ZmATRX loss-of-function mutant and application thereof

Abstract

This invention provides a ZmATRX loss-of-function mutant and its applications, belonging to the fields of plant genetics, developmental biology, and maize molecular breeding technology. This invention discloses a ZmATRX loss-of-function mutant. Zmatrx‑1 and Zmatrx‑2 ,in Zmatrx‑1 The amino acid sequence of the encoded protein is shown in SEQ ID No. 4; Zmatrx‑2 The amino acid sequence of the encoded protein is shown in SEQ ID No. 6. This invention reveals that loss of ZmATRX function leads to reduced maize plant height, shorter and narrower leaves, fewer leaves on the ear, and reduced shoot apical meristem height. This invention provides new gene resources and an application basis for maize plant architecture regulation, shoot apical meristem development research, and plant architecture improvement.

Description

Technical Field

[0001] This invention belongs to the fields of plant genetics, developmental biology and maize molecular breeding technology, and specifically relates to a ZmATRX loss-of-function mutant and its applications. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Maize is an important crop for food, feed, and industrial raw materials, and increasing yield per unit area is crucial for ensuring food security. Appropriately increasing planting density is an important way to improve maize yield per unit area; however, under high-density cultivation conditions, problems such as excessive plant height, increased risk of lodging, canopy closure, and decreased light utilization efficiency remain prominent. Maize plant architecture is a complex agronomical trait determined by multiple traits, including plant height, internode elongation, leaf size, leaf morphology, and leaf spatial distribution. It not only affects the spatial structure of individual plants but also ventilation, light penetration, lodging resistance, and light utilization efficiency under group planting conditions. Existing research shows that all aboveground organs of maize originate directly or indirectly from the shoot apical meristem, and their morphology and developmental status continuously influence leaf initiation, internode elongation, and plant spatial configuration.

[0004] Currently, research on maize plant architecture and meristem development mainly focuses on hormone signaling, transcription factors, and classical developmental pathways. In contrast, the role of chromatin remodeling factors in maize plant architecture formation remains largely unresolved. Alpha Thalassemia-mental Retardation X-linked (ATRX) is a class of conserved chromatin remodeling-related proteins involved in chromatin state maintenance and developmental regulation in various organisms. The role of ATRX-like genes in maize plant architecture and shoot apex meristem development remains unclear. Summary of the Invention

[0005] To address at least one of the technical problems mentioned above, this invention provides a ZmATRX loss-of-function mutant and its applications.

[0006] The present invention adopts the following technical solution: In a first aspect, the present invention provides a ZmATRX loss-of-function mutant, the mutant being... Zmatrx-1 and / or Zmatrx-2The mutant amino acid sequence comprises a sequence obtained by mutating amino acid residue sites as shown in SEQ ID No. 2, wherein the mutated sites are selected from any one or more of the following sites: position 167, position 772.

[0007] In a second aspect, the present invention provides a nucleic acid molecule encoding a ZmATRX loss-of-function mutant as described in the first aspect.

[0008] A third aspect of the invention provides a carrier comprising the nucleic acid molecule described in the second aspect.

[0009] In a fourth aspect, a host cell is provided, comprising the nucleic acid molecule described in the second aspect or the vector described in the third aspect.

[0010] A fifth aspect of the present invention provides the application of the ZmATRX loss-of-function mutant described in the first aspect, the nucleic acid molecule described in the second aspect, the vector described in the third aspect, or the host cell described in the fourth aspect in regulating maize plant architecture.

[0011] In a sixth aspect, the present invention provides the application of the ZmATRX loss-of-function mutant described in the first aspect, the nucleic acid molecule described in the second aspect, the vector described in the third aspect, or the host cell described in the fourth aspect in the breeding of dwarf maize varieties.

