GRF1 gene and application thereof in skin thorn character regulation and control

Abstract

The invention relates to a GRF1 gene and application thereof in skin thorn character regulation and control, and belongs to the field of plant genetic engineering. The invention discloses a GRF1 gene, and discloses an application of the GRF1 gene in regulation and control of skin thorn characters.

Description

Technical Field

[0001] The invention relates to a GRF1 gene and application thereof in regulating prickle traits, belonging to the field of plant gene engineering. Background Art

[0002] Most of the plants in the genus Rosa have high ornamental value. However, many plants in the genus Rosa, such as roses, Chinese roses, and roses, have thorns on their stems, which brings many inconveniences to the field cultivation and management of the plants, the picking and transportation of flowers, etc. Therefore, cultivating new varieties of Rosa plants without thorns or with soft thorns will effectively improve their quality, greatly increase production efficiency, and significantly reduce production costs.

[0003] Prickles are widely present in plants. They are formed by the protrusions of epidermal cells and subcutaneous tissue on plant stems and branches. In terms of origin, they have certain similarities with epidermal hairs. In recent years, some research results have been made on the molecular mechanism of plant prickle formation, and some candidate genes related to prickle development have been separated one after another, such as CPC, WER, MYB5 (Yuan Xiaoyu. Mining and application research on rose prickle formation related genes [D]. Yangzhou University, 2019.) and TTG1 (Luan Xiaofang. Cloning and expression analysis of rose thorn formation related transcription factor RrTTG1 [D]. Yangzhou University, 2014.). Therefore, it is particularly important to explore some genes that have a regulatory role in prickle formation.

[0004] To solve the above problems, the present invention analyzes the transcriptome of the prickle primordium and stem epidermis of thorny wild roses and thornless wild roses, and finds the differentially expressed genes of the prickle primordium and stem epidermis tissue. At the same time, the characteristic genes of prickle formation are found by using the temporal transcriptome analysis of wild rose prickles. The data of the two transcriptomes are integrated and analyzed to obtain 700 prickle-related genes. Through expression pattern verification, it is found that RmGRF1 is a gene that is dominantly expressed in the prickle primordium. The gene is further cloned and transformed into Arabidopsis, and it is found that the leaves of transgenic Arabidopsis become larger and the number remains unchanged, and the leaf epidermal cells and palisade cells become larger and the number remains unchanged; using RNAi technology to interfere with the GRF1 gene in roses can hinder the formation of prickles and obtain roses with fewer prickles. Summary of the invention

[0005] One of the objectives of the present invention is to provide a rose gene RmGRF1.

[0006] The second purpose of the present invention is to disclose the application of the above gene in regulating the prickly trait.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] The present invention provides an application of a gene in regulating the size of plant epidermal cells and / or palisade cells, characterized in that the gene is any one of the following:

[0009] 1) A gene whose sequence is shown in SEQ ID NO: 1 or SEQ ID NO: 3;

[0010] 2) A gene encoding a protein sequence as shown in SEQ ID NO: 2 or SEQ ID NO: 4.

[0011] The present invention also provides an application of an expression cassette in regulating the size of plant epidermal cells and / or palisade cells, characterized in that the expression cassette contains the above-mentioned gene.

[0012] In some embodiments, the expression cassette is sequentially connected by the CaMV 35S promoter, the gene, and the nos terminator.

[0013] The present invention also provides an application of an expression vector in regulating the size of plant epidermal cells and / or palisade cells, characterized in that the expression vector contains the above-mentioned expression cassette.

[0014] The present invention also provides an application of a host cell in regulating the size of plant epidermal cells and / or palisade cells, characterized in that the host cell contains the above-mentioned expression cassette or the above-mentioned expression vector; the host cell is a microbial cell or a non-renewable plant cell.

[0015] The present invention also provides a method for reducing the number of thorns in rose plants, characterized in that the expression of the above gene is reduced in the rose plants, and plants with reduced number of thorns are selected.

[0016] In some embodiments, the above method of reducing gene expression is to use RNAi interference method.

[0017] In some embodiments, the interference fragment used in the above-mentioned RNAi interference method is shown as bases 1362-1577 of SEQ ID NO.1 or bases 1362-1577 of SEQ ID NO.3 or the reverse sequence thereof.

