CdRHB1 gene for reducing cadmium absorption and accumulation in plants and application thereof

Abstract

The application relates to a CdRHB1 gene for reducing cadmium absorption and accumulation of plants and application thereof, and belongs to the technical field of biological genetic engineering. The CdRHB1 gene is a Brassica rapa BrCdRHB1 gene, and the nucleotide sequence is shown as SEQ ID NO. 1; or a radish RsCdRHB1 gene, and the nucleotide sequence is shown as SEQ ID NO. 2. The application refers to the following: knocking out the BrCdRHB1 gene can increase the cadmium absorption and accumulation of plants; or overexpressing the RsCdRHB1 gene can reduce the cadmium absorption and accumulation of plants. The application confirms for the first time through experiments that knocking out the BrCdRHB1 gene or overexpressing the RsCdRHB1 gene can increase or reduce the cadmium absorption and accumulation of plants, and lays a good theoretical and application foundation for cultivating low-cadmium and green crop varieties by using the CdRHB1 gene.

Description

Technical Field

[0001] This invention relates to a CdRHB1 gene that reduces cadmium absorption and accumulation in plants and its application, belonging to the field of bioengineering technology. Background Technology

[0002] In recent decades, due to increased industrial pollution and the irrational use of pesticides and fertilizers in agricultural production, the amount of heavy metal pollutants accumulated in soil has been increasing year by year, posing a serious threat to green agricultural production and public health. Among the many heavy metal elements, cadmium is one of the most representative, classified as a Group 1 carcinogen by the World Health Organization. Cadmium is also a major element in soil heavy metal pollution, with a national exceedance rate of 7.0%, far higher than other tested inorganic pollutants (National Soil Pollution Status Survey Bulletin, 2014). In nature, cadmium exists mostly in ionic form, and most cadmium compounds are readily soluble in water and easily absorbed by plants, thus seriously affecting the health of animals and humans through the food chain.

[0003] Using molecular biology techniques to improve plants is an effective way to address cadmium pollution. In the past decade or so, plant scientists and crop scientists have screened many cadmium transport proteins in various plants and applied them to plant and crop improvement processes. For example, the cadmium ion efflux transporter AtPDR8, discovered using current technology, is a typical ABC (ATP-binding cassette) transporter, requiring energy and having a limited capacity to efflux cadmium ions. In the molecular breeding of low-cadmium crops, researchers often use gene editing technology to knock out genes of transport proteins capable of transporting cadmium ions (such as NRAMP5 and HMA3) to cultivate low-cadmium crops. This approach, while reducing the cadmium transport capacity of these proteins, also affects their transport of other beneficial nutrients and ions, leading to a decrease in plant quality and yield. Furthermore, most of these proteins transport cadmium ions to the plant's vacuoles or a specific part of the plant, isolating the cadmium ions and posing a risk of cadmium contamination to the food chain.

[0004] Therefore, it is very important to explore and study genes that can reduce cadmium absorption and accumulation in plants, as these genes have important applications in plant improvement. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a CdRHB1 gene that reduces cadmium absorption and accumulation in plants and its applications.

[0006] The technical solution of the present invention is as follows: A CdRHB1 gene that reduces cadmium absorption and accumulation in plants, wherein the CdRHB1 gene is the BrCdRHB1 gene of Chinese cabbage, with the nucleotide sequence shown in SEQ ID NO.1; or the RsCdRHB1 gene of radish, with the nucleotide sequence shown in SEQ ID NO.2.

[0007] The above-mentioned CdRHB1 gene is used to regulate cadmium uptake and accumulation in plants.

[0008] According to a preferred embodiment of the present invention, the application refers to: knocking out the BrCdRHB1 gene can increase the absorption and accumulation of cadmium in plants; or overexpressing the RsCdRHB1 gene can reduce the absorption and accumulation of cadmium in plants.

[0009] According to a preferred embodiment of the present invention, the plant is radish or Chinese cabbage.

[0010] More preferably, the application includes: constructing a CRISPR-Cas9 knockout system, then introducing the CRISPR-Cas9 knockout system into recipient Chinese cabbage to knock out the BrCdRHB1 gene, and screening to obtain functional gene-edited Chinese cabbage; or inserting the RsCdRHB1 gene into a plasmid vector to construct an overexpression vector of the RsCdRHB1 gene, then introducing the overexpression vector of the RsCdRHB1 gene into recipient radish, and screening to obtain functional transgenic radish.

