Application of ZmSAUR72 protein and its coding gene in regulating drought resistance of plants

Abstract

The application discloses application of ZmSAUR72 protein and a coding gene thereof in regulation of drought resistance of plants and belongs to the technical field of genetic engineering breeding. The application discloses application of the ZmSAUR72 protein or an expression material for regulating the coding gene of the protein or a material for regulating the activity or content of the protein in regulation of drought resistance of plants. The amino acid sequence of the protein is shown as SEQ ID No. 1, the nucleotide sequence of the coding gene of the protein is shown as SEQ ID No. 1, and it is verified that the regulation in the above application is positive regulation. By increasing the expression amount and / or activity of the ZmSAUR72 protein, the interval of corn loose spinning time is reduced, the drought resistance of plants is enhanced, the grain number of a single ear of plants is increased, and the yield of a single ear of plants is increased. The negative regulation effect of inhibition or reduction of the expression amount of the ZmSAUR72 gene in the above application is also verified by a gene knockout method. The application further discloses a method for improving the drought resistance of plants, which comprises introducing the coding gene of the protein into a receptor plant to obtain a plant with improved drought resistance.

Description

Technical Field

[0001] This invention relates to the field of genetic engineering breeding technology, specifically to the application of the ZmSAUR72 protein and its encoding gene in regulating plant drought resistance, particularly the application of drought resistance during maize flowering. Background Technology

[0002] Drought is a major agricultural natural disaster. About 43% of the world's arable land is located in arid and semi-arid regions, and drought-induced food losses account for 60% of the total losses caused by all natural disasters. As a dryland crop with high water requirements and sensitivity to drought stress, maize's yield will be severely affected once water shortage occurs. Therefore, research on genetic improvement of maize drought resistance is particularly important.

[0003] Traditional breeding techniques suffer from drawbacks such as long cycles, high degree of uncertainty, and large workload. Moreover, the use of traditional breeding to increase grain yield has reached a certain bottleneck. In recent years, with the development of plant molecular biology and genetics, and in-depth research on the molecular mechanisms of plant stress resistance, the introduction of stress-resistance-related genes into plants through genetic engineering to improve crop stress resistance has become increasingly mature, providing possible genetic resources and theoretical basis for the genetic improvement of maize drought resistance.

[0004] As an important feed and food crop widely cultivated in my country, cloning drought-resistant genes in maize (Zeamays L.) is of great significance for improving its drought resistance and increasing its yield. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide the application of the ZmSAUR72 protein and its encoding gene in regulating plant drought resistance.

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0007] The use of the ZmSAUR72 protein, its encoding gene, or biological material containing its encoding gene in any of the following aspects:

[0008] D1) Application in improving plant drought resistance;

[0009] Application of D2 in the preparation of products that improve plant drought resistance;

[0010] Application of D3 in drought-resistant plant breeding;

[0011] The ZmSAUR72 protein is any one of the following:

[0012] A1) The amino acid sequence of this protein is that of SEQ ID No. 1;

[0013] A2) Proteins with the same biological function obtained by substituting and / or deleting and / or adding one or more amino acid residues of the amino acid sequence shown in SEQ ID No. 1 in the sequence listing.

[0014] Application of ZmSAUR72 protein, its encoding gene, or biological materials containing its encoding gene in reducing the time interval between pollen shedding and silking in maize.

[0015] The ZmSAUR72 protein is any one of the following:

[0016] A1) The amino acid sequence of this protein is that of SEQ ID No. 1;

[0017] A2) Proteins with the same biological function obtained by substituting and / or deleting and / or adding one or more amino acid residues of the amino acid sequence shown in SEQ ID No. 1.

[0018] Application of ZmSAUR72 protein, its encoding gene, or biological materials containing its encoding gene in increasing maize yield;

[0019] The ZmSAUR72 protein is any one of the following:

[0020] A1) The amino acid sequence of this protein is that of SEQ ID No. 1;

[0021] A2) Proteins with the same biological function obtained by substituting and / or deleting and / or adding one or more amino acid residues of the amino acid sequence shown in SEQ ID No. 1.

