RICE MALE FERTILITY REGULATORY GENE, MUTANT OF RICE MALE FERTILITY REGULATORY GENE, USE THEREOF AND A METHOD FOR REGULATING RICE FERTILITY

Abstract

The present invention relates to the technical field of biology, in particular to a rice male fertility regulatory gene, the use thereof and a method for regulating rice fertility by means of using CRISPR-Cas9, and a mutant of the rice male fertility regulatory gene and a molecular marker and the use thereof. The present invention provides a rice gene GMS2 with the functions of regulating male germ cell development in rice and pollen fertility. The mutant of a rice male fertility regulatory protein GMS2 provided by the present invention can make rice pollen completely sterile, resulting in rice male sterility. The rice gene GMS2 and the mutant thereof, provided by the present invention, can be used in the sterile seed production and manufacturing of rice hybrids, thereby possessing both great application value and economic value.

Claims

1.-20. (canceled)

21. A biological material, wherein, the biological material is an expression cassette, a vector, a host cell, a transgenic cell line or a transgenic plant, and the biological material comprises any of the follows: (1) a protein having an amino acid sequence represented by SEQ ID NOs: 3, 9, 10, 11, 12, 13, 14, 15 or 16; (2) a protein with the activity of regulating plant male fertility obtained by substitution and/or deletion and/or addition of one or more amino acid residues in SEQ ID NOs: 3, 9, 10, 11, 12, 13, 14, 15 or 16; (3) a nucleic acid having a nucleotide sequence represented by SEQ ID NO: 1 or 2; (4) a nucleic acid having a nucleotide sequence represented by SEQ ID NO: 4 or 69; (5) a DNA fragment capable of hybridizing with the DNA of any one of the sequences in (3) or (4) under stringent conditions; (6) a DNA fragment complementary to any one of the sequences in (3) or (4); (7) a DNA fragment capable of affecting the fertility of plant pollen formed by substitution and/or insertion and/or deletion of one or more bases or insertion/deletion/translocation/inversion of a nucleotide sequence of a large fragment based on any one of the sequences in (3) or (4); (8) a DNA fragment having 85%, 90%, 95%, 96%, 97%, 98% or 99% or more identity with the DNA fragment of any one of the sequences in (3) or (4) and encoding a rice male fertility related protein.

22. The biological material according to claim 21, wherein, the deletion in (2) refers to the deletion of at least one of three amino acids N, x and Y in a conserved sequence NxYL of SEQ ID NO: 3, 9, 10, 11, 12, 13, 14, 15 or 16; wherein, x is S or N.

23. The biological material according to claim 22, wherein, the deletion in (2) refers to the deletion of three amino acids N, x and Y in a conserved sequence NxYL of SEQ ID NO: 3, 9, 10, 11, 12, 13, 14, 15 or 16; wherein, x is S or N.

24. The biological material according to claim 23, wherein, the deletion in (2) refers to the deletion of amino acids at positions 40, 41 and 42 of SEQ ID NO: 3, 9, 10, 11, 12, 13, 14, 15 or 16.

25. The biological material according to claim 21, wherein the biological material comprises a protein having an amino acid sequence represented by SEQ ID NO.8.

26. A method for preparing a male sterile plant, comprising: mutating a male fertility related protein of a wild-type plant, wherein the male fertility related protein of the wild-type plant has a amino acid sequence represented by SEQ ID NO: 3, 9, 10, 11, 12, 13, 14, 15 or 16.

27. The method for preparing a male sterile plant according to claim 26, wherein, the method comprises: mutating the genome or transcriptome of rice, the mutation is a mutation of a nucleic acid having the nucleotide sequence represented by SEQ ID NO: 1, 2, 4 or 69, and the mutation is deletion, insertion or substitution of one or more nucleotides, or a mutation generated by the transformation of an antisense gene, co-suppression or introduction of a hairpin structure; the mutation results in reduced expression, no expression or inactivation of the protein having the amino acid sequences represented by SEQ ID NO: 3, 9, 10, 11, 12, 13, 14, 15 or 16.

28. The method for preparing a male sterile plant according to claim 26, wherein, the method comprises: making rice express a male fertility related protein mutant having a sequence represented by SEQ ID NO: 8 and not express a wild-type plant male fertility related protein represented by SEQ ID NO: 3.

29. A method for restoring the male sterility of rice caused by GMS2 gene mutation, wherein the method comprises: obtaining a GMS2 homologous gene sequence with a protein similarity of 85% or more from plant by gene synthesis or PCR amplification, and restoring wild-type traits by genetic transformation, the protein of the plant has the amino acid sequence represented by SEQ ID NOs: 3, 9, 10, 11, 12, 13, 14, 15 or 16.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0113] FIG. 1 shows the morphologies of plants of the wild type (left) and the gms2 mutant (right) at the filling stage in Example 2 of the present invention.

[0114] FIG. 2 shows the morphologies of spikelets of the wild type (left) and the gms2 mutant (right) in Example 2 of the present invention.

[0115] FIG. 3 shows the morphologies of flowers of the wild type (left) and the gms2 mutant (right) in Example 2 of the present invention.