[0012] A seventh aspect of the present invention provides a method for regulating maize plant architecture, comprising the step of introducing the ZmATRX loss-of-function mutant described in the first aspect into plant cells, plant seeds, plant tissues, plant parts, or a plant, wherein the plant is maize. An eighth aspect of the present invention provides a method for breeding dwarf maize varieties, comprising the step of introducing the ZmATRX loss-of-function mutant described in the first aspect into plant cells, plant seeds, plant tissues, plant parts or plants, wherein the plant is maize.

[0013] Compared with the prior art, the beneficial effects of the present invention are: The present invention provides a loss-of-function mutant of the maize ZmATRX gene. Zmatrx-1 and / or Zmatrx-2 It regulates maize plant height and shoot tip meristem development through mutations in the ATRX-like chromatin remodeling factor gene. Zmatrx The mutant exhibits significantly reduced maize plant height, shorter and narrower leaves, fewer leaves per ear, and abnormal leaf growth. Reduced plant height is a key trait in maize breeding for improving lodging resistance and adaptability to dense planting. By regulating the function of ZmATRX, maize materials with altered plant height, leaf morphology, and shoot apical meristem development can be obtained, providing new genetic resources for plant type improvement, germplasm creation, and molecular breeding. Attached Figure Description

[0014] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0015] Figure 1 for Zmatrx-1 Phenotypic analysis of plant type, leaf type, and shoot apical meristem of the mutant; where A is... Zmatrx-1 The plant phenotype of the mutant in the A619 genetic background, B is Zmatrx-1 The plant phenotype of the mutant in the B73 genetic background, where C is... Zmatrx-1 Compared with the wild type, D is the plant height. Zmatrx-1 Compared with wild type ear height statistics, E represents the difference between wild type and wild type. Zmatrx- 1 Leaf phenotype, F represents wild type and Zmatrx-1 Leaf length statistics, G represents wild type and Zmatrx-1 Leaf width statistics, H represents wild type and Zmatrx-1 The number of leaves on the spike was counted. I represents the morphology of the shoot apical meristem (SAM) of the wild type. The dashed arrow indicates the measurement location. J represents... Zmatrx-1 The SAM morphology is shown, with the dashed arrow indicating the measurement location, and K representing the measurement position. Zmatrx-1 / +In the offspring of the segregating population, wild-type and Zmatrx-1 SAM height statistics, L is in Zmatrx-1 / +In the offspring of the segregating population, wild-type and Zmatrx-1 SAM width statistics are presented, with bar charts representing the mean ± SD and scatter plots representing individual biological replicates. Statistical analysis of C, D, F, G, H, K, and L was performed using two-tailed unpaired t-tests. The n-value and p-value are marked in the figure, and the scale is shown in the figure. Figure 2 for Zmatrx-1 Genetic localization of candidate genes and screening of candidate variants; where A represents BSA (Bulked segregant analysis) analysis, in which variants were detected on chromosome 1. Zmatrx-1 Peaks indicating significant phenotypic association (dashed lines represent thresholds), B represents the candidate gene localized to Zm00001d032801 by map-based cloning combined with EMS (ethyl methanesulfonate) mutagenesis features. The figure marks the molecular markers used for fine mapping and their physical locations. n represents the number of plants used for linkage analysis / localization. C is the gene structure diagram of Zm00001d032801, with black boxes representing exons, broken lines representing introns, and gray areas representing untranslated regions (UTRs). Figure 3 The isotropic test confirms that Zm00001d032801 isZmatrx-1 Target gene; where A is the second independent EMS allelic mutant. Zmatrx-2 Plant type phenotype, B represents wild type and Zmatrx-1 / Zmatrx-2 Comparison of plant morphology of bisallectomy mutants, C represents wild type and Zmatrx-1 / Zmatrx-2 Plant height statistics, D represents wild type and Zmatrx-1 / Zmatrx- 2 According to the ear height statistics, E represents wild type and Zmatrx-1 / Zmatrx-2 A comparison of leaf morphology, F represents wild type and Zmatrx-1 / Zmatrx-2 Leaf length statistics, G represents wild type and Zmatrx-1 / Zmatrx-2 Leaf width statistics, H represents wild type and Zmatrx- 1 / Zmatrx-2 The number of leaves on the spike was counted, I represents the wild-type SAM morphology (dashed arrows indicate measurement locations), and J represents... Zmatrx- 1 / Zmatrx-2 SAM morphology (dashed arrows indicate measurement locations), K represents wild type and Zmatrx-1 / Zmatrx-2 SAM height statistics, L represents wild type and Zmatrx-1 / Zmatrx-2 SAM width statistics are presented, with bar charts representing mean ± SD and scatter plots representing single-plant biological replicates. Statistical analysis of C, D, F, G, H, and KL was performed using a two-tailed unpaired t-test. The n-value and p-value are marked in the figure, and the scale is shown in the figure. Figure 4 This section compares the phylogenetic relationships and protein domain composition of ATRX in plants; where A is a phylogenetic tree constructed based on ATRX protein sequences, and the species used include: poplar (… Pt , Populus trichocarpa Castor bean ( ); Rc , Ricinus communis ); alfalfa ( Mt , Medicago truncatula ); soybeans ( Gm , Glycine max );Chinese cabbage( Br , Brassica rapa Arabidopsis thaliana ( ); At , Arabidopsis thaliana ); rice ( Os , Oryza sativa );corn( Zm , Zea mays ); mice ( Mm , Mus musculus Homo sapiens ( ) Hs , Homo sapiens Fruit flies ( Dm , Drosophila melanogaster ); nematode elegans ( Ce , Caenorhabditis elegansB is a schematic diagram of the ATRX protein domains (taking Arabidopsis thaliana AtATRX, maize ZmATRX, and human HsATRX as examples). All three contain the conserved ATRX–DNA methyltransferase 3–DNA methyltransferase 3-like domain (ADD; green box), as well as the core domain of the switching defective 2 / Sucrose non-fermenting 2-like adenosinetriphosphatase (SWI2 / SNF2-like ATPase domain) located at the C-terminus, the DEAD-like helicase superfamily domain (DEXDc; purple box), and the helicase superfamily C-terminal domain (HELICc; light blue box). However, compared with human HsATRX, ZmATRX and AtATRX lack the death domain-associated interacting protein domain. protein, DAXX-I; orange box); protein length (aa) is marked on the right side of the diagram. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] As described in the background section, there is currently a lack of direct evidence regarding whether ATRX-like genes in maize are involved in plant architecture and shoot apical meristem development.