[0022] Preferred,

[0023] The gene encoding the ZmSAUR72 protein is any one of the following:

[0024] b1) The nucleotide sequence shown in SEQ ID No. 2;

[0025] b2) A nucleotide sequence of the nucleotide sequence shown in SEQ ID No. 2 that has been substituted, deleted and / or added with one or more nucleotides and expresses the same functional protein.

[0026] The preferred biomaterial is any one of B1) to B9) below:

[0027] B1) A nucleic acid molecule encoding the ZmSAUR72 protein as described in claim 1;

[0028] B2) An expression cassette containing the nucleic acid molecule described in B1);

[0029] B3) A recombinant vector containing the nucleic acid molecule described in B1), or a recombinant vector containing the expression cassette described in B2);

[0030] B4) Recombinant microorganisms containing the nucleic acid molecules described in B1), or recombinant microorganisms containing the expression cassette described in B2), or recombinant microorganisms containing the recombinant vector described in B3);

[0031] B5) A transgenic plant cell line containing the nucleic acid molecule described in B1), or a transgenic plant cell line containing the expression cassette described in B2), or a transgenic plant cell line containing the recombinant vector described in B3);

[0032] B6) Transgenic plant tissue containing the nucleic acid molecules described in B1), or transgenic plant tissue containing the expression cassette described in B2), or transgenic plant tissue containing the recombinant vector described in B3);

[0033] B7) A transgenic plant organ containing the nucleic acid molecule described in B1), or a transgenic plant organ containing the expression cassette described in B2), or a transgenic plant organ containing the recombinant vector described in B3).

[0034] Preferredly, this is achieved by increasing the expression level and / or activity of the ZmSAUR72 protein.

[0035] This invention provides that the regulation of ZmSAUR72 protein, its encoding gene, or biological materials containing its encoding gene in the above-mentioned applications is positive regulation, which increases the expression level of ZmSAUR72 protein or ZmSAUR72 gene, reduces the time interval between pollen shedding and silking, enhances plant drought resistance, increases the number of grains per spike, and increases the yield per spike.

[0036] A method to improve plant drought resistance,

[0037] Plants with improved drought resistance were obtained by increasing the expression level and / or activity of ZmSAUR72 protein.

[0038] The ZmSAUR72 protein is any one of the following:

[0039] A1) The amino acid sequence of this protein is that of SEQ ID No. 1;

[0040] A2) Proteins with the same biological function obtained by substituting and / or deleting and / or adding one or more amino acid residues of the amino acid sequence shown in SEQ ID No. 1.

[0041] Preferred

[0042] By increasing the expression level and / or activity of ZmSAUR72 protein, the time interval between pollen shedding and silking in maize can be reduced.

[0043] Preferred

[0044] By increasing the expression level and / or activity of the ZmSAUR72 protein, the number of kernels per ear of maize can be increased, thereby increasing the yield per ear of maize.

[0045] This invention obtains gene-knockout plant material by gene editing in recipient plants using the CRISPR / Cas9 system, and verifies that after the ZmSAUR72 gene is knocked out, compared with the wild type, the time interval between pollen shedding and silking of maize increases, the number of kernels per ear decreases, the yield per ear decreases, and the drought resistance of the plant decreases.

[0046] In the gene knockout method described above, the gRNA target sequence is shown in SEQ ID No. 10.

[0047] In the above applications, the plant can be any of the following:

[0048] P1) Monocotyledons,

[0049] P2) Plants of the order Poales,

[0050] P3) Gramineae plants,

[0051] P4) Plants of the genus *Zea*.

[0052] P5) Corn.

[0053] The primer pairs for amplifying the ZmSAUR72 gene have nucleotide sequences shown in SEQ ID No. 4 and SEQ ID No. 5.

[0054] The beneficial effects of this invention are:

[0055] 1. This invention experimentally verifies that the ZmSAUR72 protein and its encoding gene have a regulatory function on plant drought resistance, and that the ZmSAUR72 protein and its related biological materials can be applied to the regulation of plant drought resistance.

[0056] 2. This invention provides a method for regulating plant drought resistance, and a transgenic homozygous line with improved drought resistance can be obtained according to the technical solution provided by this invention. Attached Figure Description

[0057] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0058] Figure 1 This is a fine-grained positioning map for qDR9.

[0059] Figure 2 The figure shows the statistical results of the drought phenotype of NIL-qDR9 material.

