阅读说明：本技术 番茄SlLOB40蛋白及其编码基因在调控植物抗旱性中的应用 (Application of tomato SlLOB40 protein and coding gene thereof in regulation and control of plant drought resistance ) 是由 张娜 刘伦 张嘉龙 郭仰东 郑禾 吕红梅 王志荣 苏慧 于 2019-11-12 设计创作，主要内容包括：本发明涉及生物技术领域,具体涉及番茄SlLOB40蛋白及其编码基因在调控植物抗旱性中的应用。本发明发现番茄SlLOB40基因能够负调控植物抗旱性,通过降低SlLOB40基因的表达量,能够有效提高植物抗旱性。SlLOB40基因的抗旱性调控功能的发现为培育高抗旱性的植物新品种提供了宝贵的基因资源和新的方法。本发明利用CRISPR-Cas9基因组定点编辑系统突变番茄SlLOB40基因,创制了抗旱番茄株系,该番茄株系的抗旱能力显著提高,具有重要的应用价值。(The invention relates to the technical field of biology, in particular to application of a tomato SlLOB40 protein and a coding gene thereof in regulation and control of plant drought resistance. The invention discovers that the tomato SlLOB40 gene can negatively regulate the drought resistance of plants, and the expression level of the SlLOB40 gene is reduced, so that the drought resistance of the plants can be effectively improved. The discovery of the drought resistance regulation function of the SlLOB40 gene provides valuable gene resources and a new method for cultivating new plant varieties with high drought resistance. The invention utilizes the CRISPR-Cas9 genome fixed-point editing system to mutate the tomato SlLOB40 gene, creates a drought-resistant tomato strain, obviously improves the drought-resistant capability of the tomato strain, and has important application value.)

1. The application of the tomato SlLOB40 protein or the coding gene thereof or the inhibitor of the coding gene of the tomato SlLOB40 protein in regulating and controlling the drought resistance of plants.

2. Application of tomato SlLOB40 protein or coding gene thereof or inhibitor of coding gene of tomato SlLOB40 protein in plant genetic breeding or transgenic plant preparation.

3. The use according to claim 1 or 2, wherein the drought resistance of a plant is improved by reducing the expression level of a gene encoding the tomato SlLOB40 protein;

preferably, the expression level of the coding gene of the tomato SlLOB40 protein is reduced to inactivate the coding gene of the SlLOB40 protein.

4. The use of any one of claims 1 to 3, wherein the tomato SlLOB40 protein has any one of the following amino acid sequences:

(1) an amino acid sequence shown as SEQ ID NO. 1;

(2) the amino acid sequence of the protein with the same function is obtained by replacing, inserting or deleting one or more amino acids in the amino acid sequence shown as SEQ ID NO. 1;

(3) an amino acid sequence having at least 80% homology with the amino acid sequence shown as SEQ ID No. 1; preferably, the homology is at least 90%; more preferably 95%.

5. The use of any one of claims 1 to 4, wherein the inhibitor of the gene encoding the tomato SlLOB40 protein comprises a gRNA or an interfering RNA capable of inhibiting the expression of the gene encoding the tomato SlLOB40 protein;

preferably, the target sequence of the gRNA is 59-78 th of the first exon of the coding gene of the tomato slob 40 protein;

more preferably, the gRNA comprises a nucleotide sequence as set forth in SEQ ID No. 3.

6. A gRNA for editing the tomato slob 40 gene, wherein the target sequence of the gRNA comprises positions 59-78 of the first exon of the tomato gene;

preferably, the gRNA comprises a nucleotide sequence as set forth in SEQ ID No. 3;

the encoding protein of the tomato SlLOB40 gene has any one of the following amino acid sequences:

(1) an amino acid sequence shown as SEQ ID NO. 1;

(2) the amino acid sequence of the protein with the same function is obtained by replacing, inserting or deleting one or more amino acids in the amino acid sequence shown as SEQ ID NO. 1;

(3) an amino acid sequence having at least 80% homology with the amino acid sequence shown as SEQ ID No. 1; preferably, the homology is at least 90%; more preferably 95%.

