Application of OsbHLH167 gene in regulating deep rooting ratio of rice

Abstract

The invention discloses a rice OsbHLH167 gene and its application in regulating the deep root ratio of rice, and relates to the field of gene engineering technology. The nucleotide sequence of the gene is shown in SEQ ID NO.3, or a degenerate sequence shown in SEQ ID NO.3. By utilizing the ability of the OsbHLH167 gene of the invention to regulate the deep root ratio of rice, drought-resistant transgenic rice can be developed for arid areas, and barren-resistant transgenic rice can be developed for barren soil areas, so as to enhance the adaptability of rice germplasm to the environment and increase production and income.

Description

Technical Field

[0001] The invention relates to the technical field of gene engineering, and more specifically to the application of OsbHLH167 gene in regulating the deep root ratio of rice. Background Art

[0002] Rice is the crop that consumes the most water in agricultural production. Its water-saving and drought-resistance are of great significance to my country's food, water and ecological security.

[0003] The drought resistance of rice varieties refers to the ability of plants to provide economically valuable harvests by relying on certain traits during drought, that is, the ability of rice to use less water and obtain higher yields under drought conditions. The drought resistance mechanism of rice is very complex, and drought resistance can be roughly divided into four categories: drought escape, drought avoidance, drought tolerance and rewatering drought resistance.

[0004] Using genetic engineering, a molecular breeding technology, to transfer drought-resistant genes into the currently widely used excellent rice varieties, thereby improving their drought resistance, and cultivating new crop varieties that are both drought-resistant and high-yield and high-quality is one of the effective ways to breed drought-resistant crops. Discovering drought-resistant genes is the basis of molecular breeding for drought resistance. Therefore, discovering more rice drought-resistant genes is an urgent problem that technicians in this field need to solve. Summary of the invention

[0005] In view of this, the present invention provides an application of the OsbHLH167 gene in regulating the deep rooting ratio of rice.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A rice OsbHLH167 gene, the nucleotide sequence of the gene is shown as SEQ ID NO.3, or a degenerate sequence shown as SEQ ID NO.3.

[0008] Another object of the present invention is to provide an application of the above-mentioned OsbHLH167 gene in regulating the deep root ratio of rice, wherein the application is any one of the following:

[0009] A. enhancing the expression of the OsbHLH167 gene to improve the deep root ratio of rice;

[0010] B. Reducing the expression level of the OsbHLH167 gene reduces the deep root ratio of rice.

[0011] Another object of the present invention is to provide an application of the OsbHLH167 gene in rice stress resistance breeding, wherein the application is to enhance the expression level of the OsbHLH167 gene to cultivate drought-resistant rice varieties.

[0012] Another object of the present invention is to provide a use of a biological material for enhancing the expression of the above-mentioned OsbHLH167 gene in improving the deep root ratio of rice or cultivating drought-resistant rice varieties, wherein the biological material is any one of the following:

[0013] A. an expression cassette capable of overexpressing the above-mentioned OsbHLH167 gene;

[0014] B. A recombinant vector containing the expression cassette described in A;

[0015] C. A recombinant microorganism containing the expression cassette described in A or the recombinant vector described in B.

[0016] Another object of the present invention is to provide a biological material for reducing the expression amount of the above-mentioned OsbHLH167 gene for use in reducing the deep root ratio of rice or cultivating rice varieties resistant to barrenness, wherein the biological material is any one of the following:

[0017] A. an expression cassette capable of suppressing the above-mentioned OsbHLH167 gene;

[0018] B. A recombinant vector containing the expression cassette described in A;

[0019] C. A recombinant microorganism containing the expression cassette described in A or the recombinant vector described in B.

[0020] Another object of the present invention is to provide a method for cultivating transgenic rice, which is any one of the following:

[0021] A. obtaining rice with a deeper rooting ratio and / or drought resistance higher than that of wild type rice by enhancing the expression of OsbHLH167 gene and / or increasing the activity of OsbHLH167 protein in plants;

[0022] B. obtaining rice with a lower deep rooting ratio than that of the wild type by inhibiting the expression of the OsbHLH167 gene in the plant and / or reducing the activity of the OsbHLH167 protein;

[0023] The nucleotide sequence of the OsbHLH167 gene is shown in SEQ ID NO.3, or a degenerate sequence shown in SEQ ID NO.3.