[0060] Figure 3 Figures showing the acquisition and identification of ZmSAUR72 OE material and Zmsaur72 mutant material.

[0061] Figure 4 The figure shows the statistical results of the field drought phenotype of the Zmsaur72 mutant material.

[0062] Figure 5 Figure showing the statistical results of field drought phenotypes of ZmSAUR72 OE material. Detailed Implementation

[0063] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the following embodiments are given for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.

[0064] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0065] The maize transgenic overexpression vector pBCXUN was derived from the pCXUN (NCBI GenBank: FJ905215) vector. The modification involved replacing the selection marker gene Hyg with the Bar gene at the XhoI site. The above-mentioned biological materials are available to the public from the applicant and are intended solely for replicating the experiments of this invention; they may not be used for any other purpose.

[0066] The transgenic maize recipient material ND101 (PI 612589) is available from GRIN-Global (https: / / npgsweb.ars-grin.gov / gringlobal / search).

[0067] The maize gene-editing vector pBUE411 was kindly provided by Professor Chen Qijun of China Agricultural University. It was used in the literature "Hui-LiXing, Li..." The biological material described above is disclosed in Zhi-Ping Wang, Hai-Yan Zhang, Chun-Yan Han, Bing Liu, Xue-Chen Wang and Qi-Jun Chen (2014). A CRISPR / Cas9 toolkit for multiplex genome editing in plants. BMC Plant Biology 2014, 14:327. (in the literature, it is named pBUE411(Bar)). The public can obtain the above biological material from the applicant. The obtained biological material is only for repeating the experiments of this invention and cannot be used for other purposes.

[0068] In this invention, a two-tailed t-test is used to determine statistical significance.

[0069] Example 1: Fine-tuning of qDR9 and regulation of drought resistance during maize flowering period

[0070] Preliminary mapping analysis using parental populations revealed that qDR9, located on chromosome 9, is involved in regulating drought tolerance during maize flowering, such as... Figure 1 As shown in a. A fine-mapping population was constructed to narrow down the target region to the ZmSAUR72 gene region and its upstream 2350bp region, as shown in a. Figure 1 As shown in bd. Figure 1 b is a schematic diagram of the initially located 2.65Mb region. Figure 1 c represents the genotype-phenotype results in fine mapping. Figure 1 Figure d shows a schematic diagram of the finely located 2350bp region. A two-tailed t-test was used for significance analysis.

[0071] Example 2: Statistical results of drought phenotype of NIL-qDR9 material

[0072] NIL-qDR9 was isolated. C and NIL-qDR9 M Materials: To verify how qDR9 regulates flowering phenotype and yield in maize under drought conditions, NIL-qDR9 was studied at the Zhangye experimental base in 2023. C and NIL-qDR9 M The materials were planted. From stage V5 (the fifth leaf visible at the ligule) until silking completion, the plants were subjected to drought treatment. The total irrigation amount for the water-stressed (WS) plots was approximately 40% of that for the normally growing plots. The pollen shedding time, silking time, anthesis-to-silking interval (ASI), yield per ear, number of grains per ear, and 100-grain weight under drought conditions were statistically analyzed. A two-tailed t-test was used for significance analysis.

[0073] Figure 2 a is NIL-qDR9 C and NIL-qDR9 M Photographs of the entire plant under drought conditions. Figure 2 b represents NIL-qDR9 C and NIL-qDR9 M Enlarged photographs of parts of the female and male ears under drought conditions. Figure 2 As shown in ce, after drought treatment, NIL-qDR9 C and NIL-qDR9 M The pollen shedding time of the materials was not significantly different under drought conditions. Figure 2 c) NIL-qDR9 C Silk spinning time compared to NIL-qDR9 M Significantly delayed ( Figure 2 d), NIL-qDR9 C ASI compared to NIL-qDR9 M Significantly increased ( Figure 2 e). This indicates that qDR9 regulates maize ASI by adjusting maize silking time.

