CN110885838A - Rice OsRR22-7Mutant gene and identification method thereof, KASP typing primer for identification and application - Google Patents

Abstract

The invention discloses rice OsRR22^‑7Mutant gene and method for identifying the same, OsRR22^‑7Compared with the OsRR22 gene sequence of the japonica rice, the mutant gene comprises the following base deletion segments: presence of [ CGGCTTT/-]Deletion of 7 bp. Also discloses OsRR22 of rice^‑7Application of mutant gene in crop molecule-assisted breeding and breeding or breedingThe application in preparing the salt-tolerant phenotype rice variety obtains obvious technical effect. The invention also discloses a method for detecting, screening or obtaining the OsRR22 of rice^‑7The KASP typing primer of the mutant gene can accurately type different individuals of SNP/Indel discovered by high-depth targeted sequencing, and further improve the accuracy and efficiency of screening and identifying the existing innovative germplasm.

Description

Rice OsRR22-7Mutant gene and identification method thereof, KASP typing primer for identification and application

Technical Field

The invention belongs to the technical field of rice mutation breeding, and particularly relates to a rice mutant gene and an identification method, and also relates to a KASP typing primer for identification and related application.

Background

Among cereal crops using seeds as a propagation mode, wheat and rice are the main grain crops in China. With the rapid development of national economy and society, the contradiction between population growth and arable land reduction is increasingly prominent. China has large pieces of soil with different salt contents, and the cultivated cereal crops with improved salt tolerance can increase the arable land area of China and improve the total grain yield.

In cereal crops, rice has poor salt tolerance, and a new variety with improved salt tolerance needs to be cultivated by a genetic improvement method. Usually, mutagenesis is mostly adopted, and variant materials with improved salt tolerance are screened in the offspring; by using a cross breeding method, a trait-recombinant excellent line with improved salt tolerance is selected in the progeny thereof, and there is also a report on obtaining a line with improved salt tolerance by an anther culture method. In the field, germplasm resources with salt tolerance are urgently needed to be obtained so as to be capable of being planted on coastal saline soil in China in a large quantity and effectively utilize limited resources.

The germplasm resources are the basis of plant genetic breeding, and mutation breeding can generate abundant genetic variation, so that the variation rate is thousands of times of natural variation. According to the statistics of the world atomic energy organization in 1985, more than 500 varieties can be bred in all countries of the world through a mutagenesis method, and a large amount of valuable germplasm resources are obtained. However, mutation breeding has a number of obvious defects, the most important of which is due to random mutation positions, and the target mutants can be selected only in M2 generation, which results in low accuracy and efficiency of innovative germplasm.

With the popularization of the gene site-directed editing technology in plants, the technology effectively makes up the defect of mutation breeding by the characteristics of accuracy, high efficiency and simplicity, and is favored by the plant genetic breeding community. Although the gene site-directed editing technology overcomes the main defects of mutation breeding, the application of the gene site-directed editing technology to plants needs a transgenic means, and some important plant transgenic systems are not mature, so that the application of the gene site-directed editing technology is limited. The mutation breeding is realized by physical and chemical means without the help of transgenic technology, and most plants can obtain stably inherited mutant germplasm through mutation, so that the mutation breeding still has the irreplaceable advantages. In addition, mutation breeding has a long history of application in plants. In 1927, Muller discussed the X-ray induced Drosophila profuse variation in the third International genetics, suggesting that induced mutations improved plants. Afterwards, Stadler demonstrated for the first time that X-rays can induce maize and barley mutations. Nilsson-Ehle & Gustafsson (1930) obtained barley mutants with stiff stalk, compact ear, erect type using X-ray irradiation. In 1934 Tollenear developed the first tobacco mutant "Chlorina" by X-ray. In 1948, drought resistant cotton varieties were bred in India using X-ray mutagenesis. In 1957, the Chinese academy of agricultural sciences established the first research room for atomic energy agricultural utilization in China, and then various provinces also established related research institutions in succession. In the middle of the 60 s of the 20 th century, new varieties are bred on main crops such as rice, wheat, soybean and the like by utilizing radiation mutagenesis, and the new varieties are applied to production. In the later 70 s of the 20 th century, plant radiation mutation breeding began to be applied to breeding of vegetables, sugar, melons, fruits, feeds, medicinal plants and ornamental plants. It can be seen that mutation breeding has been examined for a long time, and has made a great contribution to genetic breeding of plants in the world, and has become a generally accepted breeding means in both the scientific and industrial fields.

The general consensus of mutagenic breeding has been that mutation selection was not performed on the mutagenic current generation (M1) because the genetic variation caused by mutagenesis is mostly recessive and is present in M1 as a chimera. Only by the time of the segregating population of the mutagenic second generation (M2) was the recessive variation produced by M1 present in homozygous form in the M2 individuals, at which time mutants could be selected for the trait of interest. Based on the irreplaceable advantages of mutation breeding, the problem that the mutation breeding is beneficial to selection and the mutation efficiency of a target gene is low is expected to be solved.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects and shortcomings in the background art and provide rice OsRR22^-7The mutant gene also provides a method for identifying whether the rice OsRR22 is contained in a physicochemical mutagenesis sample with high efficiency, good accuracy and simple operation^-7Method for mutant gene and method for detecting, screening or obtaining OsRR22 of rice^-7KASP typing primer of mutant gene and corresponding rice OsRR22^-7Application of mutant gene in crop molecule-assisted breeding and rice OsRR22^-7Mutant gene or gene having OsRR22 of rice^-7The mutant of the mutant gene is applied to breeding or preparing the salt-tolerant phenotype rice variety, and the salt-tolerant phenotype rice variety can be obtained in a mode of saving manpower and material resources, and having high efficiency and good precision.