[0116] FIG. 4 shows the morphologies of florets of the wild type (left) and the gms2 mutant (right) after dissection in Example 2 of the present invention.

[0117] FIG. 5 shows the morphologies of anthers of the wild type (left) and the gms2 mutant (right) in Example 2 of the present invention.

[0118] FIG. 6 shows the iodine staining results of pollen of the wild type (left) and the gms2 mutants (right) in Example 2 of the present invention.

[0119] FIG. 7 shows the genotypes of the sterile individual plants in the mapping population identified using the InD48490 marker in Example 4 of the present invention. The upper band is 149 bp in size and the lower band is 140 bp in size. The DNA templates of the two leftmost lanes are the gms2 mutant and Minghui 63 (MH63), respectively, and the latter lanes are the sterile individual plants in the mapping population.

[0120] FIG. 8A is a map of GMS2 gene map-based cloning in Example 4 of the present invention.

[0121] FIG. 8B is a schematic diagram of the mutation sites of the gms2 mutant in Example 4 of the present invention.

[0122] FIG. 9 shows differences in nucleotide sequences of GMS2 gene in materials 9311(48490-9311), Minghui 63(48490-MH63), Nipponbare (48490-Nip) and gms2 mutant (48490-3148) in Example 4 of the present invention. The differences are highlighted with a grey background. The position of the last nucleotide of each line in the whole gene sequence is marked at the end of the line. The start codon ATG and the stop codon TGA are marked with a square, respectively.

[0123] FIG. 10 shows differences in amino acid sequences of the GMS2-encoded protein in 9311 (48490-9311) and the gms2 mutant (48490-3148) in Example 4 of the present invention. The differences are highlighted with a light grey background. The position of the last amino acid residue in each line in the whole protein sequence is marked at the end of the line.

[0124] FIG. 11 shows the genotype identification of the offsprings of the GMS2 heterozygous plants in Example 4 of the present invention. The upper band is 149 bp in size and the lower band is 140 bp in size. The arrows points to samples from male sterility.

[0125] FIG. 12 shows the expression levels of GMS2 in different tissues and different development stages of young panicles of rice in Example 5 of the present invention. Flowers 1 to 9 represent the stage of spikelet primordium differentiation to the pollen maturation stage during the development of young panicles.

[0126] FIG. 13 is a schematic diagram of a pC9M-GMS2 vector in Example 6 of the present invention. T1 represents the target site 1, and T2 represents the target site 2.

[0127] FIG. 14A shows the sequence analysis for the target sites of some transgenic positive plants after the GMS2 gene is knocked out by using the CRISPR/Cas9 system in Example 6 of the present invention.

[0128] FIG. 14B are sequencing peak maps at the target site 1 and the target site 2 of the transgenic plant(s) PC9M-GMS2-Line17 in Example 6 of the present invention. Among them, in the sequencing peak map at the target site 1, the arrow points to a deletion site; and in the sequencing peak map at the target site 2, the arrow points to the insertion site.

[0129] FIG. 15 shows the morphologies of the whole plants of the wild type (left) and knockout plant PC9M-GMS2-Line17 (right) of GM2 in Example 6 of the present invention.

[0130] FIG. 16 shows the morphologies of glumes of the wild type (left) and knockout plant PC9M-GMS2-Line17 (right) of GM2 in Example 6 of the present invention.

[0131] FIG. 17 shows the morphologies of anthers of the wild type (left) and knockout plant PC9M-GMS2-Line17 (right) of GMS2 in Example 6 of the present invention.

[0132] FIG. 18 shows the iodine staining results of pollen of the wild type (left) and knockout plant PC9M-GMS2-Line17 (right) of GMS2 in Example 6 of the present invention.

[0133] FIG. 19 is a schematic diagram of a pUbi1301-48490-CDS vector in Example 7 of the present invention.

[0134] FIG. 20 shows the RT-PCR analysis of the expression level of GMS2 in the overexpressed plants in Example 7 of the present invention. The histogram is the result obtained by quantifying the band brightness in the RT-PCR gel image and dividing the brightness values of 48490 by the brightness values of the corresponding GAPDH.

[0135] FIG. 21 is a schematic diagram of a pC1300-48490-genome vector according to Example 8 of the present invention.

[0136] FIG. 22 shows the morphologies of plants of the wild type (left) and the gms2 mutant complementary plant (right) in Example 8 of the present invention.

[0137] FIG. 23 shows the morphologies of glumes of the wild type (left) and the gms2 mutant complementary plant (right) in Example 8 of the present invention.

[0138] FIG. 24 shows the morphologies of anthers of the wild type (left) and the gms2 mutant complementary plant in Example 8 of the present invention.

[0139] FIG. 25 shows the iodine staining results of pollen of the wild type (left) and the gms2 mutant complementary plant in Example 8 of the present invention.

[0140] FIG. 26 is a sequence alignment diagram of the protein encoded by the GMS2 gene of rice in Example 9 of the present invention with homologous proteins in genomes of other species including protein AT3G60900.1 of Arabidopsis lyrata, protein GSMUA_Achr11P03090_001 of banana (Musa acuminata), protein ORGLA04G0194100.1 of Oryza glaberrima, protein OB04G29380.1 of Oryza brachyantha, protein MLOC_7985.1 of barley (Hordeum vulgare), protein Sb06g026030.1 of sorghum (Sorghum bicolor), protein GRMZM2G003752_P01 of maize (Zea mays), and protein Si010135m of millet (Setaria italica). The conserved sequence NxYL is marked with a square.