[0074] Figure 2 f is NIL-qDR9 C and NIL-qDR9 M Images of harvested ears of grain. Figure 2 As shown in gi, after drought treatment, NIL-qDR9 C The yield per ear was significantly lower than that of NIL-qDR9. M ( Figure 2 g), NIL-qDR9 C The number of grains per ear was significantly lower than that of NIL-qDR9. M ( Figure 2 h), NIL-qDR9 C The 100-grain weight was significantly lower than that of NIL-qDR9. M ( Figure 2 i). This indicates that qDR9 mainly regulates the yield per ear of maize by adjusting the number of kernels per ear.

[0075] Example 3: Obtaining the protein ZmSAUR72 and its encoding gene

[0076] 1. Cloning of protein ZmSAUR72 and its encoding gene

[0077] Seeds of maize inbred line B73 were sown in a greenhouse and the seedlings were cultured to the mature stage. Maize silks were then flash-frozen in liquid nitrogen, ground, and total RNA was extracted. DNA digestion and reverse transcription were performed to obtain cDNA. Using this cDNA as a template, PCR amplification was performed with primers F1 and R1. The amplified product was subjected to 1% agarose gel electrophoresis, yielding a 378 bp PCR amplification product (SEQ ID No. 2).

[0078] Sequencing revealed that the PCR product derived from the maize inbred line B73 contained nucleotides 170-547 of SEQ ID No. 3 (this reference sequence can be obtained by searching Zm00001e377810 on https: / / www.gramene.org / ). The gene represented by SEQ ID No. 3 was named ZmSAUR72, and the protein encoded by this gene was also named ZmSAUR72. The amino acid sequence of this protein is shown in SEQ ID No. 1. In SEQ ID No. 3, positions 1-169 constitute the 5' untranslated region, positions 170-547 constitute the open reading frame region, and positions 548-1119 constitute the 3' untranslated region.

[0079] The primer sequences mentioned above are as follows:

[0080] F1: 5'-ATGGCGATCGTCAACAAGAAGCAG-3' (SEQ ID No. 4)

[0081] R1: 5'-TCACCGGGCGCAGGCGAG-3' (SEQ ID No. 5)

[0082] The nucleotide coding sequence of the ZmSAUR72 gene is shown in SEQ ID No. 2, and the nucleotide sequence of the ZmSAUR72 genome is shown in positions 170-547 of SEQ ID No. 3.

[0083] 2. Construction of the recombinant vector pBCXUN-ZmSAUR72

[0084] The coding sequence of the ZmSAUR72 gene (SEQ ID No. 2) was modified by adding a homologous arm to the XcmI restriction enzyme site (downstream of the ubi promoter). The vector was then digested with XcmI, and the digestion product was ligated to a pBCXUN vector fragment that had also been digested with the same enzyme. This yielded a recombinant vector containing the ZmSAUR72 coding sequence, named pBCXUN-ZmSAUR72. pBCXUN-ZmSAUR72 is a recombinant expression vector obtained by inserting a DNA molecule with the nucleotide sequence shown in SEQ ID No. 2 between the restriction endonuclease XcmI sites of the pBCXUN vector, while keeping the other nucleotide sequences of the pBCXUN vector unchanged. The promoter for initiating the ZmSAUR72 gene in the recombinant vector pBCXUN-ZmSAUR72 is Zmubiquitin1.

[0085] 3. Obtaining recombinant Agrobacterium

[0086] The recombinant vector pBCXUN-ZmSAUR72 was transformed into Agrobacterium EHA105 to obtain recombinant Agrobacterium EHA105 / pBCXUN-ZmSAUR72 containing the recombinant vector pBCXUN-ZmSAUR72 (after colony PCR, plasmid was extracted by shaking and sequencing to verify that the recombinant Agrobacterium was a positive clone).

[0087] 4. Obtaining the genetically modified homozygous ZmSAUR72 maize

[0088] Recombinant Agrobacterium EHA105 / pBCXUN-ZmSAUR72 was used to infect the immature embryos of wild-type maize ND101, yielding T1 generation seeds. Whole-genome DNA was extracted from the T1 generation transgenic plants, and PCR was performed to identify transgene positivity using primers F2 and R2. T2 generation seeds were harvested from positive plants (producing an 832 bp PCR product using F2 and R2). Genomic DNA was extracted from at least 24 T2 seeds after germination, and PCR was performed again using primers F2 and R2. If at least 24 seeds from a package showed positive PCR results, the package was likely homozygous for the transgenic ZmSAUR72. RNA was extracted from the seed plants and reverse transcribed to obtain cDNA. The maize gene ZmUbi2 (Zm00001d053838) was used as an internal control, with primers QF1 and QR1. Reverse transcription PCR (RT-qPCR) analysis was performed using primers F1 and R1, with wild-type ND101 as a control.