[0020] Based on this, the present invention provides a ZmATRX loss-of-function mutant and its applications. Through mutant screening, genetic analysis, BSA analysis, map-based cloning, allelic verification, phylogenetic analysis, and protein domain analysis, the present invention confirms that ZmATRX is an important gene regulating maize plant architecture and shoot apical meristem development. Loss of function of this gene results in maize exhibiting phenotypes such as reduced plant height, shorter and narrower leaves, fewer leaves above the ear, and reduced shoot apical meristem height.

[0021] A typical embodiment of the present invention provides a ZmATRX loss-of-function mutant, wherein the mutant is... Zmatrx-1 and / or Zmatrx-2 The mutant amino acid sequence comprises a sequence obtained by mutating amino acid residue sites as shown in SEQ ID No. 2, wherein the mutated sites are selected from any one or more of the following sites: position 167, position 772.

[0022] In some embodiments, the maize ATRX-like chromatin remodeling factor gene ZmATRX has a CDS nucleotide sequence as shown in SEQ ID No. 1. Through genetic analysis, BSA analysis, and map-based cloning, this invention locates the target gene controlling abnormal plant architecture phenotypes to the 237-239 Mb region of maize chromosome 1, and further identifies the candidate gene as Zm00001d032801, i.e., ZmATRX.

