Major locus of wheat grain polyphenol oxidase activity and SNP marker and application

Abstract

The present application provides a wheat grain polyphenol oxidase activity major site and SNP marker and application, the SNP molecular marker Marker149631 is located on the 3A chromosome of wheat, the nucleotide sequence of the molecular marker is as shown in SEQ ID NO.1 or SEQ ID NO.2; the SNP molecular marker Marker149773 is located on the 3A chromosome of wheat, the nucleotide sequence of the molecular marker is as shown in SEQ ID NO.3 or SEQ ID NO.4; the SNP site provided by the present application is of great significance for detecting wheat grain low PPO activity variety, strain, breeding material, and molecular markers can be developed according to it, and the efficiency of wheat quality breeding is accelerated.

Description

Technical Field

[0001] This invention belongs to the field of wheat breeding technology, specifically involving major QTL sites related to wheat grain polyphenol oxidase (PPO) activity and their SNP molecular markers and applications. Background Technology

[0002] Polyphenol oxidase (PPO) is distributed in different parts of wheat grains. In immature grains, PPO is mainly distributed in the endosperm. As wheat grains mature, the PPO activity in the outer layer and young embryo gradually increases. In mature wheat grains, PPO is mainly found in the aleurone layer, accounting for about 3% of the grain. It can explain most of the browning that occurs during flour processing and the storage of flour products and food. Therefore, the activity of PPO can affect the browning of almost all flour products (Liu Jianjun et al., 2002; Huawei, 2007). This browning causes a great loss to the sensory quality and nutritional value of wheat flour and its products (Zhang Dan, 2012). Therefore, breeding wheat varieties with low PPO activity is crucial for the improvement of flour and its products.

[0003] Genotype is the main factor affecting PPO activity. Besides genotype, many other factors influence wheat polyphenol oxidase activity. Furthermore, many quality parameters are significantly correlated with grain polyphenol oxidase activity. Previous studies have investigated PPO activity and identified several markers for detecting it, such as PPO18, PPO16, and PPO29. PPO18 is primarily used to distinguish between the PPO-A1a (high activity, 685 bp) and PPO-A1b (low activity, 876 bp) alleles on chromosome 2AL; PPO16 and PPO29 are used to distinguish between the PPO-D1a (low activity, 713 bp) and PPO-D1b (high activity, 490 bp) alleles on chromosome 2DL (Hu Fengling et al., 2012; Yang Jishu, 2014; Sun Jianxi, 2014; Wang Zhongxing, 2016; Chen Ling et al., 2017). Previous studies have also investigated the QTL mapping of PPO activity in wheat. Some studies have found a major gene related to PPO activity on chromosome 2 (Demekes, 2001; Mares, 2001; Zuo Aihui, 2012); other researchers have used protein electrophoresis of 60-62KD PPO activity in aneuploid wheat to locate a site on chromosome 2D (Lu Chengbin, 2005; Wang Zhongxing, 2016). Zhang et al. (2005) and Zhao et al. (2015) both used DH populations to find major sites of common wheat polyphenol oxidase activity in chromosome 2D. Among them, the major site (markers Xcfd168-Xbarc349.2) found by Zhao (2015) could be detected in all four environments, with a contribution rate of 11.65%-65.84%. Zhang (2005) also found another major site on chromosome 2AL, which was closely linked to the Xgwm312 marker. Although previous researchers have located some loci associated with PPO activity in wheat grains, there are very few major loci and SNP molecular markers that can be used for marker-assisted breeding to improve PPO activity. Therefore, this invention uses a RIL population constructed with Nongda Nuomai 1 (with differential PPO activity) as the female parent and Gaocheng 8901 as the male parent as the material. Combined with a high-density genetic map constructed using SLAF-Seq technology, QTL mapping analysis of wheat grain PPO activity was performed under three environments to identify major QTL loci, their SNP markers, and superior allelic variants. This provides gene resources and effective molecular markers for improving wheat grain PPO activity and has important value and significance for breeding new wheat varieties with low PPO activity. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides the major active site and SNP markers for wheat grain polyphenol oxidase activity, as well as their applications.

