712 results about "Mutant strain" patented technology

The present invention discloses a mutant strain of Streptomyces parvum and its application in producing glutathione, belonging to the field of genetic engineering. The present invention successfully constructs a mutant strain of Streptomyces parvum by overexpressing the glnA gene in Streptomyces parvum; wherein the nucleotide sequence of the glnA gene is shown in SEQ ID NO: 1. Experiments have shown that compared with the wild-type Streptomyces parvum, the mutant strain of Streptomyces parvum can significantly increase the content of glutathione and glucose in the fermentation product, and can also improve the utilization efficiency of ammonia nitrogen during the fermentation process. The present invention provides new strain resources and methods for mass production of bacterial-derived glutathione, and provides new agricultural antibiotic resources and strategies for preventing and controlling a variety of plant diseases.

The invention discloses a paenibacillus kribbensis spaceflight mutant strain and application of the paenibacillus kribbensis spaceflight mutant strain in preparation of nano-selenium. According to the invention, a paenibacillus kribbensis PS04-2 strain is obtained through space mutation, and the strain has high selenite reducing capacity and can tolerate high-concentration selenite, and the tolerable concentration exceeds 1000mM; the method has the capacity of efficiently converting sodium selenite to generate nano-selenium, the synthesized nano-selenium is high in conversion rate and uniform in nano-selenium particle, and the provided preparation method is simple, convenient, low in cost, high in product purity and environmentally friendly. The nano-selenium synthesized by the PS04-2 strain has a good antagonistic effect on various plant pathogenic fungi, can prevent and treat various plant diseases, and can be used for developing more selenium-enriched microbial preparations. Meanwhile, nano-selenium synthesized by the PS04-2 strain is used for sesame production, so that sesame growth can be promoted, selenium-rich sesame can be obtained, and more effective methods are provided for increasing the selenium content of crops.

The invention provides a microbial source anti-oxidation pigment feed additive for aquaculture and a preparation method of the microbial source anti-oxidation pigment feed additive, the microbial source anti-oxidation pigment feed additive for aquaculture is prepared by the following steps: carrying out low-temperature plasma physical mutagenesis on talaromyces albuminosus CY-G to generate a mutant strain, namely talaromyces albuminosus CY110, and then carrying out semi-solid state fermentation on the mutant strain, namely talaromyces albuminosus CY110 to produce wine red pigment. The pigment product obtained by the invention is high in yield of haematochrome, orange pigment and yellow pigment, low in citrinin content, stable in property and relatively strong in oxidation resistance, can be used as an aquaculture microorganism source anti-oxidation pigment feed additive, and has a wide application prospect. The preparation method disclosed by the invention is simple to operate, low in equipment requirement, high in production efficiency and suitable for large-scale production.

The invention discloses a corn kernel size regulation gene X1 as well as an SNP (Single Nucleotide Polymorphism) marker and application thereof. The invention discovers that the X1 gene has the function of regulating and controlling the grain shape and the grain weight for the first time. The invention provides a novel SNP (Single Nucleotide Polymorphism) marker related to the corn grain size, the SNP marker has two alleles AA and GG, and the allele AA is clear to be regarded as an excellent / synergistic allele. The X1 gene provided by the invention can lead to increase of grain types such as the length of a corn grain of a mutant strain compared with that of a control grain; the length and other grain types of the X1 gene overexpression strain are reduced compared with those of the control grain. Precious gene resources are provided for corn breeding, and the application prospect is wide.

The invention discloses propionibacterium capable of obtaining high-yield propionic acid through compound mutation screening and a method for fermenting propionic acid by using the propionibacterium. The high-yield propionic acid strain YCBS010 (CGMCC No.31160) is obtained by carrying out compound mutagenesis on acid-producing propionibacterium CGMCC 1.2232 serving as an original strain through microwave-ultrasonic combined mutagenesis and compound normal-pressure and room-temperature plasma (ARTP) mutagenesis means. According to the invention, YPA15 is used as a starting strain, microwave and ultrasonic combined mutagenesis is carried out for 100 seconds to screen a bacterial strain with increased propionic acid yield, then ARTP mutagenesis is carried out for 90 seconds to screen out a high-yield mutant strain YCBS010, fermentation in a 1-ton tank verifies that the highest propionic acid yield reaches 65.87 g / L and the fermentation intensity is 0.73 g / L.h after fermentation is carried out for 90 hours, and the bacterial strain has better industrial fermentation potential.

