Application of high-cadmium-resistance bacterial strain Cd2 in promoting repair of heavy metal pollution of Aster brachium

Abstract

The invention belongs to the technical field of microbiology, and particularly relates to application of a high-cadmium-resistance strain Cd2 in promoting repair of heavy metal pollution of aster katsumadai. The invention relates to a strain Cd2 with high cadmium resistance, the taxonomic name of the strain Cd2 is Pseudomonas aeruginosa, and the preservation number of the strain Cd2 is GDMCC No.64110. The strain Cd2 has the advantages that the strain Cd2 has high cadmium resistance; according to the invention, screened strains are identified through morphological observation, gram staining and 16S rRNA (ribosomal Ribonucleic Acid) sequence sequencing, and a high-cadmium-tolerance strain Cd2 is inoculated into soil during the growth period of a hyperaccumulator Aster brachium, so that the influence of Cd2 on the growth and enrichment of the hyperaccumulator Aster brachium is researched. The result shows that when the high-cadmium-tolerance strain Cd2 is inoculated into the soil for planting the aster katsumadai, the cadmium absorption amount of the underground part and the overground part of the aster katsumadai and the cadmium accumulation amount of the whole plant are remarkably increased, and a technical support can be provided for strengthening hyperaccumulation plant remediation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microbiology, and particularly relates to a use of a high cadmium-tolerant strain Cd2 in promoting Aster subulatus to repair heavy metal pollution. BACKGROUND

[0002] With the acceleration of urbanization, industrialization and agricultural intensification, the demand and use of heavy metals by human beings are increasing. At the same time, a large amount of heavy metals are discharged in disorder, causing serious pollution to the surrounding environment such as soil, surface water and groundwater. On April 17, 2014, the Ministry of Environmental Protection and the Ministry of Land and Resources jointly issued the "National Soil Pollution Status Survey Bulletin", which showed that heavy metal Cd was the primary pollutant, with an over-standard rate of 7.0%, indicating that the main heavy metal contaminating the soil in China at present was Cd.

[0003] Since heavy metals cannot be biodegraded in the environment, and heavy metal pollution has the characteristics of long-term, cumulative, hidden and irreversible, it is difficult to control heavy metal pollution. Therefore, there is an urgent need for effective and economic remediation technology to control heavy metal contaminated soil. At present, the control of heavy metal contaminated soil can be carried out mainly by physical methods, chemical methods and biological methods. Phytoremediation is a biological remediation method, which is a method of directly using green plants to isolate, remove and degrade organic and inorganic pollutants in soil and water. Phytoremediation technology has the advantages of low remediation cost, good effect, no secondary pollution, and high ecological and aesthetic value after reclamation, and can achieve permanent clean remediation of contaminated soil, and is therefore recognized as a green and environmentally friendly in-situ remediation technology. Although phytoremediation has shown great advantages in the control of heavy metal contaminated environment, it still has some limitations in practical application, such as long remediation period, few types of heavy metal hyperaccumulating plants, and problems in the treatment of residual heavy metal-containing biomass after remediation. Therefore, how to expand the advantages of phytoremediation, solve existing problems and improve the efficiency of phytoremediation has become an important issue of concern for scholars at home and abroad.

[0004] Aster subulatus Michx., also known as scissors, white chrysanthemum, earth poterwillow, nine-dragon arrow, and Aster subulatus, is a plant of the Asteraceae family and the Aster genus. It grows in humid saline soils and is distributed in Guangxi, Jiangsu, Zhejiang, Jiangxi, Hunan and Fujian. Aster subulatus is a plant with fast growth rate, large biomass, strong stress resistance and potential to accumulate or hyperaccumulate one or more heavy metals. Zhang Qianjin et al. (2013) found that Aster subulatus had strong Cr accumulation ability, with an accumulation coefficient of 0.5, and a Cd accumulation coefficient of 1.83, but the content analysis was limited to wild plant samples, and there was a lack of research on absorption and accumulation characteristics and transport mechanism under laboratory controlled conditions.

