Application of ZmLEN1 gene in regulating lateral roots of maize

Abstract

The present invention relates to the application of ZmLEN1 gene in regulating corn lateral roots. The present invention can effectively increase the number of corn lateral roots and the open angle of lateral roots, reduce the average root diameter, and effectively increase corn yield by overexpressing the ZmLEN1 gene.

Description

Technical Field

[0001] The invention relates to the field of biological gene breeding, in particular to an application of a ZmLEN1 gene in regulating corn lateral roots. Background Art

[0002] The root system is the basis for maintaining plant life activities, and its morphology and configuration largely determine the ability of plants to absorb and obtain soil nutrients. Healthy plant growth requires the absorption of 14 mineral nutrients from the soil through the root system to maintain its normal growth and development process and complete its life cycle. However, the bioavailability of most mineral elements in the soil environment is low, and the distribution is uneven and volatile in time and space. As sessile organisms, in order to cope with nutrient changes in the soil environment, plants need to constantly perceive the aboveground nutrient requirements and external nutrient availability, and then integrate systemic and local nutrient signals to dynamically adjust the root system configuration to efficiently explore the soil and obtain nutrients. Plants' perception of the local and overall nutritional status of nutrients shapes the root system's response to the nutritional environment around them.

[0003] The increase in corn yield depends on the improvement of cultivation measures and continuous genetic improvement. In the past few decades, breeders have carried out a lot of research on corn plant morphology, yield components and stress resistance, and have made good progress. In recent years, research on corn root system has also received more and more attention and gradually become a hot research field. A large number of physiological studies have revealed the important contribution of root traits in nutrient absorption and stress resistance, and based on this, the ideal root system architecture for high yield and high efficiency of corn has been summarized. These results have pointed out the direction for breeders to carry out genetic improvement of corn root system. Due to the low heritability and difficulty of phenotypic identification of root traits, the effect of traditional breeding methods in root system improvement is limited. Therefore, breeders are more expected to design and transform root system architecture by manipulating root regulatory genes. The first step to achieve this goal is to find the target gene that regulates the root system architecture. Lateral roots are an important part of plant roots and play an important role in plant fixation, nutrient absorption, support and structural stability. However, the molecular mechanism of lateral root formation in corn is still unclear. Therefore, exploring the key genes that regulate maize lateral roots and studying their molecular mechanisms are of great significance for creating new maize germplasms with high yield and high nutrient efficiency. At the same time, improving the efficiency of phosphate fertilizer use is a key way to achieve the dual goals of maintaining high yields and reducing environmental risks, and is a major demand for the green development of national agriculture. Summary of the invention

[0004] In view of the defects in the prior art, the object of the present invention is to provide an application of the ZmLEN1 gene in regulating corn lateral roots. The present invention can effectively increase the number of corn lateral roots and the open angle of the lateral roots, reduce the average root diameter, and increase corn yield by overexpressing the ZmLEN1 gene.

[0005] The research and development of the technical solution described in this invention is funded by the following projects:

[0006] New gene mining and breeding value evaluation for efficient utilization of agricultural biological resources, project number: 2023ZD04072.

[0007] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0008] Application of the ZmLEN1 gene in regulating corn lateral roots, characterized in that the application is to increase the number of corn lateral roots and the open angle of the lateral roots, reduce the average root diameter, and increase corn yield by overexpressing the ZmLEN1 gene;

[0009] The ZmLEN1 gene is shown as SEQ ID NO.1, the CDS of the ZmLEN1 gene is shown as SEQ ID NO.10, and the amino acid sequence of the ZmLEN1 protein encoded by the CDS is shown as SEQ ID NO.11.

[0010] The primer pair used to amplify the above-mentioned ZmLEN1 gene is characterized in that the sequence of the primer pair is shown in SEQ ID NO.2-3.

[0011] The application of the ZmLEN1 gene of the present invention in regulating corn lateral roots has the following beneficial effects:

[0012] The present invention can effectively increase the number of corn lateral roots and the opening angle of the lateral roots, reduce the average diameter of the root system, and thus increase corn yield by overexpressing the ZmLEN1 gene. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention has the following accompanying drawings:

[0014] Figure 1 This is the skeleton diagram of the ZmLEN1 overexpression vector.

[0015] Figure 2 This is a diagram showing the identification results of ZmLEN1 overexpression materials.