The invention discloses an EMS-ARTP compound mutation chlorella pyrenoidosa mutant strain and an application thereof. The preparation method comprises the following steps: mutagenizing a chlorella pyrenoidosa mutant strain CX41 by adopting an ethyl methanesulfonate (EMS) and normal-pressure and room-temperature plasma (ARTP) composite technology, screening and verifying to obtain a golden yellow chlorella pyrenoidosa mutant strain, naming the golden yellow chlorella pyrenoidosa mutant strain as chlorella pyrenoidosa Y11, and screening and verifying the golden yellow chlorella pyrenoidosa Y11 to obtain the chlorella pyrenoidosa Y11. The strain is preserved in Guangdong Microbial Culture Collection Center (GDMCC) on the fifth floor of the building 59, No. 100 courtyard, Xianlie Middle Road, Guangzhou on October 23, 2024, and the preservation number is GDMCC No: 65324. The chlorella pyrenoidosa mutant strain Y11 has the characteristics of high yield of protein and rich carotenoids, and can be used for fermentation production of microalgae protein and carotenoids.

The invention discloses a chlorella pyrenoidosa white mutant strain FZU65-W1 and application of the chlorella pyrenoidosa white mutant The classification name of the chlorella pyrenoidosa white mutant strain FZU65-W1 is chlorella pyrenoidosa, the chlorella pyrenoidosa white mutant strain is preserved in the China General Microbiological Culture Collection Center on September 11, 2024, the preservation number is CGMCC N0.46151, and the preservation address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing. Compared with an original strain FZU65, the chlorella pyrenoidosa white mutant strain FZU65-W1 has the advantages that the growth speed of algae cells under the heterotrophic condition is higher, and meanwhile, the cells are white due to the fact that chlorophyll and carotenoid are not synthesized in the cells. The chlorella pyrenoidosa white mutant strain FZU65-W1 can be used for producing high-quality protein through heterotrophic fermentation, so that not only can a later-stage protein extraction and preparation process be simplified, but also the sensory acceptance of algae powder can be improved, and a high-quality germplasm resource is provided for industrial production and application of microalgae protein.

The invention belongs to the field of enzyme engineering, and relates to a glycosyl transferase mutant and application thereof in synthesis of salidroside. On the basis of a glycosyl transferase amino acid sequence as shown in SEQ ID NO: 1, iterative saturated mutation is carried out through a molecular modification technology, and the enzymatic activity and catalytic efficiency of the modified glycosyl transferase mutant are greatly improved. The mutation at a specific site can significantly promote the glycosylation activity of a tyrosol substrate. The mutant enzyme is obtained by carrying out induced expression and protein purification on the obtained mutant strain. The substrate conversion rate of the transformed glycosyl transferase mutant for catalyzing the tyrosol glycosylation reaction can reach 95% or above, the yield reaches 55.0 g / L, and an efficient and green new way is provided for salidroside production.

The invention belongs to the technical field of plant genetic engineering, and particularly relates to an elongation factor subunit OsRAV9 gene for regulating and controlling resistance of rice to rice blast and application of the elongation factor subunit OsRAV9 gene. The elongation factor subunit OsRAV9 gene induced to express by magnaporthe oryzae is screened, and the nucleotide sequence of the elongation factor subunit OsRAV9 gene is as shown in SEQ ID NO: 1; the sequence of the protein coded by the gene is as shown in SEQ ID NO: 2. By means of agrobacterium tumefaciens-mediated transformation, an OsRAV9 over-expression transgenic strain and a CRISPR / Cas9 mutant strain are obtained. The rice blast inoculation identification on the transgenic material finds that the resistance of the OsRAV9 over-expression strain to the rice blast is enhanced, and the mutant strain is more susceptible to the rice blast bacteria, which indicates that the OsRAV9 is a positive regulation factor of the rice to the rice blast resistance. The OsRAV9 gene plays a positive regulation role in the rice blast resistance, and the resistance of rice to the rice blast can be remarkably improved by over-expression of the gene.

The invention discloses an Escherichia coli mutant strain which is classified and named as Escherichia coli, the strain number is CR-TK01, and the preservation number is CGMCC (China General Microbiological Culture Collection Center) No.35554. The invention further discloses a preparation method of the Escherichia coli mutant strain. The Escherichia coli CR-TK01 with high yield of cytidine provided by the invention has the characteristics of high yield and stable high-yield character, glucose is used as a carbon source, the Escherichia coli CR-TK01 is used for fermentation production of cytidine under a certain fermentation condition, and the yield of cytidine is as high as 97.23 g / L; the strain is not degraded after passage for more than 20 generations, the performance of high-yield cytidine is maintained in the passage fermentation process, and the yield of cytidine in passage fermentation is improved. The method for producing cytidine through fermentation is simple in process, high in yield and suitable for industrialization.