In order to solve the technical problems, the technical scheme provided by the invention is rice OsRR22^-7Mutant gene, the OsRR22^-7Compared with the OsRR22 gene sequence of the japonica rice, the mutant gene comprises the following base deletion segments:

the deletion of 7 bp [ CGGCTTT/- ] exists at the position 4140861-4140867 (RAP _ Locus), which is the deletion genotype of 7 bp [ CGGCTTT/- ] of the 5 th exon of the rice OsRR22 gene.

More preferably, the rice is OsRR22^-7The mutant gene has a nucleotide sequence shown in SEQ ID NO.1, or a truncated sequence thereof, or a specific sequence which has more than 95% homology with the mutant gene and encodes the same functional protein.

As a general technical concept, the invention also provides a method for identifying whether the rice OsRR22 is contained in a physicochemical mutation sample^-7A method of mutating a gene comprising the steps of:

a) carrying out mutagenesis on rice by a non-lethal dose physicochemical mutagenesis mode to obtain rice material M1 generation;

b) the obtained M1 generation plants are divided into single plants for planting, and the leaves of the single plants after planting are taken and mixed;

c) extracting mixed pool DNA from all mixed leaf materials;

d) performing high-depth target sequencing of the OsRR22 gene region of the rice on the extracted mixed pool DNA;

e) the results of high-depth target sequencing are compared with the rice OsRR22^-7Comparing related sequences of the genes, and identifying whether the rice OsRR22 exists in the population DNA sample in the high-depth target sequencing result^-7A gene;

if it contains OsRR22 of rice^-7The mutant gene can be subjected to subsequent screening operation to obtain a corresponding mutant, otherwise, the operation is terminated.

Nowadays, the second generation sequencing technology (NGS) and the latest third generation sequencing have accelerated the research in the fields of genetic diseases, cancers, etc., and themselves gradually enter the clinic as a more advanced gene detection means. Among numerous sequencing technologies, flexibility and low cost are fully considered, a targeted sequencing technology is finally selected, high-depth sequencing is carried out on a target region of a genome, the target region is transferred to rapid screening and identification of plant innovative germplasm, and accuracy and efficiency of screening of the existing innovative germplasm are greatly improved.

Preferably, the method further comprises verifying the identification result by any one or more of the following methods to verify whether the rice OsRR22 exists in the sample^-7The verification mode of the mutant gene specifically comprises the following steps:

e₁: detecting all plants in a Digital PCR (polymerase chain reaction, dPCR) identification mode;

e₂: carrying out typing identification on each individual plant by a KASP typing mode;

e₃: each individual was identified by a one-generation sequencing approach.

Digital PCR is a new generation of PCR technology that has been rapidly developed in recent years, and is an absolute quantitative technique for nucleic acid molecules, whereby a digital PCR system can easily quantitatively analyze low-frequency mutations as low as 0.01% by virtue of its ultra-high sensitivity. Because the digital PCR is an absolute quantitative technology accurate to a single DNA molecule, the method has ultrahigh precision, and can accurately verify the low-frequency mutation detected by deep sequencing by combining the digital PCR with a high-depth targeted sequencing technology, thereby further improving the accuracy and efficiency of the existing innovative germplasm screening.

KASP, competitive allele Specific PCR (Kompetitive Allelele Specific PCR), is a high throughput known SNP/Indel detection technique that detects different genotypes of the same locus with two-color fluorescence based on terminal fluorescence readings. By utilizing the KASP technology to carry out high-throughput typing identification on different individuals on the SNP/Indel discovered by high-depth targeted sequencing, the accuracy and efficiency of the existing innovative germplasm screening can be further improved.

The method described above, more preferably, the verification means comprises the following two steps:

1) firstly, detecting the population DNA in the high-depth target sequencing result by adopting a digital PCR identification mode, and identifyingDetermination of the Presence or absence of OsRR22 in Rice samples of population-specific DNA^-7A mutant gene; if yes, executing the following step 2), otherwise, terminating;

2) then aiming at SNP and/or Indel sites identified by digital PCR, KASP typing primers are utilized to carry out KASP genotyping on individual plants of a population corresponding to the mixed pool sample containing the mutation, and finally whether rice OsRR22 is contained or not is determined^-7Chimeric individual of mutant genes.

KASP is a high-throughput known SNP/Indel detection technology, and based on terminal fluorescence reading, bicolor fluorescence can detect different genotypes of the same locus. By reducing the candidate region population by using digital PCR and then carrying out accurate typing on different individuals on the SNP/Indel found by high-depth targeted sequencing by using KASP technology, the accuracy and efficiency of the screening and identifying of the existing innovative germplasm can be further improved.