[0023] In some implementations, the Zmatrx-1 In the mutant, a base mutation occurs in the ZmATRX coding region, causing the glutamine codon at position 167 to become a stop codon, resulting in premature protein termination.

[0024] In some implementations, the Zmatrx-2 In the mutant, a base mutation occurs in the ZmATRX coding region, causing the glutamine codon at position 772 to become a stop codon, resulting in premature protein termination.

[0025] In some implementations... Zmatrx-1 / Zmatrx-2 A biallelic mutant, in which one allele in the genome is as described above. Zmatrx-1 The mutation, with the other allele being the one described above. Zmatrx-2 mutation.

[0026] In some implementations... Zmatrx-1 The CDS nucleotide sequence is shown in SEQ ID No. 3, and the amino acid sequence of the protein it encodes is shown in SEQ ID No. 4; Zmatrx-2 The CDS nucleotide sequence is shown in SEQ ID No. 5, and the amino acid sequence of the protein it encodes is shown in SEQ ID No. 6.

[0027] In some implementations, maize can be modified using one or more of the following methods: EMS mutagenesis, gene editing, base editing, promoter editing, RNA interference, antisense inhibition, or mutant hybridization. ZmATRX Gene expression or protein function is reduced, disrupted, or altered to obtain the ZmATRX loss-of-function mutant described in this invention.

[0028] In another typical embodiment of the present invention, a nucleic acid molecule is provided that encodes the above-mentioned ZmATRX loss-of-function mutant.

[0029] The nucleic acid molecule is selected from the group consisting of: genomic sequences, cDNA sequences, RNA sequences, or combinations thereof.

[0030] The nucleic acid molecule can be single-stranded or double-stranded.

[0031] The nucleic acid molecule may also contain additional auxiliary elements selected from the group consisting of: signal peptides, secretory peptides, tag sequences (such as 6His), nuclear localization signals, or combinations thereof.

[0032] The nucleic acid molecule also contains a promoter that is operatively linked to the ORF sequence encoding the mutant polypeptide.

[0033] The promoter is selected from the group consisting of: constitutive promoters, tissue-specific promoters, inducible promoters, or strong promoters.

[0034] In some embodiments, the nucleic acid molecule includes: Zmatrx-1 The CDS nucleotide sequence is shown in SEQ ID No. 3; Zmatrx-2 The CDS nucleotide sequence is shown in SEQ ID No. 5.

[0035] A third typical embodiment of the present invention provides a carrier containing the nucleic acid molecule described in the present invention.

[0036] In some embodiments, the vector comprises a nucleic acid molecule encoding the ZmATRX loss-of-function mutant of the present invention. Preferably, the vector further comprises an expression regulatory element operatively linked to the aforementioned nucleic acid molecule.

[0037] In some embodiments, the vector includes a cloning vector, an expression vector, a shuttle vector, or an integration vector.

[0038] In some embodiments, the vector may be a vector that is integrated into the genome when introduced into a host cell and replicates along with the chromosome into which it is integrated.

[0039] The vector can be of the following types: plasmid, virus, granule, bacteriophage, etc., which are well known to those skilled in the art.

[0040] In a fourth typical embodiment of the present invention, a host cell is provided containing the nucleic acid molecule or vector described in the present invention.

[0041] In some embodiments, the host cell is a eukaryotic cell, such as a yeast cell, an animal cell, or a plant cell.

[0042] In some embodiments, the host cell is a prokaryotic cell, such as Escherichia coli.

[0043] In some embodiments, the plants include angiosperms and gymnosperms.

[0044] In some embodiments, the plants include monocotyledonous plants and dicotyledonous plants.

[0045] In some embodiments, the plant includes herbaceous plants and parent plants.

[0046] In some embodiments, the plants include corn, wheat, Arabidopsis thaliana, tobacco, rice, sorghum, barley, millet, soybean, tomato, potato, quinoa, lettuce, rapeseed, cabbage, strawberry, etc.

