Application of Burkholderia cepacia in promoting plant tolerance to salt and alkali and reducing the content of heavy metal cadmium

Abstract

The present invention discloses the application of Burkholderia cepacia in promoting plant tolerance to salinity-alkalinity and reducing the content of heavy metal cadmium. The research of the present invention shows that Burkholderia cepacia strain JT79 has good salinity-alkalinity tolerance and the ability to reduce the content of heavy metal cadmium, and can grow normally in high salinity-alkalinity and cadmium-containing culture media; strain JT79 can significantly improve the ability of soybeans and corn to resist salinity-alkalinity stress, promote the growth and development of soybeans and corn, and at the same time can efficiently reduce the cadmium content. It shows that strain JT79 has the functions of salinity-alkalinity tolerance, growth promotion, cadmium tolerance and cadmium content reduction, can effectively alleviate the inhibition of the vegetative growth process of plants under salinity-alkalinity stress, can prevent and control soil heavy metal cadmium pollution, improve the salinity-alkalinity tolerance and cadmium tolerance of plants, and promote plant growth. The present invention provides new methods and ideas for the utilization of saline-alkali land and the prevention and control of soil cadmium toxicity and reduction of cadmium content, and provides excellent bacterial strain resources with better salinity-alkalinity tolerance, cadmium tolerance and growth promotion.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural microorganisms, and more specifically, relates to the application of Burkholderia cepacia in promoting plant salt-alkali tolerance and reducing the content of heavy metal cadmium. Background Art

[0002] Soil salinization refers to the phenomenon or process of soluble salts accumulating on the soil surface, which is manifested as a relative decrease in soil organic matter content, which makes the soil nutritional conditions worse and the soil microbial activities are inhibited by salt and alkali. The harm of salt and alkali to crops, on the one hand, indirectly changes the physical and chemical properties of the soil, causing plants to lose a good living environment and nutritional conditions; on the other hand, it directly harms crop cells through soil solutions, affecting the normal absorption and metabolic functions of crops. The salinized soil environment can easily cause crop roots to become dehydrated due to excessive external osmotic pressure, and even corrode the roots, accelerating root death, resulting in large-scale withering of crops and no harvest. Only a very small number of salt-alkali-tolerant crops can survive in saline-alkali land.

[0003] The environmental pollution problem of heavy metal cadmium has been appearing since the 1920s along with the production of electrolytic zinc. The main sources of soil cadmium pollution are wastewater, waste gas and waste residue from mining, smelting, electroplating and basic chemical industries. The application of cadmium-containing fertilizers, pesticides and agricultural sludge is also an important source of soil cadmium pollution. The long-term application of chemical fertilizers has led to increasingly serious soil ecological problems such as soil hardening, soil heavy metal pollution and water eutrophication. At the same time, a large number of chemical pesticides are used to prevent and control various diseases, resulting in increasingly strong resistance of plant pathogens and serious problems such as pesticide residues.

[0004] At present, in alleviating plant saline-alkali stress and preventing environmental pollution caused by heavy metal cadmium, in addition to using chemical agents to neutralize saline-alkali and transform and adsorb heavy metal cadmium in the soil, microbial remediation and prevention can also be utilized, which is sustainable and environmentally friendly. Burkholderia cepacia, as a relatively new and excellent biocontrol bacterium, can secrete various substances for disease prevention and growth promotion, and has obvious effects on preventing various diseases and promoting the growth of various plants. There have been domestic patent reports on the great development potential of Burkholderia cepacia in plant growth promotion and biological control. For example, Chinese Patent CN112625970A discloses a strain of Burkholderia cepacia, which can stably colonize in the soil and can prevent more than ten diseases such as Verticillium dahliae of cotton and Colletotrichum higginsianum of flowering Chinese cabbage; however, there are few reports on the role of Burkholderia cepacia in alleviating soil saline-alkali stress in plants and preventing environmental pollution caused by heavy metal cadmium, and there is currently a lack of microbial strains that can be used for plants to alleviate soil saline-alkali stress and prevent environmental pollution caused by heavy metal cadmium. In the research on plant tolerance to soil saline-alkalization and prevention of environmental pollution caused by heavy metal cadmium, it is very necessary to screen saline-alkali-tolerant and cadmium-tolerant microbial strains, which can provide effective means for plants to resist saline-alkali stress and reduce the cadmium content in the soil, as well as more excellent strain resources, and also have great significance for the treatment of soil cadmium toxicity. Summary of the Invention

[0005] The present invention provides the application of Burkholderia cepacia in promoting plant tolerance to saline-alkali and reducing the content of heavy metal cadmium.