[0016] Figure 3 The figure shows the results of the spatiotemporal expression pattern analysis of ZmLEN1. Figure 3 A is the expression level of ZmLEN1 in different tissues at the seedling stage; Figure 3 B is the expression level of ZmLEN1 in different tissues during the jointing period; Figure 3 C is the expression level of ZmLEN1 in different tissues during the silking period; Figure 3 D is the expression level of ZmLEN1 in different tissues 15 days after pollination.

[0017] Figure 4 This is the result of analyzing the response pattern of ZmLEN1 to low phosphorus. Figure 4 A is the expression level of the marker gene ZmPHT2 in the aboveground part after phosphorus deficiency induction; Figure 4 B is the expression level of the marker gene ZmPHT2 in the root system after phosphorus deficiency induction; Figure 4 C is the expression level of the marker gene ZmLEN1 in the aboveground part after phosphorus deficiency induction; Figure 4 D is the expression level of Marker gene ZmLEN1 in the root system after phosphorus deficiency induction.

[0018] Figure 5 This is the result diagram of the functional verification of ZmLEN1 under hydroponic conditions. Figure 5 A is a typical picture of root phenotype in hydroponic culture system; Figure 5 B is the aboveground biomass phenotype result under the hydroponic culture system; Figure 5 C is the phenotypic result of the number of roots on the lower side of the hydroponic culture system; Figure 5 D is the phenotypic result of total root length under the hydroponic culture system; Figure 5 E is the average direct phenotypic result of the root system under the hydroponic culture system.

[0019] Figure 6 This is the result of the field experiment phenotype verification of OE-ZmLEN1. Figure 6 A is a typical picture of root phenotype under field conditions; Figure 6 B is the root angle phenotype result under field conditions; Figure 6 C is the plant height phenotype result under field conditions.

[0020] Figure 7 This is the result of field yield phenotype of OE-ZmLEN1×T13 hybrid. Figure 7 A is a typical picture of corn ear phenotype under field conditions; Figure 7 B is the phenotypic result of corn yield under field conditions; Figure 7 C is the phenotypic result of corn ear length under field conditions; Figure 7 D is the phenotypic result of corn ear width under field conditions; Figure 7 E is the phenotypic result of corn yield and number of kernels per row under field conditions; Figure 7 F is the phenotypic result of 100-grain weight of corn yield under field conditions. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0022] Example 1 Construction of ZmLEN1 overexpression transgenic material

[0023] The vector used in the experiment is pBCXUN-Myc vector, and the vector backbone is as follows Figure 1 As shown in Figure 1, the vector was provided by the Crop Functional Genomics and Molecular Breeding Research Center of China Agricultural University. The vector was cut with XcmI and the PCR product was connected between the restriction sites. + uptakeand distribution in maize under low K + conditions[J].Journal of IntegrativePlant Biology,2019,61(6).)

[0024] 1. Cloning of target gene CDS

[0025] Using B73 cDNA as a template, primers were designed: the primer pair for amplifying ZmLEN1 consisted of an upstream primer ZmLEN1-F and a downstream primer ZmLEN1-R, wherein both ZmLEN1-F and the downstream primer ZmLEN1-R just contained the reverse complementary sequences of the translation start codon ATG and the translation stop codon TGA.

[0026] Upstream primer: ZmLEN1-F: 5'-ATGGAACAAAAGTTGATTTC-3' (SEQ ID NO.2)

[0027] Downstream primer: ZmLEN1-R: 5'-ACATGCCACTGAAGCTTGTG-3' (SEQ ID NO. 3)

[0028] The cDNA reverse transcribed from total RNA of B73 maize root was used as a template and amplified using high-fidelity enzyme KOD (KOD high-fidelity enzyme purchased from NEB Co., Ltd.) to obtain ZmLEN1 gene fragments containing complete open reading frames.