[0047] The fifth typical embodiment of the present invention provides the application of the ZmATRX loss-of-function mutant, nucleic acid molecule, vector or host cell described in the present invention in regulating maize plant architecture.

[0048] In some embodiments, the regulation of maize plant architecture includes one or more of the following: (a1) Regulating maize plant height; (a2) Regulating maize leaves; (a3) Regulate the number of leaves above the ear; (a4) Regulate the height of shoot apical meristem.

[0049] The plant type described in this invention includes, but is not limited to, plant height, leaf length, leaf width, number of leaves above the ear, leaf morphology, and stem apical meristem height. Specifically, the regulation of maize plant type includes reduced plant height, shorter and narrower leaves, abnormal leaf posture, reduced number of leaves above the ear, and reduced stem apical meristem height, indicating that ZmATRX is an important gene regulating maize plant type and leaf type. Zmatrx The height of the shoot apical meristem in the mutant was significantly reduced, while the width did not change significantly, indicating that ZmATRX plays an important role in maintaining the normal morphology of the maize shoot apical meristem.

[0050] The sixth typical embodiment of the present invention provides the application of the ZmATRX loss-of-function mutant, nucleic acid molecule, vector or host cell described in the present invention in the breeding of dwarf maize varieties.

[0051] The seventh typical embodiment of the present invention provides a method for regulating maize plant architecture, comprising the step of introducing the above-mentioned ZmATRX loss-of-function mutant into plant cells, plant seeds, plant tissues, plant parts or plants, wherein the plant is maize.

[0052] The eighth typical embodiment of the present invention provides a method for breeding dwarf maize varieties, comprising the step of introducing the above-mentioned ZmATRX loss-of-function mutant into plant cells, plant seeds, plant tissues, plant parts or plants, wherein the plant is maize.

[0053] In some embodiments, introducing the aforementioned ZmATRX loss-of-function mutant includes steps of reducing, disrupting, or altering the expression of the ZmATRX gene or the function of the protein.

[0054] In some embodiments, the methods for reducing, disrupting, or altering ZmATRX gene expression or protein function include one or more of EMS mutagenesis, gene editing, base editing, promoter editing, RNA interference, antisense inhibition, or mutant hybridization.

[0055] Those skilled in the art can easily use known methods to reduce, disrupt, or alter the expression of the ZmATRX gene or the function of the protein in this invention. No specific process is limited here; conventional techniques in the art can be used.

[0056] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0057] Example 1 corn Zmatrx-1 Acquisition and phenotypic identification of mutants A stably inherited mutant with abnormal plant type was obtained from the B73 background EMS mutant library (https: / / maizeems.qlnu.edu.cn / ), and named [name missing]. Zmatrx-1 ( Figure 1 (A and B in the original text). To clarify the phenotypic characteristics of this mutant, a systematic observation and statistical analysis were conducted in two genetic backgrounds, B73 and A619.

[0058] Compared to the wild type, Zmatrx-1 The plants were significantly stunted overall, and exhibited a certain degree of distorted phenotype. Figure 1 (A and B in the original text). Statistical results show that... Zmatrx-1 The plant height was significantly reduced ( Figure 1 (C in the text), while ear height was not significantly different from the wild type ( Figure 1 (D in the text). Leaf phenotypic analysis showed that... Zmatrx-1The leaves are significantly shorter ( Figure 1 E and F in the middle), narrowing ( Figure 1 (G in the middle), accompanied by slight curling or twisting ( ​ The number of leaves on the ear was significantly reduced in the mutant (E); at the same time, the number of leaves on the ear was significantly reduced (E). ​ (H in the text). Part ​ The plant also exhibits leaf sheathing, meaning that new leaves occasionally emerge from the leaf sheaths of older leaves. ​ The B in the figure suggests that this mutation may affect leaf occurrence or early leaf development.