[0006] Another object of the present invention is to provide a method for promoting plant resistance to saline-alkali stress.

[0007] Another object of the present invention is to provide a method for reducing the cadmium content in a sample.

[0008] The above objects of the present invention are achieved by the following technical solutions:

[0009] The present invention provides a new use of Burkholderia cepacia JT79 strain, which has been deposited in Guangdong Provincial Microbial Culture Collection Center on September 30, 2019, with a deposit number of GDMCC NO: 60798, and a deposit address of No. 100, Xianlie Middle Road, Guangzhou. Studies have shown that the Burkholderia cepacia JT79 strain has good salt-alkali resistance and the ability to reduce the content of heavy metal cadmium, and can grow normally in a medium containing heavy metal cadmium in high salt and alkali; and the JT79 strain can significantly improve the ability of soybeans and corn to resist salt-alkali stress, promote the growth and development of soybeans and corn, indicating that the JT79 strain can effectively alleviate the situation of plant nutritional growth process being inhibited under salt-alkali stress, improve the salt-alkali tolerance of plants, and promote plant growth. At the same time, the JT79 strain can reduce the cadmium content by more than 80% by treating the cadmium-containing medium for 72 hours, indicating that the JT79 strain has a high reduction effect on soil cadmium toxicity, can be used to prevent and control soil heavy metal cadmium pollution, and improve the cadmium tolerance of plants.

[0010] Therefore, the following applications are all within the protection scope of the present invention:

[0011] Application of Burkholderia cepacia JT79 strain and / or its bacterial solution in promoting plant resistance to saline-alkali stress or reducing cadmium content.

[0012] Application of Burkholderia cepacia JT79 strain and / or its bacterial solution in preparing a preparation for improving plant salt-alkali resistance or a preparation for reducing cadmium content.

[0013] Application of Burkholderia cepacia JT79 strain and / or its bacterial solution in preventing and controlling heavy metal cadmium pollution in soil.

[0014] Application of Burkholderia cepacia JT79 strain and / or bacterial solution thereof in promoting plant growth under saline-alkali stress.

[0015] Application of Burkholderia cepacia JT79 strain and / or its bacterial solution in the preparation of salt-alkali resistant and / or growth-promoting agents.

[0016] The invention provides a method for promoting plant resistance to salt-alkali stress, and the plant is treated by using the Burkholderia cepacia JT79 strain and / or its bacterial liquid.

[0017] Furthermore, the bacterial liquid is a fermentation liquid.

[0018] The preparation method of the Burkholderia cepacia JT79 fermentation broth provided by the present invention comprises the following steps: activating the strain, taking a single colony and inoculating it into an LB culture medium, culturing it at 30°C for 48 hours to obtain a seed liquid, and then mixing the seed liquid and the liquid culture medium, and culturing them for 48 hours to obtain the product.

[0019] Preferably, the formula of the LB medium is: 5 g of yeast extract, 10 g of tryptone, 5 g of NaCl, and made up to 1 L with sterile water.

[0020] Preferably, the liquid medium is LB medium or NB medium.

[0021] More preferably, the formula of the LB medium is: 10 g of tryptone, 5 g of yeast extract, 10 g of NaCl, and made up to 1 L with sterile water; the formula of the NB medium is: 3 g of beef extract, 10 g of peptone, 5 g of NaCl, and made up to 1 L with sterile water.

[0022] Preferably, the volume ratio of the seed liquid to the liquid medium is 1:10.

[0023] Preferably, the concentration of the fermentation broth is not less than 2×10 8 cfu / mL.

[0024] Preferably, the fermentation broth is diluted 5 - 50 times before use.

[0025] More preferably, the fermentation broth is diluted 25 times before use.

[0026] Preferably, the treatment method is to carry out root irrigation.

[0027] Preferably, the plants are soybeans and corn.