[0141] FIG. 27 shows the phylogenetic tree analysis of the protein encoded by the GMS2 gene of rice in Example 9 of the present invention.

SPECIFIC MODES FOR CARRYING OUT THE EMBODIMENTS

[0142] The following examples facilitate a better understanding of the present invention but do not limit the scope of application of the present invention. All technical and scientific terms in the following examples have the same meanings as commonly understood by a person skilled in the art unless otherwise specified. The techniques used or referred to in the present invention are standard techniques recognized by a person skilled in the art unless indicated to the contrary. The test materials, unless otherwise specified, are the test materials commonly used in the field of the present invention. The test reagents used in the examples below, unless otherwise specified, are commercially available from the conventional biochemical reagent stores.

[0143] The male sterility described in the present invention specifically refers to the abnormal development of male reproductive organs of plants (unable to produce normal stamens, anthers or normal male gametophytes) and the loss of fertility due to functional changes in plant nuclear genes, which is commonly referred to as Genic male sterility rather than Cytoplasmic male sterility. Both abnormality and restoration of fertility in the male reproductive organs are controlled by genes within the nucleus.

[0144] Therefore, the present invention also includes utilizing the sequences described in the sequence listings to regulate and control the male gamete fertility of the plant, i.e., utilizing the gene sequences provided by the present invention to affect the functions of the same or homologous genes in other plants at the levels of genome, and/or transcriptome, and/or proteome so as to achieve the purpose of controlling the fertility of the male reproductive organ. For example, it includes but is not limited to the following methods: affecting or altering the functions of plant genes by mutating natural sequences and thereby resulting in inhibition of gene expression or loss of protein function, by transferring antisense sequences of said genes into plants or introducing hairpin structures, or by combining said genes with other sequences (DNA or RNA) to generate novel functionally active DNA or RNA chains. Or any of the other technical methods known to a person skilled in the art that can be used to affect male fertility in plants.

[0145] The present invention includes a rice GMS2 gene, a dominant allele of which has a key effect on male fertility of a plant, and a recessive allele with loss-of-function can lead to male sterility. The gene is located on rice chromosome 4, and the specific location of the gene is shown in FIGS. 8A and 8B.

[0146] The sequence of the gene and its homologous sequence can be obtained from various plants including, but not limited to, Selaginella moellendorffii, Populus trichocarpa, Brassica rapa, Arabidopsis lyrata, Arabidopsis thaliana, soybean (Glycine max), potato (Solanum tuberosum), grape (Vitis vinifera), Musa acuminata, millet (Setaria italica), sorghum (Sorghum bicolor), maize (Zea mays), Brachypodium distachyon, barley (Hordeum vulgare), Oryza brachyantha, Oryza glaberrima, Oryza sativa indica Group, Oryza sativa japonica Group, Physcomitrella patens and the like. The obtaining methods include, but are not limited to, retrieving from the genome sequence database, and/or cDNA sequence database, and/or protein sequence database of other plants using rice GMS2 gene sequence through blastx or blastn, or using rice GMS2 amino acid sequence through blastp; obtaining directly from genomic DNA or cDNA or RNA of other plants by using a PCR method with primers designed using the DNA or cDNA or RNA sequence of the rice GMS2 gene as a reference sequence; and isolating DNA or cDNA or RNA fragments containing the homologous gene sequences from genomic libraries by nucleic acid hybridization method using probes designed based on the sequence of GMS2 gene in rice.

[0147] The homologous sequence of GMS2 gene refers to the gene sequence of plant with Identity greater than or equal to 35% and Positive greater than or equal to 50% after blastp comparative analysis with the amino acid sequence of SEQ ID NO: 3. When performing blastp, all parameters follow the default settings shown in http://blast.ncbi.nlm.nih.gov/.

[0148] The following provides a more detailed description by way of illustration and description, but is not intended to limit the scope of the present invention.

Example 1: Screening of Rice Male Sterile Mutant Gms2

[0149] In June 2013, 10 kg of 93-11 seeds were irradiated with cobalt 60 to obtain the M.sub.0 generation. The irradiated seeds were planted in an experimental field in Lingao County, Hainan Province, and after maturity, plants were harvested individually to obtain seeds, and a total of about 6,500 materials of M.sub.1 generation were obtained. In the spring of 2014, 3,617 M.sub.1 generation materials with a higher seed amount were selected and planted into lines, with 50 individual plants per line. Various types of mutants such as plant type, panicle type, fertility and yield were screened at tillering stage, booting stage, heading stage, flowering stage and filling stage, respectively, and the seeds of the selected mutants were collected and stored. Among them, a sterile mutant named gms2 was found in line No.3148.