[0005] This invention uses Nongda Nuomai No. 1 (with differential PPO activity) as the female parent and Gaocheng 8901 as the male parent to construct a RIL population with differential PPO activity in the grains. Using SLAF-Seq technology, a high-density genetic map containing 8,095 SNP markers was constructed, with a total map length of 2,554.10 cM and linkage group lengths ranging from 90.08 to 151.67 cM. Combined with grain PPO phenotypic data, QTL mapping analysis was performed under three different environmental conditions.

[0006] Based on QTL mapping results, and through superior allele identification and phenotypic analysis of the mapping site, a stable major-effect QTL locus, Qppo3A, located on chromosome 3A controlling grain PPO activity, and its two closely linked SNP markers were identified. The major-effect locus and its linked molecular markers provide a theoretical basis for the discovery of wheat PPO activity genes and for molecular improvement in wheat quality breeding.

[0007] The technical solution of the present invention is as follows:

[0008] A SNP molecular marker, Marker149631, associated with the control of PPO activity in wheat grains, is located on chromosome 3A of wheat. The nucleotide sequence of this molecular marker is shown in SEQ ID NO.1 or SEQ ID NO.2.

[0009] The nucleotide sequence of this molecular marker is shown in Table 8: Sequence information of the active SNP site of PPO in the seed.

[0010] The physical location of the SNP molecular marker Marker149631 is 660100152 on chromosome 3A, and the base is a G / A variant.

[0011] According to a preferred embodiment of the present invention, the nucleotide sequence of the SNP molecular marker Marker 149631 is as shown in SE Q ID NO. 1, that is, wheat grains with a base type of G at this SNP site have low PPO activity.

[0012] The base variation types and phenotypic values ​​of the SNP molecular markers are shown in Table 7: Phenotypic Effects of Base Variations at SNP Sites for PPO Activity in Grains. Specifically, wheat grains with a base type of G at this position have low PPO activity.

[0013] According to a preferred embodiment of the present invention, the nucleotide sequence of the SNP molecular marker Marker 149631 is shown in SEQ ID NO. 1, that is, the base type of the SNP site is G, and the genotype of the SNP molecular marker is GG; the nucleotide sequence of the SNP molecular marker Marker 149631 is shown in SEQ ID NO. 2, that is, the base type of the SNP site is A, and the genotype of the SNP molecular marker is AA; the wheat grain PPO activity of individuals with the SNP molecular marker GG genotype is lower than that of individuals with the AA genotype.

[0014] The base variation types and phenotypic values ​​of the SNP molecular markers are shown in Table 7: Phenotypic Effects of Base Variations at SNP Sites for PPO Activity in Wheat Grains. That is, after the base variation occurs, the genotype of the sample containing the SNP molecular marker is AA, and the wheat grain PPO activity of individuals with the GG genotype of the SNP molecular marker is lower than that of individuals with the AA genotype.

[0015] A SNP molecular marker, Marker149773, associated with the control of PPO activity in wheat grains, is located on chromosome 3A of wheat. The nucleotide sequence of this molecular marker is shown in SEQ ID NO.3 or SEQ ID NO.4.

[0016] The nucleotide sequence of this molecular marker is shown in Table 8: wheat grain PPO activity SNP site sequence information.

[0017] The physical location of the SNP molecular marker Marker149773 is 661400025 on chromosome 3A, and the base is a C / T variation.

[0018] According to a preferred embodiment of the present invention, the nucleotide sequence of the SNP molecular marker Marker 149773 is as shown in SE Q ID NO. 4, that is, wheat grains with a base type of T at this SNP site have low PPO activity.

[0019] The base variation types and phenotypic values ​​of the SNP molecular markers are shown in Table 7: Phenotypic Effects of Base Variations at SNP Sites for PPO Activity in Wheat Grains. Specifically, wheat grains with a base type of T at this position have low PPO activity.

[0020] According to a preferred embodiment of the present invention, the nucleotide sequence of the SNP molecular marker Marker 149773 is shown in SEQ ID NO. 4, that is, the base type of the SNP site is T, and the genotype of the SNP molecular marker is TT; the nucleotide sequence of the SNP molecular marker Marker 149773 is shown in SEQ ID NO. 3, that is, the base type of the SNP site is C, and the genotype of the SNP molecular marker is CC; the wheat grain PPO activity of individuals with the SNP molecular marker TT genotype is lower than that of individuals with the CC genotype.

