594 results about "Mutagenesis" patented technology

A wheat variety designated 6PQAN73B, the plants and seeds of wheat variety 6PQAN73B, methods for producing a wheat plant produced by crossing the variety 6PQAN73B with another wheat plant, and hybrid wheat seeds and plants produced by crossing the variety 6PQAN73B with another wheat line or plant, and the creation of variants by backcrossing, mutagenesis or transformation of variety 6PQAN73B are disclosed. Methods for producing other wheat varieties or breeding lines derived from wheat variety 6PQAN73B and to wheat varieties or breeding lines produced by those methods are also provided.

The present disclosure provides compositions and methods for the targeted modification of RNA molecules by RNA prime editing. The compositions and methods may be conducted invitro or in vivo within cells (e.g., human cells) for the therapeutic correction of disease-causing mutations and / or installation of motifs or mutations in RNA molecules of interest as a tool for scientific research. The disclosure provides compositions and methods for conducting RNA prime editing of a target RNA molecule (e.g., an RNA transcript) that enables the incorporation of one or more nucleotide changes and / or targeted mutagenesis of a target RNA molecule. The nucleotide change can include a single-nucleotide change, an insertion of one or more nucleotides, or a deletion of one or more nucleotides. More in particular, the disclosure provides a variety of configurations of the RNA prime editors each comprising a nucleic acid programmable RNA binding proteins (napRNAbp), such as Cas13, and an RNA-dependent RNA polymerase (RDRP), which are provided as fusion proteins or which can be separately provided in trans. The RNA prime editors are guided to a target RNA site by a guide RNA, which can be a rpegRNA that includes a template region for the synthesis of an RNA sequence to be installed on the RNA molecule attached to an available 3′ terminus. In others embodiments, the RNA template can be provided in trans.

The invention relates to bacillus pumilus and application thereof. The bacillus pumilus DX-fK is obtained through a chemical mutagenesis method, the bacillus pumilus DX-fK can efficiently degrade straw, the bacillus pumilus DX-fK is used as a substrate to produce feed alternative protein, and therefore the bacillus pumilus DX-fK can be applied industrially and has good industrialization prospects.

The invention belongs to the technical field of in-vitro cultivation of calculus bovis, and particularly relates to a method for in-vitro cultivation of calculus bovis. According to the invention, firstly, the escherichia coli is subjected to bile domestication and ray induced mutation, a high-activity oxgall-resistant bezoar production engineering bacterium E.coli-NH01 is obtained through screening, a method for in-vitro cultivation of bezoar by using the engineering bacterium E.coli-NH01 is provided, the prepared bezoar meets the pharmacopoeia standard, the production efficiency of in-vitro cultivation of bezoar is improved, and the production cost is reduced. And the production cost is reduced, the overall forming period is shortened, and the key that precious traditional Chinese medicinal materials are popular can be achieved.

The present invention belongs to the field of biotechnology, and specifically relates to a GmSGT2 gene related to plant height and branch development, and a mutant thereof and the use thereof. A Glycine max mutant having fewer branches and decreased plant height is obtained by means of EMS mutagenesis, and a target gene thereof that is located by means of a map-based cloning technique is a GmSGT2 gene of Hedou 12. It is found through searching that the gene encodes soyasapogenol B glucuronide galactosyltransferase, and can galactosylate soyasapogenol B monoglucuronide, thereby affecting the plant height of Glycine max and reducing the branches of Glycine max. Therefore, the GmSGT2 mutant can be used for cultivating dwarf high-yield Glycine max varieties, and is of great significance in the breeding of ideal plant types of Glycine max and research on important agronomic traits of plants. The mutant has broad application prospects and great research value with regard to understanding the plant height and branch regulation mechanism of Glycine max and improving the process of Glycine max breeding; and can provide an excellent germplasm resource stock for regulating the close planting and high-yield breeding of Glycine max.