In the above method, preferably, the KASP typing primer comprises the following sequence:

FAM 5-’GAAGGTGACCAAGTTCATGCTGCAAGCTCCTGAAGTCCGAA-’3；

HEX 5-’GAAGGTCGGAGTCAACGGATTCAAGCTCCTGAAGTCCGCG-’3；

COMMON 5-’TTCTGCTGCTCTTCCATCTTTCA-’3。

in the above method, preferably, the subsequent screening operation further comprises the following steps:

f) extracting DNA of leaves corresponding to each ear of each chimera single plant containing the target gene region mutation, carrying out DNA identification, selecting the ears containing the mutation, and mixing the ears and the seeds;

g) mixed sowing is carried out on the mixed harvested seeds (M2 generation), then the leaves are extracted from individual plants and DNA identification is carried out, and finally the OsRR22 is obtained^-7Mutant Gene inheritance phenotype mutant (M2 individual).

The above method, preferably, in step f), the DNA identification is preferably performed by using the above designed KASP typing primer, but may be a first generation sequencing identification for the target region; the KASP typing primer is adopted for identification, so that high flux, low cost and convenience in operation can be better realized.

In the above method, preferably, in the step g), the DNA identification is preferably performed by using the above KASP typing primer which has been designed, but may be a one-generation sequencing identification for the target region. The KASP typing primer is adopted for identification, so that high flux, low cost and convenience in operation can be better realized.

The method preferably, the physical and chemical mutagenesis in step a) includes one or more of the following physical and chemical mutagenesis modes:

the physical mutagenesis comprises ultraviolet mutagenesis, X-ray mutagenesis, gamma-ray mutagenesis, β ray mutagenesis, α ray mutagenesis, high-energy particle mutagenesis, cosmic ray mutagenesis and microgravity mutagenesis, wherein Indel mutagenesis is easier to generate by the physical mutagenesis;

the chemical mutagenesis comprises alkylating agent mutagenesis, azide mutagenesis, base analogue mutagenesis, lithium chloride mutagenesis, antibiotic mutagenesis and intercalating dye mutagenesis; chemical mutagenesis is more likely to generate SNP mutations;

the alkylating agent mutagenesis comprises ethyl methyl naphthenate (EMS) mutagenesis, diethyl sulfate (DES) mutagenesis and Ethylene Imine (EI) mutagenesis.

In the above method, preferably, the non-lethal dose in step a) is a dose controlled in a range of about 20% of the semi-lethal dose. The dosage is controlled to obtain a certain mutation rate and a certain number of live seeds; for example, a semi-lethal dose. The balance relationship between mutation efficiency and the amount of the active species can be coordinated through the control of the mutagenesis mode dosage.

In the above method, preferably, in the step b), when the obtained M1 generation plants are planted in single plants, an arbitrary number of plants is used as a group, and numbering is performed in units of each group; in a subsequent step c), the leaves of each population are mixed in a centrifuge tube to extract the DNA, so that the DNA of each tube contains the genetic information of the entire population. Through the grouping operation, a larger sample amount can be contained in the sequencing, then a large amount of samples are mixed in a pool, the sequencing cost is reduced, and finally effective balance of high throughput and low cost is realized by combining the KASP technology of adding and typing later.

In the above method, preferably, in the step d), the rice OsRR22 gene region includes an exon region of rice OsRR22 gene or a non-coding region of rice OsRR22 gene (or other interested regions on the rice genome, and particularly preferably an exon region), and the high-depth targeted sequencing includes a targeted capture technology based on multiplex PCR amplification, a targeted capture technology based on liquid-phase probe capture hybridization, or a third-generation sequencing single-molecule targeted sequencing technology;

the sequencing depth of the high-depth target sequencing is determined according to the number of the single plants in each population.

Further preferably, the number of arbitrary strains in each population is 48, 96 or 192; when taking leaves of each individual plant, equal amount of leaves at different parts of the same individual plant are selected. As a further preference, in the subsequent step d, the sequencing depth of the high-depth targeted sequencing of the single population with the strain number of 48 is more than 2000, the sequencing depth of the high-depth targeted sequencing of the single population with the strain number of 96 is more than 5000, and the sequencing depth of the high-depth targeted sequencing of the single population with the strain number of 192 is more than 10000.

As a general technical concept, the present invention also provides a method for detecting, screening or obtaining OsRR22 of rice^-7A KASP typing primer for a mutant of a mutant gene, said KASP typing primer comprising the sequence:

FAM 5-’GAAGGTGACCAAGTTCATGCTGCAAGCTCCTGAAGTCCGAA-’3；

HEX 5-’GAAGGTCGGAGTCAACGGATTCAAGCTCCTGAAGTCCGCG-’3；

COMMON 5-’TTCTGCTGCTCTTCCATCTTTCA-’3。

as a general technical concept, the invention also provides rice OsRR22^-7The mutant gene is applied to molecular assisted breeding of crops.