The invention belongs to the technical field of microorganism mutation breeding, and particularly relates to a nisin high-yield mutant strain with enhanced production performance. The mutant strain is specifically lactococcus lactis 2686, and the preservation number of the mutant strain is CCTCC (China Center for Type Culture Collection) NO: M 2023219. The strain has relatively high osmotic pressure tolerance, can still normally grow and produce nisin when the osmotic pressure is higher than 0.66 osM / kg H2O, meanwhile, the strain has excellent nisin production capacity, the titer reaches 9834 IU / mL when the strain is fermented in a shake flask for 21 hours, and the titer reaches 21000 IU / mL when the strain is fermented in a fermentation tank for 22 hours. The method is high in yield, good in stability, low in production cost and suitable for further industrial application.

According to the haematococcus pluvialis strain and the application thereof, cell wall breaking operation can be carried out more easily when astaxanthin is extracted, astaxanthin can be extracted more effectively, and the cost of natural astaxanthin is reduced. The haematococcus pluvialis RMC16 strain provided by the invention has the preservation number of CCTCC (China Center for Type Culture Collection) NO: M 20241404. The haematococcus pluvialis mutant strain obtained by screening has the characteristics of thin wall, no secondary cell wall, high astaxanthin content and the like, the haematococcus pluvialis mutant strain is high in growth speed and can quickly reach a plateau phase, the individual proportion of parental cells in a population bred by the haematococcus pluvialis mutant strain serving as a parent is higher, the cost required by extraction of natural astaxanthin can be remarkably reduced, and the haematococcus pluvialis mutant strain is suitable for industrial production. The method is suitable for large-scale popularization.

The invention belongs to the technical field of food microorganisms, and particularly discloses a ganoderma lucidum mutant strain capable of producing polysaccharides and triterpenoids at high yield. The strain is named as Ganoderma lucidum in Latin, the preservation number is CGMCC NO: 41680, the preservation unit is China General Microbiological Culture Collection Center, and the preservation date is December 4, 2024. The strain is named as Ganoderma lucidum, the preservation number is CGMCC NO: 41680, and the preservation number is CGMCC NO: 41680. The polysaccharide content in the ganoderma lucidum spore powder produced by the ganoderma lucidum mutant strain is more than or equal to 8%, and the total triterpenoid content is more than or equal to 12%; a culture medium formula of the ganoderma lucidum mutant strain comprises potato leachate, glucose and monopotassium phosphate, the culture temperature is 25-28 DEG C, and the pH value is 5.5-6.5. The ganoderma lucidum mutant strain is high in genetic stability, the content of active ingredients is remarkably higher than that of parent strains, and the ganoderma lucidum mutant strain is suitable for large-scale fermentation production.

The invention discloses an E3 ubiquitin ligase gene ulA, the nucleotide sequence of which is shown as SEQ ID NO: 1. The gene is knocked out from fusarium oxysporum by using a homologous recombination method to obtain a mutant strain ulA; compared with a wild strain, the mutant hulA has the advantages that the spore yield is reduced, the spore germination is delayed, the response capability to various abiotic stresses is reduced, the pathogenicity to panax notoginseng plants is reduced, and the sensitivity to six bactericides is increased, and experimental results show that the gene plays an important role in pathogenicity, drug resistance and the like of fusarium oxysporum. The gene can be used as a target gene for developing an anti-fusarium oxysporum preparation.

The invention relates to the technical field of gene engineering, in particular to an L-rhamnose isomerase mutant, a recombinant plasmid, a mutant strain and application. The amino acid sequence of the mutant is as shown in SEQ ID NO.4, and the nucleotide sequence of the coding gene is as shown in SEQ ID NO.3. A specific mutant gene sequence is designed, a recombinant plasmid pET28a (+)-L-Rhi is successfully constructed, the gene sequence is connected between enzyme cutting sites BamH I and Hind III of an escherichia coli expression vector pET-28a (+) to construct a mutant expression vector (the recombinant plasmid pET-28a (+)-L-Rhi), the mutant expression vector is transformed into an escherichia coli BL21 competent cell, a mutant strain is obtained, and the recombinant plasmid pET-28a (+)-L-Rhi is obtained. The obtained mutant strain can overexpress L-rhamnose isomerase, the conversion rate of D-allose is remarkably improved, the thermal stability of the enzyme is remarkably improved through the design of mutation sites, and the half-life period is effectively prolonged.

