CN109355228B

CN109355228B - Forest rhizosphere bacterium bacillus mycoides JYZ-SD5 and application thereof

Info

Publication number: CN109355228B
Application number: CN201811389328.1A
Authority: CN
Inventors: 吴小芹; 徐秀倩; 叶建仁; 吴天宇; 刘辉
Original assignee: Nanjing Forestry University
Current assignee: Nanjing Forestry University
Priority date: 2018-11-20
Filing date: 2018-11-20
Publication date: 2020-01-24
Anticipated expiration: 2038-11-20
Also published as: CN109355228A

Abstract

The invention discloses a forest rhizosphere bacterium JYZ-SD5 and application thereof, the forest rhizosphere bacterium is classified and named as Bacillus mycoides JYZ-SD5, is preserved in China center for type culture collection with the preservation number: CCTCC NO: m2018469. The biological characteristics of the strain JYZ-SD5 are detected, so that the strain has the capabilities of fixing nitrogen, dissolving phosphorus and potassium, producing IAA, has an obvious promotion effect on the growth of forest trees, has a certain antagonistic effect on certain forest pathogenic fungi, and has a certain Ni antagonistic effect²⁺、Gr⁶⁺、Mn⁷⁺The heavy metal has high tolerance and good application prospect.

Description

Forest rhizosphere bacterium bacillus mycoides JYZ-SD5 and application thereof

Technical Field

The invention belongs to the technical field of microorganisms, and particularly relates to a forest rhizosphere bacterium JYZ-SD5 and application thereof.

Background

Soil microbial communities are abundant and have different biological functions. Plant growth-promoting rhizobacteria (PGPR) exist in Plant rhizosphere and root surface, and have the functions of promoting Plant growth, antagonizing pathogenic microorganisms, raising Plant resistance, repairing soil, maintaining soil quality, etc. For example, PGPR can be rapidly propagated at plant rhizosphere, fix nitrogen in the atmosphere, make full use of soil nutrients and promote better plant growth. Liu et al screened a strain of pseudomonas fluorescens (Pseudomonas fluorescens) JW-JS1 from the root of poplar, and can remarkably promote the growth of seedlings of NL-895 poplar and populus deltoides and improve the content of nutrient elements. The prevention effect of rhizosphere bacterium, namely, Laurencia amabilis (Rahnella aquatilis) JZ-GX 1 on the chrysosporium cucumerinum (Cytospora chrysosperma) can reach 84 percent by Songhua and the like. Some Bacillus (Bacillus Cohn) bacteria also improve plant tolerance to heavy metals, and Kuramshina et al have found that treatment of seeds of Sinapis alba with endophytes of Bacillus subtilis improves plant resistance to the toxic effects of cadmium and nickel and reduces the damage manifestations in aerial parts.

The beneficial functions of PGPR on plants under natural conditions are the result of multifaceted interactions, however, most of the current studies on PGPR focus on certain biological functions and relatively few studies on the comprehensive properties of PGPR.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the defects in the prior art, the invention aims to provide a forest rhizosphere bacterium JYZ-SD5 which has the functions of fixing nitrogen, dissolving phosphorus and potassium, producing indole-3-acetic acid (IAA), obviously promoting the growth of forest trees and the like. Another object of the invention is to provide an application of the above forest rhizosphere bacterium JYZ-SD 5.

The technical scheme is as follows: in order to achieve the purpose of the invention, the invention adopts the technical scheme that:

a forest rhizosphere bacterium is classified and named as Bacillus mycoides (Bacillus paramycoides) J YZ-SD5, and is preserved in China center for type culture Collection with the preservation number as follows: CCTCC NO: m2018469, preservation date 2018, 7 months and 13 days, and preservation place Wuhan university in Wuhan, China.

The application of the bacillus mycoides JYZ-SD5 in nitrogen fixation, organic phosphorus dissolution and potassium dissolution.

The application of the bacillus mycoides JYZ-SD5 in IAA production.

The application of the bacillus mycoides JYZ-SD5 in promoting plant growth.

The plant is metasequoia.

The application of the bacillus mycoides JYZ-SD5 in heavy metal resistance.

The application of the bacillus mycoides JYZ-SD5 in treating heavy metal pollution.

The heavy metal is Ni²⁺、Cr⁶⁺、Mn⁷⁺。

The application of the bacillus mycoides JYZ-SD5 in the production of cellulase and protease.