As a general technical concept, the invention also provides rice OsRR22^-7Mutant gene or gene having OsRR22 of rice^-7Mutations in mutant genesThe variant is applied to breeding or preparing a salt-tolerant phenotype rice variety. The application preferably comprises the following steps:

1) taking the mutant as a donor parent and taking any other rice variety Y (such as rice Huazhan or Y58s) as a receptor parent, and carrying out hybridization transformation to obtain F1 seeds;

2) after F1 seeds are sown in a group, selecting a single plant to be hybridized with the recurrent parent rice variety Y to obtain BC1F1 seeds;

3) sowing seeds of BC1F1, extracting DNA of BC1F1 colony by single plant, using the KASP typing primer to mark for foreground selection, and carrying out OsRR22 of rice^-7Selecting a background of a single plant of the mutant gene, and selecting the single plant with the highest background similarity with the recurrent parent to carry out backcross continuously to obtain BC2F1 seeds;

4) sowing seeds of BC2F1, extracting DNA of BC2F1 colony by single plant, using the KASP typing primer to mark for prospect selection, and carrying out OsRR22 of rice^-7Selecting a background of a single plant of the mutant gene, and selecting the single plant with the highest background similarity with the recurrent parent to carry out backcross continuously to obtain BC3F1 seeds;

5) sowing seeds of BC3F1, extracting DNA of BC3F1 colony by single plant, using the KASP typing primer to mark for foreground selection, and carrying out OsRR22 of rice^-7Selecting a background of a single plant of the mutant gene, and selecting a single plant with the highest background similarity with the recurrent parent for selfing and fructification to obtain BC3F2 seeds;

6) sowing seeds of BC3F2, extracting DNA of BC3F2 colony by single plant, using the KASP typing primer to mark for foreground selection, and carrying out OsRR22 of rice^-7Selecting the background of the mutant gene individual plant, and selecting the individual plant Y-OsRR22 with the same genetic background as the rice variety Y^-7Harvesting seeds; obtaining the salt-tolerant phenotype rice variety Y-OsRR22^-7。

Compared with the prior art, the invention has the advantages that:

1) the invention creatively combines the high-depth targeted sequencing technology with one or more of the targeted sequencing technology, the digital PCR technology and the KASP genotyping technology and creatively transfers the high-depth targeted sequencing technology to the field of mutation breeding mutation screening, thereby realizing high-throughput accurate selection of the mutation of a target gene in the mutation M1 generation and accurately positioning the mutation to a chimera single plant containing the mutation of the target gene;

2) based on the identification method and the screening method, the rice OsRR22 is creatively obtained^-7Mutant gene and rice OsRR22^-7The application of the mutant gene in molecular assisted breeding of crops and in breeding or preparation of salt-tolerant phenotypic rice varieties achieves remarkable technical effects, and finally the salt-tolerant phenotypic rice varieties are obtained;

3) the invention relates to a method for detecting, screening or obtaining OsRR22 of rice^-7The KASP typing primer of the mutant gene can accurately type different individuals of SNP/Indel found by high-depth targeted sequencing, and can further improve the accuracy and efficiency of screening and identifying the existing innovative germplasm;

4) the technical scheme of the invention not only saves the time cost required for breeding a first generation, but also solves the problem of too high cost of land, manpower and mutation selection caused by a large increase of the number of groups after breeding a first generation, and has significant progress significance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 shows the identification of OsRR22 in the present invention from physical and chemical mutagenesis samples^-7Schematic flow chart of the method for mutant genes.

FIG. 2 shows the results of population typing using KASP typing primer set No. 34 in example 1 of the present invention.

FIG. 3 shows the mutated form Huazhan-OsRR 22 in example 2 of the present invention^-7Photographs of shoots initiated simultaneously with Huazhan (WT).

Detailed Description

In order to facilitate an understanding of the invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Example 1:

rice OsRR22^-7A mutant gene having a nucleotide sequence shown in SEQ ID No. 1. From the detection results of the New Biotechnology Co., Ltd of Ongzhike, the rice OsRR22^-7The mutant gene is the 5 th exon [ CGGCTTT/-]7 bp (4140861) -4140867 positions).

A method for identifying OsRR22 of above rice from physical and chemical mutagenesis sample as shown in FIG. 1^-7A method of mutating a gene comprising the steps of:

1. with 80MeV/u carbon ions (¹²C⁶⁺) Twenty thousand seeds of the rice variety 638S were irradiated at a dose of 180Gy to obtain the M1 generation of the rice variety 638S (hereinafter, 638S).

2. And planting the plants of which twenty thousand seeds of 638S M1 generations are raised in a single plant. 96 plants are used as a group, 8 rows of each group and 12 plants are used as a row, 100 groups are planted, 9600 plants are obtained, and each group is numbered from 1 to 100.

3. Taking the same amount of leaves of each individual plant as a unit of each population, mixing 96 equal parts of leaves in 1 centrifugal tube to extract DNA, and extracting 100 parts of DNA in total, wherein the DNA number corresponds to 1-100 of each population.

4. And taking the DNA of each population as a sequencing sample, and carrying out targeted high-depth sequencing on the exon region of the OsRR22 gene (Os06g0183100), wherein the sequencing depth is more than 5000 times.