[0005] At present, the treatment of heavy metal contaminated soil can be carried out by physical methods, chemical methods and biological methods. Phytoremediation is a biological remediation method, which is a method of directly using green plants to isolate, remove and degrade organic and inorganic pollutants in soil and water. Phytoremediation technology has the advantages of low remediation cost, good effect, no secondary pollution, high ecological benefit and aesthetic value after reclamation, and can achieve permanent clean remediation of contaminated soil, and is therefore recognized as an in-situ remediation technology of green environmental protection. Although phytoremediation has shown great advantages in the treatment of heavy metal contaminated environment, it still has some limitations in practical application, such as long remediation period, few types of heavy metal hyperaccumulator plants, and treatment of residual heavy metal-containing biomass after remediation.

[0006] At present, there are some measures to strengthen phytoremediation, mainly including exogenous substance strengthening, genetic engineering strengthening, agricultural technology strengthening, and microbial strengthening. Among them, microbial strengthening of plant heavy metal enrichment is a very promising contaminated soil remediation technology. Plant-microbe combined remediation is considered as an efficient, environmentally friendly and low-cost method, which can be used for large-scale pollution control and has attracted widespread attention in practical application research.

[0007] Draba leaf Aster is a Cd hyperaccumulator plant found and reported in China, which has the advantages of fast growth, large biomass, strong stress resistance and Cd hyperaccumulation ability, and has a high application prospect in the field of phytoremediation of Cd contaminated soil. Previous studies have shown that the Cd concentration in the aboveground part (stem and leaf) of Draba leaf Aster is lower than that in the root, but the root is most significantly inhibited by Cd stress, resulting in low remediation efficiency. Therefore, it is necessary to improve the Cd remediation efficiency of Draba leaf Aster through strengthening measures.

[0008] Current studies have shown that some extracellular secretions regulated by plant growth-promoting bacteria, such as rhamnolipids, pyocyanin, siderophores, extracellular enzymes, and indole acetic acid (IAA), can promote phytoremediation. A large number of studies have shown that in pot experiment of phytoremediation, Pseudomonas aeruginosa can promote plant growth and increase Cd accumulation. For example, in the study of Liang et al. (2014), inoculation of Pseudomonas aeruginosa isolated from heavy metal contaminated sludge significantly enhanced the Cd accumulation of Corydalis saxicola; Xi et al. (2015) showed that inoculation of Pseudomonas aeruginosa could alleviate the toxicity of Cd, promote the growth of ramie, and increase Cd accumulation; Biswas et al. (2015) showed that Pseudomonas aeruginosa KUJM screened from wastewater had multiple heavy metal resistance potential and could promote the growth of Mucuna seed, which had potential for phytoremediation of contaminated soil. In summary, heavy metal resistant Pseudomonas aeruginosa can promote plant growth, alleviate the stress of heavy metals on plants and increase Cd accumulation, and has great application potential in the aspects of strengthening phytoremediation of heavy metal contaminated environment.

[0009] The strain Cd2 is a high cadmium-tolerant Pseudomonas aeruginosa isolated from rhizosphere soil, and inoculation of the high cadmium-tolerant strain Cd2 can effectively promote the absorption, enrichment and transport of cadmium by Asteriscus graveolens, and improve the remediation effect of Asteriscus graveolens on cadmium-contaminated soil, which can support the enhanced hyperaccumulating plant remediation technology.

[0010] Currently, there is no related report on the use of the strain Cd2 to promote the remediation of heavy metal pollution by the hyperaccumulating plant Asteriscus graveolens.

[0011] The information disclosed in the background section is only intended to increase the understanding of the overall background of the present application, and should not be considered as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art. SUMMARY

[0012] The purpose of the present application is to provide a use of a high cadmium-tolerant strain Cd2 in promoting the remediation of heavy metal pollution by Asteriscus graveolens.

[0013] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0014] A high cadmium-tolerant strain Cd2 is isolated from the soil of a mine in Hechi, Guangxi Zhuang Autonomous Region, and is identified as Pseudomonas aeruginosa by morphology and molecular biology. It was preserved in the Guangdong Microbial Culture Collection Center on December 5, 2022, at address: 100 Xianlie Road, Guangzhou, China, 59 Building, 5th Floor, and the preservation number is GDMCC No. 64110.

[0015] The present application also provides a heavy metal pollution remediation agent, which comprises the high cadmium-tolerant strain Cd2.