[0018] Compared with the existing technology, the invention has the following beneficial effects: the invention obtains the prickle dominant expression gene RmGRF1, and finds that the gene has the function of regulating the size of plant epidermal cells and / or palisade cells. Inhibiting the gene can reduce the number of prickles in rose plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Sampling sites of Rosa multiflora and its thornless accessions for comparative transcriptome sequencing.

[0020] Figure 2 Sampling sites of Rosa multiflora for temporal transcriptome sequencing of skin prickles.

[0021] Figure 3 Spatiotemporal expression pattern of RmGRF1. Prickle represents the prickly tissue.

[0022] Figure 4 Map of the RmGRF1 overexpression vector used for heterologous transformation of Arabidopsis thaliana.

[0023] Figure 5 Performance of transgenic Arabidopsis plants. a-b) Rosette leaf phenotype; cf) Leaf length, leaf width, petiole length, leaf area and leaf number of the fifth true leaf. n>18.

[0024] Figure 6 Transgenic Arabidopsis leaf epidermal cells. a) Morphology of epidermal cells of wild type and three RmGRF1 transgenic lines (1, 2, 11); b) Statistical analysis of epidermal cell area of ​​leaves; c) Statistical analysis of epidermal cell number of leaves.

[0025] Figure 7 Palisade cells in transgenic Arabidopsis leaves. a) Palisade cell morphology of wild type and three RmGRF1 transgenic lines (1, 2, 11); b) Palisade cell area statistics of leaves; c) Palisade cell number statistics of leaves.

[0026] Figure 8 Map of RrGRF1-RNAi vector. DETAILED DESCRIPTION

[0027] The following definitions and methods are provided to better define this application and guide those of ordinary skill in the art in the practice of this application. Unless otherwise specified, terms are understood according to the conventional usage of those of ordinary skill in the relevant field. All patent documents, academic papers, industry standards and other public publications cited herein are incorporated herein by reference in their entirety.

[0028] Unless otherwise indicated, nucleic acids are written from left to right in the 5' to 3' direction; amino acid sequences are written from left to right in the amino to carboxyl direction. Amino acids may be represented herein by their commonly known three-letter symbols or by the single-letter symbols recommended by the IUPAC-IUB Biochemical Nomenclature Committee. Similarly, nucleotides may be represented by commonly accepted single-letter codes. Numerical ranges include numbers that define the range. As used herein, "nucleic acid" includes deoxyribonucleotides or ribonucleotide polymers in single-stranded or double-stranded form, and unless otherwise limited, includes known analogs (e.g., peptide nucleic acids) having the basic properties of natural nucleotides, which hybridize with single-stranded nucleic acids in a manner similar to naturally occurring nucleotides. As used herein, the term "encoding" or "encoded" when used in the context of a specific nucleic acid refers to the nucleic acid containing the necessary information to direct the translation of the nucleotide sequence into a specific protein. Codons are used to represent information encoding proteins. As used herein, the "full-length sequence" of a specific polynucleotide or its encoded protein refers to the entire nucleic acid sequence or the entire amino acid sequence having a natural (non-synthetic) endogenous sequence. The full-length polynucleotide encodes the full-length, catalytically active form of the particular protein. The terms "polypeptide," "polypeptide," and "protein" are used interchangeably herein to refer to polymers of amino acid residues. The term is used for amino acid polymers in which one or more amino acid residues are artificial chemical analogs of the corresponding naturally occurring amino acids. The term is also used for naturally occurring amino acid polymers. The terms "residue" or "amino acid residue" or "amino acid" are used interchangeably herein to refer to an amino acid that is incorporated into a protein, polypeptide, or peptide (collectively, "protein"). Amino acids can be naturally occurring amino acids, and unless otherwise limited, known analogs of natural amino acids can be included that can function in a manner similar to naturally occurring amino acids.

[0029] "Plant" includes reference to whole plants, plant organs, plant tissues, seeds and plant cells and their progeny. Plant cells include, but are not limited to, cells from seeds, suspension cultures, embryos, meristematic regions, callus, leaves, roots, seedlings, gametophytes, sporophytes, pollen and microspores. "Progeny" includes any subsequent generations of a plant.

[0030] In this application, the words "comprise", "comprising" or their variants are to be understood as including other elements, numbers or steps in addition to the described elements, numbers or steps. "Test plant" or "test plant cell" refers to a plant or plant cell in which a genetic modification has been effected, or a progeny cell of a plant or cell so modified, which progeny cell comprises the modification. "Control" or "control plant" or "control plant cell" provides a reference point for measuring phenotypic changes in the test plant or plant cell.