[0024] The term "degenerate sequence" of the present invention refers to a sequence generated after one or more codons in the nucleotide sequence of SEQ ID NO.3 are replaced by degenerate codons encoding the same amino acid. Due to the degeneracy of codons, a degenerate sequence with a sequence homology of as low as about 70% with SEQ ID NO.3 can also encode a sequence identical to the amino acid encoded by SEQ ID NO.3. The term also includes nucleotide sequences that can hybridize with SEQ ID NO.3 under moderately stringent conditions (70-85% identity), and more preferably under highly stringent conditions (85% identity or more). The term also includes nucleotide sequences that have at least 70% homology to the nucleotide sequence of SEQ ID NO.3, preferably at least 80%, more preferably at least 90%, and most preferably at least 95%.

[0025] The term "expression cassette" of the present invention refers to a DNA capable of expressing a target gene in a host cell, which may include not only a promoter for initiating transcription of a protein-coding gene, but also a terminator for terminating transcription of a protein-coding gene. Preferably, the expression cassette may also include an enhancer sequence.

[0026] The term "vector" of the present invention refers to various vectors known in the art, such as commercially available vectors, including plasmids, cosmids, etc. When producing the rice OsbHLH167 polypeptide of the present invention, the rice OsbHLH167 coding sequence can be operably linked to the expression regulatory sequence to form a rice OsbHLH167 protein expression vector.

[0027] Beneficial effects:

[0028] The OsbHLH167 gene of the present invention has the ability to regulate the deep root ratio of rice. By utilizing this ability, drought-resistant transgenic rice can be developed for arid areas, and barren-resistant transgenic rice can be developed for soil-poor areas, thereby enhancing the adaptability of rice germplasm to the environment and increasing production and income. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0030] Figure 1 Schematic diagram of the basket method for identifying the deep rooting ratio of rice.

[0031] Figure 2Detection of OsbHLH167 gene expression in transgenic lines; AT4 is an overexpression line, at4 is a knockout line, and **** indicates that the t-test p value is less than 0.0001 compared with the wild-type plant.

[0032] Figure 3 The OsbHLH167 gene significantly regulates the deep root ratio of rice. WT indicates wild type, AT4 indicates overexpression line, at4 indicates knockout line, error bars indicate standard error of 3 replicates; * indicates t-test p value less than 0.05 compared with wild-type plants; ** indicates t-test p value less than 0.01.

[0033] Figure 4 The OsbHLH167 gene significantly regulates rice drought resistance; a is the fruit setting rate, b is the 100-grain weight, and c is the yield per plant; AT4 is the overexpression line, at4 is the knockout line, * indicates that the t-test p value is less than 0.05, ** indicates that the t-test p value is less than 0.01, and *** indicates that the t-test p value is less than 0.001. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The experimental methods in the following examples where specific conditions are not specified are generally performed under conventional conditions, such as those described in Sambrook et al. Molecular Cloning: A Laboratory Manual (New York: Cold Spring Harbor Laboratory Press, 1989), or under conditions recommended by the manufacturer.

[0036] Example 1

[0037] Identification of the deep root ratio of rice root system (basket method)

[0038] Method: Fill a plastic basket with paddy soil, place it on a metal rack, and place it in a cement pool filled with water so that the water surface is flush with the top of the basket. Germinate rice seeds (IRAT109 with deep roots and Zhenshan 97 with shallow roots) and transplant individual plants to the middle of the top of the basket. After about 30 days, when the rice grows to the peak tillering stage, take the basket out of the water and count the number of roots extending from the bottom (deep roots) and the side (shallow roots) of the basket to calculate the deep root ratio (see Appendix Figure 1 ). The deep root ratio is an important indicator for identifying rice drought tolerance.

[0039] Deep root ratio = number of deep roots / (number of deep roots + number of shallow roots)*100.