[0059] Further observation of the morphology of the shoot apical meristem revealed that ​ The height of the shoot apical meristem was significantly reduced, while the width remained largely unchanged. ​ (I, K, and L in the text). This result indicates that... ​ It does not only affect the morphology of a single organ, but also manifests related defects in multiple aspects such as plant height, leaf morphology, number of leaves on the spike, and morphology of shoot apical meristem.

[0060] The above results show that ​ It is a maize plant type abnormal mutant, whose phenotype is closely related to plant height, leaf development and shoot tip meristem morphology.

[0061] Example 2 ​ Genetic analysis and map-based cloning of phenotypes For analysis ​ The genetic basis of phenotype, ​ The F1 generation was obtained by crossing with the A619 inbred line, and the F2 segregating population was constructed through self-pollination of the F1 generation. Of the 337 F2 plants, 261 were wild-type and 76 were mutant. Statistical analysis showed that the segregation ratio of wild-type to mutant was 3:1, indicating... ​ Phenotype is controlled by a single gene recessive mutation.

[0062] Subsequently, wild-type and mutant mixed pools were constructed using the F2 population obtained by backcrossing and self-crossing with B73, and BSA analysis was performed. The BSA results showed that a variant of B73 existed on chromosome 1 of maize. ​ The main peak showing a significant phenotypic association suggests that the target gene is located on maize chromosome 1. ​ (A in the original text). Further combining molecular marker analysis and fine mapping, the candidate region was narrowed down to the range of 237-239 Mb on maize chromosome 1 (…). ​ (B in the middle).

[0063] Within this target region, whole-genome sequencing results from wild-type and mutant pools were combined, and candidate variants were screened based on the predominant G / C to A / T conversion mutation characteristic of EMS mutagenesis. Several candidate SNPs matching the EMS mutation type were obtained within the target region. Further analysis revealed that a mutation in the Zm00001d032801 exon region could lead to premature termination of the encoded protein. ​ (C in the text). This result indicates that Zm00001d032801 is the control... ​ The most likely candidate gene for the phenotype.

[0064] Example 3 Isometric Verification of Zm00001d032801 To verify whether Zm00001d032801 is ​ The target gene was identified, and a second independent mutant of Zm00001d032801 was obtained from the EMS mutant library and named [name missing]. ​ ( ​ (C in the middle).

[0065] Phenotypic observation results showed that ​ homozygous mutants exhibit the same characteristics as ​ Highly similar phenotypes, including dwarfism, abnormal leaf development, and altered leaf morphology. ​ A in the middle). Further... ​ Hybrid plants and ​ Hybrid plants were crossed to obtain ​ The biallelic mutants were identified, and their phenotypes were analyzed. ​ (B in the middle).

[0066] The results showed that ​ The biallelic mutant exhibits the same characteristics as ​ Consistent typical mutant phenotype. Compared with the wild type, the biallelic mutant showed a significantly reduced plant height, while the ear height remained largely unchanged. ​ (C and D in the text); the leaves are significantly shorter and narrower, and the number of leaves on the ear is significantly reduced ( ​ E, F, G, and H in the model; the height of the shoot apex meristem was significantly reduced, while the width remained largely unchanged (E, F, G, and H in the model model); ​ (I, J, K, and L in the text).

[0067] The above results indicate that both independent mutant alleles can lead to similar plant type, leaf type, and shoot apical meristem defects, and the allelic test results support the conclusion that Zm00001d032801 is the control. ​ The target gene for the phenotype.

[0068] Example 4 The target gene encodes the ATRX-like chromatin remodeling factor ZmATRX. To clarify the functional properties of the protein encoded by Zm00001d032801, protein sequence analysis, phylogenetic analysis, and conserved domain prediction were performed.