The invention relates to a Kluyveromyces marxianus strain with high protein yield and application of the Kluyveromyces marxianus strain, which is characterized in that the Kluyveromyces marxianus strain is firstly cultured on a slant, then is transferred into a seed culture medium for seed preparation, and then is inoculated into a fermentation tank, and yeast protein is obtained by adopting index feeding; the bacterial strain is a dominant mutant strain Kluyveromyces marxianus YWX-1, the protein content in a dry thallus reaches 55% or above and is increased by 26% or above compared with that of an original bacterial strain, the bacterial strain can be used for production of single-cell protein, the essential amino acid index (EAAI) value in the protein reaches 1.2, and the bacterial strain is rich in arginine, threonine and lysine and can be applied to production of single-cell protein. These amino acids play a key role in immune regulation, intestinal mucosal barrier function and muscle protein synthesis of young animals. The YWX-1 kluyveromyces marxianus strain has a wide application prospect in the production of neoplasm protein.

The invention discloses a method for improving the synthesis level of L-tryptophan in escherichia coli based on ARTP mutagenesis high-throughput screening, and belongs to the technical field of bioengineering. According to the invention, the L-tryptophan biosensor pSensor-trp3 is constructed, and the L-tryptophan biosensor pSensor-trp3 is good in response under the condition that the exogenous addition concentration range of L-tryptophan is 0-300mg. L <-1 >. High-throughput screening is performed by using a flow cytometry, a dominant mutant strain YB-2 is obtained through iterative mutagenesis, and the shake flask L-tryptophan yield and the sugar-acid conversion rate of the dominant mutant strain YB-2 are 5.68 g.L <-1 > and 0.103 g.g <-1 > respectively and are increased by 11.4% and 10.7%. Through second-generation whole genome re-sequencing comparative analysis, it is speculated that the genes ynfB and waaO possibly have a promoting effect on synthesis of L-tryptophan. The L-tryptophan biosensor used in the invention also provides reference for high-throughput screening and transformation of other related L-tryptophan production strains.

The invention relates to the technical field of gene engineering, in particular to an L-rhamnose isomerase mutant, a recombinant plasmid, a mutant strain and application. The amino acid sequence of the mutant is as shown in SEQ ID NO. 2, and the nucleotide sequence of the coding gene is as shown in SEQ ID NO. 1. A specific mutant gene sequence is designed, a recombinant plasmid pET28a (+)-L-Rhi is successfully constructed, the gene sequence is connected between enzyme cutting sites BamH I and Hind III of an escherichia coli expression vector pET-28a (+) to construct a mutant expression vector (the recombinant plasmid pET-28a (+)-L-Rhi), the mutant expression vector is transformed into an escherichia coli BL21 competent cell, a mutant strain is obtained, and the recombinant plasmid pET-28a (+)-L-Rhi is obtained. The obtained mutant strain can overexpress L-rhamnose isomerase, the conversion rate of D-allose is remarkably improved, the thermal stability of the enzyme is remarkably improved through the design of mutation sites, and the half-life period is effectively prolonged.

The invention relates to rhodosporidium toruloides with high grease yield and application of the rhodosporidium toruloides. The rhodosporidium toruloides mutant strain with high grease content and high grease yield is obtained through a compound mutation method. According to the invention, a wild rhodosporidium toruloides strain RT is taken as a starting strain, a method of combining normal-pressure and room-temperature plasma mutagenesis with genome rearrangement is adopted, a stable genetic mutant strain RT-55 with the oil content and the yield obviously improved is obtained through oil content screening, and under the condition of a nitrogen-limited culture medium, the oil content of the mutant strain reaches 70.1% and is improved by 14.2%, and the yield of the mutant strain is greatly improved. The biomass is 4.11 g / L and is reduced by 0.8%, and the grease yield reaches 2.832 g / L and is improved by 10.9%. The rhodosporidium toruloides mutant strain provided by the invention can be used as a substitute of a grease raw material and is applied to the fields of aquatic feed additives and the like.