[0016] Further, the heavy metal pollution remediation agent is a high cadmium-tolerant strain Cd2 bacterial suspension, and the OD600 value of the high cadmium-tolerant strain Cd2 bacterial suspension is 1.0.

[0017] The present application also provides a use of the high cadmium-tolerant strain Cd2 or the heavy metal pollution remediation agent in promoting the remediation of heavy metal pollution by hyperaccumulating plants.

[0018] Further, the hyperaccumulating plant comprises Asteriscus graveolens.

[0019] Further, the heavy metal comprises cadmium.

[0020] The present application also provides a method for promoting the remediation of heavy metal pollution by Asteriscus graveolens using the high cadmium-tolerant strain Cd2, specifically: during the growth period of Asteriscus graveolens, inoculate the high cadmium-tolerant strain Cd2 bacterial suspension in the soil once every 10 days, a total of 2 times, and harvest the Asteriscus graveolens plants after 40 days of inoculation.

[0021] Further, the OD600 value of the high cadmium-resistant strain Cd2 bacterial suspension is 1.0.

[0022] Compared with the prior art, the present application has the following beneficial technical effects:

[0023] The present application identifies the screened strain through morphological observation, gram staining and 16S rRNA sequence sequencing, inoculates the high cadmium-resistant strain Cd2 in the soil during the growth of the super-hyperaccumulator plant Dracaena cochinchinensis, and studies the influence of Cd2 on the growth and enrichment of the super-hyperaccumulator plant Dracaena cochinchinensis. The results show that when the high cadmium-resistant strain Cd2 is inoculated into the soil where Dracaena cochinchinensis is planted, the cadmium absorption of the underground and the aboveground of Dracaena cochinchinensis and the cadmium accumulation of the whole plant are significantly increased, which can support the technology of strengthening the super-hyperaccumulator plant remediation.

[0024] DEPOSIT INFORMATION

[0025] The strain Cd2 has a preservation number of GDMCC No. 64110, a preservation date of December 5, 2023, a preservation unit of Guangdong Microbial Culture Collection Center, and a preservation address of 5th Floor, Building 59, 100 Middle Martyrs Road, Guangzhou. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a confrontation culture diagram of the strain Cd2 and Pseudocercospora pyri;

[0027] Figure 2 It is a cadmium tolerance plate diagram of the strain Cd2;

[0028] Figure 3 It is a colony morphology of the strain Cd2 on the NA plate;

[0029] Figure 4 It is the morphology of the strain Cd2;

[0030] Figure 5 It is a 16S rDNA gene sequence phylogenetic tree of the strain Cd2;

[0031] Figure 6 It is the effective state content of cadmium in the soil;

[0032] Figure 7 It is the cadmium content of Dracaena cochinchinensis;

[0033] Figure 8 It is the cadmium accumulation of Dracaena cochinchinensis.

[0034] Explanation of reference signs:

[0035] Figure 1 In the figure, the left side is the treatment group, and the right side is the control group DETAILED DESCRIPTION

[0036] The technical solutions of the patent application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the patent application, rather than all the embodiments. Based on the embodiments in the patent application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the patent application.

[0037] In the following examples, the medium formula is as follows:

[0038] NA solid medium: 5.0 g of proteose peptone, 3.0 g of beef extract, 2.5 g of glucose, 15 g of agar powder, and distilled water to 1 L, pH 7.0±0.2.

[0039] NB liquid medium: 5.0 g of proteose peptone, 3.0 g of beef extract, 2.5 g of glucose, and distilled water to 1 L, pH 7.0±0.2.

[0040] Example

[0041] 1. Test material

[0042] The organic and inorganic phosphorus bacterial medium, CAS medium, King'B medium and Ashby nitrogen-free medium were purchased from Qingdao Haibo Biotechnology Co., Ltd., cadmium chloride (CdCl2·2.5H2O, AR, National Pharmaceutical Group Chemical Reagent Co., Ltd.), and Salkowski reagent (National Pharmaceutical Group Chemical Reagent Co., Ltd.).

[0043] Drill leaf aster seeds were collected from a lead-zinc mining area about 120 km away from Yulin City, Guangxi Zhuang Autonomous Region.