The application of the bacillus mycoides JYZ-SD5 in bacteriostasis.

Has the advantages that: compared with the prior art, the invention has the following advantages:

1) test results show that the forest rhizosphere bacterium JYZ-SD5 has the capabilities of fixing nitrogen, decomposing organic phosphorus and decomposing potassium, has higher IAA production capability, and produces 6.8186 mu g/mL of IAA without adding tryptophan precursors. Potted plant experiments show that the forest rhizosphere bacteria JYZ-SD5 have good growth promoting effect on the metasequoia, can obviously improve the plant height and the ground diameter of the metasequoia, and improves the net growth amount of the metasequoia by 74 percent and 88 percent respectively compared with the control group seedling height and ground diameter after the bacteria are applied for 40 days. The forest rhizosphere bacterium JYZ-SD5 can promote plant growth.

2) Test results show that the rhizosphere bacterium JYZ-SD5 strain has good heavy metal resistance and Mn resistance⁷⁺、Cr⁶⁺The tolerance of the alloy can reach 400mg/L at most, and the alloy is heavy metal Ni²⁺The tolerance of the strain can reach 200mg/L at most. The forest rhizosphere bacterium JYZ-SD5 strain can produce cellulase and protease, and the protease and the cellulase can degrade protein and cellulose in fungal cell walls, destroy pathogenic hyphae and inhibit the growth of pathogenic bacteria; meanwhile, the bacteriostasis rate of the rhizosphere bacterium JYZ-SD5 to Alternaria alternata can reach 20.22%, and the rhizosphere bacterium JYZ-SD5 also has certain bacteriostasis effect to other forest pathogenic bacteria. As can be seen, the JYZ-SD5 strain has good application value in the aspects of heavy metal pollution areas and forest disease control.

3) The forest rhizosphere bacterium JYZ-SD5 was identified as Bacillus mycoides (Bacillus paramycoides), belonging to the genus Bacillus. Bacteroides is a new species Bacillus paramycoides sp.nov.type strain NH24A2T re-demarcated in 2017 by Liu et al by heterogeneous taxonomic method, based on phenotypic and 16S rRNA gene sequence analysis data, as belonging to low dDDH and ANI value strains in Bacillus cereus. In contrast, the strain JYZ-SD5 from the rhizosphere of forest was identified as Bacillus mycoides in this application, which was the first report that the strain was isolated from the terrestrial ecosystem. The result shows that the Bacteroides mycoides JYZ-SD5 has better growth-promoting and stress-resisting characteristics and has the potential of being used as a novel microbial strain resource for development and application.

Drawings

FIG. 1 is a graph showing the colony morphology (A, B), gram stain (C) and spore stain (D) of a rhizosphere bacterium JYZ-SD5 cultured on an NA plate for 24 hours;

FIG. 2 is a phylogenetic tree diagram of JYZ-SD5 strain constructed based on 16S rRNA gene sequence;

FIG. 3 is a graph showing the results of measurement of nitrogen fixation (A) and organophosphorus desorption (B) of a rhizosphere bacterium JYZ-SD5 strain;

FIG. 4 is a graph showing the results of quantitative detection of IAA by the rhizosphere bacterium JYZ-SD 5; a: an IAA standard curve; b: the IAA amount is produced by different treatment strains JYZ-SD 5; the different lower case letters in the figure indicate that the inter-treatment differences were at a significant level (P <0.05), the same below;

FIG. 5 is a graph showing antagonistic effects of rhizosphere bacterium JYZ-SD5 on forest pathogenic fungi; in the figure, A: alternaria alternate; b: alternaria tenuissima; c: culturing Camellia sinensis; d: peptosphaeroides versicolor. Wherein A1-D1 is CK; A2-D2 is the inoculation streak treatment;

FIG. 6 is a graph showing the results of detection of protease (A) and cellulase (B) by the rhizobacteria JYZ-SD 5;

FIG. 7 is a growth curve of rhizosphere bacterium JYZ-SD5 under different heavy metal stresses (A: Mn; B: Cr; C: Ni) (heavy metal units (mg/L);

FIG. 8 is a graph showing the results of growth promotion of the wood rhizosphere bacterium JYZ-SD5 on Metasequoia glyptostroboides.

Detailed Description

The present invention will be further described with reference to the following specific examples.