[0040] Deep root ratio is an indicator of plant root development. Deep rooting means that the taproot of a plant can penetrate deep into the soil and mainly develop in the vertical direction; shallow rooting means that the root system of a plant mainly develops in the horizontal direction. Deep root plants have a deeper root system and can absorb more soil moisture and nutrients from deeper soil, thereby enhancing their drought resistance. Shallow root plants have stronger adaptability and can grow in relatively dry and poor soils, and grow rapidly.

[0041] Example 2

[0042] Cloning of Rice OsbHLH167 Gene

[0043] 1. Seedling cultivation: Rice (variety "IRAT109") was collected and preserved by the Germplasm Resource Bank of Shanghai Agricultural Biological Gene Center. The rice was placed at 35°C for germination for 48 hours and then sown in a greenhouse. When the rice leaves were 3-5, the roots were taken and frozen in liquid nitrogen in preparation for extraction of DNA or RNA.

[0044] 2. RNA extraction: The root tip tissues of deep roots and shallow roots were taken separately, frozen with liquid nitrogen in a mortar and ground into powder, added to a 1.5 mL EP tube containing TRIzol reagent (Tiangen Biochemical Technology Co., Ltd.), fully shaken, placed at room temperature for 5 minutes, centrifuged at 4°C, 12000r / min for 15 minutes, and the supernatant was transferred to a new 1.5 mL EP tube. After chloroform deproteinization, RNA was precipitated with an equal volume of isopropanol, dissolved, and digested with DNase to degrade residual DNA. The quality of total RNA was identified by formaldehyde denaturing gel electrophoresis, and then the RNA content was determined on a spectrophotometer.

[0045] 3. Full-length cloning of the gene: According to the sequence information provided in the rice database information in GeneBank, primers were designed and the full-length cDNA was cloned using the RT-PCR method.

[0046] A cDNA sequence (SEQ ID NO.3) containing a complete open reading frame was obtained by RT-PCR [Pf1 (SEQ ID NO.1) + Pr1 (SEQ ID NO.2)], with a length of 705 bp; recovered, connected to the pGEMT-Easy vector, and sequenced on an ABI 377 sequencer (Perkin-Elmer, USA) using SP6 or T7 as universal primers and a terminator fluorescent labeling (Big-Dye, Perkin-Elmer, USA). Analysis of the sequencing results showed that the encoded protein had a total of 234 amino acid residues (SEQ ID NO.4), a molecular weight of 25.1k Daltons, an isoelectric point (pI) of 9.15, a bHLH motif, DNA binding ability, and was a transcriptional regulator.

[0047] Pf1: 5ˋ-ATGGATCAGGAGAAGGCGGA-3ˋ, SEQ ID NO.1;

[0048] Pr1: 5ˋ-TCAAGACCGGATCACCAATG-3ˋ, SEQ ID NO.2.

[0049] CDS Sequence:

[0050] ATGGATCAGGAGAAGGCGGACGGCGGCGGCAGGAGGAGGAGGAGCAGGGCGACGAGTAGCAGCGGCAGCGGCGCGAGCAGCACGGCGGCGGCGGCGGCGGCGGAGAGGAAGGAGATGGAGCGCAGGAGGCGGCAGGACATGAAGGGCCTCTGCGTCAAGCTCGCCTCTCTCATCCCCAAAGAACACTGCTCCATGTCCAAGATGCAGGCGGCGTCTAGGACCCAGCTGGGCAGCCTGGACGAAGCGGCGGCCTACATCAAGAAGCTCAAGGAAAGGGTGGACGAGCTGCACCACAAGAGGAGCATGATGAGTATCACATCATCGCGCTGCCGCTCAGGAGGAGGAGGAGGACCAGCTGCTGCTGCTGGCCAGTCGACGAGCGGCGGCGGCGGCGGGGAAGAAGAAGAAGAAGATATGACGAGGACGACGGCGGCGGCGGCGGTGGTGGAGGTGCGGCAGCACGTGCAGGAGGGGTCGCTGATCAGCTTGGACGTGGTGCTGATCTGCAGCGCAGCGAGGCCGGTCAAGTTCCACGACGTCATCACCGTCCTCGAGGAAGAAGGCGCCGACATCATCTCCGCCAACTTCTCCCTCGCCGCCCACAATTTCTACTACACCATCTACTCCAGGGCCTTTAGCTCAAGAATTGGCATAGAGGCTTCGAGGATTTCTGAGAGACTACGGGCATTGGTGATCCGGTCTTGA, SEQ ID NO.3。