[0031] Negative or control plants can include, for example: (a) wild-type plants or cells, i.e., plants or cells having the same genotype as the genetically modified starting material that produced the test plant or cell; (b) plants or plant cells having the same genotype as the starting material but that have been transformed with an empty construct (i.e., with a construct that has no known effect on the trait of interest, such as a construct containing a marker gene); (c) plants or plant cells that are non-transformed segregants of the test plant or plant cell; (d) plants or plant cells that are genetically identical to the test plant or plant cell but have not been exposed to conditions or stimuli that would induce expression of the gene of interest; or (e) the test plant or plant cell itself, which is under conditions where the gene of interest is not expressed.

[0032] Those skilled in the art will readily recognize that advances in the field of molecular biology, such as site-specific and random mutagenesis, polymerase chain reaction methods, and protein engineering techniques, provide a wide range of appropriate tools and procedures for modifying or engineering the amino acid sequence and underlying gene sequence of proteins of agricultural interest.

[0033] In some embodiments, the nucleotide sequence of the present application can be changed to perform conservative amino acid substitutions. The principles and examples of conservative amino acid substitutions are further described below. In certain embodiments, the nucleotide sequence of the present application can be replaced without changing the amino acid sequence according to the disclosed monocot codon preference, for example, the codons encoding the same amino acid sequence can be replaced with codons preferred by monocot plants without changing the amino acid sequence encoded by the nucleotide sequence. In some embodiments, a portion of the nucleotide sequence in the present application is replaced with different codons encoding the same amino acid sequence, thereby not changing the amino acid sequence encoded by the nucleotide sequence while changing the nucleotide sequence. Conservative variants include those sequences that encode an amino acid sequence of one of the proteins of the embodiment due to genetic codon degeneracy. In some embodiments, a portion of the nucleotide sequence in the present application is replaced according to monocot plant preference codons. Those skilled in the art will recognize that amino acid additions and / or substitutions are generally based on the relative similarity of amino acid side chain substituents, for example, the hydrophobicity, charge, size, etc. of the substituent. Exemplary amino acid substitution groups with various aforementioned properties considered are well known to those skilled in the art and include arginine and lysine; glutamic acid and aspartic acid; serine and threonine; glutamine and asparagine; and valine, leucine and isoleucine. Guidance on appropriate amino acid substitutions that do not affect the biological activity of the target protein can be found in the model of Dayhoff et al. (1978) Atlas of Protein Sequence and Structure (Natl. Biomed. Res. Found., Washington, DC) (incorporated herein by reference). Conservative substitutions such as replacing one amino acid with another amino acid having similar properties can be performed. Identification of sequence identity includes hybridization techniques. For example, all or part of a known nucleotide sequence is used as a probe for selective hybridization with other corresponding nucleotide sequences, and the other corresponding nucleotide sequences are present in a cloned genomic DNA fragment or cDNA fragment group (i.e., a genomic library or a cDNA library) from a selected organism. The hybridization probe can be a genomic DNA fragment, a cDNA fragment, an RNA fragment or other oligonucleotide, and can be marked with a detectable group such as 32P or other detectable markers. Thus, for example, a hybridization probe can be prepared by marking a synthetic oligonucleotide based on the embodiment sequence. The method for preparing hybridization probes and constructing cDNA and genomic libraries is generally known in the art. The hybridization of the sequence can be carried out under stringent conditions. As used herein, the term "stringent conditions" or "stringent hybridization conditions" means the following conditions, i.e., under these conditions, relative to hybridization with other sequences, the probe will hybridize with its target sequence to a greater extent (e.g., at least 2 times, 5 times or 10 times of background) that can be detected.Stringent conditions are sequence-dependent and vary in different environments. By controlling the stringency of hybridization and / or controlling the washing conditions, a target sequence that is 100% complementary to the probe can be identified (homologous probe method). Alternatively, stringent conditions can be adjusted to allow some sequence mismatches to detect lower similarities (heterologous probe method). Typically, the probe length is less than about 1000 or 500 nucleotides. Typically, stringent conditions are conditions in which the salt concentration is less than about 1.5M Na ions, typically about 0.01M to 1.0M Na ion concentration (or other salts) at pH 7.0 to 8.3, and the temperature conditions are: when used for short probes (e.g., 10 to 50 nucleotides), at least about 30°C; when used for long probes (e.g., greater than 50 nucleotides), at least about 60°C. Stringent conditions can also be achieved by adding destabilizing agents such as formamide. Exemplary low stringency conditions include hybridization using 30% to 35% formamide buffer, 1M NaCl, 1% SDS (sodium dodecyl sulfate) at 37°C, and washing in 1× to 2× SSC (20×SSC=3.0MNaCl / 0.3M trisodium citrate) at 50°C to 55°C. Exemplary moderate stringency conditions include hybridization in 40% to 45% formamide, 1.0M NaCl, 1% SDS at 37°C, and washing in 0.5× to 1× SSC at 55°C to 60°C. Exemplary high stringency conditions include hybridization in 50% formamide, 1M NaCl, 1% SDS at 37°C, and a final wash in 0.1× SSC at 60°C to 65°C for at least about 20 minutes. Optionally, the wash buffer may contain about 0.1% to about 1% SDS. The duration of hybridization is typically less than about 24 hours, typically about 4 hours to about 12 hours. Specificity is usually dependent on post-hybridization washes, with the key factors being the ionic strength and temperature of the final wash solution. The Tm (thermodynamic melting point) of a DNA-DNA hybrid can be approximated by the formula of Meinkoth and Wahl (1984) Anal. Biochem. 138: 267-284: Tm = 81.5°C + 16.6 (log M) + 0.41 (% GC) - 0.61 (% formamide) - 500 / L; where M is the molar concentration of monovalent cations, % GC is the percentage of guanosine and cytosine nucleotides in the DNA, "% formamide" is the percentage of formamide in the hybridization solution, and L is the base pair length of the hybrid. The Tm is the temperature (under defined ionic strength and pH) at which 50% of the complementary target sequence hybridizes to a perfectly matched probe. Washing is usually performed at least until equilibrium is reached and a low level of hybridization background is achieved, such as for 2 hours, 1 hour, or 30 minutes. Each 1% mismatch should reduce the Tm by about 1°C; thus, the Tm, hybridization, and / or washing conditions can be adjusted to hybridize to sequences of the desired identity. For example, if sequences with ≥90% identity are desired, the Tm can be reduced by 10°C.Typically, stringent conditions are selected to be about 5°C lower than the Tm of the specific sequence and its complementary sequence at a defined ionic strength and pH. However, under very stringent conditions, hybridization and / or washing can be performed at 4°C lower than the Tm; under moderately stringent conditions, hybridization and / or washing can be performed at 6°C lower than the Tm; and under low stringency conditions, hybridization and / or washing can be performed at 11°C lower than the Tm.