[0044] 2. Strain isolation and purification

[0045] Soil was collected from the rhizosphere soil of Asteriscus graveolens planted in Hechi mine soil in Guangxi Zhuang Autonomous Region, 10.0 g of which was placed in a flask containing glass beads and sterile water, and shaken at 28°C and 180 r / min for 30 min. Gradient dilution was performed with the original solution, and 10 -3 , 10 -4 and 10 -5 gradients were coated on NA solid plates, and cultured at 37°C for 24 h. The growth conditions of the colonies were observed, and the plates with moderate density were selected for single colony picking and streaking purification. Different morphological colonies were repeatedly streaked and purified, and the purified strains were preserved.

[0046] 2. Strain screening

[0047] Pseudocercosporella herpotrichoides antagonistic bacteria were screened by plate confrontation method. Pseudocercosporella herpotrichoides was provided by the Institute of Agricultural Products Quality Safety and Detection Technology, Guangxi Academy of Agricultural Sciences. The results are shown in Table 1.Figure 1 .

[0048] 2.1 Screening of cadmium-resistant strains

[0049] The isolated strains were cultured in NB liquid at 180 r / min and 30°C overnight. Under sterile conditions, 100 μL of the bacterial solution was inoculated on NA solid medium (50 mg / L of cadmium) and cultured in an incubator at 30°C. Strains with larger colonies and greater morphological differences were inoculated on NA solid medium with higher cadmium concentrations (100, 200, 300, 400, 500, and 600 mg / L) in turn. In this way, dominant strains with high cadmium resistance and fast growth were gradually selected. As a result, a strain with high cadmium resistance was obtained, which was numbered as Cd2.

[0050] The growth of strain Cd2 on a plate with a cadmium concentration of 600 mg / L is shown in Figure 2 .

[0051] As shown in Figure 2 , strain Cd2 can grow normally on a plate with a cadmium concentration of 600 mg / L, indicating that the strain has high cadmium resistance.

[0052] 3. Morphological identification of the strain

[0053] 3.1 The Cd2 strain was inoculated on NA medium and cultured at 30°C for 24 h. The colony morphological characteristics of the strain were observed, and the results are shown in Figure 3 .

[0054] As shown in Figure 3 , the Cd2 strain on the NA plate was a single colony, smooth, slightly raised, with a neat wavy edge, and yellow-green in color.

[0055] 3.2 The above cultured Cd2 strain was subjected to Gram staining and microscopic examination. The observed morphological results were microphotographed, and the results are shown in Figure 4 .

[0056] Gram staining found that the Cd2 strain was Gram-negative. As shown in Figure 4 , the morphology of the Cd2 strain was: no spores, and the bacterial body was long and uneven in length.

[0057] 4. Sequencing of the strain and construction of a phylogenetic tree

[0058] 4.1 Preparation of a DNA template

[0059] (a) 1.5 mL of bacterial overnight culture was placed in a sterile EP tube and centrifuged at 12000 rpm for 1 min. The supernatant was discarded, and the bacterial body was collected;

[0060] (b) Add 400 μL lysis buffer to the precipitate, mix by repeatedly pipetting with a pipette; wherein the lysis buffer is: Tris-Ac (pH 7.8) 40 mM, NaAc 20 mM, EDTA 1 mM, SDS 1% (w / v);

[0061] (c) Add 200 μL 5M NaCl, mix well, centrifuge at 12000 rpm for 10 min;

[0062] (d) Take 600 μL supernatant of step (c), add equal volume of phenol / chloroform (1:1), mix well by gently inverting several times, centrifuge at 12000 rpm for 10 min, transfer the supernatant to another clean EP tube;

[0063] (e) Add equal volume of chloroform to the supernatant, mix well, centrifuge at 12000 rpm for 10 min, transfer the supernatant to another clean EP tube;

[0064] (f) Add equal volume of isopropanol to the supernatant, mix well, place at room temperature for 10 min, centrifuge at 12000 rpm for 15 min, discard the supernatant and reserve the precipitate;

[0065] (g) Wash the obtained precipitate with 70% ethanol by volume, dry, and the DNA is obtained;

[0066] (h) Dissolve the dried DNA in 30 μL double distilled water (ddH2O), and store at -20°C.

[0067] 4.2 PCR amplification

[0068] The PCR reaction system of 16S rDNA sequence in Table 1 is used for amplification. The sequence of 16S rDNA is shown in Table 2.