[0069] Sequence analysis showed that the protein encoded by Zm00001d032801 lacks a transmembrane domain, consistent with the basic characteristics of nuclear chromatin regulators. Phylogenetic analysis indicated that this protein clustered with ATRX homologs from plants such as Arabidopsis and rice, and was relatively separated from the animal ATRX branch, suggesting that it belongs to the plant ATRX family. ​ (A in the original text). Therefore, Zm00001d032801 is named ZmATRX.

[0070] Further domain analysis revealed that ZmATRX, Arabidopsis thaliana AtATRX, and human HsATRX all contain a conserved ATRX–DNA methyltransferase 3–DNA methyltransferase 3-like domain (ADD). Furthermore, all three contain a switching defective 2 / Sucrose non-fermenting 2-like adenosine triphosphatase domain (SWI2 / SNF2-like ATPase domain) at their C-terminus. This core domain is primarily composed of a DEAD-like helicase superfamily domain (DEXDc) and a helicase superfamily C-terminal domain (HELICc). Compared to human HsATRX, ZmATRX and AtATRX lack the death domain-associated interacting protein (DAXX-I) domain. ​ (B in the text). These conserved domains are typically involved in chromatin remodeling, histone modification recognition, and chromatin state regulation.

[0071] Mutation site analysis showed that, ​ A base mutation occurs in the coding region of ZmATRX, causing the glutamine codon at position 167 to become a stop codon, resulting in premature protein termination. ​Another independent mutation occurred in the ZmATRX coding region, causing the glutamine codon at position 772 to be replaced with a stop codon, which also led to premature protein termination. Both independent mutations truncated the ZmATRX protein and caused similar plant type and shoot apical meristem phenotype, indicating that the loss of ZmATRX function is the main cause of the above-mentioned developmental defects.

[0072] In summary, ZmATRX encodes an ATRX-like chromatin remodeling factor, and its loss of function can lead to reduced maize plant height, abnormal leaf development, and reduced shoot apical meristem height. This invention thus confirms that ZmATRX is an important gene regulating maize plant architecture and shoot apical meristem development, and provides new genetic material and candidate genes for further research on maize plant architecture improvement and chromatin regulation.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A ZmATRX loss-of-function mutant, characterized in that, The mutant is Zmatrx-1 and / or Zmatrx-2 The mutant amino acid sequence comprises a sequence obtained by mutating amino acid residue sites as shown in SEQ ID No. 2, wherein the mutated sites are selected from any one or more of the following sites: position 167, position 772.

2. The ZmATRX loss-of-function mutant as described in claim 1, characterized in that, The glutamine at position 167 is mutated into a stop codon; the glutamine at position 772 is mutated into a stop codon.

3. A nucleic acid molecule, characterized in that, Encode the ZmATRX loss-of-function mutant as described in claim 1.

4. A carrier, characterized in that, It includes the nucleic acid molecule as described in claim 3.

5. A host cell, characterized in that, It contains the nucleic acid molecule of claim 3 or the vector of claim 4.

6. The application of the ZmATRX loss-of-function mutant of claim 1, the nucleic acid molecule of claim 3, the vector of claim 4, or the host cell of claim 5 in regulating maize plant architecture.

7. The application as described in claim 6, characterized in that, The regulation of maize plant architecture includes one or more of the following: (a1) Regulating maize plant height; (a2) Regulating maize leaves; (a3) Regulate the number of leaves above the ear; (a4) Regulate the height of shoot apical meristem.

8. The application of the ZmATRX loss-of-function mutant of claim 1, the nucleic acid molecule of claim 3, the vector of claim 4, or the host cell of claim 5 in the breeding of dwarf maize varieties.

9. A method for regulating maize plant architecture, characterized in that, The step includes introducing the ZmATRX loss-of-function mutant of claim 1 into plant cells, plant seeds, plant tissues, plant parts or plants, wherein the plant is maize.

10. A method for breeding dwarf maize varieties, characterized in that, The step includes introducing the ZmATRX loss-of-function mutant of claim 1 into plant cells, plant seeds, plant tissues, plant parts or plants, wherein the plant is maize.

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