7. Biological material comprising grnas for editing the tomato SlLOB40 gene of claim 6, wherein the biological material comprises an expression cassette, a vector, a transgenic cell, or an engineered bacterium.

8. A method of modulating drought resistance in a plant comprising: regulating and controlling the expression level of tomato SlLOB40 gene in the plant;

the encoding protein of the tomato SlLOB40 gene has any one of the following amino acid sequences:

(1) an amino acid sequence shown as SEQ ID NO. 1;

(2) the amino acid sequence of the protein with the same function is obtained by replacing, inserting or deleting one or more amino acids in the amino acid sequence shown as SEQ ID NO. 1;

(3) an amino acid sequence having at least 80% homology with the amino acid sequence shown as SEQ ID No. 1; preferably, the homology is at least 90%; more preferably 95%.

9. The method of claim 8, wherein the drought resistance of the plant is increased by reducing the expression level of the tomato SlLOB40 gene in the plant; or, the tomato SlLOB40 gene inactivation mutant strain is crossed with other strains to cultivate a drought-resistant strain.

10. The method according to claim 9, wherein the reducing the expression of the tomato SlLOB40 gene in the plant is achieved using the CRISPR/Cas9 system, wherein the target sequences of grnas used in the CRISPR/Cas9 system comprise a sequence comprising the NGG sequence characteristic of the first exon of the tomato SlLOB40 gene;

preferably, the target sequence of the gRNA is 59 th to 78 th of the first exon of the coding gene of the SlLOB40 protein.

Technical Field

The invention relates to the technical field of biology, in particular to application of a tomato SlLOB40 protein and a coding gene thereof in regulation and control of plant drought resistance.

Background

Tomato, an important horticultural crop, is susceptible to water deficit in growth and development, and today, due to the increasing shortage of water resources, drought stress has become one of the important factors affecting tomato yield and quality.

Research shows that LOB gene family has various biological functions, not only has transcription regulation and control capability, but also can play a role by interacting with other proteins. The LOB gene was originally found to be specifically expressed in the lateral organs of plants, and is closely related to the morphogenesis and growth and development of plants. Research has shown that the ALR1 gene in rice encodes LOB protein, which controls the initiation of adventitious root primordium development in rice (Liu et al 2005); the AS2 gene in arabidopsis encodes a LOBmx protein that can interact with an AS1(MYB gene family member) protein to form a functional complex to affect leaf development at the transcriptional level (Xu et al 2003). The LOB gene is also closely related to the synthesis and metabolism of plant hormones. It was reported that overexpression of the arabidopsis AtASL4 gene could activate the downstream BAS1 gene and thereby regulate brassinosteroid accumulation, and that the arabidopsis LOB family gene DDA1 could respond to auxin signals, the transcription level of which could be down-regulated by exogenous auxin induction (Mangeon et al.2010).

Researchers have improved drought resistance in tomatoes by a variety of methods. Research reports that the overexpression of the SlWD6 gene in tomatoes can obviously enhance the tolerance of tomatoes to drought and salt stress (Yangzhi et al, 2015). Tomatoes which excessively express SlWRKY39 can accumulate more proline and lower content MDA under drought stress by improving the expression of stress-resistant genes SlRD22 and SlDREB2A, so that the drought resistance of the tomatoes is improved (SUN et al, 2015). In addition, studies prove that the exogenous ABA spraying can improve the seedling stage drought resistance of the tomato variety Moneymoker (admitted to the sun, etc., 2018). Improving the tolerance of tomato crops to drought stress can greatly help the development of the tomato industry. To date, no mechanism has been reported for the effect of tomato LOB family transcription factors on drought stress tolerance.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention aims to provide the application of the tomato SlLOB40 protein and the coding gene thereof in regulating and controlling the drought resistance of tomatoes.

In order to achieve the purpose, the wild tomato material is subjected to drought treatment, RNA is extracted, a gene capable of obviously responding to drought is screened by utilizing fluorescent quantitative PCR, and the gene SlLOB40 is obtained after analysis. The CDS sequence of the gene is shown as SEQ ID NO.2, and the amino acid sequence of the encoded SlLOB40 protein is shown as SEQ ID NO. 1.