An epigenetic regulatory factor ZmULT1 related to corn grain size regulation and heat stress response and the use thereof, which solve the technical problems of how to increase the grain size and / or heat resistance and / or lodging resistance of corn. Use of a substance for reducing the content of the protein ZmULT1 or a substance for inhibiting the expression of the encoding gene of the protein ZmULT1, which use is any one of the following: P1, the use in increasing the grain size of corn; P2, the use in improving the heat resistance of corn; P3, the use in increasing the lodging resistance of corn; and P4, the use in plant breeding. The homozygous mutant strain with knockout of the ZmULT1 gene has a reduced plant height and an increased grain size, and exhibits significant heat stress resistance, this indicates that the research on the gene can further enrich the use of epigenetics in crops and is of important significance for improving the grain size, heat resistance and lodging resistance of corn.

The invention discloses a tryptophan response type promoter as well as a construction method and application thereof. A tryptophan specific biosensor is created by constructing a tryptophan response type hybrid promoter, and a tryptophan high-throughput screening platform is established in combination with a flow cytometry sorting technology. And the mutant strain TrpES94N beneficial for improving the yield of the L-tryptophan is successfully screened from a random mutation library of the key enzyme TrpE for synthesizing the L-tryptophan. The strain is over-expressed in an engineering strain TRP30, and after the strain is cultured in a 5L fermentation tank for 48h, it is determined that the yield of L-tryptophan is increased to 50.8 g / L and is increased by 19.53% compared with the yield of L-tryptophan of a control strain.

The invention discloses a method for obtaining and culturing ED pathway regulated and controlled engineering bacteria for fermentation production of vitamin B12, a mutant strain is based on ensifer adhesion, an ED pathway key gene edd gene in the ensifer adhesion of a vitamin B12 production strain is overexpressed by a homologous recombination single exchange method, an edd gene overexpressed mutant strain is constructed, and the edd gene overexpressed mutant strain is used for producing the vitamin B12. The purpose of disturbing the ED pathway to realize the metabolic migration of central carbon is achieved, and the method is applied to the production of vitamin B12. A shake flask fermentation experiment proves that overexpression of the edd gene can remarkably promote synthesis of a VB12 product, and the edd gene has good commercial and scientific research values.

The invention provides a phaffia rhodozyma mutant strain for high yield of astaxanthin as well as a screening method and application of the phaffia rhodozyma mutant strain, belongs to the technical field of fermentation microorganism screening, and can solve the problems of low astaxanthin yield, high cost and low growth temperature of wild type phaffia rhodozyma existing in synthesis of astaxanthin from a phaffia rhodozyma strain. The invention provides a phaffia rhodozyma mutant strain capable of producing astaxanthin at high yield, the phaffia rhodozyma mutant strain is a phaffia rhodozyma AA0529 mutant strain, the phaffia rhodozyma AA0529 mutant strain is preserved in China Center for Type Culture Collection in Wuhan, Hubei on September 7, 2023, and the preservation number is CCTCC (China Center for Type Culture Collection) NO: M20231637. According to the method, the yield of the astaxanthin can be increased, and the yield of the astaxanthin is increased to 3.3 mg / g at 26 DEG C.

The invention is suitable for the technical field of molecular biology, and provides a rice transcription factor OsGATA16 and application thereof in regulation and control of rice blast resistance of rice. The method comprises the following steps: firstly, cloning a rice OsGATA16 gene, then constructing an overexpression vector and a mutant vector, and transforming rice to obtain a corresponding strain. Research finds that after a mutant strain with OsGATA16 knocked out is inoculated with germs, the number of scabs is obviously smaller than that of a wild type control group, the disease resistance of rice can be accurately regulated and controlled, and the rice blast resistance is obviously improved. The regulation and control mode can effectively reduce pesticide use and reduce environmental pollution and residual risk. Meanwhile, the successfully constructed stable genetic regulation material can be stored for a long time and used for multiple times in molecular and phenotype levels through verification. Besides, the OsGATA16 gene can be used as a disease-resistant molecular marker or a functional gene to be applied to various breeding systems, a new target is provided for breeding new rice materials with high rice blast resistance, and the OsGATA16 gene has a wide practical application prospect.

The invention discloses a primer probe combination for identifying a group A streptococcus M1UK strain and application of the primer probe combination, and belongs to the technical field of streptococcus mutant strain detection. The primer probe combination provided by the invention can specifically amplify the target gene of the M1UK strain. Furthermore, a method for identifying the M1UK strain is designed according to the primer probe combination, the M1UK strain and other group A streptococcus can be effectively distinguished, and besides the advantages of being high in specificity and accurate in detection result, the method is easy, convenient and rapid to operate and high in detection efficiency, labor cost and time cost are reduced, and the method is suitable for popularization and application. The method can realize rapid and effective non-sequencing-dependent variant strain detection, and has important significance in disease prevention and control and improvement of disease treatment efficiency.