[0011] The beneficial effects of this invention are: 1. This invention utilizes genetic engineering technology to knock out the BrCdRHB1 gene. Specifically, a CRISPR-Cas9 knockout system was constructed and introduced into the recipient Chinese cabbage to knock out the BrCdRHB1 gene. After screening, functionally edited Chinese cabbage was obtained, significantly increasing the plant's (especially Chinese cabbage's) ability to absorb and accumulate cadmium. This invention is the first to experimentally confirm that knocking out the BrCdRHB1 gene can increase cadmium absorption and accumulation in plants. Based on the functional verification results of the BrCdRHB1 gene, it can be considered that this gene has potential application value in reducing cadmium absorption and accumulation in plants, laying a solid theoretical and applied foundation for using the BrCdRHB1 gene to cultivate low-cadmium, green crop varieties.

[0012] 2. This invention utilizes genetic engineering technology to overexpress the RsCdRHB1 gene. Specifically, the RsCdRHB1 gene is inserted into a plasmid vector to construct an overexpression vector for the RsCdRHB1 gene. This vector is then transformed into plant lines, and after screening, RsCdRHB1 gene overexpression lines are obtained, thereby significantly improving the ability of plants (especially radishes) to reduce cadmium absorption and accumulation. This invention is the first to experimentally confirm that overexpression of the RsCdRHB1 gene can reduce cadmium absorption and accumulation in plants. Based on the functional verification results of the RsCdRHB1 gene, it can be considered that this gene has potential application value in reducing cadmium absorption and accumulation in plants, laying a good theoretical and applied foundation for using the RsCdRHB1 gene to cultivate low-cadmium, green crop varieties.

[0013] 3. This invention is the first to utilize biological methods to improve plants through the CdRHB1 gene, representing an effective means of addressing cadmium pollution in plants. Specifically, this invention successfully introduced the RsCdRHB1 gene into a commercial radish variety using Agrobacterium-mediated transformation, and gene editing knocked out the BrCdRHB1 gene in a commercial Chinese cabbage variety. Field trials showed that under cadmium stress, the cadmium accumulation in the edible parts of the radish was significantly reduced without causing yield loss. Attached image description: Figure 1 The expression level of the RsCdRHB1 gene in the root hair-specific transgenic line of radish RsCdRHB1 and wild-type radish at 45 days of age; In the figure: the vertical axis represents the expression level of RsCdRHB1 mRNA; WT: control group; OE1: experimental group 1; OE2: experimental group 2.

[0014] Figure 2 Sanger sequencing chromatograms of the BrCdRHB1 gene-edited line and wild-type Chinese cabbage; In the figure, compared with the black underlined characters of wild-type Chinese cabbage (WT), the red underlined characters of the Chinese cabbage BrCdRHB1 gene-edited lines (BrCdRHB1-1 and BrCdRHB1-2) represent gene editing sites.

[0015] Figure 3 A statistical graph showing the average cadmium ion current in the roots of 3-day-old RsCdRHB1 transgenic radish and wild-type radish in an electrode solution containing 50 µM CdCl2. In the figure: the vertical axis represents the cadmium current intensity (pmol / cm). 2 / s); WT: control group; OE1: experimental group 1; OE2: experimental group 2.

[0016] Figure 4Statistical graph of cadmium ion current in the roots of 3-day-old RsCdRHB1 gene-transformed radish and wild-type radish. In the figure: the horizontal axis represents time (min), and the vertical axis represents cadmium current intensity (pmol / cm). 2 / s); WT: control group; OE1: experimental group 1; OE2: experimental group 2.

[0017] Figure 5 Results of the effect of the RsCdRHB1 gene on the cadmium accumulation capacity of radish seedlings In the figure: the horizontal axis represents the group, and the vertical axis represents the cadmium content; WT: control group; OE1: experimental group 1; OE2: experimental group 2.

[0018] Figure 6 A statistical graph showing the average cadmium ion current in the roots of 3-day-old Chinese cabbage with the BrCdRHB1 gene knocked out and wild-type Chinese cabbage in an electrode solution containing 50 µM CdCl2. In the figure: the vertical axis represents the cadmium current intensity (pmol / cm). 2 / s); WT: control group; BrCdRHB1-1: experimental group 1; BrCdRHB1-2: experimental group 2.