Specifically, the technical scheme of the invention is as follows:

in a first aspect, the invention provides an application of a tomato SlLOB40 protein or an encoding gene thereof or an inhibitor of an encoding gene of a tomato SlLOB40 protein in regulation and control of plant drought resistance.

In a second aspect, the invention provides an application of a tomato SlLOB40 protein or a coding gene thereof or an inhibitor of a coding gene of a tomato SlLOB40 protein in plant genetic breeding or transgenic plant preparation.

The genetic breeding of the plants or the preparation of the transgenic plants aims at the cultivation of drought-resistant plants.

In the application, the drought resistance of the plant can be improved by reducing the expression level of the coding gene of the tomato SlLOB40 protein.

Preferably, the expression level of the coding gene of the tomato SlLOB40 protein is reduced to inactivate the coding gene of the SlLOB40 protein.

In the invention, the tomato SlLOB40 protein has any one of the following amino acid sequences:

(1) an amino acid sequence shown as SEQ ID NO. 1;

(2) the amino acid sequence of the protein with the same function is obtained by replacing, inserting or deleting one or more amino acids in the amino acid sequence shown as SEQ ID NO. 1;

(3) an amino acid sequence having at least 80% homology with the amino acid sequence shown as SEQ ID No. 1; preferably, the homology is at least 90%; more preferably 95%.

The amino acid sequence shown as SEQ ID No.1 is the amino acid sequence of tomato SlLOB40 protein, and a person skilled in the art can substitute, delete and/or add one or more amino acids according to the amino acid sequence of tomato SlLOB40 protein and conservative substitution of amino acids and other conventional technical means in the art on the premise of not influencing the activity of the tomato SlLOB40 protein to obtain a SlLOB40 protein mutant with the same function as the tomato SlLOB40 protein.

In the invention, the CDS sequence of the coding gene of the tomato SlLOB40 protein has any one of the following nucleotide sequences:

(1) nucleotide as shown in SEQ ID NO. 2;

(2) the nucleotide sequence of the protein with the same function is obtained by replacing, inserting or deleting one or more nucleotides in the nucleotide sequence shown in SEQ ID NO. 2.

The nucleotide sequence shown as SEQ ID NO.2 is the CDS sequence of SlLOB40 protein in tomato. All nucleotide sequences encoding the tomato slob 40 protein are within the scope of the present invention, taking into account the degeneracy of the codons.

In the invention, the inhibitor of the coding gene of the tomato SlLOB40 protein comprises gRNA or interfering RNA capable of inhibiting the expression of the coding gene of the tomato SlLOB40 protein.

Preferably, the target sequence of the gRNA is 59-78 th of the first exon of the coding gene of the tomato slob 40 protein.

More preferably, the gRNA comprises a nucleotide sequence as set forth in SEQ ID No. 3.

The target site of the gRNA is obtained by screening a large number of gRNAs, and the high-efficiency knockout of tomato SlLOB40 can be realized by using the gRNAs, so that tomato SlLOB40 is inactivated.

In a third aspect, the invention provides a gRNA that edits a tomato slob 40 gene, the target sequence of the gRNA comprising positions 59-78 of the first exon of the tomato slob 40 gene.

The gRNA can be matched with a CRISPR/Cas9 gene editing system to realize high-efficiency knockout of a tomato SlLOB40 gene.

Preferably, the gRNA comprises a nucleotide sequence as set forth in SEQ ID No. 3.

In a fourth aspect, the invention provides a biological material comprising the gRNA for editing the tomato slob 40 gene, the biological material comprising an expression cassette, a vector, a transgenic cell, or an engineered bacterium.

The expression cassette can be an expression cassette containing the AtU6 promoter and the gRNA.

The vector can be a CRISPR-Cas9 gene editing vector containing AtU6 promoter, the gRNA, and Cas9 expression cassette.

The engineering bacteria can be escherichia coli or agrobacterium containing the CRISPR-Cas9 gene editing vector.