The following examples used the main materials and data processing methods: pathogenic bacteria of the tested trees: b, red blight of metasequoia: alternaria tenuissima (Alternaria tenuissima), Pestalotiopsis variabilis (Pestalotiopsis heteroceronicis); leaf blight of tea tree: tee-tee camellia (Guignardia camellia); tea tree alternaria bacterium: pestalotiopsis vesicolor (Pestalotiopsis vesicolor); conidiobacter sphaerocephalus: conidiobolus pinicola (sphaeropsissapoinea); poplar canker pathogen: fusarium aesculi (Fusicoccus aesculi); ginkgo leaf blight bacteria: alternaria alternata sp. All strains were stored in the forest pathology laboratory at Nanjing university of forestry. Plant material 2-year-old metasequoia potted seedling, and the matrix is selected from the topsoil of the root of the northern mountain forest of Nanjing forestry university. The test medium is beef extract peptone (NA) medium, the Monkina medium is used for measuring the capacity of the strain for dissolving organic phosphorus, the nitrogen-free medium is used for qualitatively measuring the nitrogen fixation capacity, the potassium decomposition capacity is used for detecting the medium, and the cellulose congo red medium is used for measuring the capacity of decomposing cellulose. The protease detection medium, King' S medium B (KB) was used for the determination of IAA production by the strains. Data processing measured data are plotted by using Excel 2013 software, and statistical data analysis is carried out by using prism cracked software.

Example 1

The bacterium JYZ-SD5 separated from the rhizosphere of Shandong poplar is preserved in China center for type culture Collection with the preservation number: CCTCC NO: m2018469.

1) And (3) observing the shape and characteristics of the thallus and measuring physiological and biochemical indexes: the physiological and biochemical measurements of the strain JYZ-SD5 are carried out according to Bergey's Manual of bacteria identification and Manual of general bacteria System identification, and the colony morphology and characteristics are described.

The bacterial colony of the strain JYZ-SD5 on the NA culture medium is nearly circular, irregular in edge, milky white, moist and glossy, and has no protrusion in the middle (FIG. 1A, B). The bacterial body is short rod-shaped, has no flagellum, is gram-positive bacteria, can see green spores in spore staining observation, and indicates spore production (figure 1C).

The strain JYZ-SD5 has positive results in VP test, methyl red test, indole test and nitric acid reduction test, and can hydrolyze starch and gelatin. The test results of the catalase and the oxidase are positive, the test result of glucose acidogenesis is positive, the test result of phenylalanine deaminase, glucose aerogenesis, xylose and mannitol is negative in the fermentation test of sugar and alcohol (table 1), and the results are basically consistent with the characteristics of Bacillus paramycoides.

TABLE 1 physiological and biochemical measurement results of JYZ-SD5 Strain

Measurement index	Characteristics of the strains
		Nitrate reduction	+
Methyl Red	+
		V-P	+
Gelatin liquidation for liquifying Gelatin	+
		Catalase	+
Oxidase	+
		Phenylalanine deaminase Phenylalanine deaminase	–
Glucose gas production Glucose products gas	–
		Glucose production acid produced by Glucose	+
D-xylose	–
		D-mannose D-mannase	–

Note: "+" positive; "-" negative

2)16S rDNA gene sequence analysis and phylogenetic tree: the bacterial genomic DNA was amplified using a pair of universal primers (upstream primer 27f (5'-AGAGTTTGATCCTGGCTCAG-3'), downstream primer 1492r (5'-TACGGCTACCTTGTTACGACTT-3')) for bacterial 16SrDNA using the extracted bacterial total DNA as a template.

And (3) PCR reaction system: mix10 uL, upstream and downstream primers 1 uL, DNA template 1 uL, ddH2O7 uL. And (3) PCR reaction conditions: pre-denaturation at 94 ℃ for 5min, denaturation at 94 ℃ for 30s, annealing at 55 ℃ for 30s, extension at 72 ℃ for 1min, 33 cycles, extension at 72 ℃ for 10min, electrophoresis of the obtained PCR product in 1% agarose gel, EB staining, and taking pictures under ultraviolet light. If the PCR product is banding, the obtained PCR product is sent to Nanjing Kingsry biotechnology company for purification and sequencing. The measured 16S rRNA was subjected to gene sequence alignment with sequences in Ez Taxon and GenBank, and a phylogenetic tree was constructed using MEGA 8.0.

The 16S rDNA amplification product of the strain JYZ-SD5 is detected by electrophoresis through 1% agarose gel, and a bright PCR target band is obtained near 1500bp without other non-specific bands. The target DNA fragment obtained by 16S rDNA amplification can be used for sequencing. The 16S rDNA gene of strain JYZ-SD5 obtained by sequencing had 1420 bases (GenBank accession number: MH 894221).