5. And comparing the high-depth targeted sequencing data with the Nipponbare sequence to obtain the SNP and Indel data of the OsRR22 gene exon in 100 samples. The detection of Beijing Ongko New technology Limited company finds that 7 bp deletion exists in 4140861-4140867 (RAP _ Locus) of OsRR22 gene in No. 34 sample, and the deletion is located in the 5 th exon.

6. Verifying indels in sequencing data of the population No. 34 sample by adopting a digital PCR technology, wherein the verification result shows that the samples all have deletion mutation genotypes in the target sequencing data, namely the rice OsRR22 of the invention exists^-7A gene.

7. Based on the deletion mutant genotype of DNA in the population sample No. 34, a KASP typing primer was designed as follows (produced by Biotechnology Co., Ltd., New science, Beijing Optimalaceae):

FAM 5-’GAAGGTGACCAAGTTCATGCTGCAAGCTCCTGAAGTCCGAA-' 3 (shown in SEQ ID NO.2, underlined part indicates a fluorescent tag primer);

HEX 5-’GAAGGTCGGAGTCAACGGATTCAAGCTCCTGAAGTCCGCG-' 3 (shown in SEQ ID NO.3, underlined part indicates a fluorescent tag primer);

COMMON 5- 'TTCTGCTGCTCTTCCATCTTTCA-' 3 (shown in SEQ ID NO. 4).

8. And (3) typing 96 individuals of the population No. 34 by using KASP typing primers of deletion mutation sites, wherein the typing operation is as follows:

(1) extracting DNA of rice leaves by a CTAB method;

(2) KASP typing system 5. mu.l:

(3) PCR reaction procedure

After typing, 3 rows 6 strains (34-C-6) in the No. 34 population are found to contain 7 bp deletion genotypes of the 5 th exon [ CGGCTTT/- ] of the OsRR22 gene (see figure 2), and finally, 1M 1 generation single strain with deletion mutation of the target gene, namely OsRR22 gene frameshift mutation chimera 34-C-6, is obtained.

9. DNA is extracted from corresponding leaves on each ear of the 34-C-6 individual plant, sequencing detection is carried out according to Indel mutation existing in the individual plant, and 4 ears in the 34-C-6 individual plant are found to contain the [ CGGCTTT/- ] mutation genotype. And (3) mixing and harvesting seeds containing mutant genotype ears by taking the individual plant as a unit.

10. Sowing the seeds of the 34-C-6 individual plant, typing the individual plant with the KASP primer designed in the step 7, and finally obtaining OsRR22 in the 34-C-6M 2 population^-7Mutant of the genetic phenotype of the mutant gene.

Example 2:

rice OsRR22^-7Mutant Gene or Rice having OsRR22 obtained in example 1^-7The application of mutant gene in breeding and preparing salt-tolerant phenotype rice variety specifically comprises the following steps:

1) having OsRR22 obtained in example 1^-7Taking mutant of mutant gene genetic phenotype as a donor parent and taking rice Huazhan as a receptor parent, and carrying out hybridization transformation to obtain F1 seeds;

2) after F1 seeds are sown in a group, single plants and recurrent parent rice Huazhan are hybridized to obtain BC1F1 seeds;

3) the seeds of BC1F1 are sown, the DNA of BC1F1 colony is extracted by individual plant, the KASP typing primer marker designed in the example 1 is used for prospect selection, and the rice OsRR22 is contained^-7Selecting a background of a single plant of the mutant gene, and selecting the single plant with the highest background similarity with the recurrent parent to carry out backcross continuously to obtain BC2F1 seeds;

4) the seeds of BC2F1 are sown, the DNA of BC2F1 colony is extracted by single plant, the KASP typing primer marker designed in the example 1 is used for prospect selection, and the rice OsRR22 is contained^-7Selecting the background of the single plant of the mutant gene, and selecting the single plant with the highest background similarity with the recurrent parent to continue the selectionBackcrossing to obtain BC3F1 seeds;

5) the seeds of BC3F1 are sown, the DNA of BC3F1 colony is extracted by single plant, the KASP typing primer marker designed in the example 1 is used for prospect selection, and the rice OsRR22 is contained^-7Selecting a background of a single plant of the mutant gene, and selecting a single plant with the highest background similarity with the recurrent parent for selfing and fructification to obtain BC3F2 seeds;

6) the seeds of BC3F2 are sown, the DNA of BC3F2 colony is extracted by single plant, the KASP typing primer marker designed in the example 1 is used for prospect selection, and the rice OsRR22 is contained^-7Selecting the background of the mutant gene individual plant, and selecting the individual plant Huazhan-OsRR 22 with the same genetic background as the rice Huazhan^-7Harvesting seeds; the salt tolerant phenotype rice variety Huazhan-OsRR 22 shown in figure 3 is obtained^-7。

The mutant Huazhan-OsRR 22 obtained in this example was used^-7Seedlings are grown simultaneously with Huazhan (WT), when rice seedlings are in a three-leaf one-heart period, the rice seedlings are placed in a sodium chloride aqueous solution with the concentration of 0.8% for continuous stress treatment for 10 days and then photographed, 10 mutants and a control group are respectively taken, washed clean by pure water, and after water is absorbed, the root length, the plant height and the fresh weight of the seedlings are measured, and the detection results are shown in the following table 1.