In a fifth aspect, the present invention provides a method of modulating drought resistance in a plant, comprising: regulating and controlling the expression level of tomato SlLOB40 gene in the plant;

the encoding protein of the tomato SlLOB40 gene has any one of the following amino acid sequences:

(1) an amino acid sequence shown as SEQ ID NO. 1;

(2) the amino acid sequence of the protein with the same function is obtained by replacing, inserting or deleting one or more amino acids in the amino acid sequence shown as SEQ ID NO. 1;

(3) an amino acid sequence having at least 80% homology with the amino acid sequence shown as SEQ ID No. 1; preferably, the homology is at least 90%; more preferably 95%.

Preferably, in the above method, drought resistance of the plant is increased by reducing the expression level of the solanum lycopersicum SlLOB40 gene in the plant; or, the drought-resistant strain is cultivated by crossing the inactivated mutant strain of the tomato SlLOB40 gene with other strains.

The above reduction of the expression level of the solanum lycopersicum SlLOB40 gene in the plant can be achieved by means of conventional techniques in the art.

Preferably, the reduction of the expression level of the tomato SlLOB40 gene in the plant is achieved by using a CRISPR/Cas9 system, wherein the target sequence of the gRNA used in the CRISPR/Cas9 system comprises a sequence containing NGG sequence features on the first exon of the tomato SlLOB40 gene, in particular positions 59-78 of the first exon of the SlLOB40 gene.

As a preferred embodiment of the present invention, the construction method of the CRISPR-Cas9 system is as follows: the AtU6-26-sgRNA-SK plasmid containing the AtU6 promoter and the gRNA sequence shown in SEQ ID No.3 was cloned into the pCAMBIA1300-pYAO Cas9 vector.

In the present invention, the plant is a monocotyledon or a dicotyledon. Such plants include, but are not limited to, tomato, rice, Arabidopsis, grape, soybean, cucumber, wheat, corn, and the like.

The invention provides application of tomato SlLOB40 protein and coding gene thereof in regulating and controlling plant drought resistance, which has the following beneficial effects:

according to the invention, screening analysis shows that the tomato SlLOB40 gene can negatively regulate plant drought resistance, and the plant drought resistance can be effectively improved by reducing the expression level of SlLOB40 gene. The discovery of the drought resistance regulation function of the SlLOB40 gene provides valuable gene resources and a new method for cultivating new plant varieties with high drought resistance: on one hand, a tomato line with stronger drought resistance can be obtained by site-directed mutagenesis of the SlLOB40 gene of cultivated tomatoes; on the other hand, the SlLOB40 gene-inactivated plants (LOB-KO-3 and LOB-KO-5) provided by the invention can be used for hybridizing with other tomato varieties to culture drought-resistant strains and enrich drought-resistant germplasm resources of tomatoes. The SlLOB40 gene and the inhibitor thereof have great application value in tomato drought resistance breeding.

Drawings

FIG. 1 shows the gene structure of SlLOB40 gene and the LOB gene target sequence mutation of homozygous mutant plants in example 1, wherein KO-3 and KO-5 represent two homozygous knockout lines LOB-KO-3 and LOB-KO-5, and WT is wild type; -represents a base deletion;

FIG. 2 is a diagram showing the results of electrophoresis detection of transgenic plants containing Cas9 gene screened by PCR in example 1, wherein Lane 1 is transgenic plant LOB-KO-3, Lane 2 is transgenic plant LOB-KO-5, M is DNA Mark, and the sizes of the bands are 2000bp, 1000bp and 750bp from top to bottom;

FIG. 3 is a diagram showing the result of electrophoresis detection of the SlLOB40 gene in the PCR-amplified transgenic plant of example 1, wherein the 1 st lane is LOB-KO-3, the 2 nd lane is LOB-KO-5, M is DNA Mark, and the sizes of the bands are 2000bp, 1000bp and 750bp from top to bottom;

FIG. 4 is a graph showing the growth status of SlLOB40 knock-out lines (LOB-KO-3 and LOB-KO-5) and wild-type (WT) materials before and after drought stress treatment, as provided in example 2 of the present invention;

FIG. 5 is a comparison graph of the water loss rate of leaves of SlLOB40 knock-out lines (LOB-KO-3 and LOB-KO-5) and wild-type (WT) materials provided in example 2 of the present invention during the drying process.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.