[0089] The sequences of the primers mentioned above are as follows:

[0090] F2: 5'-GACAGGCGTCTTCTACTGGTGCTAC-3' (SEQ ID No. 6)

[0091] R2: 5'-TATTCACTAGCTCGGGATAGTTGGC-3' (SEQ ID No. 7)

[0092] QF1: 5'-TGGTTGTGGCTTCGTTGGTT-3' (SEQ ID No. 8)

[0093] QR1: 5'-GCTGCAGAAGAGTTTTGGGTACA-3' (SEQ ID No.9)

[0094] T1 generation homozygous seeds or seeds produced by self-pollination of homozygous T1 generation plants (T2 generation) are used for experiments such as drought phenotype testing. T1 represents the seeds produced by the current generation of the transformation recipient plant and the plants that grow from it; T2 generation represents the seeds produced by self-pollination of the T1 generation and the plants that grow from it; and so on.

[0095] RNA was extracted from the filaments of positive plants and wild-type ND101 (control) and reverse transcribed to obtain cDNA. The maize gene ZmUbi2 (Zm00001d053838) was used as an internal control, with primers QF1 and QR1. Reverse transcription PCR (RT-qPCR) analysis of the ZmSAUR72 gene was performed using primers F1 and R1, and the expression level of the ZmSAUR72 gene was analyzed using ImageJ grayscale values. Results are as follows: Figure 3 As shown in figure a, the relative expression levels of the T2 generation transgenic ZmSAUR72 maize lines named OE#1 and OE#2 are more than 40 times higher than those of wild-type maize, indicating that the T2 generation transgenic ZmSAUR72 maize lines OE#1 and OE#2 are positive transgenic maizes.

[0096] Example 4: Functional study of protein ZmSAUR72 and its encoding gene

[0097] 1. Obtaining the ZmSAUR72 gene mutant in maize

[0098] A gRNA target (5'-GCAGCATCAGCGCAGCGTT-3') (SEQ ID No. 10) was designed on the exon of ZmSAUR72 using CRISPR-P (http: / / crispr.hzau.edu.cn / CRISPR2 / ). The target was constructed into the pBUE411 vector. After identifying positive clones by colony PCR, plasmids were extracted and sequenced. The correctly sequenced plasmids were transformed into Agrobacterium EHA105. Agrobacterium colony PCR-positive bacteria infected maize ND101 embryos to obtain T0 generation plants. T0 generation plants were self-pollinated to obtain T1 generation seeds. T1 generation seeds were germinated, planted, and maize cotyledons were harvested. Genomic DNA was extracted, and genotyping was performed using F1 and R1 primers. Self-pollination yielded T2 generation seeds of maize ZmSAUR72 gene mutants with two edited types. CRISPR Cas9 free was identified in the F2 and R2 generations of materials from these two genotypes, with wild-type ND101 as a control. PCR-negative plants were CRISPR Cas9 free. Seeds of Cas9-free T2 generation homozygous edited lines from the two edited maize ZmSAUR72 gene mutants were obtained through self-pollination and named KO#1 and KO#2. Figure 3 As shown in b, it is used for subsequent experiments.

[0099] like Figure 3 The mutant KO#1 shown in b, compared with wild-type maize ND101, exhibits the following mutation in the ZmSAUR72 gene in the maize genome on both homologous chromosomes: 5'-AGCATCAGCGCAGCGTTGGGGATGAGGAGGAGGAAG-3' replaces the 5'-AGCATCAGCGCAGCGTTGGGGATGAGGAGGAGGAAG-3' (positions 264-299 of SEQ ID No. 3) in the ZmSAUR72 gene genomic DNA. This results in a frameshift mutation after position 105 of the CDS of the ZmSAUR72 gene, thereby knocking out the ZmSAUR72 gene (wild-type). This mutated gene is named ZmSAUR72-1.