[0028] The present invention also provides a method for reducing the cadmium content in a sample, which uses Burkholderia cepacia JT79 and / or its bacterial solution and fermentation broth to treat a cadmium-containing culture solution.

[0029] The present invention has the following beneficial effects:

[0030] The present invention provides a new use of Burkholderia cepacia strain JT79. The research of the present invention shows that Burkholderia cepacia strain JT79 has good characteristics of salt and alkali tolerance and heavy metal cadmium tolerance, and can grow normally in high-salt-alkali and cadmium-containing culture media; and it shows that strain JT79 can effectively prevent and control the harm of high salt and alkali to crops and promote the growth and development of crops, can significantly improve the ability of soybeans and corn to resist salt-alkali stress, and promote the growth and development of soybeans and corn, increasing plant height, lateral root number, aboveground fresh weight, and underground fresh weight. It shows that strain JT79 can effectively alleviate the inhibition of the vegetative growth process of plants under salt-alkali stress, improve the salt-alkali tolerance of plants, and promote plant growth. At the same time, strain JT79 has the effect of significantly reducing cadmium content. Treating cadmium-containing samples with JT79 bacterial liquid and its 25-fold dilution for 72 h can reduce the cadmium content by more than 80%, indicating that strain JT79 has a highly efficient reducing effect on the cadmium content of samples and can be used to prevent and control soil heavy metal cadmium pollution and improve the cadmium tolerance of plants. The present invention provides a new method and idea for the utilization of saline-alkali land and the prevention and control of environmental pollution caused by heavy metal cadmium, and provides excellent bacterial strain resources with better salt-alkali and cadmium tolerance and the ability to promote growth for production selection. Description of the Drawings

[0031] Figure 1 It is the colony morphology of strain JT79 on the salt-alkali-containing culture medium.

[0032] Figure 2 It is the treatment effect of JT79 on soybean salt-alkali stress (A: plant height; B: fibrous root number; C: aboveground fresh weight; D: underground fresh weight. CK: treated with clear water; SA: salt-alkali treatment; SA+Bc: salt-alkali treatment plus JT79 fermentation broth; SA+Bc×5: salt-alkali treatment plus 5-fold dilution of JT79 fermentation broth; SA+Bc×25: salt-alkali treatment plus 25-fold dilution of JT79 fermentation broth; SA+Bc×50: salt-alkali treatment plus 50-fold dilution of JT79 fermentation broth).

[0033] Figure 3 It is the treatment effect of JT79 on corn salt-alkali stress (A: plant height; B: lateral root number; C: aboveground fresh weight; D: underground fresh weight. CK: treated with clear water; SA: salt-alkali treatment; SA+Bc: salt-alkali treatment plus JT79 fermentation broth; SA+Bc×5: salt-alkali treatment plus 5-fold dilution of JT79 fermentation broth; SA+Bc×25: salt-alkali treatment plus 25-fold dilution of JT79 fermentation broth; SA+Bc×50: salt-alkali treatment plus 50-fold dilution of JT79 fermentation broth).

[0034] Figure 4This is the treatment effect of JT79 bacterial suspension on soybean saline-alkali stress (CK: clean water treatment; SA: saline-alkali treatment; SA+Bc (Solution): saline-alkali treatment plus JT79 fermentation liquid; SA+Bc (Thallus): saline-alkali treatment plus JT79 bacterial suspension).

[0035] Figure 5 This is a diagram showing the growth-promoting effect of JT79 bacterial suspension on soybean saline-alkali stress (from left to right: non-saline-alkali treatment, saline-alkali treatment, saline-alkali + bacterial suspension treatment, saline-alkali + bacterial suspension treatment).

[0036] Figure 6 This is the result of the tolerance test of JT79 strain on cadmium-containing culture medium.

[0037] Figure 7 These are the test results of cadmium content before and after treatment of JT79 fermentation broth. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0039] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0040] Example 1 Preparation of Burkholderia cepacia JT79 fermentation broth

[0041] The Burkholderia cepacia JT79 strain used in this example is a strain preserved by the research group of the present invention, which was deposited in the Guangdong Provincial Microbiological Culture Collection Center on September 30, 2019, with a deposit number of GDMCC NO: 60798, and the deposit address is No. 100 Xianlie Middle Road, Guangzhou.

