention provides a new method for breeding new corn varieties resistant to white spot disease by using modern molecular breeding technology, so as to assist in improving corn white spot disease resistance, avoid complicated and time-consuming resistance screening process, shorten the breeding period, and improve the efficiency of molecular breeding of corn resistance to white spot disease. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Leaf images of corn with different grades of white spot disease; HR: highly resistant to white spot disease, R: resistant to white spot disease, M: moderately resistant to white spot disease, S: sensitive to white spot disease, HS: highly susceptible to white spot disease.

[0019] Figure 2 .Correlation heat map of white spot disease resistance in six populations; describes the correlation of the overall performance of the six RIL populations under different environments. The narrower the circle and the redder the color, the stronger the correlation.

[0020] Figure 3 .SNP density plot and LD decay plot; (a) Chromosome-specific SNP density within 1 Mb interval, the ordinate represents the chromosome, the abscissa represents the position on each chromosome, the redder the corresponding position, the more variant sites there are; (b) The whole genome LD decay (r2) of all chromosomes in 941 maize RILs changes with physical distance (Kb).

[0021] Figure 4 .Population structure diagram; different colors indicate different subpopulations: yellow: YML32×Ye107 (pop1); purple: YML418×Ye107 (pop2); green: CML171×Ye107 (pop3); blue: TML139×Ye107 (pop4); brown: CML226×Ye107 (pop5); orange: NK40-1×Ye107 (pop6).

[0022] Figure 5 .Manhattan plot and QQ plot; Manhattan plot (left) and QQ plot (right) of YS21(a), YS22(b), YS23(c), and BLUP(d) show SNPs associated with MWS resistance. Each point in the left figure represents a SNP, the black line represents the threshold of <1×10-5, and different colors represent different chromosomes. The red line in the right figure is the trend line that the ideal QQ plot should correspond to in each case.

[0023] Figure 6.Identification diagram of the candidate gene Zm00001eb107230 for white spot disease resistance; (a) Candidate gene LD block; (b) Schematic diagram of the mutation sites that form different haplotypes in the Zm00001eb107230 gene; (c) Overall differences in the levels of MWS resistance among the five haplotypes, * indicates p<0.05, **** indicates p<0.0001; (d) Relative positions of Zm00001eb107230 and SNP, as well as base variations and amino acid variations in the resistant parent TML139. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of 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.

[0025] The invention is based on genome-wide association analysis, uses tropical maize inbred lines (YML32, TRL418, CML171, TML139, YML226, NK40-1) as resistant parents, hybridizes with temperate susceptible excellent inbred line Ye107, and selects 6 F9 recombinant inbred lines (RILs) after 9 consecutive generations of single-grain self-pollination. These RILs were planted in Yanshan County, Yunnan Province for three consecutive years to carry out phenotypic identification of white spot disease resistance. Combined with high-quality SNPs of the RIL population, GWAS analysis identified SNPs that were consistently significantly associated with maize white spot disease resistance in multiple environments: 2-212792117 molecular markers and functional genes Zm00001eb107230, and molecular breeding can be used to apply the resistance gene to maize white spot disease resistance breeding in the future.

[0026] The utility of the molecular markers provided by the present invention is fully explained through the following examples:

[0027] Example 1

[0028] 1. Experimental Materials and Design

[0029] The present invention selects six tropical maize inbred lines (YML32, TRL418, CML171, TML139, YML226, NK40-1) resistant to white spot disease and with wide genetic variation as female parents, and uses the excellent temperate maize inbred line Ye107 susceptible to white spot disease as a common parent for hybridization (the pedigree, heterotic group, ecological group and related resistance level of the seven parents are shown in Table 1), and self-pollinates for nine consecutive generations through the single seed transmission method to produce six recombinant inbred line (RIL) populations: pop1 (YML32×Ye107), pop2 (TRL418×Ye107), and pop3 (TRL418×Ye107). 07), pop3 (CML171×Ye107), pop4 (TML139×Ye107), pop5 (YML226×Ye107) and pop6 (NK40-1×Ye107). Initially, each population contained 200 recombinant inbred (RIL) lines, but due to environmental selection, inbreeding depression and other factors, only 904 RIL lines were finally available for this study (pop1: 145; pop2: 141; pop3: 147; pop4: 160; pop5: 152; pop6: 159). These RIL lines were planted in Yanshan County, Yunnan Province (23°19'-23°59'N, 103°35'-104°45'E) in 2021, 2022, and 2023. The experiment was designed with a completely randomized block design, with 14 plants per row, 4 m row length, and 25 cm plant spacing, and was conducted according to standard farmland management.