Example 2: Phenotypic Analysis of Rice Male Sterile Mutant Gms2

[0150] Compared with the wild type, the plants and spikelets of the gms2 mutant were morphologically normal (FIG. 1), and the flowering stage was slightly late (FIG. 2). There is no significant difference in palea and lemma size, floret opening size and opening time from those of the wild type (FIG. 3). The floret morphology of the mutant was observed under the stereoscopic microscope, and it was found that the ovary, style and stigma were slightly larger than those of the wild type (FIG. 4), but the anthers were thinner, smaller and lighter in color as compared with the wild type (FIG. 5). The pollen was stained with iodine-potassium iodide solution (0.6% KI, 0.3% 12, w/w), and as shown in FIG. 6, the wild-type pollen grains were large and round and stained blue-black, while the mutant pollen grains were shrunken and could not be stained. The wild-type plants in the same family were normally fruit-bearing after bagging selfing, while the gms2 mutants were not. However, using rice variety 93-11 as a male parent to pollinate gms2 mutant, the gms2 mutant can bear fruit. This indicates that the mutant is a male sterile mutant.

Example 3: Genetic Analysis of Rice Male Sterile Mutant Gms2

[0151] In M5 generation, 80 plants of segregating population of gms2 were planted, of which 64 were normal in fertility and 16 were sterile, and the segregation ratio of fertile and sterile plants was 3:1 (χ.sup.2=0.57, P>0.05). By backcrossing gms2 with 93-11, all the F1 generation plants were fertile. In the F2 generation, 70 plants of segregating population of gms2 were planted, of which 57 were normal in fertility and 13 were sterile, and the segregation ratio of fertile to sterile plants was 3:1 (χ.sup.2=0.85, P>0.05). The above results indicated that the male sterility of gms2 is controlled by a single recessive gene.

Example 4: Cloning of Rice Male Sterility Gene GMS2

[0152] The GMS2 gene was mapped by the map-based cloning method. An F.sub.2 population containing 66 mutant plants was constructed by crossing Minghui 63 as a male parent with the gms2 mutant. Using this population, GMS2 was mapped to 6861.252 Kb between SSR markers RM17332 and RM280 on chromosome 4, and was closely linked to SSR marker RM303 and Indel marker 4826. There were 8, 1, 1 and 32 recombinant individual plants between GMS2 gene and the above four markers, respectively. The linkage markers were used to select the gms2 heterozygous plants in the F.sub.2 population to develop an F.sub.3 population containing 1937 mutant individual plants. There were 10, 7 and 8 recombinant individual plants between RM303, 4826 and S10, and GMS2 genes in the F.sub.3 population, respectively. By analyzing and comparing the sequences of 93-11 and Minghui 63 genomes between RM303 and S10, five new Single Nucleotide Polymorphism (SNP) markers S4b, S3b, S2, 51 and S8 were developed and experimentally confirmed. In the F.sub.3 population, there were 6, 6, 1, 4 and 8 recombinant individual plants for the above markers, respectively (FIG. 7). Using 77 kb upstream and downstream of S2 as the candidate segment, a total of 11 annotation genes were found in this segment, among which LOC_Os04g48490 was predicted to encode a fasciclin-like arabinogalactan protein, and presumed to be the GMS2 gene. In Nipponbare, the nucleotide sequence of the LOC_Os04g48490 in genome was 1582 bp long (denoted as 48490-Nip, the sequence was represented by SEQ ID NO: 1) and the nucleotide sequence of CDS was 1296 bp long (the sequence was represented by SEQ ID NO: 2), one exon (FIGS. 8A and 8B) was contained, and a protein with a length of 432 amino acid residues (the sequence was represented by SEQ ID NO: 3) was encoded. The sequences of the marker primer pairs used for mapping the GMS2 gene are shown in Table 1 (SEQ ID NOs. 39-68).

TABLE-US-00001 TABLE 1 Sequences of the marker primer pairs used for mapping the GMS2 gene Name of the markers Forward primers Reverse primers RM17332 CGGTACATCACGGTATCAAATCG  TAAATGCTGGAGCGATGCTAAC (SEQ ID NO: 39) C (SEQ ID NO: 40) RM280 GTGCTCTCCATGTCGGATTATGC  CAAGGCAACAAGATTGGTTAGT (SEQ ID NO: 41) GG (SEQ ID NO: 42) RM17351 ATAAAGGAGGAGGGCCTCAGATGG  CACGGTTTGGAGGTTGGAAGC (SEQ ID NO: 43) (SEQ ID NO: 44) RM17352 GCTTGGCATCTGCTTCTGTTGTTGG CTCGCTGCTGATCGAGGTGTCG (SEQ ID NO: 45) (SEQ ID NO: 46) RM303 ATCGATGTAGGTAGAGGGACACC  CAGATCTAGTCGACATGGTTGG (SEQ ID NO: 47) (SEQ ID NO: 48) 4826 ACACCATCTCTCTTCTTTTTCTAT  ATATGGGTAGGTTTGGATATTC (SEQ ID NO: 49) G (SEQ ID NO: 50) S4b GTGTGTGTGAGTAAAATCCTAGTGC ATTTGTACTCCTATGTTTAGAA A (SEQ ID NO: 51) TAGC (SEQ ID NO: 52) AAAAAGTGTGTGTGAGTAAAATCCT AGAGCC (SEQ ID NO: 53) S3b ACAAATATATAGCAAAATCGGTGAC GTGGTTTTGTGGATGTTTTGTA C (SEQ ID NO: 54) ACT (SEQ ID NO: 55) AAAAAACAAATATATAGCAAAATCG GTTACG (SEQ ID NO: 56) S2 AAGTATTTGTAATGCACTATGTAAA TTAAGAGCACACACTTCCAATA GGT (SEQ ID NO: 57) ATATGT (SEQ ID NO: 58) AAAAAAAGTATTTGTAATGCACTAT GTAATGGC (SEQ ID NO: 59) S1 CTGGGCGCGGTGCGGCGGGCGAGGC CCGCCTCAGCGCCACCGCCAAG (SEQ ID NO: 60) CTGA (SEQ ID NO: 61) AAAAACTGGGCGCGGTGCGGCGGGC GTGGT (SEQ ID NO: 62) S8 AAGTTGTGTTTAGCACTATGTTATT TTTAGCATAATAACTACTATTC ACG (SEQ ID NO: 63) ATCATT (SEQ ID NO: 64) AAAAAAAGTTGTGTTTAGCACTATG TTATGACA (SEQ ID NO: 65) S10 GCAGGAGACACTTGGTGCCGCCTCT GCAGATTATTTTCGGTGGGTCC C (SEQ ID NO: 66) CGTCTC (SEQ ID NO: 67) AAAAAGCAGGAGACACTTGGTGCCG CCACTT (SEQ ID NO: 68)