[0042] The strain stored at -80°C was activated, and the activated colonies were picked out and placed in LB liquid culture medium (5 g yeast extract, 10 g tryptone, 5 g NaCl, 1000 mL water, pH 7.2), sterilized at 121°C for 15 min, and cultured at 30°C for 48 h to obtain seed solution.

[0043] The seed liquid containing Burkholderia cepacia JT79 was added to NB liquid medium (3 g of beef extract, 10 g of peptone, 5 g of NaCl, made up to 1 L with sterile water) at a volume ratio of 1:10, and cultured at 30 °C and 180 r / min for 48 h to obtain the fermentation broth of Burkholderia cepacia JT79. Among them, the concentration of the fermentation broth of Burkholderia cepacia JT79 was 2×10 8 cfu / mL.

[0044] Example 2 Tolerance test of Burkholderia cepacia JT79 to saline-alkali medium

[0045] 1. Preparation of saline-alkali medium

[0046] NA solid saline-alkali medium: 3 g of beef extract, 10 g of peptone, 20 g of agar, 0.06 mM saline-alkali, pH 9.0, made up to 1 L with sterile water, and sterilized at 121 °C for 15 min.

[0047] 2. Test treatment

[0048] After appropriately diluting the fermentation broth containing Burkholderia cepacia JT79 in a laminar flow hood, 200 μL was taken and evenly spread on the NA solid saline-alkali plate with a spreading rod. After it was completely air-dried, the plate was sealed with a sealing film and placed in a room temperature incubator. The colony growth was observed and recorded every day, and the NA solid medium was used as a control.

[0049] 3. Result analysis

[0050] The results were as Figure 1 shown. Burkholderia cepacia JT79 had good salt and alkali tolerance and could grow normally under 0.06 mM and pH = 9.0 saline-alkali.

[0051] Example 3 Promoting effect of Burkholderia cepacia fermentation broth on saline-alkali stress resistance of soybeans

[0052] After 15 soybean seedlings with the same growth vigor grew to 4 leaves, they were transplanted into a pot container with a diameter of 6 cm and a height of 12 cm, and 100 g of substrate soil was added to each for planting. After 2 days of planting, the treatment was carried out. Five experimental treatments were set, with 3 replicates for each treatment:

[0053] Treatment 1: Non-saline-alkali treatment, watering 20 mL of sterile water.

[0054] Treatment 2: Saline-alkali treatment, adding 10 mL of saline-alkali solution (0.06 mM, pH 9.0) and 10 mL of sterile water.

[0055] Treatment 3: Saline-alkali + bacterial liquid treatment, add 10 mL of saline-alkali solution (0.06 mM, pH 9.0), and then add 10 mL of JT79 fermentation broth.

[0056] Treatment 4: Saline-alkali + diluted bacterial liquid treatment, add 10 mL of saline-alkali solution (0.06 mM, pH 9.0) and 10 mL of 5-fold diluted bacterial liquid of JT79.

[0057] Treatment 5: Saline-alkali + diluted bacterial liquid treatment, add 10 mL of saline-alkali solution (0.06 mM, pH 9.0) and 10 mL of 25-fold diluted bacterial liquid of JT79.

[0058] Treatment 6: Saline-alkali + diluted bacterial liquid treatment, add 10 mL of saline-alkali solution (0.06 mM, pH 9.0) and 10 mL of 50-fold diluted bacterial liquid of JT79.

[0059] Place the plants after the above treatments in the greenhouse for cultivation, treat them once every 7 days. After 30 days of cultivation, measure the plant height, number of lateral roots, fresh weight of the above-ground part, and fresh weight of the underground part of the plants.

[0060] The experimental results are as Figure 2 shown. Compared with Control Treatment 1, under saline-alkali treatment, the plant height, number of lateral roots, fresh weights of the above-ground and underground parts of soybeans decreased by 60.23%, 66.71%, 40.52%, and 50.23% respectively, with significant differences. Under saline-alkali stress of soybeans, when adding the original fermentation broth of JT79 and 5-fold, 25-fold, and 50-fold diluted solutions, the plant height of soybeans increased by 3.71%, 81.82%, 20.37%, and 64.81% respectively; the number of lateral roots increased by 30.31%, 42.42%, 96.97%, and 81.82% respectively; the fresh weight of the above-ground part increased by 48.38%, 33.79%, 38.63%, and 49.66% respectively; the fresh weight of the underground part increased by -8.9%, 23.64%, 47.13%, and 61.97% respectively, indicating that the addition of the fermentation broth of Burkholderia cepacia JT79 can alleviate the saline-alkali stress of soybeans, thereby promoting the growth of soybeans.