[0019] Figure 7 Statistical graph of cadmium ion current in the roots of 3-day-old Chinese cabbage with BrCdRHB1 gene knockout and wild-type Chinese cabbage. In the figure: the horizontal axis represents time (min), and the vertical axis represents cadmium current intensity (pmol / cm). 2 / s); WT: control group; BrCdRHB1-1: experimental group 1; BrCdRHB1-2: experimental group 2.

[0020] Figure 8 Results of the effect of the BrCdRHB1 gene on the cadmium accumulation capacity of Chinese cabbage seedlings In the figure: the horizontal axis represents the group, and the vertical axis represents the cadmium content; WT: control group; BrCdRHB1-1: experimental group 1; BrCdRHB1-2: experimental group 2. Detailed Implementation

[0021] The present invention will be further described below with reference to embodiments. However, the scope of the present invention is not limited to the following embodiments. Those skilled in the art will understand that various changes and modifications can be made to the present invention without departing from the spirit and scope thereof. The present invention provides a general and / or specific description of the materials and test methods used in the experiments. Although many materials and operating methods used to achieve the objectives of the present invention are known in the art, the present invention is still described in as much detail as possible herein.

[0022] Example 1: Obtaining the root hair-specific transgenic line of radish RsCdRHB1 1. Extraction of radish genomic DNA using the CTAB method CTAB extraction solution: 4 g CTAB, 16.364 g NaCl, 20 mL 1M Tris-HCl (pH=8.0), 8 mL 0.5 MEDTA, and double-distilled water to a final volume of 200 mL before sterilization.

[0023] Grind the leaves of "Weixian Green" radish (W150) and add CTAB extraction solution (0.2% mercaptoethanol); dispense into several 1.5mL centrifuge tubes and incubate at 65℃ for 30 min; centrifuge at 12000 rpm for 12 min, then pour the supernatant into several other 1.5mL centrifuge tubes; add an equal volume of chloroform, mix well, centrifuge at 12000 rpm for 5 min, and collect the supernatant; add 2 volumes of anhydrous ethanol, precipitate for 5-10 min, centrifuge at 12000 rpm for 12 min; wash 3 times with 70% ethanol, air dry for 5-10 min, and obtain radish genomic DNA; add 40μL of TE buffer to the radish DNA to dissolve the radish DNA, and obtain the radish genomic DNA solution.

[0024] 2. Using the radish genomic DNA extracted in step 1 as a template, specific amplification primers RsCdRHB1-F / R were designed, and the RsCdRHB1 gene containing the promoter was obtained by PCR amplification. The RsCdRHB1 gene containing the promoter is 1794 bp in length, as shown in SEQ ID NO.2. The promoter is 2000 bp upstream of the RsCdRHB1 gene.

[0025] The sequence of the specific amplification primer RsCdRHB1-F / R is as follows: RsCdRHB1-F: 5'-ACTAAATTCTCATGTGGTATCAGAG-3'; RsCdRHB1-R: 5'-GTCCAAGGGATCAGGTTTCT-3'.

[0026] The PCR amplification system (50 μL) is as follows: 0.5 μL Pfu DNA polymerase, 10 μL 5×Trans Start Fast Pfu buffer, 4 μL d NTP mixture, 2 μL primer RsCdRHB1-F, 2 μL primer RsCdRHB1-R, 2 μL genomic DNA, and 29.5 μL sterile distilled water.

[0027] PCR amplification program: 98℃ pre-denaturation for 30 sec; 98℃ denaturation for 10 sec, 58℃ annealing for 30 sec, 72℃ extension for 1 min (35 cycles); 72℃ extension for 5-10 min; and finally, incubation at 4℃.

[0028] The RsCdRHB1 gene containing the promoter was ligated into the pCambia1300 vector (purchased from Takara Bio) using DNA ligase. After transforming *E. coli*, the transformed bacterial culture was plated onto LB agar containing kanamycin resistance. Colonies were picked and cultured in a medium containing the appropriate antibiotic to confirm the colony growth. Plasmids from positive clones were extracted, digested with enzymes, and subjected to electrophoresis. The target band was then recovered. The recovered product was transformed into *E. coli*, plated, screened for positive clones, and the plasmid was extracted to obtain the RsCdRHB1 gene overexpression vector, which was used for experiments such as *Agrobacterium* transformation.