[0021] The base variation type and phenotypic value of the SNP molecular marker are shown in Table 7: Phenotypic effect of base variation of SNP site for PPO activity in wheat grains. That is, after the base variation occurs, the genotype of the sample where the SNP molecular marker is located is TT type, and the PPO activity of wheat grains of individuals with the SNP molecular marker TT genotype is lower than that of individuals with the CC genotype.

[0022] The use of SNP molecular markers in the breeding of wheat varieties or lines with low PPO activity in wheat grains, wherein the SNP molecular markers include one or more of the above-mentioned SNP molecular markers Marker149631 and Marker149773.

[0023] According to a preferred embodiment of the present invention, in the aforementioned use, the nucleotide sequence of the SNP molecular marker Marker149631 is as shown in SEQ ID NO.1, that is, wheat grains with a base type of G at this SNP site have low PPO activity.

[0024] The nucleotide sequence of the SNP molecular marker Marker 149631 is shown in SEQ ID NO.1, that is, the base type of this SNP site is G, and the genotype of the SNP molecular marker is GG; the nucleotide sequence of the SNP molecular marker Marker 149631 is shown in SEQ ID NO.2, that is, the base type of this SNP site is A, and the genotype of the SNP molecular marker is AA; the wheat grain PPO activity of individuals with the SNP molecular marker GG genotype is lower than that of individuals with the AA genotype.

[0025] According to a preferred embodiment of the present invention, in the aforementioned use, the nucleotide sequence of the SNP molecular marker Marker149773 is as shown in SEQ ID NO.4, that is, wheat grains with a base type of T at this SNP site have low PPO activity.

[0026] The nucleotide sequence of the SNP molecular marker Marker 149773 is shown in SEQ ID NO.4, that is, the base type of this SNP site is T, and the genotype of the SNP molecular marker is TT; the nucleotide sequence of the SNP molecular marker Marker 149773 is shown in SEQ ID NO.3, that is, the base type of this SNP site is C, and the genotype of the SNP molecular marker is CC; the wheat grain PPO activity of individuals with the SNP molecular marker TT genotype is lower than that of individuals with the CC genotype.

[0027] According to a preferred embodiment of the present invention, in the aforementioned use, wheat with SNP site base type G for SNP molecular marker Marker149631 and SNP site base type T for SNP molecular marker Marker149773 is selected.

[0028] Wheat varieties with the genotype GG for SNP molecular marker Marker149631 and the genotype TT for SNP molecular marker Marker149773 were selected.

[0029] A method for screening wheat grains with low PPO activity, using one or more of the above-mentioned SNP molecular markers Marker149631 and Marker149773 for screening.

[0030] According to a preferred embodiment of the present invention, in the method, the nucleotide sequence of the SNP molecular marker Marker149631 is as shown in SEQ ID NO.1, that is, wheat grains with a base type of G at this SNP site have low PPO activity.

[0031] The nucleotide sequence of the SNP molecular marker Marker 149631 is shown in SEQ ID NO.1, that is, the base type of this SNP site is G, and the genotype of the SNP molecular marker is GG; the nucleotide sequence of the SNP molecular marker Marker 149631 is shown in SEQ ID NO.2, that is, the base type of this SNP site is A, and the genotype of the SNP molecular marker is AA; the wheat grain PPO activity of individuals with the SNP molecular marker GG genotype is lower than that of individuals with the AA genotype.

[0032] According to a preferred embodiment of the present invention, in the method, the nucleotide sequence of the SNP molecular marker Marker149773 is as shown in SEQ ID NO.4, that is, wheat grains with a base type of T at this SNP site have low PPO activity.

[0033] The nucleotide sequence of the SNP molecular marker Marker 149773 is shown in SEQ ID NO.4, that is, the base type of this SNP site is T, and the genotype of the SNP molecular marker is TT; the nucleotide sequence of the SNP molecular marker Marker 149773 is shown in SEQ ID NO.3, that is, the base type of this SNP site is C, and the genotype of the SNP molecular marker is CC; the wheat grain PPO activity of individuals with the SNP molecular marker TT genotype is lower than that of individuals with the CC genotype.

[0034] According to a preferred embodiment of the present invention, in the method, wheat with SNP site base type G for SNP molecular marker Marker149631 and SNP site base type T for SNP molecular marker Marker149773 are screened.

[0035] Wheat samples were screened for those with the genotype GG for SNP molecular marker Marker149631 and the genotype TT for SNP molecular marker Marker149773.