[0153] According to the sequence of 48490-Nip, primers were designed and used to amplify and sequence the alleles of LOC_Os04g48490 gene in 93-11, Minghui 63 and the gms2 mutant, the primer sequences are shown in Table 2. All PCR amplifications were performed using KOD FX DNA Polymerase (TOYOBO CO., LTD. Life Science Department, Osaka, Japan) and PCR amplification was performed on Thermo Scientific Arktik Thermo cycler according to the reaction system and conditions described in the product description. The PCR products were sent to Nanjing GenScript Biotechnology Co., Ltd. for sequencing. The sequencing results were assembled with DNAman 6.0. The LOC_Os04g48490 genes in 93-11, Minghui 63, and the gms2 mutant were recorded as 48490-9311 (the sequence was represented by SEQ ID NO: 4), 48490-MH63 (the sequence was represented by SEQ ID NO: 5) and 48490-3148 (the sequence was represented by SEQ ID NO: 6), respectively.

TABLE-US-00002 TABLE 2 Sequences of a primer pair for amplification of LOC_Os04g48490 Name of the markers Forward primers Reverse primers LOC_ AAACAGAAAGCCCCA TGCCGCAGTACGCGC Os04g48490_1 ATG CCAAG (SEQ ID NO: 21) (SEQ ID NO: 22) LOC_ TTGTCCATGCCGGTG GGTCACGGCACAAAC Os04g48490_2 TCCAT TCA (SEQ ID NO: 23) (SEQ ID NO: 24)

[0154] Multiple sequence alignments of 48490-9311, 48490-3148, 48490-MH63 and 48490-Nip were performed, and the results are shown in FIG. 9. Compared with 48490-9311, 48490-3148 has only one deletion of AACAGCTAC starting at base 118 behind ATG (FIGS. 8B and 9). Amino acid sequence analysis revealed that this mutation would lead to the deletion of asparagine, serine, and tyrosine residues at positions 40 to 42 in the protein encoded by the LOC_Os04g48490 gene (FIG. 10). Compared with 48490-MH63 and 48490-Nip, 48490-3148 has the same difference at base 118 behind ATG as described above (FIG. 9). This indicates that the deletion mutation of AACAGCTAC starting at base 118 behind ATG is responsible for the male sterility of the gms2 mutant. In addition, the sequences of 48490-9311 and 48490-MH63 were identical, and compared with 48490-Ni, there is a SNP from A to C at position 8, a SNP from C to G at position 109, a SNP at position 1288 from T to C, and an insertion of G base at position 1515 (FIG. 9). Two nucleotide differences fall in 5′UTR and 3′UTR respectively, and the other two nucleotide differences fall in the exons, but they do not affect the coded protein. This indicates that the LOC_Os04g48490 gene is highly conserved in rice, and the nucleotide sequence thereof differs in only 4 bases even between subspecies of indica and japonica, while there is no difference in protein sequences. The CDS nucleotide sequence of LOC_Os04g48490 in 93-11 is represented by SEQ ID NO: 69, and the coded protein sequence is represented by SEQ ID NO: 3. The CDS nucleotide sequence and the amino acid sequence of LOC_Os04g48490 in the gms2 mutant are represented by SEQ ID NO: 7 and SEQ ID NO: 8, respectively.