[0029] 3. Constructing root hair-specific transgenic lines of radish RsCdRHB1 Remove Agrobacterium tumefaciens GV3101 competent cells and freeze-thaw them on ice. Add 2 μL of the RsCdRHB1 gene overexpression vector obtained in step 2 to 100 μL of Agrobacterium tumefaciens GV3101 competent cells and gently mix with a pipette tip. Transfer the mixture of cells and plasmids to an electroporation cuvette, pre-cool it, and electroporate it at 2500V. Remove the electroporation cuvette, add 800 μL of pre-cooled LB liquid medium, gently mix by pipetting, and transfer the bacterial solution to a 1.5 mL centrifuge tube. Incubate at 28℃ and 200 rpm for 5 h with shaking. Spread 35 μL of the bacterial solution onto LB solid medium containing the corresponding antibiotics and incubate upside down at 28℃ for 2 days. Then, screen Agrobacterium tumefaciens resistant to rifampicin and kanamycin for colony PCR, select positive colonies, and expand the culture by shaking.

[0030] Agrobacterium containing the RsCdRHB1 gene overexpression vector was selected and "Weixian Green" radish seedlings were infected using the inflorescence infection method to obtain the T1 generation radish RsCdRHB1 root hair-specific transgenic line.

[0031] 4. Ten T1 generation radish RsCdRHB1 root hair-specific transgenic lines were divided into experimental group 1 (OE-1) and experimental group 2 (OE-2), while wild-type W150 radish seedlings were used as the control group (WT).

[0032] The three groups of radish seedlings were grown in the field for 45 days. The radish roots were then separated, washed several times with clean water, and air-dried at room temperature. Genomic DNA was then extracted from the root hairs of the radish plants according to the method described in step 1. The expression level of the RsCdRHB1 gene in the root hairs of the radish plants was detected by quantitative real-time PCR (qPCR). The results are as follows: Figure 1 As shown.

[0033] Depend on Figure 1 It can be seen that the expression level of the RsCdRHB1 gene in the root hair-specific transgenic line of T1 generation radish RsCdRHB1 is significantly higher than that in wild-type W150 radish seedlings. This indicates that the present invention successfully transgenic the RsCdRHB1 gene and constructed radish seedlings transgenic with the RsCdRHB1 gene (RsCdRHB1).

[0034] Example 2: Obtaining the BrCdRHB1 gene-edited line of Chinese cabbage 1. Genomic DNA of “Guangdong Early” Chinese cabbage (CCF) was extracted using the CTAB method and sequenced. Then, targeting the 300bp upstream of the Chinese cabbage BrCdRHB1 gene (as shown in SEQ ID NO.1) in the Chinese cabbage genomic DNA, a target sequence and guide RNA (sgRNA) were designed and synthesized. The target sequence and guide RNA (sgRNA) were then ligated to obtain a fragment containing the target sequence and sgRNA sequence.

[0035] The specific sequence information of the target sequence and guide RNA (sgRNA) is as follows: Target sequence: 5'-AGGAGGTCCCACGCTGTTAT-3'; The sgRNA sequence is: 5'-GUUUUAGAGCUAGAAAUAGCAAGUUAAAAUAAGGCUAGUCCGUUAUCAACUUGAAAAAGUGGCACCGAGUCGGUGCUUUU-3'.

[0036] The fragment containing the target sequence and sgRNA sequence was double-digested using restriction endonucleases Spe1 and Nhe1, and then ligated into the shuttle vector pCambia1300 containing the Cas9 enzyme to obtain the CRISPR-Cas9 knockout system.

[0037] The nucleotide sequence encoding the Cas9 enzyme gene is shown in SEQ ID NO.3. 2. Construction of the BrCdRHB1 gene-edited line in Chinese cabbage Remove Agrobacterium tumefaciens GV3101 competent cells and freeze-thaw them on ice. Add 2 μL of the CRISPR-Cas9 knockout system obtained in step 1 to 100 μL of Agrobacterium tumefaciens GV3101 competent cells and gently mix with a pipette tip. Transfer the mixture of cells and plasmids to an electroporation cuvette, pre-cool it, and then electroporate it at 2500V. Remove the electroporation cuvette, add 800 μL of pre-cooled LB liquid medium, gently mix by pipetting, and transfer the bacterial solution to a 1.5 mL centrifuge tube. Incubate at 28℃ and 200 rpm for 5 h with shaking. Spread 35 μL of the bacterial solution onto LB solid medium containing the corresponding antibiotics and incubate upside down at 28℃ for 2 days. Then, screen Agrobacterium tumefaciens resistant to rifampicin and kanamycin for colony PCR, select positive colonies, and expand the culture by shaking.