Table 1: Huazhan-OsRR 22^-7Comparison with Huazhan (WT) salt tolerance test

Sample (I)	Root length (mm)	Plant height (mm)	Weight of Miao (g)
				Huazhan (WT)	87.37±2.24	106.10±1.22	0.16±0.01
Huazhan-OsRR 22-7	107±3.12	116±4.34	0.23±0.01

As can be seen from the results in Table 1, Huazhan (WT) stress died after 10 days, while the mutant Huazhan-OsRR 22^-7Can still normally grow, and the root length, plant height and fresh seedling weight are also obviously higher than that of Huazhan (WT), thus indicating that the mutant Huazhan-OsRR 22^-7The growth potential under salt stress was significantly stronger than the wild type control.

Sequence listing

<110> research center for hybrid rice in Hunan province

<120> rice OsRR22-7 mutant gene and identification method thereof, KASP typing primer for identification and application

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aactcattta tgtttgtgtc cttttttttt ttttacctca ctgttgatgc agaagctgta 2160

ccaaaaagaa ttcttgagct tatgaatgtg gagaaactca ccagggaaaa tgttgcaagt 2220

catctacagg tatagcattt acttccatga caaaattatc tgggtgcctt ttttttttct 2280

tttcttttta tccattcatg agagctcttg aattttgctc aaccgtcatc ctttacatgt 2340

tcttctgtac cttcagttgt tgatgcgttt ttacttcagt ttatgaggtc gtccatcatt 2400

cattcattca tcaggcctgc acaaagtgac agaaaatctc ttatcattat acatgttgca 2460

aatgctgatg ctgcacagca tcgagaattc aagattccac cacatggttg tctgaactct 2520

gaaaaactca ccattttatc acatcattta ctcaacctgc acagaaatgt agtacaacaa 2580

acttcagatc aggattgatc cacacagact gcacattttc ttccctgatg caaaattatc 2640

atcgatcccg atgaacacca tcgaatcaaa gcttcatcca ccatttgatt tcatcaatga 2700

aatggaggag tctgcacctg agcacacacg gccacacagc atatgtagct gggtagacct 2760

tcactctacc agagtaagcg atccaggcgg cctcgatggc gccgccgcgg ctcaaactgg 2820

ccggcctcgt cgctgtggca gcgggccagc taggggatgg cggcggcgca ggggctccgg 2880

cgatgggatc tgaatccaaa cagcagagag ggttttggtt gagttgccac tgaactgaac 2940

ctgcatatat tttggtcatc catatctgaa aaatgtgcaa tacttcagat gtttagatca 3000

gtatttcctc caaattcttg caaatatttt cttcggctca cgaaattctt gttagcattg 3060

ttggttgtga agtggcacac ctataatcat gtttgaattt gactcagtct ctcatcacct 3120

tttatttagt gttgatgcag taagagtact agaacagagc tgatgtttcc tactactttc 3180

atggctagct agaattttat ggtgtcatac aggataaatt gaacgaggtt ccaccatttt 3240

atctttgttg ttcatatgca actagatttt attaaactgt tgaaatgcaa gaatgtgcaa 3300

acatctcgta tgacaaatcc taaacaatgt gctatctaaa tctgaaaata ggtgatttgc 3360

tgtttaaaaa ctcaagtcca tatctaatca gttgattttc atgtgacatg cagaagtaca 3420

ggctttacct caagagacta ggtgctgtag catcacaaca agccagcatt gttgctgcct 3480

ttggaggcag agatccctcc ttcttgcata ttggagcatt tgaaggactc cagagctatc 3540

aaccttttgc accttctgct gctcttccat ctttcaatcc acatggcctg ctaacccgaa 3600

ctagcgccgc cgcggacttc aggagcttgc tgccccctcc agcacaattc agacttctac 3660

aggaaatgtc acagttggcc attgcttgga agaaaaccag caggcaaatc tagcacaagg 3720

cttgaccgcg gcgatcgggc aacctcagct tcaacagaac tggattcatc aagaaggtaa 3780

tggtctgtct gatgtttttt ctgggagttc tctgaccaac actttgtcca gcacactcca 3840

aagagttcca agcagttcat tgccaccaca agaactcttg gagtgcaaac aagccaaagt 3900

tagcatgccg ccatcgatac ggataccgcc ttctagttca gcacttcttg agaggactct 3960

tggggtttcc accaatttgg gagattctag tatatcccag cagggtgctc ttccaataga 4020

tggtggattt tctgctgaca ggttaccatt gcacagttca tttgatggcg ctgttgcaac 4080

aaagctagat actagtttgg cagcttcaca gagagagatt ggccagcagg ggaaattttc 4140

agttagcatg cttgtctccc cttctgacaa tcttgcatta gccaaaaatg ccaaaactgg 4200

agctagttct tctggcagta ctataattct ccctcttgat actgcaagac attcagacta 4260

cttgcagttc ggaggtgcaa gcaattcttt gcagaaaatg gatggacaga aacaagatca 4320

tatacagagc tcaaacatta tatggagttc aatgccaagc actcaactgc caagtgatac 4380

ccaaattcat aatactcaaa accaaagatt ggacagcgga agttttaacc ataatattgg 4440

tgcccatttg gctgaccaaa caaatgcaag tgcgtcaata cttccgcaaa tgaagtttga 4500

cacaagaata tcagaagaga aaatgaagca gaagaataca tatgacttgg gtagttcaaa 4560

gctgcagggt ggatttaatt ctagtggctg caattttgat ggccttctca attccataat 4620

caaagtggta tgaacctcta attttccttt cctttttccc catatagttt taaatattta 4680

tctacatgaa tatgctcttc cttctcattg agtaatttaa attgactcca ctgtatttaa 4740

gcacaaagaa caaaggccac tctaaatatt aagctgtaaa cagttgtaac ctacacataa 4800