[0029] Amplification system:

[0030]

[0031] PCR reaction procedure:

[0032]

[0033]

[0034] PCR product recovery

[0035] Take 5 μL of PCR product and perform electrophoresis on 1.0% agarose gel. Select the target band with the correct size and single band and directly use the recovery kit (EZNA Cycle Pure Kit, OMEGA) for recovery and purification. The test method refers to the instructions of the kit, which are as follows:

[0036] (1) Estimate the volume of PCR reaction products;

[0037] (2) Transfer the PCR product to a 1.5 mL centrifuge tube, add 1.5 times CP Buffer, and mix by inverting;

[0038] (3) Place the DNA binding column into a 2 mL collection tube, add the mixture from step (3) to the column, centrifuge at maximum speed for 1 minute at room temperature, and discard the filtrate;

[0039] (4) Place the DNA binding column back into a 2 mL collection tube, add 700 μL DNA Wash Buffer, centrifuge at maximum speed for 1 minute, and discard the filtrate;

[0040] (5) Repeat step (4);

[0041] (6) Place the DNA binding column back into a 2 mL collection tube, centrifuge the empty column at maximum speed for 2 minutes, and discard the filtrate in the collection tube;

[0042] (7) Place the DNA binding column into a new 1 mL centrifuge tube, add 50 μL Elution Buffer, let stand at room temperature for 2 minutes, and centrifuge at maximum speed for 1 minute;

[0043] (8) Store DNA at -20°C.

[0044] 2. Construction of plant expression vector

[0045] The ZmLEN1 CDS recovery product was used as a template and PCR amplification was performed again using new primers with vector homology arms. The amplification primers consisted of the upstream primer Infusion-ZmLEN1-F and the downstream primer Infusion-ZmLEN1-R. The vector was constructed using the in-fusion method (the infusion kit was purchased from Beijing Zhuangmeng International Biogene Technology Co., Ltd., SE seamless cloning and assembly kit catalog number: ZC231), and the specific method was as follows:

[0046] Primer sequences:

[0047] Infusion-ZmLEN1-F: AGATCTTCCAATACTA ATGGAACAAAA GTTGATTTC(SEQ ID NO.4)

[0048] Infusion-ZmLEN1-R: CGGATCCCCAATACT ACATGCCACTGA AGCTTGTG(SEQ ID NO.5)

[0049] (1) Reaction system:

[0050]

[0051] (2) After mixing, react in a 37°C water bath or PCR instrument for 5 to 30 minutes, then transfer to ice or store at -20°C;

[0052] (3) Conduct competent transformation test.

[0053] Competent transformation:

[0054] (1) Take an EP tube containing 100 μL of competent cells from -80°C and thaw it on ice. Add 5 μL of the reaction solution to 100 μL of competent cells and continue to place on ice for 10 to 30 minutes;

[0055] (2) Incubate in a 42°C water bath for 1 minute, then place on ice for 2 minutes;

[0056] (3) Add 400 μL of LB or PBS without antibiotics and culture at 37°C with shaking for 60 min;

[0057] (4) Take 100-200 μL of competent cells and spread them evenly on an LB plate containing the corresponding resistance. Incubate at 37°C overnight. On the next day, pick the positive single clone for the next genetic transformation.

[0058] 3. Maize genetic transformation

[0059] The recombinant plasmid from the previous step was transformed into Agrobacterium by electroporation. The Agrobacterium transformation strain carrying the target gene was used to transform the immature embryos of the maize inbred line B73-329, and single-copy homozygous positive seedlings were obtained after screening. This step was assisted by the Crop Functional Genomics and Molecular Breeding Research Center of China Agricultural University.

[0060] 4. Identification of expression levels of different transformation events of ZmLEN1 overexpression

[0061] Two different transformation events of maize inbred lines B73-329 and OE-ZmLEN1 were first cultured in 1 / 2 nutrient solution for 3 days, then transferred to normal nutrient solution for 14 days, and the culture solution was changed every 3 days. The whole root system of maize was taken, and one sample was mixed for every 3 plants, with 3 replicates. The maize roots were harvested with liquid nitrogen.

[0062] Total RNA from maize roots was extracted using the Trizol method. The total RNA was reverse transcribed into cDNA after removing DNA from the total RNA using a reverse transcription kit. Real-time PCR was used to amplify the maize ZmLEN1 gene with primers qPCR-ZmLEN1-F and qPCR-ZmLEN1-R, and the maize ZmTUB4 gene was amplified with primers qPCR-ZmTUB4-F and qPCR-ZmTUB4-R as an internal reference. The expression level of the ZmLEN1 gene in the same sample was divided by the expression level of the ZmTUB4 gene as the relative expression level of the ZmLEN1 gene to study the expression level of the ZmLEN1 gene in different transformation events. The maize ZmTUB4 gene was used as an internal reference to determine the expression of the ZmLEN1 gene in different transformation events.