[0034] In some embodiments, a fragment of a nucleotide sequence and an amino acid sequence encoded therein is also included. As used herein, the term "fragment" refers to a portion of the nucleotide sequence of the polynucleotide of the embodiment or a portion of the amino acid sequence of the polypeptide. The fragment of the nucleotide sequence can encode a protein fragment, and the protein fragment retains the biological activity of the natural or corresponding full-length protein, and thus has protein activity. Mutant proteins include biologically active fragments of natural proteins, which contain continuous amino acid residues that retain the biological activity of natural proteins. Some embodiments also include transformed plant cells or transgenic plants, which include the nucleotide sequence of at least one embodiment. In some embodiments, an expression vector is used to transform a plant, and the expression vector includes the nucleotide sequence of at least one embodiment and a promoter that drives expression in a plant cell operably connected thereto. Transformed plant cells and transgenic plants represent plant cells or plants that contain heterologous polynucleotides in the genome. In general, the heterologous polynucleotides are stably integrated in the genome of the transformed plant cell or transgenic plant, so that the polynucleotides are passed to offspring. The heterologous polynucleotides can be integrated into the genome individually or as part of an expression vector. In some embodiments, the plants involved in the present application include plant cells, plant protoplasts, plant cell tissue cultures that can regenerate plants, plant calli, plant masses and plant cells, which are complete plants or parts of plants, such as embryos, pollen, ovules, seeds, leaves, flowers, branches, fruits, kernels, spikes, cobs, shells, stalks, roots, root tips, anthers, etc. The present application also includes plant cells, protoplasts, tissues, calli, embryos, flowers, stems, fruits, leaves and roots derived from the transgenic plants of the present application or their progeny, and thus at least partially comprising the nucleotide sequences of the present application.