[0061] Example 4 Growth-promoting effect of Burkholderia cepacia fermentation broth on maize under saline-alkali stress

[0062] After cultivating 15 maize seedlings with the same growth vigor until they have 4 leaves, transplant them into a pot container with a diameter of 6 cm and a height of 12 cm, and add 100 g of substrate soil for each for planting. After 2 days of planting, conduct the treatment. Set five experimental treatments, with 3 replicates for each treatment:

[0063] Treatment 1: Non-saline-alkali treatment, irrigate with 20 mL of sterile water.

[0064] Treatment 2: Saline-alkali treatment, adding 10 mL of saline-alkali solution (0.06 mM, pH 9.0) and 10 mL of sterile water.

[0065] Treatment 3: Saline-alkali + bacterial solution treatment, adding 10 mL of saline-alkali solution (0.06 mM, pH 9.0), and then adding 10 mL of JT79 bacterial solution.

[0066] Treatment 4: Saline-alkali + diluted bacterial solution treatment, adding 10 mL of saline-alkali solution (0.06 mM, pH 9.0) and adding 10 mL of 5-fold diluted bacterial solution of JT79.

[0067] Treatment 5: Saline-alkali + diluted bacterial solution treatment, adding 10 mL of saline-alkali solution (0.06 mM, pH 9.0) and adding 10 mL of 25-fold diluted bacterial solution of JT79.

[0068] Treatment 6: Saline-alkali + diluted bacterial solution treatment, adding 10 mL of saline-alkali solution (0.06 mM, pH 9.0) and adding 10 mL of 50-fold diluted bacterial solution of JT79.

[0069] The plants treated with the above groups were placed in a greenhouse for cultivation, treated once every 7 days. After 30 days of cultivation, the plant height, lateral root number, fresh weight of the above-ground part, and fresh weight of the underground part of the plants were measured.

[0070] The experimental results are as Figure 3 shown. Compared with control treatment 1, under saline-alkali treatment, the plant height, lateral root number, fresh weight of the above-ground and underground parts of maize decreased by 40%, and saline-alkali conditions severely inhibited maize growth. After maize was treated with saline-alkali, after adding the original solution of JT79 fermentation broth and 5-fold, 25-fold, and 50-fold diluted solutions, the plant height of maize increased by 0%, 47.06%, 58.82%, and 11.76% respectively; the lateral root number increased by 2, 4, 4, and 1 respectively; the fresh weight of the above-ground part increased by 19.67%, 87.83%, 133.35%, and 31.65% respectively; the fresh weight of the underground part increased by -7.39%, 28.24%, 72.36%, and 11.82% respectively. Among them, the growth promotion effect was the best after the bacterial solution was diluted 25-fold. Under the treatment of 25-fold diluted solution of JT79 fermentation broth, the plant height, lateral root number, fresh weight of the above-ground and underground parts were 13.5 cm, 4 fibrous roots, 0.3275 g, and 0.4996 g respectively. There was no significant difference from treatment 1.

[0071] Example 5 Anti-stress growth promotion effect of JT79 cell suspension

[0072] After cultivating 12 soybean seedlings with the same growth trend until they had 4 leaves, they were transplanted into a pot container with a diameter of 6 cm and a height of 12 cm, and 100 g of substrate soil was added to each for planting. After 2 days of planting, the treatment was carried out.

[0073] The preparation method of the JT79 bacterial cell suspension is as follows: Take 100 mL of JT79 fermentation broth, aliquot it into 50 mL sterile centrifuge tubes, and centrifuge at 6000 rpm for 10 min. Discard the supernatant, add an equal volume of sterile water to wash the bacterial cells, invert to form a bacterial suspension, and then centrifuge at 6000 rpm for 10 min. Discard the supernatant, resuspend the bacterial cell pellet in 10 mL of sterile water, and measure the OD 600 value, and adjust it to OD 600 = 1.0. Set five experimental treatments, with 3 replicates for each treatment:

[0074] Treatment 1: Non-saline-alkali treatment, irrigate with 20 mL of sterile water.