[0155] Based on the sequencing results of the mutation site of LOC_Os04g48490 gene, specific primers IND48490_F: GCTCCGGCTGTTGATCT (SEQ ID NO: 19) and IND48490_R: GCCTGCTCTTCCTCCTG (SEQ ID NO: 20) were designed on both sides of the mutation site. When InD48490_F and InD48490_R were paired to amplify the wild type LOC_Os04g48490 gene, a 149 bp band would be generated, while a 140 bp band would be generated when the mutant LOC_Os04g48490 gene was amplified. Genotyping was performed on the M6 segregating population of 41 gms2 plants using InD48490_F and InD48490_R primer pairs. As shown in FIG. 11, the wild type amplified either 2 bands of 149 bp and 140 bp or 1 band of 149 bp, while all of the sterile mutants could only amplify 1 band of 140 bp. This indicates that the mutant genotype co-segregates with the sterile phenotype, and LOC_Os04g48490 is the GMS2 gene.

Example 5: Expression Analysis of GMS2 Gene

[0156] Total RNA was extracted from tissues at every period from 93-11 and reverse transcribed into cDNA. The expression level of the GMS2 gene was detected using primers InD48490_F: GCTCCGGCTGTTGATCT (SEQ ID NO: 19) and InD48490_R: GCCTGCTCTTCCTCCTG (SEQ ID NO: 20). The expression level of the internal reference gene GAPDH was detected using primers GAPDH-RTF: GAATGGCTTTCCGTGTT (SEQ ID NO: 25) and GAPDH-RTR: CAAGGTCCTCCTCAACG (SEQ ID NO: 26). Real-time quantitative PCR was used for expression analysis. As shown in FIG. 12, the expression level of GMS2 gene was significantly lower in roots and stems than in other tissues, and significantly higher in seeds than in other tissues. In stem nodes, leaves, sheaths and spikes, the expression level of GMS2 gene was moderate, but not the same. In Flowers 1 (flower length of 1 mm), 2 (flower length of 2 mm), 3 (flower length of 3 mm), 4 (flower length of 4 mm), 5 (flower length of 5 mm), 6 (flower length of 5.5 mm), 7 (flower length of 6 mm), 8 (flower length of 7 mm) and 9 (flower length of 8 mm), that is, in spikes from the stage of spikelet primordium differentiation to the pollen maturation stage, the expression amount of GMS2 decreased first, then increased and finally decreased again.

Example 6: Acquisition and Phenotypic Analysis of GMS2 Gene Knockout Lines

[0157] Targeted knockout of GMS2 gene was performed using CRISPR-Cas9 system. In order to improve the knockout efficiency, two target sites were selected for simultaneous knockout. Target site 1 was located on the negative strand of the exon, and the sequence is GCGGTCGGTGGCGGCCATGG (SEQ ID NO: 17, located at positions 45 to 64 of SEQ ID NO: 1), and Target site 2 was located on the exon and the sequence is CGCCTCCCTCGCCGTCGCGG (SEQ ID NO: 18, located at positions 85 to 104 of the sequence of SEQ ID NO: 1). Target site 1 and Target site 2 were ligated into the vector pC9M to obtain the vector pC9M-GMS2 (FIG. 13) according to the method of Ma et al. (Ma X, et al. A Robust CRISPR-Cas9 System for Convenient, High-Efficiency Multiplex Genome Editing in Monocot and Dicot Plants. Mol Plant, 2015, 8: 1274-84). E. coli with pC9M-GMS2 is designated E. coli-pC9M-GMS2. The pC9M-GMS2 was transformed into Agrobacterium strain EHA105 by electroporation, and the resulting strain was designated Ab-pC9M-GMS2.

[0158] The callus of the japonica rice Zhonghua 11 (ZH11) was infected with the recombinant Agrobacterium Ab-pC9M-GMS2, and 25 regenerated transgenic lines were obtained through hygromycin resistance screening, differentiation and rooting. After acclimation and transplantation, 22 surviving plants were obtained, and the total DNA of the leaves of the plants was extracted, and primers SP1: CCCGACATAGATGCAATAACTTC (SEQ ID NO: 29) and SP2: GCGCGGTGTCATCTATGTTACT (SEQ ID NO: 30) were used for positive detection, all of the plants were positive plants. The genomic DNA was amplified with primers of target 1-F: AAACCCACGCCCAGAAA (SEQ ID NO: 31) and target 1-R: GCCAGGAGGAAGAGCAG (SEQ ID NO: 32) on both sides of Target site 1 and primers of target 2-F: GCCTGCTCTTCCTCCTG (SEQ ID NO: 33) and 2-R: GTGCTCCGGCTGTTGAT (SEQ ID NO: 34) on both sides of Target site 2. The amplified products were sequenced and subjected to genome alignment. The results showed that gene editing was occurred in 14 plants of T0, wherein homozygous mutation was occurred in one plant, and 8 seedlings of T0-generation were not edited.

[0159] Homozygous mutations were occurred at both Target site 1 and Target site 2 of the genomic DNA of plant PC9M-GMS2-Line17, in which deletion of TG bases (SEQ ID NO: 27) occurs at Target site 1, and insertion of T base (SEQ ID NO: 28) occurs at Target site 2 (FIG. 14B). Biallelic mutation was occurred at Target site 1 of the genomic DNA of PC9M-GMS2-Line1, in which insertion of A base occurs at allele 1, and deletion of T base occurs at allele 2; biallelic mutation was also occurred at Target site 2 of the genomic DNA of PC9M-GMS2-Line1, with a G/T base SNP at allele 1, and a G/C base SNP at allele 2. Biallelic mutation was occurred at Target site 1 of the genomic DNA of PC9M-GMS2-Line3, with deletion of TG bases at allele 1 and insertion of A base at allele 2; biallelic mutation was also occurred at Target site 2 of the genomic DNA of PC9M-GMS2-Line3, with a G/T base SNP at allele 1 and deletion of C base at allele 2. However, the genotypes of transgenic-negative individual plants PC9M-GMS2-Line2, PC9M-GMS2-Line5, and PC9M-GMS2-Line7 were not altered (FIG. 14A).