[0036] The SNP molecular marker Marker149631 is located on wheat chromosome 3A. The nucleotide sequences of the 300 bp before and after the molecular marker are shown in Table 8: wheat grain PPO activity SNP site sequence information. The base of the SNP molecular marker Marker149631 is A, and the base of the reference genome at this position is G, which is marked as a G / A variant.

[0037] The SNP molecular marker Marker149773 is located on wheat chromosome 3A. The nucleotide sequences 300 bp before and after the molecular marker are shown in Table 8: wheat grain PPO activity SNP site sequence information. The base of the SNP molecular marker Marker149773 is T, and the base of the reference genome at this position is C, which is marked as a C / T variant.

[0038] Beneficial effects of the present invention

[0039] The SNP sites provided by this invention are of great significance for the detection and selection of wheat varieties, lines and breeding materials with low PPO activity in wheat grains. Molecular markers can be developed based on them to accelerate the efficiency of wheat quality breeding. Attached Figure Description

[0040] Figure 1 This is a frequency distribution diagram of the average grain polyphenol oxidase activity in three environments.

[0041] Figure 2 This is a diagram of the genetic map results. Detailed Implementation

[0042] 1. Materials and Methods

[0043] 1.1 Test Materials

[0044] The material used in this experiment was a recombinant inbred line (RIL) population of 268 stable homozygous families obtained by crossing Gaocheng 8901 (male parent) with different PPO activities with Nongda Nuomai 1 (female parent) through single-seed transmission.

[0045] The two parents showed significant differences in grain and flour quality traits:

[0046] Nongda Nuomai No. 1 is a fully glutinous wheat variety bred by crossing "Jiangsu Baihuomai" and "Guandong 107", with low PPO activity in its grains.

[0047] Gaocheng 8901 is a high-quality, strong-gluten wheat variety bred from "77546-2" and "Linzhang", with high PPO activity in its grains.

[0048] The RIL population and its parents were planted in the experimental field of Shandong Agricultural University in Tai'an City, Shandong Province in the 2017-2018 environment (E1) and 2018-2019 environment (E2) using a randomized block design; and in the 2019-2020 environment (E3) using the Wenyang experimental field in Tai'an City, Shandong Province using a randomized block design; all were replicated three times; field management was the same as local field management.

[0049] Grown according to local standard management methods, no serious pests, diseases, or lodging occurred during the growing period. Harvested by plot at maturity, dried, and then stored indoors using standard methods.

[0050] 1.2 Test Methods

[0051] (1) Wheat grain milling: Wheat grains were milled into whole wheat flour as required for the experiment using a Perten 3100 experimental mill according to milling standards. The milled flour was stored in a cold storage at 4℃ for later use.

[0052] (2) Determination of PPO activity in wheat grains:

[0053] A: Extraction of crude enzyme solution: The method was carried out according to that of Kruge et al. (1992) and Morris et al., with some modifications. Weigh about 0.5g of wheat flour into a 10mL centrifuge tube, add 5mL of 0.2mol / L phosphate buffer solution, place the centrifuge tube on a shaker and shake evenly (100r / min, 15min, 37℃). After shaking, place it in a refrigerator at 4℃ for 4h for extraction, and then centrifuge at 10000r / min for 15min at 4℃. Take the supernatant and store it in a refrigerator at 4℃.

[0054] B: Determination of polyphenol oxidase activity: The method of Kruge et al. (1992) was followed with some modifications. 5.6 mL of phosphate buffer solution and 2 mL of catechol were added to a centrifuge tube in sequence. 0.4 mL of enzyme solution was added by pipette and mixed well. The absorbance was measured at a wavelength of 420 nm using a UV6100 ultraviolet spectrophotometer. The remaining solution was quickly placed in a 37°C water bath and incubated for 5 min. The absorbance was measured again. Three parallel experiments were performed.