Phylogenetic trees (FIG. 2) were constructed by MEGA8.0 software by aligning the gene sequences of strain JYZ-SD5 with the sequences in Ez Taxon and GenBank and constructing the sequence information of the model bacterium with the highest homology, strain JYZ-SD5 clustered with the model Bacillus mycoides NH24A2 strain with 99% similarity. According to phylogenetic tree similarity analysis and by combining morphological and physiological and biochemical characteristic comparison, the strain JYZ-SD5 is preliminarily identified as Bacillus mycoides (Bacillus paramycoides).

Example 2 measurement of Nitrogen fixation, phosphorus dissolution and potassium dissolution performances of rhizosphere bacteria JYZ-SD5

1) And (3) detecting nitrogen fixation characteristics: the test strains were inoculated in nitrogen-free medium by streaking, 3 times for each treatment, and placed in a 28 ℃ cryostat (MIR-553, Japan) to continuously observe the growth of the bacteria.

2) And (3) organophosphorus dissolving characteristic detection: inoculating the test strains in an organophosphorus decomposing culture medium by a three-point inoculation method, repeating each treatment for 3 times, placing in an incubator at 28 ℃, and continuously observing the existence of transparent rings around colonies.

3) And (3) potassium-dissolving capacity determination: inoculating test strain into potassium-dissolving test liquid culture medium by liquid culture method, repeating each treatment for 3 times, shake culturing at 28 deg.C at rotation speed of 200r/min for several days, and detecting potassium-dissolving ability of bacteria with flame spectrophotometer (FP6410, Shanghai) ((

P1 is blank control and P2 is inoculum treatment).

The measurement shows that the rhizosphere bacterium JYZ-SD5 strain can grow on a nitrogen fixing culture medium (figure 3A) and grow on an organophosphorus dissolving culture medium to form a transparent ring (figure 3B), which indicates that the bacterium has the capabilities of fixing nitrogen and dissolving organophosphorus; meanwhile, in the potassium-dissolving capacity detection, the potassium content in the control group is 7.90 mu g/mL, the potassium content in the treatment group is 10.97 mu g/mL, the potassium-dissolving capacity is improved by 3.07 mu g/mL compared with the control group, and the potassium-dissolving capacity of the strain JYZ-SD5 is 39% (Table 2).

TABLE 2 determination of Potassium-solubilizing ability of Strain JYZ-SD5

Example 3 detection of IAA-producing ability of rhizobacteria JYZ-SD5

1) And (3) qualitative detection: picking single colony to be inoculated into a King's medium B, culturing for 24h at 37 ℃ by a constant temperature shaking table (multitron Standard, Switzerland), sucking 1mL of bacterial liquid into a sterile centrifuge tube by using a sterile gun head, adding 4 mLSackowcki's color developing agent, quickly and fully mixing, developing color for 40min in the dark at room temperature, and observing color change.

2) And (3) quantitative detection: accurately weighing IAA10mg, dissolving with a small amount of ethanol, diluting with distilled water to 100mL (concentration of 100 μ g/mL), diluting to 0, 4, 8, 12, 16, 20, and 24 μ g/mL, adding 4mL color developing agent into 1mL of each concentration, keeping the temperature at 40 deg.C in dark for 40min, and determining OD value with OD535 to draw a standard curve. Centrifuging the cultured strain suspension and a blank control for 10min (10000r/min), adding 4mL of supernatant into an equivalent colorimetric solution, standing for 40min in the dark, immediately measuring the OD535 value by using a HexIOS spectrophotometer (Lamnda365, Korea), repeatedly measuring each sample for 3 times, adjusting the value to zero by using the blank control added with the colorimetric solution, calculating the IAA secretion amount of the strain by comparing with a standard curve, and continuously measuring for 7 d.

The color of the strain is light red in a colorimetric reaction containing a tryptophan culture solution as shown by a Salkowski colorimetric method, which indicates that the strain JYZ-SD5 has certain IAA production capacity. Adopting standard IAA to make a standard curve for quantitative analysis, obtaining that the concentration of IAA secreted in a culture solution without tryptophan is 3.9385 mu g/mL after the strain JYZ-SD5 is cultured for 1 d; the IAA concentration in the culture broth containing L-tryptophan reached 7.1520. mu.g/mL (FIG. 4B), and strain JYZ-SD5 produced the highest amount of IAA after 4d of culture. The IAA secreted in the culture solution without tryptophan has the highest concentration of 6.8186 mu g/mL; the IAA concentration in the culture broth containing L-tryptophan was at most 12.1996. mu.g/mL.