[0160] Phenotypic analysis was performed on the above positive plants after flowering. Compared with wild-type ZH11, GMS2 knockout plant PC9M-GMS2-Line17 showed no significant difference in leaf and spikelet morphology (FIGS. 15 and 16). However, the anthers of the GMS2 knockout plants were significantly thinner and smaller (FIG. 17). The results of iodine staining of pollen showed that the pollen of wild type ZH11 was large and round and could be stained, while the pollen of the GMS2 knockout plants was small and shrunken and could not be stained (FIG. 18). Other GMS2 biallelic mutant plants also exhibited the trait of male sterility.

Example 7: Acquisition and Phenotypic Analysis of a GMS2 Gene Overexpressing Lines

[0161] Using the RNA reverse transcription product of 9311 as a template, a DNA fragment with a GMS2 complete coding nucleotide sequence (SEQ ID NO: 2) was obtained by amplification using primers 31480X-F: CggggtaccATGGCCGCCACCGAC: (SEQ ID NO: 35) and 31480X-R: CGCggatccTCACAAGAACGACGC (SEQ ID NO: 36). The fragment was double-digested with Kpn I and BamH I and then ligated into pBLU5 to obtain plasmid pUbi1301-48490-CDS (FIG. 19). E. coli with pUbi1301-48490-CDS is designated E. coli-pUbi1301-48490-CDS. The pUbi1301-48490-CDS was transformed into Agrobacterium strain EHA105 by electroporation, and the resulting strain was designated Ab-pUbi1301-48490-CDS.

[0162] The callus of the japonica rice Zhonghua 11 was infected with the recombinant Agrobacterium Ab-pUbi1301-48490-CDS, and 6 transgenic positive plants were obtained through hygromycin resistance screening, differentiation and rooting. The expression amounts of GMS2 in transgenic positive plants were analyzed using the real-time quantitative PCR method with the primers InD 48490-F: GCTCCGGCTGTTGATCT (SEQ ID NO: 19) and InD 48490-R: GCCTGCTCTTCCTCCTG (SEQ ID NO: 20), GAPDH-RTF: GAATGGCTTTCCGTGTT (SEQ ID NO: 25) and GAPDH-RTR: CAAGGTCCTCCTCAACG (SEQ ID NO: 26) in Example 5. As shown in FIG. 20, compared with transgenic negative individual plants 2 and 8, the expression amounts of GMS2 in overexpression plants 20 and 28 were increased by 9-fold and 45-fold, respectively, however, there was no significant phenotype that was co-segregated with the expression amount in the overexpressed plants, which indicates that the overexpression of GMS2 gene had no significant effect on rice phenotype.

Example 8: Acquisition and Phenotypic Analysis of a Transgenic Complementary Line of Gms2 Mutant

[0163] Using the genomic DNA of 9311 as a template, a full-length fragment of the gene with 2 kb upstream of the starting codon ATG of GMS2 and 515 bp downstream of the stopping codon TGA of GMS2 was obtained by amplification with primers 3148HB-F: CgcgtttcgaaatttTGATTTCTTCATCGCACT (SEQ ID NO: 37) and 3148HB-R: GtcgcgatcgcatgcACAACATGGTGCAACAGTG (SEQ ID NO: 38). The fragment was ligated into the pC1300 after double digestion with Kpn I and BamH I to obtain the plasmid pC1300-48490-genome (FIG. 21). The E. coli with pC1300-48490-genome is designated E. coli-pC1300-48490-genome. The PC1300-48490-genome was transformed into Agrobacterium strain EHA105 by electroporation, and the resulting strain was designated Ab-pC1300-48490-genome. The callus of gms2 mutant was infected with recombinant Agrobacterium Ab-pC1300-48490-genome, and 4 transgenic positive plants were obtained through resistance screening, differentiation and rooting, and the fertility of the four plants was restored to normal (FIGS. 22, 23, 24 and 25). This further proved that the GMS2 gene regulates and controls pollen development, and the mutation of this gene would lead to pollen abortion.

Example 9: Sequence Alignment and Phylogenetic Tree Analysis of GMS2-Encoded Protein and its Homologous Proteins

[0164] Performing homology search on the amino acid sequence of the protein encoded by the rice GMS2 gene in Genbank database of NCBI by using a blastp tool, the predicted homologous proteins in the genomes of Arabidopsis lyrata, banana (Musa acuminata), Oryza glaberrima, Oryza brachyantha, barley (Hordeum vulgare), sorghum (Sorghum bicolor), maize (Zea mays) and millet (Setaria italica) were obtained, these protein sequences were aligned and analyzed, and the results showed that the homologous proteins from different plants all had very similar conserved sequences and high homology with each other (FIGS. 26 and 27), indicating that the protein has a conservative biological function and plays a very important role during the development of male organs of plant flowers.