[0051] Amino acid sequence:

[0052] MDQEKADGGGRRRRSRATSSSGSGASSTAAAAAAERKEMERRRRQDMKGLCVKL

[0053] ASLIPKEHCSMSKMQAASRTQLGSLDEAAAYIKKLKERVDELHHKRSMMSITSSRCRSGG

[0054] GGGPAAAAGQSTSGGGGGEEEEEDMTRTTAAAAVVEVRQHVQEGSLISLDVVLICSAARPVKFHDVITVLEEEGADIISANFSLAAHNFYYTIYSRAFSSRIGIEASRISERLRALVIRS, SEQ ID NO.4.

[0055] Example 3

[0056] Creation of transgenic mutants of rice OsbHLH167 gene

[0057] 1. Construction of gene knockout vector for rice OsbHLH167 gene:

[0058] According to the full-length cDNA sequence of the rice gene OsbHLH167 (SEQ ID NO.3), the CRISPER / Cas9 system was used to design a gene knockout target sequence (5ˋ-ATGGATTGACGAAGCAGAAGAGG-3ˋ; SEQ ID NO.5) upstream of the gene coding region. The reverse primer u6a-R (5ˋ-TCTCCTGATCCATAATTAGTcggcagccaagccagca-3ˋ; SEQ ID NO.6) for U6a promoter amplification and the forward primer gRNAf (5ˋ-ACTAATTATGGATCAGGAGAgttttagagctagaaat-3ˋ; SEQ ID NO.7) for guide RNA sequence amplification were designed according to the target site sequence and paired with the universal primers to amplify the U6a fragment containing the target sequence and the guide RNA fragment, respectively. The two fragments were purified and mixed, and the U6a: gRNA expression cassette fragment of the sweating target site was amplified by bridge PCR. The fragment was introduced into the CRISPER / Cas9 vector pYLCRISPR / Cas9Pubi-H (Ma et al., 2015, DOI: 10.1016 / j.molp.2015.04.007) using homologous recombinase. The vector was transformed into Escherichia coli JM109, screened in a medium containing kanamycin, and the plasmid was extracted and sequenced.

[0059] It was then transferred into Agrobacterium EHA105 and transformed into the model plant deep-rooted rice Zhonghua 11 (due to the low genetic transformation rate of the shallow-rooted Zhenshan 97 rice variety, another shallow-rooted rice variety Zhonghua 11 was used for further research).

[0060] 2. Construction of rice OsbHLH167 gene overexpression vector:

[0061] According to the full-length sequence of the rice gene OsbHLH167 (SEQ ID NO.3), primers for amplifying the complete coding reading frame were designed, and restriction endonuclease sites were introduced on the upstream and downstream primers respectively (this depends on the selected vector) to construct an expression vector. Using the amplified product obtained in Example 2 as a template, after PCR amplification, the cDNA of the rice gene OsbHLH167 was cloned into an intermediate vector (such as pBI121), and further cloned into a binary expression vector (such as pCAMBIA1300). Under the premise of ensuring the correct reading frame, the binary expression vector was transferred into Agrobacterium and transformed into the model plant rice Zhonghua 11.

[0062] 3. Rice genetic transformation

[0063] Callus induction: Rinse the seeds with sterile water for 15-20 minutes, disinfect with 70% ethanol for 1 minute, and then shake and disinfect with sodium hypochlorite (1.5% effective concentration) solution for 20 minutes. Finally, rinse with sterile water for 5 times. Dry the washed seeds with absorbent paper and inoculate them in callus induction medium, and culture them in the dark at 25℃ for 2 weeks.

[0064] Subculture: Cut the embryonic callus, inoculate it into the subculture medium, and culture it in the dark at 25℃ for 2 weeks.