Example 4 determination of antagonistic forest pathogen Activity by rhizosphere bacterium JYZ-SD5

1) Plate antagonism: inoculating the pathogenic fungi to be tested in a PDA culture medium, inoculating one strain in each dish, repeating for 3 times, dipping the liquid with an inoculating ring, shaking and culturing for 24h, symmetrically marking lines on two sides of a bacterial colony, culturing in an incubator at 25 ℃, and continuously observing and recording the bacteriostatic effect of the strain.

2) Extracellular metabolite antagonistic activity: obtaining fermentation liquor of the test bacteria, transferring the fermentation liquor into a sterilized 50mL centrifuge tube, centrifuging for 10min at 10000r/mim and 4 ℃, taking supernatant, and passing through a bacteria filter membrane to obtain a sterile extracellular metabolite. The sterilized extracellular metabolite was added to the PDA medium at a ratio of 0.5%, and the plate was shaken up. The forest pathogenic bacteria were inoculated on a plate, repeated 3 times, cultured in an incubator at 25 ℃, and the bacteriostatic effect of the strain was observed (bacteriostatic ratio ═ control colony diameter-treated colony diameter)/control colony diameter × 100%).

The determination shows that the extracellular metabolite of the strain has obvious bacteriostatic effect on alternaria alternata, cladosporium esculentum and pestalotiopsis variabilis, wherein the bacteriostatic effect on alternaria solani of ginkgo biloba leaf blight is the maximum, and the bacteriostatic rate is 20.22% (table 3). The results of the plate confrontation of the strain JYZ-SD5 and pathogenic fungi of the forest to be tested show that the strain has obvious inhibition effects on the heterochromous pestalotiopsis, alternaria, tea leaf blight camellia tee fungus and alternaria tenuissima (FIG. 5).

TABLE 3 bacteriostasis rate of extracellular metabolite of rhizosphere bacterium JYZ-SD5 on pathogenic fungi of forest trees

EXAMPLE 5 cellulase and protease production assay by the rhizosphere bacterium JYZ-SD5

1) And (3) cellulase detection: inoculating the test strains in a cellulase detection culture medium by adopting a three-point inoculation method, repeating each treatment for 3 times, placing in an incubator at 28 ℃, and continuously observing the existence of a transparent ring around a bacterial colony.

2) And (3) protease detection: inoculating the test strains in a protease detection culture medium by adopting a three-point inoculation method, repeating each treatment for 3 times, placing in an incubator at 28 ℃, and continuously observing the existence of a transparent ring around a bacterial colony.

The strain JYZ-SD5 has obvious transparent rings on a protease detection culture medium and a cellulase detection culture medium (figure 6), which shows that the strain contains protease and cellulose hydrolase and has certain capabilities of hydrolyzing protein and decomposing cellulose.

Example 6 determination of heavy Metal tolerance of the rhizosphere bacterium JYZ-SD5

1) Preparing NA culture medium, and respectively adding KMnO₄、NiCl₂.6H₂O、K₂Cr₂O₇、CuSO₄.5H₂And O. Making Mn⁷⁺、Ni²⁺、Cr⁶⁺、Cu²⁺The concentration gradient is 5, 10, 15, 20, 30, 40, 50, 80, 100, 200, 300, 400mg/L (pure Mn⁷⁺、Ni²⁺、Cr⁶ ⁺、Cu²⁺Meter), control was pure medium. The strain is inoculated in the culture medium and placed in an incubator for 24h and then observed.

2) Determination of growth curves of the strain JYZ-SD5 under stress of different heavy metal concentrations: inoculating the strain JYZ-SD5 into liquid NB culture medium with different heavy metal concentrations, and measuring OD under different salt stresses every 2h by using a microorganism full-automatic growth curve analyzer (Bioscreen C, Finland)₆₀₀Value and time as abscissa, OD₆₀₀Values are plotted on the ordinate as growth curves for strain JYZ-SD 5.