acaggatatg cctagcagta cctaatattt gcattttcca tcttgtttta tattatagaa 4860

atgttcttga gccacattta acttggttct aacttatcta atctccatgg gactttacct 4920

tttgcatata ttcttctgaa agaaatgatg gtttactgaa gccttaattc taattccaat 4980

gcaggagaag gatgatctcc cattcatgga caatgaattg ggctgtgacc tttttccact 5040

tggtgcctgc atatgaatcc atcatttcgg acaccaaaga ttttgcataa tctaaaagag 5100

tcagctgtgc tgcctgatct gtgctacttc atccaggctt tgtgtatact aggatctagg 5160

gacagtagtg gcttgtaatc ttgctttatc tcttctctag ggttggctat ggaagtatgg 5220

ttagatcaag ataagaagaa aatataatgc tgtaatgtca gcgccttttc tagtcaaaat 5280

ctgtgtttgt ttctaaccaa gcaaccacat ctagtgtttg ctgcaccttc tcagactgaa 5340

aaaatatgga aactcaccat ggcatagata aatcaaaagg gaagtcttta accatccaag 5400

tttgctac 5408

<210>2

<211>41

<212>DNA

<213> Artificial Sequence (Artificial Sequence)

<400>2

gaaggtgacc aagttcatgc tgcaagctcc tgaagtccga a 41

<210>3

<211>40

<212>DNA

<213> Artificial Sequence (Artificial Sequence)

<400>3

gaaggtcgga gtcaacggat tcaagctcct gaagtccgcg 40

<210>4

<211>23

<212>DNA

<213> Artificial Sequence (Artificial Sequence)

<400>4

ttctgctgct cttccatctt tca 23

Claims (16)

1. Rice OsRR22^-7Mutant gene, characterized in that said OsRR22^-7Compared with OsRR2 of Nipponbare rice2, the gene sequence comprises the following base deletion segments:

at positions 4140861-4140867 (RAP _ Locus) there were 7 bp deletions [ CGGCTTT/- ].

2. The rice OsRR22 of claim 1^-7The mutant gene is characterized by having a nucleotide sequence shown in SEQ ID NO.1, or a truncated sequence thereof, or a specific sequence which has more than 95 percent of homology with the nucleotide sequence and encodes the same functional protein.

3. A method for identifying the presence of OsRR22 in rice of claim 1 or 2 from a sample obtained by physical and chemical mutagenesis^-7A method for producing a mutant gene, comprising the steps of:

a) carrying out mutagenesis on rice by a non-lethal dose physicochemical mutagenesis mode to obtain rice material M1 generation;

b) the obtained M1 generation plants are divided into single plants for planting, and the leaves of the single plants after planting are taken and mixed;

c) extracting mixed pool DNA from all mixed leaf materials;

d) performing high-depth target sequencing of the OsRR22 gene region of the rice on the extracted mixed pool DNA;

e) the results of high-depth target sequencing are compared with the rice OsRR22^-7Comparing related sequences of the mutant genes, and identifying whether the rice OsRR22 exists in the population DNA sample in the high-depth target sequencing result^-7A mutant gene;

if it contains OsRR22 of rice^-7The mutant gene can be subjected to subsequent screening operation to obtain a corresponding mutant, otherwise, the operation is terminated.

4. The method according to claim 3, wherein the subsequent screening operation further comprises verifying the result of step e) by any one or more of the following methods to verify the presence of OsRR22 in the sample^-7The verification mode of the mutant gene specifically comprises the following steps:

e₁: detecting and verifying all plants in a digital PCR identification mode;

e₂: carrying out typing verification on each single plant in a KASP typing mode;

e₃: each individual was verified by a one-generation sequencing approach.

5. The method of claim 4, wherein the authentication mode comprises the following two steps:

1) firstly, detecting the population DNA in the high-depth target sequencing result by adopting a digital PCR identification mode, and identifying whether the OsRR22 exists in a population DNA sample^-7Target SNPs and/or indels of the gene; if yes, executing the following step 2), otherwise, terminating;

2) then aiming at SNP and/or Indel sites identified by digital PCR, KASP typing primers are utilized to carry out KASP genotyping on individual plants of a population corresponding to the mixed pool sample containing the mutation, and finally whether rice OsRR22 is contained or not is determined^-7Chimeric individual of mutant genes.