[0035] The term "amplification" in the context of nucleic acid amplification is any process in which additional copies of a selected nucleic acid (or a transcribed form thereof) are produced. Common amplification methods include a variety of polymerase-based replication methods, including polymerase chain reaction (PCR), ligase-mediated methods such as ligase chain reaction (LCR), and RNA polymerase-based amplification (e.g., by transcription) methods.

[0036] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Without departing from the spirit and substance of the present invention, the modification or replacement of the inventive method, step or condition, all belong to the scope of the present application. If not otherwise specified, the embodiments are according to conventional experimental conditions, such as Sambrook et al.'s Molecular Cloning Laboratory Manual (Sambrook J & Russell DW, Molecular cloning: alaboratory manual, 2001), or according to the conditions of the manufacturer's instructions. If not otherwise specified, the chemical reagents used in the embodiments are conventional commercial reagents, and the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0037] Example 1 Discovery process and expression detection of prickle development genes

[0038] Rosa multiflora is a deciduous shrub of the genus Rosa, a diploid plant with prickles on its stems and petioles, and is one of the main parents of modern roses. Rosa multiflora Thunb. var. inermis is a variant of Rosa multiflora, with smooth stems and no thorns at all. The Rosa multiflora and the Rosa multiflora Thunb. var. inermis used in the present invention are common species planted in Huazhong Agricultural University, and are also planted in many other places and are available to the public.

[0039] Total RNA was extracted from prickle primordium from R. multiflora stem (PP), immature bark from R. multiflora stem (IB) and immature bark from R. multiflora 'inermis' No.1 stem (IBI) (see the sampling sites for details). Figure 1 Total RNA was extracted from the prickles of Rosa multiflora at five developmental stages (I–V) (see Sampling sites for details). Figure 2). After total RNA extraction and DNaseI treatment, mRNA was isolated with Oligo (dT) magnetic beads and cDNA libraries were constructed. The quality of the cDNA library was tested using the ABI StepOnePlus Real-Time PCR system and the Agilent 2100 Bioanalyzer, and sequencing was performed on the Illumina HiSeq TM2000 sequencing platform. In the comparative transcriptome experiment of wild rose and thornless wild rose, three biological replicates and three samples were set for each sample, for a total of nine samples. After the sequencing experiment was completed, the data were analyzed to find differentially expressed genes in different samples. In the temporal transcriptome experiment of wild rose prickles, four biological replicates and five samples were set for each sample, for a total of 20 samples. After the sequencing experiment was completed, the data were analyzed to find characteristic genes in different samples.

[0040] A total of 6728 differentially expressed genes were obtained in the comparisons of PP vs IB, PP vs IBI and IB vs IBI, and a total of 11976 characteristic genes were obtained in the temporal transcriptome analysis of Rosa multiflora prickles. The two sets of RNA-seq data were jointly analyzed, and a total of 700 prickle-related genes were obtained.

[0041] Among the prickles-related genes mentioned above, genes with high expression levels in PP tissues and low or no expression levels in IB and IBI tissues were searched; at the same time, the gene also had to meet the characteristics of the highest expression level in the prickles of stage I and then continued to decline. Based on the above screening conditions, a gene homologous to the Arabidopsis GROWTH-REGULATING FACTOR 1 (GRF1) gene was found to meet the above conditions at the same time. The present invention named the gene in wild rose RmGRF1. The RmGRF1 gene sequence is shown in SEQ ID NO.1, and the encoded amino acid sequence is shown in SEQ ID NO.2.

[0042] The inventors conducted further functional tests on RmGRF1. The temporal and spatial expression pattern of the RmGRF1 gene was detected by qRT-PCR technology. The results showed that the gene was expressed at the highest level in the prickle primordium, with higher expression in the apical buds, lateral buds and leaves, and low or very low expression in other tissues. Samples of wild rose prickle development stages I–V were collected, and the expression levels in these samples were detected by qRT-PCR. The results showed that the gene was expressed at the highest level in the prickle of stage I, very low in the prickle of stage II, and then continued to decline until stage V ( Figure 3 These results indicate that RmGRF1 has the characteristics of prickles-dominant expression and its expression pattern is closely related to the initiation of prickles.