The invention discloses an application of an SCAB82331 gene or a protein coded by the SCAB82331 gene in regulation and control of synthesis of thaxtominA, and belongs to the technical field of gene engineering. According to the application disclosed by the invention, the SCAB82331 gene in the streptomyces scabies is deleted through a genetic engineering way, so that the high-yield strain of the thaxtominA is obtained, and the yield of the thaxtominA in the streptomyces scabies is increased. When the SCAB82331 gene is deleted in the streptomyces scabies, the yield of the thaxtominA is obviously increased by 66.2%; after the SCAB82331 gene is supplemented in the delta SCAB82331 mutant strain, the yield of the thaxtominA is recovered, and the yield of the thaxtominA is recovered; the deletion of the SCAB82331 gene can be used for directionally improving the biosynthesis yield of the thaxtominA in streptomyces scabies.

The invention relates to the technical field of plant genetic engineering, in particular to application of a rice OsERF141 protein and a coding gene thereof in improving low-temperature tolerance of plants. Experiments show that the low-temperature resistance of an OsERF141 function deletion mutant strain is remarkably reduced, and the low-temperature resistance of an overexpressed OsERF141 transgenic strain is remarkably improved. The invention provides a new gene resource for the cold resistance problem of rice, and has important significance for the molecular mechanism research of low-temperature stress and the cultivation of new low-temperature-resistant varieties.

The invention discloses a broad-spectrum novel coronavirus-resistant double-target polypeptide and application thereof, and relates to the field of biological medicines. The polypeptide drug provided by the invention can more effectively and synergistically inhibit the infection process of the virus by simultaneously acting on two key targets of RBD and HR1 of the virus. On one hand, through targeting RBD, combination of viruses and host cells can be blocked, so that the phenomenon that the viruses are adsorbed on the surfaces of the host cells is blocked, and the adsorption process of the viruses is restrained; on the other hand, by targeting HR1, formation of virus 6-HB can be interfered, and the fusion process of a virus envelope and a host envelope is further inhibited. The polypeptide capable of simultaneously targeting the double targets RBD and HR1 of the novel coronavirus, particularly R1L25HR2, provided by the invention, can effectively inhibit SARS-CoV-2 and a mutant strain thereof, and has broad-spectrum activity for resisting the novel coronavirus.

The invention discloses application of protein TaTDM and related biological materials thereof, and belongs to the field of plant breeding. The amino acid sequence of the protein TaTDM is as shown in SEQ ID NO: 2 or SEQ ID NO: 4 or SEQ ID NO: 6. The TaTDM gene knockout homozygous mutant strains tatdmm1 and tatdmm2 are obtained by carrying out gene knockout on wild type wheat Fielder, and it is found that at the temperature of 25 DEG C, the total floret number of each spike of the Fielder, the tatdmm1 and the tatdmm2 and the survival rate under the water shortage treatment condition are remarkably higher than those of the wild type wheat Fielder. The protein TaTDM has an important application value in regulation and control of wheat ear type characters and stress tolerance, provides a high-quality germplasm resource, and is of great significance in cultivation of drought-enduring plant varieties and improvement of crop yield.

The invention discloses construction and application of a streptococcus suis serotype 2 cps2C gene knockout mutant strain. The invention relates to a streptococcus suis serotype 2 cps2C gene knockout mutant strain 05ZYH33 delta cps2C. A coding gene, from the 31st site to the 1000th site, of the cps2C gene in the strain 05ZYH33 is replaced by a spectinomycin resistance gene cassette SpcR. The mutant strain 05ZYH33 delta cps2C is applied to preparation of a streptococcus suis type 2 attenuated vaccine and a subunit vaccine. The capsule of the mutant strain 05ZYH33 delta cps2C is obviously reduced; in-vitro experiments show that the macrophage phagocytosis resistance of the mutant strain 05ZYH33 delta cps2C is reduced, and animal toxicity test results show that the toxicity of the mutant strain is obviously reduced. The mutant strain provides an important clue for screening of protective antigens of multivalent subunit vaccines, and can be applied to development of S.suis attenuated vaccines and multivalent subunit vaccines.