[0030] Table 1. Pedigrees, ecotypes and white spot resistance of the seven parents used in the experiment

[0031]

[0032] 2. Disease grade score

[0033] The white spot disease resistance phenotype of RILs from a multi-parent population was evaluated in Yanshan County, Yunnan Province, China in 2021, 2022, and 2023. Maize white spot disease outbreaks occur from early August to late September each year, when maize is in the grain filling to maturity stage, which is suitable for resistance assessment. The disease severity grading of white spot disease follows the symptom recognition criteria outlined in the Maize Disease and Pest Manual, and the average disease severity of a single plot is evaluated on a scale of 1 to 9, such as Figure 1 , as shown in Table 2.

[0034] Table 2. Classification standards for corn white spot disease

[0035]

[0036]

[0037] 3. Phenotypic Identification and Statistical Analysis

[0038] Descriptive analyses of phenotypic data were performed using SPSS (SPSS Statistics) and ORIGIN (Origin 2022) software. Mean, minimum, maximum, standard deviation (SD), coefficient of variation (CV), skewness, and kurtosis were calculated. Frequency distribution of phenotypic data was performed using SPSS software. Kurtosis and skewness were used to assess the normality of the frequency distribution. Broad-sense heritability was calculated following the method outlined by Knapp et al.

[0039] 4. Whole-genome resequencing

[0040] DNA was extracted from maize seedling leaves using a modified CTAB method and subjected to whole-genome resequencing. DNA libraries were prepared according to standard procedures and sequenced using Illumina Hi Seq TM The filtered reads were then aligned to the maize reference genome B73_RefGen_v5 (full name: Zm-B73-REFERENCE-NAM-5.0) to identify SNP markers, which were annotated using SNPeff software.

[0041] 5. Population structure analysis and LD decay

[0042] The distance matrix was calculated using TreeBeST (version: Treebest-1.9.2) software, and the phylogenetic tree was constructed based on this distance matrix using the neighbor-joining method (NJ). To ensure accuracy, the bootstrap values ​​were calculated up to 1000 times. PCA analysis was performed using GCTA. After obtaining the PCA results, the values ​​of the first two PCs were used to display the samples involved in the analysis in two dimensions. PopLDdecay software was used to calculate the degree of linkage disequilibrium (r 2 ) and used the software's own script Plot_OnePop.pl to plot LD decay.

[0043] 6. Genome-wide association analysis

[0044] A genome-wide association analysis was performed using GEMMA software (http: / / www.xzlab.org / software.html) based on 6,390,967 high-quality SNP analyses. The analysis used a mixed linear model (MLM) for GWAS for phenotypes and best linear unbiased estimates (BLUPs) for all environments. A significance threshold of -log10(p)>5 was used to identify significant SNPs associated with corn white spot resistance, and bedtools v1.7 was used to extract SNP sites that met or exceeded the threshold. Based on the B73_RefGen_v5 reference genome and annotation information, candidate genes associated with corn white spot resistance were screened within a 50 kb interval upstream and downstream of the significant SNPs.

[0045] 7. Epistasis analysis of resistance-related SNP loci

[0046] PLINK software was used for linear model regression analysis, and the formula was y=u+gi+gj+gigj, where y represented the white spot disease resistance score, gi and gj represented the main effects associated with marker i and marker j, respectively, and gigj represented the interaction effect between marker i and marker j alleles, respectively. Significant epistasis results were obtained at p<0.05.

[0047] 8 Candidate gene analysis

[0048] Haploview v4.2 software was used to perform haplotype analysis of candidate genes. The corresponding gene sequences were extracted from the reference genome B73_RefGen_v5 according to the candidate gene IDs and compared with the parent with the strongest resistance, TML139. The corresponding coding regions and amino acid variation information were extracted, and the functional gene motifs were predicted using MEME online software (https: / / meme-suite.org / meme / tools / meme).

[0049] (II) Experimental results

[0050] 1. Phenotypic Data Analysis

[0051] The white spot disease resistance phenotypic data of six RIL groups in Yanshan were collected for three years, and descriptive statistical analysis was performed (Table 3). The results showed that the coefficient of variation of the six RIL groups in Yanshan was between 0.25-0.79, indicating that there were differences between the samples. At the same time, the average disease level of white spot disease in plants of the six RIL groups was between 2.90-5.81, and the absolute values ​​of the skewness and kurtosis coefficients of the six groups in three years were close to 1, indicating that the white spot disease resistance phenotypes of the test groups in the three-year resistance identification were in line with the normal distribution and met the quantitative trait characteristics. Further analysis showed that the heritability of the severity of white spot disease of each RIL group ranged from 76.47-98.79%, and there was a strong correlation (0.46-0.98) in the resistance phenotypes of the same group under different environments (Table 3, Figure 2 ), indicating that the RIL lines have strong consistency in resistance to white spot disease in different environments. The phenotypic identification results show that corn white spot disease resistance has a high heritability and corn white spot disease resistance is mainly determined by genes.