[0038] Agrobacterium containing the CRISPR-Cas9 knockout system was selected and used to infect Chinese cabbage seedlings using the inflorescence infection method. T1-band seeds were collected. After the T1 generation seeds reached the seedling stage, leaf DNA was extracted. Primers were designed at both ends of the target site, and high-fidelity enzyme PCR amplification was performed. Sequencing was used to detect the knockout site information, and the selected lines with altered DNA sequences were designated as the BrCdRHB1 gene-edited Chinese cabbage lines, specifically the BrCdRHB1 gene-knockout Chinese cabbage seedling-1 (BrCdRHB1-1). This BrCdRHB1 gene-edited Chinese cabbage line is a functional gene-edited Chinese cabbage line that knocks out the BrCdRHB1 gene.

[0039] Continue to cultivate Chinese cabbage seedlings with the BrCdRHB1 gene knocked out -1 (BrCdRHB1-1), collect seeds with T2 generation, and grow the T2 generation seeds to the seedling stage to obtain Chinese cabbage seedlings with the BrCdRHB1 gene knocked out -2 (BrCdRHB1-2).

[0040] Sanger sequencing chromatograms of the BrCdRHB1 gene-edited line and wild-type Chinese cabbage, as shown in the figure. Figure 2 As shown.

[0041] Example 3: Effect of the RsCdRHB1 gene on the ability of radish seedlings to absorb cadmium under cadmium stress. Five radish seedlings (RsCdRHB1) transformed with the RsCdRHB1 gene obtained in Example 1 were designated as experimental group 1 (OE-1) and experimental group 2 (OE-2), respectively, while wild-type W150 radish seedlings were used as the control group (WT).

[0042] The above three groups of radish seedlings were germinated for 3 days at 60% RH and 23℃. They were then transferred to an electrode buffer solution containing 50µM CdCl2 (100µM KCl, 50µM CdCl2, 300µM MES, pH=5.8) for non-invasive microelectrophysiological (NMT) detection of the radish seedling roots. The results are as follows: Figure 3 and Figure 4 As shown.

[0043] The specific method for non-invasive microelectrophysiological (NMT) detection is as follows: Using a non-invasive microelectrophysiological system (NMT100; YoungerUSA), the electrodes are placed in the root elongation zone of the radish seedling (700 μm from the root tip), and Cd at the epidermis is measured. 2+ The current was measured every 6 seconds, and the measurement time was 3 minutes.

[0044] Depend on Figures 3-4 It was found that at different time points, the current values ​​and average current values ​​of the elongation zone of RsCdRHB1 gene-transgenic radish seedlings were significantly lower than those of wild-type radish seedlings, indicating that under Cd stress, RsCdRHB1 gene-transgenic radish seedlings excrete Cd. 2+ Or block Cd 2+ The ability to absorb cadmium was significantly enhanced, indicating that overexpression of the RsCdRHB1 gene can effectively reduce the ability of radishes to absorb cadmium.

[0045] Example 4: Effect of the RsCdRHB1 gene on the ability of radish seedlings to accumulate cadmium under cadmium stress. Five radish seedlings of the RsCdRHB1 gene obtained in Example 1 were designated as experimental group 1 (OE-1) and experimental group 2 (OE-2), respectively, while wild-type W150 radish seedlings were used as the control group (WT).

[0046] The three groups of radish seedlings were grown in a field with a cadmium content of 0.163 mg / kg for 50 days until the radish roots matured. The mature radish roots were separated, washed several times with clean water, air-dried at room temperature, and weighed. After nitric acid digestion, the cadmium content was detected using inductively coupled plasma mass spectrometry (ICP-MS). The results are as follows: Figure 5 As shown.

[0047] Depend on Figure 5 It was found that the cadmium content in the mature roots of RsCdRHB1 transgenic radish seedlings was significantly lower than that in the mature roots of wild-type radish seedlings, indicating that under Cd stress, RsCdRHB1 transgenic radish seedlings excrete Cd. 2+ Or block Cd 2+ The ability to absorb and accumulate cadmium in radishes has been significantly enhanced, indicating that overexpression of the RsCdRHB1 gene can effectively reduce cadmium absorption and accumulation in radishes.