[0065] Agrobacterium infection and callus co-cultivation: Cultivate Agrobacterium, take positive single colonies, and culture them in 1ml Agrobacterium culture solution (containing antibiotics) at 28℃ overnight; take the above culture, add it to 50ml Agrobacterium culture solution (containing antibiotics), and culture it at 28℃ until OD600=0.6-1.0. Centrifuge the obtained Agrobacterium culture, add the collected bacteria to the suspension culture solution, and shake and culture for 30min until OD600=0.6-1.0. Then put the callus into the suspension culture solution containing Agrobacterium culture solution, and shake and culture for about 20min. Dry the callus on sterile filter paper, transfer it to the co-cultivation medium, and culture it in the dark at 25℃ for 5d.

[0066] Screening culture: After 3 days of co-culture, select good callus tissue, transfer to screening medium, culture in the dark at 25°C for 2 weeks, and screen twice.

[0067] Differentiation culture: Embryonic callus was selected and inoculated into differentiation medium. Cultured at 24°C with 16h / 8h light and dark to induce differentiation buds (4-6 weeks).

[0068] Rooting culture: When the buds grow to about 2 cm, cut off the young buds and insert them into the rooting medium. Culture them at about 25°C with 16h / 8h light and dark conditions to induce rooting.

[0069] Transform the plants for cultivation; after the root system is well developed, open the test tube, add sterile water to train the seedlings for 2-3 days, take out the plants, wash the attached solid culture medium with sterile water, and move them into the soil. Provide shade and shelter from the wind at the beginning, and carry out conventional field or greenhouse management and cultivation after the plants are strong.

[0070] All culture media involved in this embodiment (callus induction medium, subculture medium, co-cultivation medium, screening medium, differentiation induction medium, rooting medium) are conventional culture media.

[0071] The positive identification and mutation detection of transgenic rice were performed by PCR. The overexpression transgenic positive plants and gene knockout mutant homozygous mutants were quantitatively detected. The results showed that the expression level of OsbHLH167 gene in overexpression plants was significantly higher than that in wild-type rice; while the expression level of OsbHLH167 gene in mutant rice was significantly decreased (see Appendix Figure 2 ).

[0072] Example 4

[0073] 1. OsbHLH167 gene regulates rice root development

[0074] We constructed a plant transformation vector and introduced it into rice Zhonghua 11, obtaining mutant materials and overexpression materials of the OsbHLH167 gene; through sequencing to identify homozygous and frameshift mutant materials, expression level detection, etc., we obtained knockout mutant strains and overexpression strains.

[0075] The knockout mutant strains and overexpression strains were hydroponically cultured, and the rice root volume was measured at the 6-leaf stage. The specific method was as follows: rice seeds were germinated on 1 / 2MS culture medium, the roots were wrapped with sponges, inserted into the holes of the support frame, and transplanted into a planting box filled with rice liquid culture medium; 5 individual plants were planted for each material, and 18 plants could be planted in each box; the rice liquid culture medium was replaced every 3 days and cultured to the 4-leaf stage. For normal culture, the rice liquid culture medium was continued for 7 days; for 18% PEG stress, 180g PEG6000 was dissolved in each 1L rice liquid culture medium, and the stress culture was carried out for 7 days. Root traits were examined.

[0076] At the same time, the deep root ratio of these mutants and the wild-type parent Zhonghua 11 was detected by the basket method at the peak tillering stage.

[0077] By analyzing the deep root ratio data, it was found that the deep root ratio of the knockout mutant rice and the wild-type rice was significantly reduced by 20%-30%, while the deep root ratio of the overexpression material was significantly increased by about 10% (see Appendix Figure 3 ). Therefore, we determined that the OsbHLH167 gene significantly regulates the root volume of rice under drought stress, and also significantly regulates the deep root ratio phenotype of rice, and it is reasonable to speculate that it has the function of improving the drought resistance of rice.