6. The method of claim 4, wherein the KASP typing primer comprises the following sequence:

FAM 5-’GAAGGTGACCAAGTTCATGCTGCAAGCTCCTGAAGTCCGAA-’3；

HEX 5-’GAAGGTCGGAGTCAACGGATTCAAGCTCCTGAAGTCCGCG-’3；

COMMON 5-’TTCTGCTGCTCTTCCATCTTTCA-’3。

7. the method according to any one of claims 3 to 6, wherein the subsequent screening operation further comprises the steps of:

f) for the identification of the gene containing OsRR22^-7Extracting DNA of leaves corresponding to each ear of a chimera individual plant of the mutant gene to carry out DNA identification, selecting the ear containing the mutation, and mixing and collecting seeds of the ear;

g) mixed sowing is carried out on the mixed seeds, then the leaves are extracted by individual plants and DNA identification is carried out, and finally O-containing DNA is obtainedsRR22^-7Mutant of the genetic phenotype of the mutant gene.

8. The method according to claim 7, wherein in step f), the DNA identification is performed by using KASP typing primers which have been designed; in said step g), said DNA identification is carried out using a KASP typing primer which has been designed.

9. The method according to any one of claims 3 to 6, wherein the non-lethal dose in step a) is a dose controlled within a range of 20% of the semi-lethal dose.

10. The method according to any one of claims 3 to 6, wherein in the step b), the obtained M1 generation plants are divided into individual plants, and the individual plants are planted to form a group with a certain plant number, and each group is numbered in unit; in the subsequent step c), the leaves of each population are mixed in a centrifuge tube to extract DNA.

11. The method according to any one of claims 3 to 6, wherein in step d), the high-depth targeted sequencing comprises a multiplex PCR amplification-based targeted capture technology, a liquid phase probe capture hybridization-based targeted capture technology or a third generation sequencing single-molecule targeted sequencing technology;

the sequencing depth of the high-depth target sequencing is determined according to the number of the single plants in each population.

12. The method of claim 11, wherein the number of strains per population is 48, 96 or 192; the sequencing depth of the high-depth targeted sequencing of the single population with the strain number of 48 is more than 2000, the sequencing depth of the high-depth targeted sequencing of the single population with the strain number of 96 is more than 5000, and the sequencing depth of the high-depth targeted sequencing of the single population with the strain number of 192 is more than 10000.

13. One kind is usedDetecting, screening or obtaining OsRR22 of rice^-7A KASP typing primer for a mutant of a mutant gene, said KASP typing primer comprising the sequence:

FAM 5-’GAAGGTGACCAAGTTCATGCTGCAAGCTCCTGAAGTCCGAA-’3；

HEX 5-’GAAGGTCGGAGTCAACGGATTCAAGCTCCTGAAGTCCGCG-’3；

COMMON 5-’TTCTGCTGCTCTTCCATCTTTCA-’3。

14. rice OsRR22^-7The mutant gene is applied to molecular assisted breeding of crops.

15. Rice OsRR22^-7Mutant gene or gene having OsRR22 of rice^-7The mutant of the mutant gene is applied to breeding or preparing the rice variety with salt-tolerant phenotype.

16. The use according to claim 15, characterized in that it comprises in particular the following steps:

1) taking the mutant as a donor parent and taking any other rice variety Y as a receptor parent, and carrying out hybridization transformation to obtain an F1 seed;

2) after F1 seeds are sown in a group, selecting a single plant to be hybridized with the recurrent parent rice variety Y to obtain BC1F1 seeds;

3) seeding BC1F1 seed, extracting DNA of BC1F1 population by single plant, selecting foreground by using KASP typing primer as claimed in claim 13, and performing OsRR22 containing rice^-7Selecting a background of a single plant of the mutant gene, and selecting the single plant with the highest background similarity with the recurrent parent to carry out backcross continuously to obtain BC2F1 seeds;

4) seeding BC2F1 seed, extracting DNA of BC2F1 population by single plant, selecting foreground by using KASP typing primer as claimed in claim 13, and performing OsRR22 containing rice^-7Selecting a background of a single plant of the mutant gene, and selecting the single plant with the highest background similarity with the recurrent parent to carry out backcross continuously to obtain BC3F1 seeds;

5) sowing BC3F1 seeds, and separatingIndividual plant-extracted BC3F1 population DNA, for future selection using the KASP typing primer set of claim 13, for OsRR 22-containing rice^-7Selecting a background of a single plant of the mutant gene, and selecting a single plant with the highest background similarity with the recurrent parent for selfing and fructification to obtain BC3F2 seeds;

6) seeding BC3F2 seed, extracting DNA of BC3F2 population by single plant, selecting foreground by using KASP typing primer as claimed in claim 13, and performing OsRR22 containing rice^-7Selecting the background of the mutant gene individual plant, and selecting the individual plant Y-OsRR22 with the same genetic background as the rice variety Y^-7Harvesting seeds; obtaining the salt-tolerant phenotype rice variety Y-OsRR22^-7。

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