[0043] Example 2 Gene Function Study

[0044] The inventors transformed RmGRF1 into Arabidopsis to study its function. The vector used CaMV 35S as the promoter and NOS as the terminator. For the convenience of research, the gene was preceded by a GFP reporter gene and a His tag (see the vector diagram for details). Figure 4 The Arabidopsis transformation method used the conventional Agrobacterium-mediated transformation method in the art. The phenotypes of the transformed Arabidopsis T1 and T2 plants were observed and recorded throughout the growth period. The results showed that when the plants grew to 4 weeks old, the leaf size of the RmGRF1 transgenic line was significantly larger than that of the wild type ( Figure 5 ab). The leaf length, leaf width, petiole length, leaf area and other indicators of the three lines were measured, and the fifth true leaf was selected for statistical analysis compared with the true leaves of the wild type at the same period. The results showed that compared with the wild type, the leaf length, petiole length and leaf area of ​​the fifth true leaf of the three transgenic lines were significantly larger than those of the wild type ( Figure 5 cf). However, the total number of leaves remains unchanged ( Figure 5 g). Thus, RmGRF1 affects leaf size, but not leaf number.

[0045] The inventors further studied the effect of RmGRF1 on the development of transgenic Arabidopsis leaves from a cytological perspective, and observed the epidermis and lower palisade cells of the fifth true leaf of the three transgenic Arabidopsis strains. The results showed that under the same proportional field of view, the cell area of ​​epidermal cells and palisade cells of the three transgenic strains was significantly larger than that of the wild-type control, while the number of epidermal cells and palisade cells did not change ( Figure 6 and Figure 7 ). Therefore, RmGRF1 affects leaf development by promoting the expansion of leaf epidermal cells and palisade cells rather than cell proliferation, resulting in leaf enlargement.

[0046] Since the RmGRF1 gene promotes the expansion of leaf epidermal cells and palisade cells, inhibiting the RmGRF1 gene can inhibit the expansion of prickly cells, thereby reducing the number of prickles. To verify the effect of this technology, the inventors amplified the homologous gene RrGRF1 of RmGRF1 in the closely related species of wild rose, Rosa rugosa'Baobai', and determined the gene sequence (as shown in SEQ ID NO.3). The sequence similarity between RrGRF1 and RmGRF1 is very high, with only a few bases different. The 1362-1577 base fragment of SEQ ID NO.1 or SEQ ID NO.3 was selected as the interference fragment of RrGRF1, and the fragment and its reverse sequence were used together to construct an RNAi vector. Using Rose 'Baobai' as the transformation receptor, the Agrobacterium-mediated method was used, and a vector containing RrGRF1 RNAi (see vector map) was used. Figure 8 ) was used to infect rose 'Baobai' somatic embryos, and finally transformed seedlings were obtained. Transformed seedlings were selected by expression detection to select plants with significantly reduced expression levels. By investigating the prickles of these plants, it was found that the number of prickles after GRF1 gene interference was significantly reduced compared with the control, indicating that the technical effect of reducing prickles can be achieved by inhibiting the GRF1 gene.

[0047] Table 1 Statistics of the number of prickles in the stem segments of rose 'Baobai' after GRF1 gene interference

[0048]

[0049] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. Use of a gene in regulating the size of plant epidermal cells and / or palisade cells, characterized in that: The gene is any one of the following: 1) A gene whose sequence is shown in SEQ ID NO: 1 or SEQ ID NO: 3; 2) A gene encoding a protein sequence as shown in SEQ ID NO: 2 or SEQ ID NO:

4.

2. Use of an expression cassette in regulating the size of plant epidermal cells and / or palisade cells, characterized in that: The expression cassette contains the gene described in claim 1.

3. The use according to claim 2, characterized in that: The expression cassette is composed of the CaMV 35S promoter, the gene described in claim 1, and the nos terminator connected in sequence.

4. Use of an expression vector in regulating the size of plant epidermal cells and / or palisade cells, characterized in that: The expression vector contains the expression cassette according to any one of claims 2 to 3.

5. Use of a host cell in regulating the size of plant epidermal cells and / or palisade cells, characterized in that: The host cell contains the expression cassette described in any one of claims 2 to 3 or the expression vector described in claim 4; the host cell is a microbial cell or a non-renewable plant cell.

6. A method for reducing the number of prickles in rose plants, characterized in that: The expression of the gene of claim 1 is reduced in plants of the genus Rosa, and plants with reduced number of prickles are selected.

7. The method according to claim 6, characterized in that The method for reducing the expression of the gene in claim 1 is to use RNAi interference method.

8. The method according to claim 7, characterized in that The interference fragment used in the RNAi interference method is shown by bases 1362-1577 of SEQ ID NO.1 or bases 1362-1577 of SEQ ID NO.3 or the reverse sequence thereof.

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