[0052] Table 3. Descriptive statistics of six RIL subpopulations for resistance to white spot disease

[0053]

[0054]

[0055] Note: MWS phenotypic statistical analysis of 6 RIL populations in 2021, 2022 and 2023. 21YS, 22YS and 23YS represent the experiments conducted in Yanshan in 2021, 2022 and 2023, respectively.

[0056] 2SNP density and LD decay

[0057] Through whole genome resequencing, a total of 6,390,967 high-quality SNPs were identified in the whole genome. These SNPs were evenly distributed on the 10 chromosomes of maize ( Figure 3 a) The numbers of SNPs identified on chromosomes 1 to 10 are as follows: 1,354,402, 699,661, 716,354, 880,880, 668,865, 485,243, 563,392, 545,220, 472,482, and 462,679. The highest number of SNPs was on chromosome 1, and the lowest was on chromosome 10. The 6,390,967 SNPs identified were used to assess linkage disequilibrium (LD) decay in the association mapping population. Figure 3 As shown in b, when r 2 When the decline rate tends to be flat, the physical distance is about 50kb. Therefore, we selected the 50kb range upstream and downstream of the significant SNP site as the standard for screening candidate genes.

[0058] 3. Group structure analysis

[0059] We used TreeBeST to analyze the population phylogenetic tree and divided the 941 RIL lines into 6 subgroups. We then used GCTA to perform principal component analysis (PCA), and also divided the 941 RIL lines into 6 subgroups, which were consistent with the 6 RIL populations we assembled. Some mixed or overlapping families appeared in the figure, which may be due to the common parent Ye107 in the 6 subgroups and the gene introgression during the breeding process ( Figure 4 ac). Therefore, the possibility that population structure may lead to false positives in GWAS needs to be considered in subsequent analyses.

[0060] 4. Genome-wide association analysis

[0061] We used GEMMA (http: / / www.xzlab.org / software.html) software to conduct GWAS analysis on the white spot disease resistance phenotype data of 941 RIL lines in the multi-parent population in Yanshan for three years and 6390967 high-quality SNPs obtained by whole genome resequencing, and used mixed linear model (MLM) to correct for both population structure and individual kinship, and identified a total of 679 SNPs. Among them, 109 significant SNPs were identified in the GWAS analysis of 21YS ( Figure 5 b), explained 0.06%-7.17% of the phenotypic variance; in the GWAS analysis of 22YS, 183 significant SNPs were identified ( Figure 5 c), explaining 0.18%-6.76% of the phenotypic variance; in the GWAS analysis of 23YS, 204 significant SNPs were identified ( Figure 5 d), explaining 0.19%-7.41% of the phenotypic variance; in the GWAS analysis of BLUP, 183 significant SNPs were identified ( Figure 5 a), explaining 0.27%-7.24% of the phenotypic variance. These significant SNPs are distributed on all 10 chromosomes of maize.

[0062] Since artificial populations may cause false positives in GWAS analysis results, multiple results in multiple environments are needed to cross-validate SNPs. By comparing the three-year GWAS analysis results of Yanshan (YS), multiple consistent and significant SNPs that co-localize in all environments were identified. Epistasis analysis was performed on the co-localized SNP sites, and the results showed that SNP: 2-212792117 and SNP: 8-149695036 showed the most significant epistatic interaction, with a STAT value of 9.066, indicating that epistasis has a greater impact on resistance to corn white spot disease.

[0063] 5. Candidate gene mining

[0064] In this study, the B73_RefGen_v5 reference genome was used to screen the 50Kb region upstream and downstream of the significant locus SNP: 2-212792117 with consistency and high effect value in multiple environments, and the candidate genes were annotated and functionally predicted using databases such as MaizeGDB, InterPro, UniProt and NCBI. Finally, the candidate functional gene Zm00001eb107230 (Chr2: 212799375-212800757, NCBI gene ID: 100192691) for white spot disease resistance located on chromosome 2 was screened out using SNP: 2-212792117. SNP: 2-212792117 and Zm00001eb107230 were co-located in 21YS, 22YS, 23YS, and BLUP, and the SNP explained a total of 20.39% of the phenotypic variation. Epistasis analysis showed that this SNP had a significant epistatic effect with SNP:8-149695036 on chromosome 8, and its epistatic effect was significantly associated with white spot disease resistance. The candidate functional gene Zm00001eb107230 associated with SNP:2-212792117 is located 7790bp downstream of SNP:2-212792117 and mainly encodes Remorin family proteins. Remorin protein is a plant-specific oligomeric filamentous protein family that is connected to the plasma membrane / membrane raft and localized in the membrane microdomain. It participates in the regulation of plant metabolism, cell cycle and growth and development, hormone signaling and pathogen perception, and as a new member of the signal transduction cascade, it participates in plant innate immune signal transduction.