[0048] Example 5: Effect of the BrCdRHB1 gene on the cadmium uptake capacity of Chinese cabbage seedlings under cadmium stress. Five Chinese cabbage seedlings with the BrCdRHB1 gene knocked out in Example 2 were designated as experimental group 1 (BrCdRHB1-1) and experimental group 2 (BrCdRHB1-2), respectively. Wild-type CCF Chinese cabbage seedlings were used as the control group (WT).

[0049] The three groups of Chinese cabbage seedlings were germinated for 3 days at 60% RH and 23℃. Then, they were transferred to an electrode buffer solution containing 50µM CdCl2 (100µM KCl, 50µM CdCl2, 300µM MES, pH=5.8) for non-invasive microelectrophysiological (NMT) detection of the seedling roots. The results are as follows: Figure 6 and Figure 7 As shown.

[0050] The specific method for non-invasive microelectrophysiological (NMT) detection is as follows: Using a non-invasive microelectrophysiological system (NMT100; YoungerUSA), the electrodes are placed in the root elongation zone of a Chinese cabbage seedling (400 μm from the root tip), and Cd at the epidermis is measured. 2+ The current was measured every 6 seconds, and the measurement time was 3 minutes.

[0051] Depend on Figures 6-7 It was found that at different time points, the current values ​​and average current values ​​of the elongation region of Chinese cabbage seedlings with the BrCdRHB1 gene knocked out were significantly higher than those of wild-type Chinese cabbage seedlings, indicating that under Cd stress, the BrCdRHB1 gene knocked-out Chinese cabbage seedlings excreted Cd. 2+ Or block Cd 2+ The ability to absorb cadmium was significantly reduced, indicating that knocking out the BrCdRHB1 gene can effectively increase the ability of Chinese cabbage to absorb cadmium.

[0052] Example 6: Effect of the BrCdRHB1 gene on the ability of Chinese cabbage seedlings to accumulate cadmium under cadmium stress. Five Chinese cabbage seedlings with the BrCdRHB1 gene knocked out in Example 2 were designated as experimental group 1 (BrCdRHB1-1) and experimental group 2 (BrCdRHB1-2), respectively. Wild-type CCF Chinese cabbage seedlings were used as the control group (WT).

[0053] The three groups of Chinese cabbage seedlings were grown in a field with a cadmium content of 0.163 mg / kg for 50 days until they matured into heads. The mature heads were separated, washed several times with water, air-dried at room temperature, and weighed. After nitric acid digestion, the cadmium content was detected using inductively coupled plasma mass spectrometry (ICP-MS). The results are as follows: Figure 8 As shown.

[0054] Depend on Figure 8 It was found that the cadmium content in the mature heads of Chinese cabbage seedlings with the BrCdRHB1 gene knocked out was significantly higher than that in the mature heads of wild-type Chinese cabbage seedlings, indicating that under Cd stress, Chinese cabbage seedlings with the BrCdRHB1 gene knocked out excrete Cd. 2+ Or block Cd 2+ The ability to absorb and accumulate cadmium in Chinese cabbage was significantly reduced, indicating that knocking out the BrCdRHB1 gene can effectively increase cadmium absorption and accumulation in Chinese cabbage.

Claims

1. A CdRHB1 gene that reduces cadmium absorption and accumulation in plants, characterized in that, The CdRHB1 gene is the BrCdRHB1 gene of Chinese cabbage, with the nucleotide sequence shown in SEQ ID NO.1; or the RsCdRHB1 gene of radish, with the nucleotide sequence shown in SEQ ID NO.

2.

2. The application of the CdRHB1 gene as described in claim 1 in regulating cadmium uptake and accumulation in plants.

3. The application as described in claim 2, characterized in that, The application refers to the following: knocking out the BrCdRHB1 gene can increase the absorption and accumulation of cadmium in plants; or overexpressing the RsCdRHB1 gene can reduce the absorption and accumulation of cadmium in plants.

4. The application as described in claim 3, characterized in that, The plant in question is either a radish or a Chinese cabbage.

5. The application as described in claim 4, characterized in that, The applications include: constructing a CRISPR-Cas9 knockout system, then introducing the CRISPR-Cas9 knockout system into recipient Chinese cabbage to knock out the BrCdRHB1 gene, and screening to obtain functional gene-edited Chinese cabbage; or inserting the RsCdRHB1 gene into a plasmid vector to construct an overexpression vector of the RsCdRHB1 gene, then introducing the overexpression vector of the RsCdRHB1 gene into recipient radish, and screening to obtain functional transgenic radish.

Images