[0069] Table 1 PCR reaction system of 16S rDNA sequence

[0070]

[0071] Table 2 16S rDNA sequence

[0072]

[0073] PCR reaction procedure: denaturation at 95°C for 3 min; denaturation at 94°C for 30 s, annealing at 55°C for 30 s, extension at 72°C for 1 min, for a total of 35 cycles; extension at 72°C for 5 min.

[0074] The PCR amplification product was sequenced, and the nucleotide sequence is SEQ ID No. 1; the measured 16S rDNA sequence was compared with the 16S rDNA sequences of bacteria in the GenBank gene library by MAFFT (v7.490), the system evolution tree was constructed by Maximum Likelihood (Maximum Likelihood) of IQ-TREE (v2.0.7), and ggtree (v3.6.2) was used for display, and the system evolution tree is Figure 5 .

[0075] Through Genebank database comparison and IQ-TREE (v2.0.7) analysis, it is determined that the strain Cd2 is Pseudomonas aeruginosa, the strain code is Cd2, and the name is Pseudomonas aeruginosa Cd2.

[0076] 5. Promoting characteristics of high cadmium-tolerant strain Cd2

[0077] 5.1 Phosphorus solubilization ability determination

[0078] Prepare organic and inorganic phosphorus solid medium, inoculate the screened strains on the medium, and cultivate at 30°C for 3d. The strains with phosphorus solubilization ability will form transparent dissolution circles around the colonies. The results are shown in Table 3.

[0079] 5.2 Amylase production ability determination

[0080] Prepare a starch-containing solid medium, inoculate the screened strains on the medium, and cultivate at 30°C for 2d. Drop 1 drop of Lugol iodine solution on the single colony. The strains with amylase production ability will form transparent dissolution circles around the colonies. The results are shown in Table 3.

[0081] 5.3 siderophore production ability determination

[0082] Inoculate the screened strains on the CAS detection medium, cultivate at 30°C for 5d, and observe the colonies. If there is a clear transparent dissolution circle around the colonies, it proves that the strain has siderophore production ability. The results are shown in Table 3.

[0083] 5.4 IAA production ability determination

[0084] Inoculate the screened strains in King'B liquid medium, cultivate for 3d, mix 500μL of centrifuged supernatant and Salkowski colorimetric solution, and stand in the dark for 30min. Replace the bacterial liquid with King'B liquid medium and 50mg / L IAA as negative and positive controls respectively. Preliminarily judge whether IAA is produced by color change. The results are shown in Table 3.

[0085] 5.5 Determination of nitrogen fixation ability

[0086] The selected strains were inoculated on Ashby nitrogen-free solid medium and incubated at 30°C for 3 days, and the colonies were observed. If there was a clear transparent dissolution ring around the colony, it was proved that the strain had nitrogen fixation ability, and the results are shown in Table 3.

[0087] 5.6 Determination of protease enzyme production ability

[0088] A defatted milk solid medium was prepared, and the selected strains were inoculated on the medium and incubated at 30°C for 2 days. The strains with protease enzyme production ability would form a transparent dissolution ring around the colony, and the results are shown in Table 3.

[0089] Table 3 Plant growth-promoting properties of strain Cd2

[0090]

[0091] Note: "+" in Table 3 means positive, and "-" means negative.

[0092] As can be seen from Table 3, Cd2 has the abilities of organic phosphorus degradation, inorganic phosphorus degradation, siderophore production, protease production, and nitrogen fixation, indicating that the Cd2 strain has certain plant growth-promoting ability and can improve the stress resistance of plants.

[0093] 6. Effect of high cadmium-tolerant strain Cd2 on the available state of cadmium in soil

[0094] In the cadmium concentration of 100 mg / kg soil, inoculate the Cd2 bacterial suspension with OD 600 value of 1.0 (experimental group: Cd2), and after 30 days of equilibrium, measure the cadmium available state content of the soil, and at the same time, set a group of non-inoculated treatment (control group: CK). The results are shown in Figure 6 .

[0095] As can be seen from Figure 6 , inoculation of Cd2 strain increases the available state content of cadmium in soil by 18.25%. It is beneficial to the absorption and transport of cadmium by plants.