[0075] Treatment 2: Saline-alkali treatment, add 10 mL of saline-alkali solution (0.06 mM, pH 9.0) and 10 mL of sterile water.

[0076] Treatment 3: Saline-alkali + bacterial liquid treatment, add 10 mL of saline-alkali solution (0.06 mM, pH 9.0), and then add 10 mL of JT79 fermentation broth.

[0077] Treatment 4: Saline-alkali + bacterial cell treatment, add 10 mL of saline-alkali solution (0.06 mM, pH 9.0), and then add 10 mL of JT79 bacterial cell suspension.

[0078] After the above treatments for each group, treat once every 7 days. After 30 days of cultivation, measure the plant height, number of lateral roots, fresh weight of the above-ground part, and fresh weight of the underground part of the plants.

[0079] The experimental results are as Figure 4 shown. The plant height of the control group of soybeans was 14.3 cm, and the plant height of the plants in the saline-alkali treatment was 4.3 cm, which was 30% of the plant height of the control group, and the difference between the two was significant; the plant height of the plants after treatment with JT79 bacterial liquid was 13.8 cm, which was 96.5% of the plant height of the control group, and the difference between the two was not significant; the plant height of the plants after treatment with JT79 bacterial cells was 11 cm, which was 76.9% of the plant height of the control group, and the difference between the two was not significant. The growth-promoting effect of JT79 bacterial liquid on soybean saline-alkali stress is as Figure 5 shown, indicating that the growth-promoting effect of using JT79 fermentation broth on plants under saline-alkali stress is better than that of JT79 bacterial cell suspension, and its growth-promoting effect is comparable to that of the control group under normal conditions.

[0080] Example 6 Tolerance test of Burkholderia cepacia JT79 to cadmium-containing medium

[0081] 1. Preparation of cadmium-containing medium

[0082] NA solid cadmium-containing medium (15 mg cadmium chloride, 3 g beef extract, 10 g peptone, 5 g NaCl, 20 g agar, made up to 1 L with sterile water and sterilized at 121 °C for 15 min).

[0083] 2. Experimental treatments

[0084] After appropriately diluting the seed solution containing Burkholderia cepacia JT79 in a laminar flow hood, 200 μL was taken and evenly spread on the NA solid cadmium-containing plate with a spreading rod. After it was completely air-dried, the plate was sealed with a sealing film and placed in an incubator at room temperature. The growth of colonies was observed and recorded every day, and the NA solid medium was used as a control.

[0085] 3. Result analysis

[0086] The results are as Figure 6 shown. Burkholderia cepacia JT79 has good cadmium tolerance and can grow normally in an environment with a cadmium content of 15 mg / L.

[0087] Example 7 Experiment on reducing cadmium content in Burkholderia cepacia JT79 cadmium-containing medium

[0088] 1. Preparation of cadmium-containing medium

[0089] NB liquid cadmium-containing medium (15 mg cadmium chloride, 3 g beef extract, 10 g peptone, 5 g NaCl, made up to 1 L with sterile water and sterilized at 121 °C for 15 min).

[0090] 2. Experimental treatments

[0091] According to the volume ratio of the seed solution containing Burkholderia cepacia JT79 to the liquid medium of 1:10, the seed solution containing Burkholderia cepacia JT79 was added to the NB liquid cadmium-containing medium respectively, and cultured at 30 °C and 180 r / min for 72 h and 96 h respectively to obtain the cadmium-containing fermentation broth of Burkholderia cepacia JT79. Among them, in this experiment, the cadmium-containing (5 mg / L) NB medium was used as a control, and the medium treated with the fermentation broth of Burkholderia cepacia JT79 (concentration of 2×10 8 cfu / mL) was used as the experimental group, and each treatment was repeated 5 times. The fermentation broth of strain JT79 prepared in Example 1 was used. After culturing the above media for a certain period of time, samples were taken respectively. A certain amount of fermentation broth was centrifuged at high speed (1000 r / min) to obtain 10 mL of supernatant, and then the supernatant was filtered and sterilized (500 mesh) and then subjected to cadmium determination.