[0065] 6. Candidate Gene Analysis

[0066] In order to clarify whether the candidate functional gene Zm00001eb107230 is related to the resistance to corn white spot disease, Zm00001eb107230 was analyzed and it was found that the Zm00001eb107230 gene was mutated at bases 212800397, 212800429 and 212800459 on chromosome 2 of corn ( Figure 6 a, 6b), showing five major haplotypes (CAT, AGT, CGG, AGG and CGT) in the test population, among which the plants with haplotype AGT showed better resistance to corn white spot disease ( Figure 6c). By comparing the sequence of the gene in the resistant material TML139, three specific C / G, A / G, and C / G mutations were found in the 212800221, 212800219, and 212800217 positions of the Zm00001eb107230 gene of TML139, which resulted in the corresponding amino acid sequence of the resistant material TML139 changing from alanine to asparagine and from glycine to glutamic acid, respectively ( Figure 6 d).

[0067] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A molecular marker associated with corn white spot disease resistance, characterized in that: The molecular marker gene sequence is shown in SEQ ID NO:1 and / or SEQ ID NO:2; as shown in SEQ ID NO:1, the sequence presents A / T polymorphism at the 201st base from the 5′ end; as shown in SEQ ID NO:2, the sequence corresponds to the corn Chr2:212799375-212800757 sequence, and the bases at the 212800221, 212800219 or 212800217 positions from the 5′ end present C / G, A / G, C / G polymorphism.

2. A molecular marker associated with corn white spot disease resistance, characterized in that: The molecular markers are SNP sites, including at least one of the sites 212792117, 212800397, 212800429, 212800459, 212800221, 212800219 or 212800217 located on chromosome 2 of corn, and the reference genome version where the SNP sites are located is Zm-B73-REFERENCE-NAM-5.

0.

3. Any of the following uses of the molecular marker according to claim 1 or 2, a) Genetic diversity analysis of maize resistant to white spot disease; b) Construction of molecular genetic map of maize resistant to white spot disease; c) Whole genome association analysis of maize resistant to white spot disease; d) Identification of maize varieties resistant to white spot disease; e) Molecular marker-assisted selection breeding of maize resistant to white spot disease; f) Whole genome selection breeding of maize resistant to white spot disease.

4. A method for detecting a product labeled with a molecule according to claim 1 or 2, characterized in that: The product includes a reagent, a kit or a gene chip, and the product detects the genotype of the molecular marker.

5. A method for detecting a product of a molecular marker according to claim 1 or claim 2, characterized in that: The products include products prepared by PCR, qPCR, Sanger sequencing, high-throughput sequencing, fluorescent in situ hybridization, TaqMan probe method, ARMS-PCR method or KASP method, and the products detect the genotype of the molecular marker.

6. Any of the following uses of the product according to claim 4 or 5, a) Genetic diversity analysis of white spot disease resistant maize; b) Construction of molecular genetic map of white spot disease resistant maize; c) Whole genome association analysis of white spot disease resistant maize; d) Identification or auxiliary identification of white spot disease resistant maize varieties; e) Molecular marker-assisted selection breeding of white spot disease resistant maize; f) Whole genome selection breeding of white spot disease resistant maize.

7. A method for screening corn resistant to white spot disease, characterized in that: A corn sample to be tested is taken, and the gene sequence shown in SEQ ID NO: 1 is detected. If the base at the 201 bp position from the 5′ end of the sequence shown in SEQ ID NO: 1 is T, it is judged to be a corn variety with white spot disease resistance.

8. A method for screening corn resistant to white spot disease, characterized in that: Take a corn sample to be tested and detect the gene sequence shown in SEQ ID NO:

2. If the sequence shown in SEQ ID NO: 2 corresponds to the corn Chr2: 212799375-212800757 sequence, and when the bases at positions 212800221, 212800219 or 212800217 from the 5′ end are all G, it is judged to be a corn variety with white spot disease resistance.

9. A method for screening corn resistant to white spot disease, characterized in that: Take a corn sample to be tested and detect the SNP site, wherein the SNP site includes at least one of the sites 212792117, 212800397, 212800429, 212800459, 212800221, 12800219 or 212800217 located on chromosome 2 of corn, and the reference genome version where the SNP site is located is Zm-B73-REFERENCE-NAM-5.

0. When the bases of the SNP site are T, A, G, T, G, G and G respectively, it is judged to be a corn variety with white spot resistance.

Images