[0063] Gene upstream primer: qPCR-ZmLEN1-F: 5'-AGGCGGTTATGGTGTGGT TT-3' (SEQ ID NO.6)

[0064] Gene downstream primer: qPCR-ZmLEN1-R: 5'-TTCCTCCCCTTTTGCTTT GT-3' (SEQ ID NO.7)

[0065] Internal reference upstream primer: qPCR-ZmTUB4-F: 5'-GCTATCCTGTGATCTGCC CTGA-3' (SEQ ID NO.8)

[0066] Internal reference downstream primer: qPCR-ZmTUB4-F: 5'-CGCCAAACTTAATAACCC AGTA-3' (SEQ ID NO.9)

[0067] Extraction of total RNA from plants

[0068] (1) Grind the collected plant roots in a mortar containing liquid nitrogen, and place approximately 200 mg of the ground sample in a 2 mL RNaseA-free centrifuge tube for RNA extraction;

[0069] (2) Add 1 mL of RNAisoPlus, shake vigorously to mix the sample and solution thoroughly, and let stand at room temperature for 5 minutes;

[0070] (3) Add 200 μL of chloroform, shake vigorously for 30 seconds, let stand at room temperature for 8-10 minutes, and centrifuge at 12000 rpm at 4°C for 15 minutes;

[0071] (4) Carefully transfer the supernatant to a new 1.5 mL RNaseA-free centrifuge tube, add 500 μL of isopropanol and gently invert to mix, and let stand at room temperature or 4°C for 10 minutes. Centrifuge at 12,000 rpm for 10 minutes at 4°C;

[0072] (5) Discard the supernatant and add 1 mL of 75% ethanol (prepared with 0.1% DEPC water) to wash the precipitate. Repeat twice.

[0073] (6) Place on a clean bench, blow dry, and then add 30-50 μL of nucleic acid-free ddH2O to dissolve the precipitate;

[0074] (7) RNA concentration and purity were measured using Nanodrop and stored at -80°C.

[0075] mRNA reverse transcription

[0076] Test method reference PrimeScript TM RT reagent kit with gDNA Eraser kit (Takara) instructions are as follows:

[0077] (1) Genomic DNA removal reaction:

[0078]

[0079] (2) 42°C for 10 minutes and 4°C for 2 minutes;

[0080] (3) Reverse transcription reaction

[0081]

[0082] (4) Incubate at 42°C for 60 minutes, 95°C for 5 minutes, 4°C for 2 minutes, and store at -20°C.

[0083] qPCR reaction solution configuration:

[0084]

[0085] qPCR reaction procedure

[0086]

[0087]

[0088] The results are as follows Figure 2As shown in the figure, compared with the wild type, the expression levels of the two transformation events of OE-ZmLEN1 have increased significantly to varying degrees, among which the expression level of OE-ZmLEN1-1 is increased by 860 times compared with the wild type, and the expression level of OE-ZmLEN1-2 is increased by 505 times compared with the wild type. This shows that the two overexpression transformation events of ZmLEN1 are overexpressed successfully and can be further used for subsequent functional studies.

[0089] Example 2 Analysis of spatiotemporal expression patterns of ZmLEN1 and analysis of low-phosphorus-induced expression patterns

[0090] 1. Analysis of spatiotemporal expression patterns of ZmLEN1

[0091] In order to further clarify the function of ZmLEN1, we used the inbred line B73-329 as the experimental material to analyze the spatiotemporal expression pattern of ZmLEN1. The experiment set up four periods: seedling stage (14 days after emergence), jointing stage (30 days after emergence), silking stage (60 days after emergence), and 15 days after pollination. In each period, the root tip, underground node root, aerial root, base, stem, leaf and other parts were sampled. After sampling, they were wrapped with tin foil and quickly stored in liquid nitrogen. The tissues were ground in a mortar and pestle, and the total RNA of corn was extracted using the Trizol method. The total RNA obtained was reverse transcribed into cDNA after removing the DNA in the total RNA using a reverse transcription kit. Real-time PCR was used to amplify the maize ZmLEN1 gene with primers qPCR-ZmLEN1-F and qPCR-ZmLEN1-R. The maize ZmTUB4 gene was amplified with primers qPCR-ZmTUB4-F and qPCR-ZmTUB4-R as an internal control. The expression level of the ZmLEN1 gene in the same sample was divided by the expression level of the ZmTUB4 gene as the relative expression level of the ZmLEN1 gene. The expression level of the ZmLEN1 gene in different tissues was studied.