The bacterium is in Mn⁷⁺、Cr⁶⁺Can grow under the existing test concentration, the tolerance concentration can reach 400mg/L at most, and Ni²⁺The concentration of 0-200mg/L can be better grown in Cu²⁺In the presence of this microorganism, the microorganism cannot grow. In Cr⁶⁺、Ni²⁺When the concentration is not more than 200mg/L, the bacterium has no obvious difference compared with the bacterium under the normal growth condition; in Mn⁷⁺In the presence of this strain, the time to reach stationary phase was significantly delayed, indicating that Mn is present⁷⁺The presence of Mn inhibits the rate of propagation of the bacterium, and when Mn is present⁷⁺When the concentration is 200-300mg/L, the bacterium grows better in the first 30h, and the bacterium amount is reduced suddenly after 30h, which shows that under the concentration of 200-300mg/L, the tolerance of the bacterium is weakened, and a large amount of bacteria can die in the later culture period. In combination, when the concentration of heavy metal is between 0 and 200mg/L, the tolerance of the strain to heavy metal stress is Ni²⁺>Cr⁶⁺>Mn⁷⁺>Cu²⁺(ii) a When the heavy metal concentration is higher than 200mg/L, only Mn can be added⁷⁺、Cr⁶⁺Slow growth in the presence (Table 4, figure)7)。

TABLE 4 growth conditions of the forest rhizosphere bacterium JYZ-SD5 strain after 24h under different heavy metal stresses

Note: "+" indicates the growth of strain JYZ-SD5 (+: normal, + +: good, + + + +: good); "-" indicates no growth.

Example 7 growth promotion of Metarhizium species by the rhizosphere bacterium JYZ-SD5 on Metarhizium anisopliae

Single colonies were picked with an inoculating loop and cultured in a 100mL Erlenmeyer flask containing 50mL NA liquid medium at 28 ℃ for 24h with shaking at 200 r/min. Obtaining bacterial fermentation liquor, diluting the fermentation liquor by 5 times, applying the diluted fermentation liquor to 2-year-old metasequoia potted seedlings, applying 50mL of diluted solution (the bacterial amount is 5 multiplied by 108cfu/mL) to each strain, and inoculating a control group with the NA culture medium after shaking culture for 24h in equal amount. After the application of the strains, the metasequoia seedlings are placed outdoors, and after 20 days and 40 days after the application of the strains, a hand-held chlorophyll meter (SPAD-502plus, Japan KONICA MINOLTA manufacturing company) is adopted to measure the relative chlorophyll content of the treated group and the control group and measure the height and the ground diameter of the seedlings.

After the bacterial treatment, the seedling height and the ground diameter of the metasequoia seedlings are obviously improved compared with those of a control group. After 20 days of fungus application, the height of the seedlings and the net increase of the ground diameter are both improved by about 200 percent; after the strain is applied for 40 days, the relative content of the chlorophyll of the yew is increased by 37.8 percent relative to the contrast, the net growth amounts of the height and the ground diameter of the seedling are respectively increased by 74 percent and 88 percent, and the strain application treatment and the contrast treatment have significant difference. The inoculation of the rhizosphere bacterium JYZ-SD5 strain is proved to have obvious promotion effect on the growth of the metasequoia (figure 8).

Claims

1. A forest rhizosphere bacterium is classified and named as Bacillus mycoides JYZ-SD5, and is preserved in China center for type culture Collection with the preservation number as follows: CCTCC NO: m2018469, deposit date: 7/13/2018, storage location: wuhan university in Wuhan, China.

2. The use of Bacillus mycoides JYZ-SD5 as claimed in claim 1 in nitrogen fixation, organophosphorus decomposition and potassium decomposition.

3. The use of Bacillus mycoides JYZ-SD5 of claim 1 for the production of indole-3-acetic acid.

4. Use of bacillus mycoides JYZ-SD5 according to claim 1 for promoting plant growth.

5. The use of claim 4, wherein said plant is Metasequoia glyptostroboides.

6. The use of Bacillus mycoides JYZ-SD5 of claim 1 in heavy metal tolerance, wherein the heavy metal ion is Ni²⁺、Cr⁶⁺、Mn⁷⁺。

7. The use of Bacillus mycoides JYZ-SD5 of claim 1 in treating heavy metal pollution, wherein the heavy metal ion is Ni²⁺、Cr⁶⁺、Mn⁷⁺。

8. The use of Bacillus mycoides JYZ-SD5 of claim 1 in the production of cellulase and protease.

9. The use of bacillus mycoides JYZ-SD5 of claim 1 for bacteriostasis.