[0100] like Figure 3The mutant KO#2 shown in b, compared with wild-type maize ND101, exhibits the following mutation in the ZmSAUR72 gene in the maize genome on its two homologous chromosomes: 5'-AGCATCAGCGCAGCGTTGGGGATGAGGAGGAGGAAG-3' replaces the 5'-AGCATCAGCGCAGCGTTGGGGATGAGGAGGAGGAAG-3' (positions 262-297 of SEQ ID No. 3) in the ZmSAUR72 gene genomic DNA. This results in a frameshift mutation after position 102 of the CDS of the ZmSAUR72 gene, thereby knocking out the ZmSAUR72 gene (wild-type). This mutated gene is named ZmSAUR72-2. The d4 and d7 mutant strains were obtained, and their seeds were harvested after self-pollination, becoming the T2 generation seeds. Plants grown from the T2 generation seeds are the T2 generation plants.

[0101] Example 5: Field drought phenotypic analysis of transgenic maize

[0102] 1. Field drought phenotypic analysis of Zmsaur72 mutant homozygous lines

[0103] Under field experimental conditions, the tolerance of wild-type maize ND101 (WT) and homozygous mutant Zmsaur72 lines (KO#1 and KO#2) to drought treatment was tested. This experiment was conducted in Zhangye, 2023, with WT, KO#1, and KO#2 lines planted. Drought treatment involved water control 30 days after sowing, with soil water potential automatically monitored using a buried Watermark200SS sensor. During the drought treatment, water was replenished as the soil water potential gradually decreased to approximately -150 kPa. Irrigation was carried out approximately every 10 days, with each application of 45-450 tons of water per hectare, depending on soil moisture. The total irrigation amount for the drought-affected plots was approximately 40% of that for the normally growing plots. Pollen shedding time, silking time, ASI (average seed index), ear yield, number of grains per ear, and 100-grain weight were statistically analyzed. The drought treatment was replicated three times, with at least 10 plants per line, and the average values ​​were used for statistical analysis.

[0104] Figure 4 a is a photograph of the whole plant under drought conditions of maize ND101 wild-type (WT) and Zmsaur72 mutant homozygous lines (KO#1 and KO#2). Figure 4 b is a magnified photograph of the female and male ears under drought conditions of homozygous lines of wild-type (WT) maize ND101 and Zmsaur72 mutant (KO#1 and KO#2). Figure 4 As shown in ce, after drought treatment, there was no significant difference in powder dispersal time between KO#1 and KO#2 and WT materials under drought conditions. Figure 4c), the spin-out time of KO#1 and KO#2 was significantly delayed compared to WT. Figure 4 d) The ASI of KO#1 and KO#2 was significantly higher than that of WT. Figure 4 e). This indicates that KO#1 and KO#2 regulate corn ASI by adjusting the corn silking time.

[0105] Figure 4 Image f shows harvested ears of ND101 wild-type (WT) and Zmsaur72 mutant homozygous lines (KO#1 and KO#2). Figure 4 As shown in gi, after drought treatment, the single ear yield of KO#1 and KO#2 was significantly lower than that of WT ( Figure 4 g), the number of grains per ear of KO#1 and KO#2 was significantly lower than that of WT ( Figure 4 h), there was no significant difference in the 100-grain weight between KO#1 and KO#2 and WT (h). Figure 4 i). Zmsaur72 regulates the yield per ear of maize by adjusting the number of kernels per ear.

[0106] 2. Field drought phenotypic analysis of ZmSAUR72 OE lines

[0107] Under field experimental conditions, the tolerance of wild-type maize ND101 (WT) and ZmSAUR72 transgenic homozygous lines (OE#1 and OE#2) to drought treatment was tested. This experiment was conducted in Zhangye, 2023, with WT, OE#1, and OE#2 plants planted. Drought treatment involved water control 30 days after sowing, with soil water potential automatically monitored using a buried Watermark200SS sensor. During the drought treatment, water was replenished as the soil water potential gradually decreased to approximately -150 kPa. Irrigation was carried out approximately every 10 days, with each application of 45-450 tons of water per hectare, depending on soil moisture. The total irrigation amount for drought-affected plots was approximately 40% of that for normally growing plots. Pollen shedding time, silking time, ASI (average seed index), ear yield, number of grains per ear, and 100-grain weight were statistically analyzed. The drought treatment was replicated three times, with at least 10 plants per line, and the average values ​​were used for statistical analysis.