[0092] Gene upstream primer: qPCR-ZmLEN1-F: 5'-AGGCGGTTATGGTGTGGT TT-3'

[0093] Gene downstream primer: qPCR-ZmLEN1-R: 5'-TTCCTCCCCTTTTGCTTT GT-3'

[0094] Internal reference upstream primer: qPCR-ZmTUB4-F: 5'-GCTATCCTGTGATCTGCC CTGA-3'

[0095] Internal reference downstream primer: qPCR-ZmTUB4-F:5'-CGCCAAACTTAATAACCC AGTA-3'

[0096] The results are as follows Figure 3As shown, it can be found that ZmLEN1 is constitutively expressed and is expressed in all tissues at all stages of corn growth and development, but is expressed in large quantities in leaves.

[0097] 2. Analysis of the expression pattern of ZmLEN1 induced by low phosphorus

[0098] In order to further clarify the expression pattern of ZmLEN1 induced by low phosphorus, we used the inbred line B73-329 as the experimental material to study the low phosphorus expression pattern of ZmLEN1. The experiment was carried out under hydroponic conditions. After 3 days of cultivation under normal phosphorus supply (0.25mM), it was transferred to low phosphorus (0.25μM) nutrient solution for cultivation. Normal phosphorus supply was used as the control. Samples were taken on 1 day, 3 days, 10 days, and 15 days respectively. The aboveground and root samples were taken. After sampling, they were wrapped with tin foil and quickly stored in liquid nitrogen. The total RNA of corn was extracted by Trizol method. The obtained total RNA was reverse transcribed into cDNA using a reverse transcription kit. Real-time PCR was used to amplify the maize ZmLEN1 gene with primers qPCR-ZmLEN1-F and qPCR-ZmLEN1-R, and the maize ZmTUB4 gene was amplified with primers qPCR-ZmTUB4-F and qPCR-ZmTUB4-R as internal reference. The relative expression of the ZmLEN1 gene was obtained by dividing the expression of the ZmTUB4 gene in the same sample to study the expression of the ZmLEN1 gene at different times. At the same time, the low-phosphorus-induced Marker gene ZmPHT2 was used to verify the feasibility of the experimental system.

[0099] Gene upstream primer: qPCR-ZmLEN1-F: 5'-AGGCGGTTATGGTGTGG TTT-3'

[0100] Gene downstream primer: qPCR-ZmLEN1-R: 5'-TTCCTCCCCTTTTGCTT TGT-3'

[0101] Marker gene upstream primer: qPCR-ZmPHT2-F: 5'-CATCGGGGCCTT TGGGTTC-3'

[0102] Marker gene upstream primer: qPCR-ZmPHT2-R: 5'-AGGATAAAGCCA AGCAAGTTGGA-3'

[0103] Internal reference upstream primer: qPCR-ZmTUB4-F: 5'-GCTATCCTGTGATCTGC CCTGA-3'

[0104] Internal reference downstream primer: qPCR-ZmTUB4-F:5'-CGCCAAACTTAATAACC CAGTA-3'

[0105] The results are as follows Figure 4 As shown, the marker gene ZmPHT2 can be induced significantly and quickly after phosphorus deficiency, whether in the root system or the aboveground part. This shows that there is no problem with the experimental system. For the target gene ZmLEN1, whether in the aboveground part or the root system, with normal phosphorus supply as the control, the expression level of ZmLEN1 was significantly higher than the control after 10 days of low phosphorus treatment. This shows that the induction of ZmLEN1 by low phosphorus is caused by phosphorus deficiency nutrition and is not affected by phosphorus deficiency signals.