[0078] 2. OsbHLH167 gene regulates rice drought resistance

[0079] The field water stress test was conducted on the OsbHLH167 gene overexpression rice lines and gene knockout mutant lines using the soil natural drought method in the field to analyze the drought resistance of rice OsbHLH167 gene. We planted the wild type Zhonghua 11 (WT, drought-sensitive type) and two independent transformation lines AT4-32 and AT4-34 overexpressing the OsbHLH167 gene, and three different types of independent mutant lines at-106, at-107, and at-108 in Hainan drought-resistant greenhouses, and carried out conventional water management (from transplanting, the field was covered with 5-10cm water layer, and water was cut off for 7 days during the tillering peak period, and then irrigated to maintain a 5-10cm water layer until maturity) and natural drought stress treatment (no watering from the seedling stage to the field), each treatment set up 3 replicate plots, and 36 plants of each material were planted in each plot. The fields under natural drought stress had no plowed bottom layer, and water was cut off after the seedlings reached full height; agronomic traits were investigated after maturity.

[0080] The results showed that under normal water conditions, there were no significant differences in the wild-type Zhonghua 11 (WT) and rice materials overexpressing the OsbHLH167 gene and the knockout rice materials in terms of fruit setting rate, 1000-grain weight, yield per plant and other traits; however, under drought stress, the fruit setting rate, 1000-grain weight, yield per plant and other agronomic traits of rice overexpressing the OsbHLH167 gene were significantly higher than those of WT rice, reaching a significant or extremely significant level; on the contrary, the fruit setting rate, 1000-grain weight and yield per plant of the knockout rice were significantly lower than those of WT rice, also reaching a significant or extremely significant level (see Appendix). Figure 4 ). These results indicate that the rice OsbHLH167 gene regulates rice drought resistance and that the drought resistance of rice can be improved by increasing its expression level in rice.

[0081] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0082] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. OsbHLH167 The application of the gene in regulating the deep rooting ratio of rice is characterized in that: The application is any of the following: A. Enhance the OsbHLH167 The expression of the gene increases the deep rooting ratio of rice; B. Weaken the OsbHLH167 The expression of the gene reduces the deep rooting ratio of rice; Said OsbHLH167 The nucleotide sequence of the gene is shown in SEQ ID NO.3, or a degenerate sequence shown in SEQ ID NO.

3.

2. OsbHLH167 The application of the gene in rice stress resistance breeding is characterized in that: The application is to enhance the OsbHLH167 Breeding drought-resistant rice varieties by adjusting the expression level of genes; Said OsbHLH167 The nucleotide sequence of the gene is shown in SEQ ID NO.3, or a degenerate sequence shown in SEQ ID NO.

3.

3. Enhancement OsbHLH167 The use of a biomaterial with a high gene expression level in improving the deep root ratio of rice or cultivating drought-resistant rice varieties is characterized in that: The biological material is any one of the following: A.Can make OsbHLH167 expression cassettes for gene overexpression; B. A recombinant vector containing the expression cassette described in A; C. A recombinant microorganism containing the expression cassette described in A or the recombinant vector described in B; Said OsbHLH167 The nucleotide sequence of the gene is shown in SEQ ID NO.3, or a degenerate sequence shown in SEQ ID NO.

3.

4. Reduce OsbHLH167 The use of a biomaterial with a gene expression amount in reducing the deep root ratio of rice is characterized in that: The biological material is any one of the following: A.Can make OsbHLH167 expression cassettes for gene suppression; B. A recombinant vector containing the expression cassette described in A; C. A recombinant microorganism containing the expression cassette described in A or the recombinant vector described in B; Said OsbHLH167 The nucleotide sequence of the gene is shown in SEQ ID NO.3, or a degenerate sequence shown in SEQ ID NO.

3.

5. A method for cultivating transgenic rice, characterized in that: The method is any of the following: A. By enhancing the OsbHLH167 By increasing the expression of the gene and / or the activity of the OsbHLH167 protein, a rice with a deeper rooting ratio and / or drought resistance higher than that of the wild type is obtained; B. By inhibiting the OsbHLH167 By regulating the expression of the gene and / or reducing the activity of the OsbHLH167 protein, rice with a lower deep rooting ratio than the wild type is obtained; Said OsbHLH167 The nucleotide sequence of the gene is shown in SEQ ID NO.3, or a degenerate sequence shown in SEQ ID NO.3.

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