[0108] Figure 5 a is a photograph of the whole plant under drought conditions of maize ND101 wild-type (WT) and ZmSAUR72 transgenic homozygous lines (OE#1 and OE#2). Figure 5 b is a magnified photograph of the female and male ears of maize ND101 wild-type (WT) and ZmSAUR72 transgenic homozygous lines (OE#1 and OE#2) under drought conditions. Figure 5 As shown in ce, after drought treatment, the pollen shedding time of OE#1 and OE#2 was significantly earlier than that of WT. Figure 5c), the spin time of OE#1 and OE#2 was significantly earlier than that of WT. Figure 5 d) The ASI of OE#1 and OE#2 was significantly lower than that of WT. Figure 5 e).

[0109] Figure 5 Image f shows harvested ears of ND101 wild-type (WT) and ZmSAUR72 transgenic homozygous lines (OE#1 and OE#2). Figure 5 As shown in gi, after drought treatment, the single ear yield of OE#1 and OE#2 was significantly higher than that of WT ( Figure 5 g), the number of grains per ear in OE#1 and OE#2 was significantly higher than that in WT ( Figure 5 h), OE#1 and OE#2 showed no significant difference in 100-grain weight compared to WT (h). Figure 5 i). This indicates that ZmSAUR72 regulates maize yield per ear by adjusting the number of kernels per ear.

[0110] The above results indicate that overexpression of the gene encoding the protein ZmSAUR72 in plants can increase the yield per ear under drought conditions, while reducing the expression level of the gene encoding the protein ZmSAUR72 can significantly reduce the yield per ear under drought conditions.

[0111] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0112] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The use of the ZmSAUR72 protein, its encoding gene, or biological material containing its encoding gene in any of the following aspects: D1) Application in improving the drought resistance of maize; D2) Application in the preparation of products that improve the drought resistance of maize; Application of D3 in drought-resistant maize breeding; The amino acid sequence of the ZmSAUR72 protein is shown in SEQ ID No.

1.

2. The application according to claim 1, characterized in that: The nucleotide sequence of the gene encoding the ZmSAUR72 protein is shown in SEQ ID No.

2.

3. The application according to claim 1, characterized in that: The biomaterial is any one of B1) to B7) below: B1) A nucleic acid molecule encoding the ZmSAUR72 protein as described in claim 1; B2) An expression cassette containing the nucleic acid molecule described in B1); B3) A recombinant vector containing the nucleic acid molecule described in B1), or a recombinant vector containing the expression cassette described in B2); B4) Recombinant microorganisms containing the nucleic acid molecules described in B1), or recombinant microorganisms containing the expression cassette described in B2), or recombinant microorganisms containing the recombinant vector described in B3); B5) A transgenic plant cell line containing the nucleic acid molecule described in B1), or a transgenic plant cell line containing the expression cassette described in B2), or a transgenic plant cell line containing the recombinant vector described in B3); B6) Transgenic plant tissue containing the nucleic acid molecules described in B1), or transgenic plant tissue containing the expression cassette described in B2), or transgenic plant tissue containing the recombinant vector described in B3); B7) A transgenic plant organ containing the nucleic acid molecule described in B1), or a transgenic plant organ containing the expression cassette described in B2), or a transgenic plant organ containing the recombinant vector described in B3).

4. The application according to claim 1, characterized in that: This was achieved by increasing the expression level of the ZmSAUR72 protein.

5. A method for improving the drought resistance of maize, characterized in that: By increasing the expression level of ZmSAUR72 protein, plants with improved drought resistance were obtained; The nucleotide sequence of the gene encoding the ZmSAUR72 protein is shown in SEQ ID No.

2.

6. The method for improving the drought resistance of maize according to claim 5, characterized in that: By increasing the expression level of ZmSAUR72 protein, the time interval between corn cob shedding and silking can be reduced.

7. The method for improving the drought resistance of maize according to claim 5, characterized in that: By increasing the expression level of ZmSAUR72 protein, the number of kernels per ear of maize can be increased, thereby increasing the yield per ear of maize.

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