[0106] Example 3 Phenotypic Identification of ZmLEN1 under Hydroponic Conditions

[0107] The experimental materials are two different transformation events, B73-329 (wild type) and OE-ZmLEN1. Take 3 times the amount of corn seeds required for the experiment, put them into a beaker, add 2% sodium hypochlorite solution to completely immerse the seeds, disinfect for 30 minutes, pour out the sodium hypochlorite, and add a saturated CaSO4 solution to treat for about 16 hours. After washing with ddH2O 5 times, spread the seeds on filter paper and germinate in the dark for 2 days. After germination, roll up with filter paper, place vertically in deionized water, grow in the dark for 2 days, and then expose to light. When the corn grows to the V1 stage, the endosperm is removed, and the seedlings with consistent growth are selected and moved to 1 / 2 complete nutrient solution for 2 days. After the seedlings are slowed down, they are cultured with normal corn nutrient solution, and the nutrient solution is changed every 2 days. After 18 days of culture, the harvest is harvested, and the root traits of the segmented roots and main radicle seed roots are measured

[0108] The results are as follows Figure 5 As shown, OE-ZmLEN1 did not affect the aboveground biomass, but compared with the wild type, the number of lateral roots increased significantly, and the total length of the root system increased significantly. Compared with the wild type, the number of lateral roots increased by an average of 120%, and the total length of the root system increased by an average of 119%. The average root diameter decreased significantly, and the average root diameter decreased by 17% compared with the wild type. This shows that the formation of maize lateral roots can be affected by regulating the expression of ZmLEN1.

[0109] Example 4 Field Phenotypic Function Verification of ZmLEN1

[0110] Field phenotypic test design: This experiment was conducted in Hainan, China in 2021. The experimental materials were two different transformation events: wild-type B73-329 and overexpression OE-ZmLEN1. The experimental design adopted a randomized block experiment with three replicates, single-row planting, each row was 4 meters long, the row spacing was 50 cm, the plant spacing was 25 cm, and double seed sowing was performed. After the seedlings emerged, they began to be thinned out when they grew to two leaves and one heart. After thinning, 17 plants were left in each row. Standard cultivation and management methods were adopted. Samples were taken during the silking period to analyze related traits such as the aboveground part and root system architecture.

[0111] The test results are as follows Figure 6 As shown: The study found that compared with the wild type, the lateral roots of overexpressed ZmLEN1 increased significantly. At the same time, we also found that after overexpressing ZmLEN1, the opening angle increased significantly compared with the wild type ( Figure 6 However, there was no significant difference in the aboveground plant height ( Figure 6 C). Therefore, we proved that ZmLEN1 has the function of regulating maize lateral roots and also affects the root angle, but does not affect the aboveground plant height. Therefore, ZmLEN1 has the function of specifically regulating the maize root architecture.

[0112] Example 5 ZmLEN1 hybrid horizontal yield evaluation

[0113] Field phenotypic test design: This experiment was conducted in Beijing, China in 2022. Wild-type B73-329 and overexpression OE-ZmLEN1-2 were used as female parents, and self-bred line T13 was used as male parent. The hybrids were tested and matched, recorded as WT×T13 and OE-ZmLEN1×T13. The experimental design adopted a randomized block experiment with 3 replicates, double-row planting, each row was 4 meters long, the row spacing was 60 cm, the plant spacing was 25 cm, and double seeds were sown. After the seedlings emerged and grew to two leaves and one heart, thinning began. After thinning, 17 plants were left in each row. Standard cultivation and management methods were adopted. Yield was measured at maturity.

[0114] The test results are as follows Figure 7 As shown: The study found that compared with WT×T13, OE-ZmLEN1×T13 had a significantly increased yield. Through the determination of yield formation factors, it was found that the increase in OE-ZmLEN1×T13 yield was mainly due to the increase in ear length, ear width, number of grains per row, and 100-grain weight. This shows that the increase in OE-ZmLEN1×T13 yield is closely related to the regulation of lateral root number by ZmLEN1. Therefore, we proved that ZmLEN1 can significantly increase corn yield while regulating lateral root formation.

[0115] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. Application of ZmLEN1 gene in regulating corn lateral roots, characterized in that: The application is to increase the number of corn lateral roots and the opening angle of the lateral roots, reduce the average root diameter, and increase corn yield by overexpressing the ZmLEN1 gene; The ZmLEN1 gene is shown as SEQ ID NO.1, the CDS of the ZmLEN1 gene is shown as SEQ ID NO.10, and the amino acid sequence of the ZmLEN1 protein encoded by the CDS is shown as SEQ ID NO.

11.

2. A primer pair for amplifying the ZmLEN1 gene as claimed in claim 1, characterized in that: The sequence of the primer pair is shown in SEQ ID NO.2-3.

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