[0165] The amino acid sequence of the fertility gene in Arabidopsis lyrata is represented by SEQ ID NO: 9; the amino acid sequence of the fertility gene in banana (Musa acuminata) is represented by SEQ ID NO: 10; the amino acid sequence of the fertility gene in Oryza glaberrima is represented by SEQ ID NO: 11; the amino acid sequence of the fertility gene in Oryza brachyantha is represented by SEQ ID NO: 12; the amino acid sequence of the fertility gene in barley (Hordeum vulgare) is represented by SEQ ID NO: 13: the amino acid sequence of the fertility gene in sorghum (Sorghum bicolor) is represented by SEQ ID NO: 14; the amino acid sequence of the fertility gene in maize (Zea mays) is represented by SEQ ID NO: 15; and the amino acid sequence of the fertility gene in millet (Setaria italica) is represented by SEQ ID NO: 16.

Example 10: Breeding of Recessive Genic Male Sterile Line with GMS2 Gene

[0166] Hybridizing, backcrossing and selfing were performed on the gms2 mutant with a fertility-normal receptor such as H28B, and the gms2 gene and genetic background were selected with molecular markers in the process, and the recessive genic male sterile line with the homozygous GMS2 mutation gene under the background of H28B was finally obtained. The specific implementation steps were as follows:

[0167] 1. a receptor parent such as H28B was used as a male parent to hybridize with a gms2 mutant to obtain F.sub.1.

[0168] 2. F.sub.1 was used as a female parent to backcross with a receptor parent such as H28B to obtain BC.sub.1F.sub.1.

[0169] 3. BC.sub.1F.sub.1 was planted, and the gms2 genotypes were detected using the primers InD48490_F: GCTCCGGCTGTTGATCT (SEQ ID NO: 19) and InD48490_R: GCCTGCTCTTCCTCCTG (SEQ ID NO: 20). The plant with heterozygous gms2 genotype (the plant that may amplify 149 bp and 140 bp bands simultaneously) was selected.

[0170] 4. the individual plants selected in step 3 was subjected to genetic background identification using a set (e.g., 100, or 200 and the like) of evenly distributed molecular markers (which may be but not limited to SSR, SNP, INDEL, EST, RFLP, AFLP, RAPD, SCAR, and other types of molecular markers) with genotype polymorphism between the genomes of gms2 mutant and the recurrent parent, and the plants with high genotype similarity to the recurrent parent (e.g., greater than 88% similarity, or 2% selection rate and the like) were selected.

[0171] 5. the plant selected in step 4 was used to backcross with a receptor parent such as H28B to obtain BC.sub.1F.sub.1.

[0172] 6. BC.sub.2F.sub.1 was planted, and steps 3 and 4 were repeated to select the plants with heterozygous gms2 genotype and high genetic background recovery rate (e.g., greater than 98%, or a selection rate of 2%, etc.) and the selfed seeds BC.sub.2F.sub.2 were harvested.

[0173] 7. BC.sub.2F.sub.2 was planted, and steps 3 and 4 were repeated to select the plants with heterozygous gms2 genotype and the highest homozygosity rate of the genetic background, and the selfed seeds BC.sub.2F.sub.3 were harvested. The gms2 homozygous plant segregated from the offsprings of BC.sub.2F.sub.3 was the gms2 recessive genic male sterile line, and BC.sub.2F.sub.3 was used to preserve the germplasm resources of the gms2 recessive genic male sterile line.

[0174] Although the present invention has been described in detail by general description and specific embodiments above, some modifications or improvements can be made on the basis of the present invention, which is obvious to a person skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention are within the scope claimed to be protected by the present invention.

INDUSTRIAL APPLICABILITY

[0175] The present invention provides a rice male fertility regulatory gene, the use thereof and a method for regulating rice fertility using CRISPR-Cas9, and a mutant of the rice male fertility regulatory gene and a molecular marker and the use thereof. The present invention provides a rice gene GMS2 with the function of regulating male germ cell development in rice and pollen fertility, the nucleotide sequence of which is represented by SEQ ID NO: 1, the CDS sequence is represented by SEQ ID NO: 2 and the amino acid sequence is represented by SEQ ID NO: 3. The rice male fertility regulatory protein GMS2 mutant provided by the present invention can make the rice pollen completely sterile, resulting in rice male sterility, the genome nucleotide sequence of the GMS2 mutant is represented by SEQ ID NO: 6, the CDS sequence is represented by SEQ ID NO: 7 and the amino acid sequence is represented by SEQ ID NO: 8. The genic sterile mutant of the present invention can be used for culturing a new genic sterile line, which provides a simple, rapid and effective method for the cultivation of the rice genic sterile line. The genic sterile rice material of the present invention can be used for replacing artificial emasculation during rice hybridization and saving labor, can be particularly used for recurrent selection breeding which needs a large amount of hybridization and plays an important role in expanding the germplasm basis of rice. The rice gene GMS2 and the mutant thereof provided by the present invention can be used for sterility breeding and production of rice hybrid seeds, and have a great application and economic value.