[0055]

[0056] (3) SLAF library construction and SNP marker detection

[0057] The wheat genome was selected as the reference genome. After enzyme digestion prediction, the optimal restriction enzyme was determined to be HaeIII. Sequences with digestion fragment lengths between 464-494 bp were defined as SLAF tags. The predicted SLAF tag data was then analyzed. GC content analysis and Q30 analysis were performed on the filtered sequencing data, and the data volume was evaluated. Nipponbare rice was used as a control to evaluate and monitor the results of this control data, verifying the correctness of the experimental procedure and determining the effectiveness of the enzyme digestion scheme. (Note: Wheat reference genome download address: http: / / www.wheatgenome.org / News / Latest-news / IWGSC-Reference-Sequence-v1.0-browser-now-available-at-URGI; Nipponbare rice genome download address: [link missing])

[0058] http: / / rapdb.dna.affrc.go.jp

[0059] Based on the sequencing reads' localization results on the reference genome, GATK was used for local realignment, GATK variant detection, and samtools variant detection. Intersection of the GATK and samtools results was also performed to ensure the accuracy of the obtained SNPs. The final SNP set is shown in Table 1. The aaxbb type is suitable for the RIL population in this experiment, while the other markers are suitable for the hybrid population.

[0060] Table 1 SNP genotype coding rules

[0061]

[0062] (4) Construction of high-density genetic maps and QTL mapping

[0063] To ensure the quality of the genetic map, polymorphic SNP tags were filtered. Severely segregated polymorphic markers (chi-square test P < 0.01) were filtered according to standards. The selected SNP tags were then analyzed by calculating the MLOD value between two tags, setting minimum and maximum population numbers, and sorting tags by MLOD value from smallest to largest according to a pre-defined MLOD value range. Tags with the highest MLOD values ​​were grouped into the same linkage group. Tags with MLOD values ​​below 5 with other SNP tags were filtered out. These were then designated as mapping markers. Using linkage groups as units, HighMap software was used to analyze the linear arrangement of markers within each group, and the genetic distance between adjacent markers was calculated to obtain the final genetic map. Simultaneously, monomeric origin assessment was performed: the monomeric origin of each sample in all linkage groups was statistically analyzed to identify potential double crossover sites. Double crossovers within a linkage group are typically controlled to below 3%. Linkage assessment is also conducted; the closer the markers are, the lower the recombination rate. Linkage analysis was performed on the RIL population data using QTL IciMapping software and R / QTL localization software. The QTL naming followed the method of McIntosh et al. (2005).

[0064] (5) Candidate gene prediction

[0065] QTL loci with stable and high contribution rates to grain PPO traits were selected as candidate regions for functional annotation. The wheat genome sequence from the BioMed public database platform was used as the reference genome sequence. The located QTL locus regions were aligned to the reference genome scaffold sequence using BLAST software. Matching candidate regions were compared with published wheat templates to obtain corresponding coding gene information, such as genes. Furthermore, a BLAST (Basic Local Alignment Search Tool) search was performed on the International Wheat Genome Sequencing Consortium database (IWGSC; http: / / www.wheatgenome.org / ). When the SNP marker sequence was 100% identical to any wheat contig, the IWGSC BLAST results were used to extend the sequence of each marker by 5000 bp. Then, the extended sequences were used in the National Center for Biotechnology Information (NCBI) database (http: / / www.ncbi.nlm.nih.gov) and Ensembl Plants (http: / / ...

[0066] The `plant.ensembl.org / Triticum_aestivum / Tools / Blast` function is used to identify potential candidate genes and their functions.

[0067] 2. Results

[0068] 2.1 Phenotypic Analysis of PPO Activity in Wheat from RIL Population

[0069] Under three different environmental conditions, the PPO activity of Nongda Nuomai No. 1 was lower than that of Gaocheng 8901 in all grains. The RIL population exhibited significant phenotypic variation in grain PPO activity, showing superphile segregation. Under the three environmental conditions, the mean grain PPO activity ranged from 126.03 to 186.8, with a minimum of 0.6 and a maximum of 342.1, and a coefficient of variation ranging from 33.22% to 69.81% (see Table 2). The segregation within the population was continuous and conformed to a normal distribution. Figure 1 It exhibits typical quantitative traits.

[0070] Table 2 Phenotypic analysis of wheat flour protein traits in RIL population

[0071]

[0072] Note: E1: 2017-2018 Tai'an, E2: 2018-2019 Tai'an, E3: 2019-2020 Tai'an

[0073] 2.2 Atlas Information

[0074] After rigorous screening, 13,658 SNP tags were finally obtained that could be used for mapping, and the linkage clustering is shown in Table 3. The 13,658 selected SNP tags were then processed by calculating the MLOD values ​​between each pair of tags. SNP tags with MLOD values ​​lower than 5 were filtered out, resulting in 8,095 tags being mapped, representing a mapping rate of 59.27%.