[0092] 3. Result analysis

[0093] The results are as Figure 7As shown, the cadmium concentration in the control group reached 15.51 mg / L. After treatment with the fermentation broth of strain JT79 for 72 and 96 hours respectively, the cadmium concentrations in the solution were 0.92 mg / L and 0.75 mg / L respectively. The reduction rate of cadmium content in the solution exceeded 90%, indicating that strain JT79 has a significant effect on passivating or enriching cadmium.

[0094] In summary, Burkholderia cepacia strain JT79 has good salt and alkali tolerance and the ability to reduce the content of heavy metal cadmium. It can grow normally in high-salt-alkali culture media and cadmium-containing environments, showing good salt-alkali and cadmium tolerance. It also shows that strain JT79 can effectively prevent and control the damage of high salt and alkali to crops and promote the growth and development of crops. It can significantly improve the salt-alkali stress resistance of soybeans and corn, and promote the growth and development of soybeans and corn, increasing plant height, lateral root number, above-ground fresh weight, and underground fresh weight. This indicates that strain JT79 can effectively alleviate the inhibition of the vegetative growth process of plants under salt-alkali stress, improve the salt-alkali tolerance of plants, and promote plant growth. At the same time, treatment of cadmium-containing samples with the JT79 bacterial solution and its 10-fold dilution for 72 hours can reduce the cadmium content by more than 80%, indicating that strain JT79 has a highly efficient reducing effect on the cadmium content of samples. The present invention provides new methods and ideas for the utilization of saline-alkali land and the prevention, control, and utilization of cadmium-metal contaminated soil, and obtains excellent bacterial strain resources with better salt-alkali tolerance, growth-promoting activity, and capable of being used for the prevention and control of heavy metal contaminated soil for production selection.

[0095] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. Use of Burkholderia cepacia strain JT79 and / or its bacterial solution in promoting plant resistance to saline-alkali stress, characterized in that, The Burkholderia cepacia JT79 strain was deposited in the Guangdong Provincial Microbiological Culture Collection Center on September 30, 2019, with the deposit number GDMCC NO: 60798, and the deposit address is No. 100 Xianlie Middle Road, Guangzhou City; the plants are soybeans and corn.

2. Use of Burkholderia cepacia strain JT79 and / or its bacterial solution in the preparation of a preparation for improving plant salt-alkali tolerance, characterized in that, The Burkholderia cepacia JT79 strain was deposited in the Guangdong Provincial Microbiological Culture Collection Center on September 30, 2019, with the deposit number GDMCC NO: 60798, and the deposit address is No. 100 Xianlie Middle Road, Guangzhou City; the plants are soybeans and corn.

3. Use of Burkholderia cepacia strain JT79 and / or its bacterial solution in promoting plant growth under saline-alkali stress, characterized in that, The Burkholderia cepacia JT79 strain was deposited in the Guangdong Provincial Microbiological Culture Collection Center on September 30, 2019, with the deposit number GDMCC NO: 60798, and the deposit address is No. 100 Xianlie Middle Road, Guangzhou City; the plants are soybeans and corn.

4. Use of Burkholderia cepacia strain JT79 and / or its bacterial solution in the preparation of a saline-alkali tolerance agent, characterized in that, The Burkholderia cepacia JT79 strain was deposited in the Guangdong Provincial Microbiological Culture Collection Center on September 30, 2019, with the deposit number GDMCC NO: 60798, and the deposit address is No. 100 Xianlie Middle Road, Guangzhou City.

5. A method for promoting plant resistance to saline-alkali stress, characterized in that, The plants are treated with the Burkholderia cepacia JT79 strain and / or its bacterial liquid; the Burkholderia cepacia JT79 strain has been deposited in the Guangdong Provincial Microbiological Culture Collection Center on September 30, 2019, with a deposit number of GDMCC NO: 60798, and a deposit address of No. 100, Xianlie Middle Road, Guangzhou; the plants are soybeans and corn.

6. The method according to claim 5, characterized in that, The bacterial liquid is a fermentation broth, and the concentration of the fermentation broth is not less than 2×10 8 cfu / mL.

7. The method according to claim 6, characterized in that, Use fermentation broth diluted 5 to 50 times.

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