[0096] 7. Effect of high cadmium-tolerant strain Cd2 on the cadmium enrichment ability of Asteriscus maritimus

[0097] The experiment was set up as follows:

[0098] Control group (CK): Asteriscus maritimus was planted in cadmium-contaminated soil.

[0099] Experimental group (Cd2): Asteriscus maritimus was planted in cadmium-contaminated soil, and 50 mL of Cd2 bacterial suspension with OD 600 value of 1.0 was inoculated after 10 days, and 50 mL of Cd2 bacterial suspension with OD 600 value of 1.0 was inoculated again after 10 days.

[0100] There were two treatment groups, with three parallel control groups in each group, for a total of six pots. Each pot contained 2.0 kg of soil and three Aster tataricus plants were planted in each pot. The plant height, number of leaves and growth of Aster tataricus were basically the same in the control and experimental groups.

[0101] Forty days after the last inoculation of the experimental group, the cadmium content of *Aster tataricus* was determined. The entire *Aster tataricus* plant was removed from the pot, washed with tap water, and the roots were rinsed to remove fine fibers. The roots were then soaked in a 20 mmol / L Na2-EDTA solution for 20 min to remove adsorbed cadmium ions, followed by repeated rinsing with deionized water. The *Aster tataricus* was divided into above-ground and underground parts, placed in an oven at 105℃ for 30 min to blanch, and then dried at 70℃ to constant weight. The sample was ground in stainless steel and passed through a 40-mesh sieve. The sample was digested using a mixed solvent of H2O2-HNO3 in an intelligent electrothermal digester, and the heavy metal content of the digest was determined using a flame-graphite furnace atomic absorption spectrometer. The effect of strain Cd2 on the cadmium content of *Aster tataricus* is described in [reference needed]. Figure 7 The effect on cadmium accumulation in *Aster tataricus* leaves is shown in [reference needed]. Figure 8 .

[0102] Depend on Figure 7 It can be seen that, compared with the control group, when inoculated with strain Cd2, the cadmium content in both the underground and aboveground parts of Aster tataricus increased, and the cadmium content of the whole plant of Aster tataricus increased by 47.22%, which is quite significant.

[0103] Depend on Figure 8 It can be seen that, compared with the control group, inoculation with strain Cd2 increased the cadmium accumulation in Aster tataricus by 45.36%, which is a significant effect.

[0104] In summary, strain Cd2 possesses various plant growth-promoting factors, which can enhance plant resistance and survival ability under cadmium stress, promote plant growth and development, and increase the content of available cadmium in the soil. This facilitates cadmium absorption and translocation by plants, thereby increasing cadmium accumulation. Compared with phytoremediation alone, exogenous application of strain Cd2 can improve the remediation efficiency of Aster tataricus for cadmium pollution, thus reducing the cadmium content in the environment.

[0105] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A cadmium-tolerant bacterial strain Cd2, characterized in that, The taxonomic name of the high cadmium-resistant strain Cd2 is Pseudomonas aeruginosa, and the preservation number is GDMCC No. 64110.

2. A heavy metal contamination remediation agent characterized by, The heavy metal pollution remediation agent comprises the high cadmium-resistant strain Cd2 in claim 1.

3. The heavy metal contamination remediation agent of claim 2, wherein The heavy metal pollution remediation agent is a high cadmium-resistant strain Cd2 bacterial suspension, and the OD value of the high cadmium-resistant strain Cd2 bacterial suspension is 1.

0. 600 1.

0.

4. Use of the high cadmium-resistant strain Cd2 in claim 1 or the heavy metal pollution remediation agent in claim 2 in promoting remediation of heavy metal pollution by hyperaccumulating plants.

5. Use according to claim 4, characterized in that, The hyperaccumulating plant comprises Astragalus bockii.

6. Use according to claim 4, characterized in that, The heavy metal comprises cadmium.

7. A method for promoting the remediation of heavy metal pollution by Drimy heterophylla using the high cadmium-resistant strain Cd2 of claim 1, characterized in that, Specifically, during the growth period of Astragalus bockii, the high cadmium-resistant strain Cd2 bacterial suspension is inoculated into the soil once every 10 days, a total of 2 times, and the Astragalus bockii plants are harvested 40 days after the inoculation is completed.

8. The method of claim 7, wherein, The high cadmium-resistant strain Cd2 bacterial suspension OD 600 The value is 1.0.

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