[0075] Table 3. Statistical Table of Marker Linkage Grouping Projects

[0076]

[0077] Using linkage groups as units, HighMap software was used to analyze and obtain the linear arrangement of markers within each linkage group, and the genetic distance between adjacent markers was estimated, as follows: Figure 2 As shown, the final genetic map with a total map distance of 2,554.10 cM was obtained (Table 4).

[0078] Table 4. Basic Map Information

[0079]

[0080]

[0081] 2.3 QTL analysis of PPO activity in wheat grains

[0082] QTL analysis of wheat grain PPO activity (Table 5) revealed one QTL site associated with wheat grain PPO activity, QPpo-3A, located on chromosome 3A. This site was detected in both environments, with an additive effect of 10.1 and a phenotypic contribution of 12.8%, indicating it is a stable major additive gene site.

[0083] Table 5 QTL loci of PPO traits in wheat grain of RIL population

[0084]

[0085] Note: E1: 2017-2018 Tai'an, E2: 2018-2019 Tai'an, E3: 2019-2020 Tai'an

[0086] As shown in Table 6, the major QTL site QPpo-3A on chromosome 3A, which controls the stability of grain PPO activity, has two SNP sites, Marker149631 and Marker149773, and their variation information is related to grain PPO activity.

[0087] Table 6. QTL and SNP markers for grain PPO traits of wheat in RIL population

[0088]

[0089] As shown in Table 7, Marker 149631 is located on wheat chromosome 3A, and base G is a superior variant base. Compared with allelic variant base A, grains containing the base G variant have a 19.79% lower PPO activity. Marker 149773 is also located on wheat chromosome 3A, and base T is a superior variant base. Compared with allelic variant base C, grains containing the base C variant have an 11.52% lower PPO activity. The SNP sequence information for each marker is shown in Table 8.

[0090] Table 7. Phenotypic effect of SNP base variation of wheat grain PPO traits

[0091]

[0092]

[0093] Table 8. SNP locus sequence information of grain PPO traits

[0094]

[0095] Table 9 shows that the most superior haplotype among the two SNP markers affecting grain PPO activity is GT, while the least superior haplotype is AC. As the number of superior alleles at the SNP marker sites increases, grain PPO activity gradually decreases. When both SNP markers are simultaneously the less superior haplotype AC, the grain PPO activity value is high (>200). When one of the two SNP markers is a superior allele, the grain PPO activity value decreases. When both SNP markers have superior alleles (GT), the grain PPO activity is significantly reduced, reaching a minimum of 6.6. Therefore, the combination of haplotypes AC results in high grain PPO activity, while the combination of superior haplotypes GT results in low grain PPO activity. Furthermore, the number of superior alleles has a cumulative effect on grain PPO activity. Thus, these two SNP sites play a crucial role in the level of wheat grain PPO activity.

[0096] Table 9. Haplotypes of PPO activity with different base variation in wheat grain.

[0097]

[0098] 2.4 Prediction of candidate genes for major PPO activity values ​​in wheat grains

[0099] Gene alignment revealed 11 genes (Table 10) at the major QTL site Qppo3A on chromosome 3A that controls the stability of PPO activity in wheat grains. The gene TraesCS3A01G418100 is associated with the MYB transcription factor, which participates in multiple developmental processes, such as root hair development, pollen formation, and seed germination. The MYB transcription factor also plays a role in regulating abiotic stress in plants. Furthermore, the MYB transcription factor is closely related to the quality of certain economic crops. The protein containing a pentapeptide repeat sequence controlled by the gene TraesCS3A01G418500 participates as a structural element in the formation and maintenance of cells and tissues in organisms. It also interacts with other proteins to participate in biological processes such as signal transduction, cell proliferation, and gene expression, and possesses enzymatic activity involved in metabolism and regulation. The gene TraesCS3A01G418600 controls transmembrane proteins, which play an irreplaceable role in transmembrane transport, energy conversion, signal transduction, and membrane homeostasis maintenance. The genes TraesCS3A01G418700 and TraesCS3A01G418800 are associated with signal transduction functions. Therefore, these genes may affect wheat grain PPO activity by controlling plant signal transduction and participating in metabolic and regulatory processes.

[0100] Table 10. Prediction of Qppo3A candidate genes

[0101]

[0102] The SNP sites provided by this invention are of great significance for the detection and selection of wheat varieties, lines and breeding materials with low PPO activity in wheat grains. Molecular markers can be developed based on them to accelerate the efficiency of wheat quality breeding.

Claims

1. A SNP molecular marker, Marker149631, associated with the control of PPO activity in wheat grains, characterized in that, It is located on chromosome 3A of wheat, and the nucleotide sequence of this molecular marker is shown in SEQ ID NO.1 or SEQ ID NO.

2.

2. The use of SNP molecular markers in the breeding of wheat varieties or lines with low PPO activity in wheat grains, wherein the SNP molecular marker is the SNP molecular marker Marker149631 as described in claim 1; Alternatively, the SNP molecular markers are the SNP molecular markers Marker149631 and Marker149773 as described in claim 1; The SNP molecular marker Marker149773 is located on chromosome 3A of wheat, and its nucleotide sequence is shown in SEQ ID NO.3 or SEQ ID NO.

4.

3. The use as described in claim 2, characterized in that, The nucleotide sequence of the SNP molecular marker Marker 149631 is shown in SEQ ID NO.1, that is, the base type of this SNP site is G, and the genotype of the SNP molecular marker is GG; the nucleotide sequence of the SNP molecular marker Marker 149631 is shown in SEQ ID NO.2, that is, the base type of this SNP site is A, and the genotype of the SNP molecular marker is AA; the wheat grain PPO activity of individuals with the SNP molecular marker GG genotype is lower than that of individuals with the AA genotype.

4. The use as described in claim 2, characterized in that, The nucleotide sequence of the SNP molecular marker Marker149773 is shown in SEQ ID NO.4, that is, the base type of this SNP site is T, and the genotype of the SNP molecular marker is TT; the nucleotide sequence of the SNP molecular marker Marker149773 is shown in SEQ ID NO.3, that is, the base type of this SNP site is C, and the genotype of the SNP molecular marker is CC; the wheat grain PPO activity of individuals with the SNP molecular marker TT genotype is lower than that of individuals with the CC genotype.

5. The use as described in claim 2, characterized in that, Wheat varieties with SNP site base type G in SNP molecular marker Marker149631 and SNP site base type T in SNP molecular marker Marker149773 were selected. Wheat with the genotype GG for SNP molecular marker Marker149631 and the genotype TT for SNP molecular marker Marker149773 was selected.

6. A method for screening wheat grains with low PPO activity, using the SNP molecular marker Marker 149631 as described in claim 1; Alternatively, screening can be performed using the SNP molecular markers Marker149631 and Marker149773 as described in claim 1; The SNP molecular marker Marker149773 is located on chromosome 3A of wheat, and its nucleotide sequence is shown in SEQ ID NO.3 or SEQ ID NO.

4.

7. The method as described in claim 6, characterized in that, The nucleotide sequence of the SNP molecular marker Marker 149631 is shown in SEQ ID NO.1, that is, the base type of this SNP site is G, and the genotype of the SNP molecular marker is GG; the nucleotide sequence of the SNP molecular marker Marker 149631 is shown in SEQ ID NO.2, that is, the base type of this SNP site is A, and the genotype of the SNP molecular marker is AA; the wheat grain PPO activity of individuals with the SNP molecular marker GG genotype is lower than that of individuals with the AA genotype.

8. The method as described in claim 6, characterized in that, The nucleotide sequence of the SNP molecular marker Marker149773 is shown in SEQ ID NO.4, that is, the base type of this SNP site is T, and the genotype of the SNP molecular marker is TT; the nucleotide sequence of the SNP molecular marker Marker149773 is shown in SEQ ID NO.3, that is, the base type of this SNP site is C, and the genotype of the SNP molecular marker is CC; the wheat grain PPO activity of individuals with the SNP molecular marker TT genotype is lower than that of individuals with the CC genotype.

9. The method as described in claim 6, characterized in that, Wheat samples were screened for SNP sites with base type G in SNP marker Marker149631 and SNP sites with base type T in SNP marker Marker149773. Wheat samples were screened for those with the genotype GG for SNP marker Marker149631 and the genotype TT for SNP marker Marker149773.

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