The present invention belongs to the technical field of biological prevention and treatment for viral diseases. Disclosed in the present invention are a tomato disease-resistant gene mutant, and the use thereof in the prevention and treatment of ToBRFV. It is found in the present invention that mutating the nucleotide at position 1927 of the coding region sequence of tomato Tm-22 gene from G to A, or mutating the amino acid at position 643 of the LRR domain of a protein that is encoded by tomato Tm-22 gene from glycine to arginine can remarkably reduce the accumulation level of ToBRFV capsid protein (CP). The gene (named Tm-22-Mut5) can serve as a novel ToBRFV resistant gene, and also retains the resistance to TMV, ToMV and ToMMV. The Tm-22-Mut5 and a pre-screened Tm-22-Mut3-1 mutant (tyrosine at position 767 of the LRR domain thereof is mutated to phenylalanine) undergo combinatorial mutagenesis to obtain a mutant Tm-22-Mut6. Analysis shows that the Tm-22-Mut6 can remarkably reduce the accumulation level of the ToBRFV capsid protein. Compared with the pFGCTm-22-Mut3-1 mutant obtained by screening in the previous research and the newly obtained mutant Tm-22-Mut5, the Tm-22-Mut6 has further improved resistance to ToBRFV.

The invention discloses a yellow flammulina velutipes ZJJZG002 and InDel marker with high resistance and high brittleness and application of the yellow flammulina velutipes ZJJZG002 and InDel marker, and relates to the technical field of edible mushroom cultivation, the preservation number of the yellow flammulina velutipes is CGMCC NO.41174, and the yellow flammulina velutipes is classified and named as flammulina velutipes. The strain ZJJZG002 takes yellow flammulina velutipes F24 and white flammulina velutipes W1 as parents, the parent materials are subjected to ultraviolet mutagenesis treatment and then are subjected to single spore isolation, hybridization (a hybrid combination XB51 * YU19) and fruiting tests, and the strain ZJJZG002 is not prone to umbrella opening, rich in mushroom fragrance, crisp and refreshing in taste, neat in fruiting, suitable for production in various cultivation modes and capable of injecting a new seed source for the domestic flammulina velutipes market.

The invention provides a pichia pastoris strain for efficiently converting methanol to produce high-methionine-content single-cell protein and application of the pichia pastoris strain, and belongs to the technical field of biology. According to the invention, a strain of pichia pastoris (named as Pichiapastoris CN-SCP 00 with a preservation number of CCTCC (China Center For Type Culture Collection) NO: M2025657) is obtained through separation, and is subjected to multiple rounds of ARTP iterative mutation breeding, so that a strain Pichiapastoris CN-SCPYE421 (with a preservation number of CCTCC NO: M2025658) for efficiently converting methanol to produce single-cell protein containing high methionine is obtained. Compared with a commercial strain, the Pichiapastoris CN-SCPYE421 has higher methanol tolerance and utilization capacity, the fermentation time is remarkably shortened, and in addition, the Pichiapastoris CN-SCPYE421 can well grow at the temperature of 35 DEG C. The Pichiapastoris CN-SCPYE421 is subjected to fermentation culture in a 5L fermentation tank, the dry weight of thalli reaches 120-150g / L, the protein content reaches 65-75% of the dry weight of the thalli, the Pichiapastoris CN-SCPYE421 is rich in various essential amino acids, and the methionine content reaches 2.3%. The invention provides an excellent strain for industrial development of single-cell protein, and has great social significance and economic value for the feed protein industry.

The invention relates to the field of hybrid rice breeding, and discloses a method for directionally breeding mutant hybrid rice parents. According to the method, mutation tillering is accurately positioned in the M1 tillering stage through the KASP technology, and a directional pollination / harvesting strategy is combined, so that the genetic bottleneck caused by chimeras and low fertility (especially sterile lines) is effectively overcome, the mutation transmission efficiency is maximized, and the M1 generation mutation transmission efficiency is remarkably improved. Through early accurate identification and efficient propagation of the M1 generation, homozygotes can be obtained and screened from the M2 generation, and compared with a traditional process, the method has the advantages that the obtaining process of low-cadmium homozygous parents is obviously accelerated, and the breeding period is greatly shortened. Heavy ion mutagenesis, targeted sequencing, high-throughput KASP typing and directional propagation technologies are integrated, and the whole process from mutagenesis to obtaining of the homozygous low-cadmium parent is rapid, accurate and efficient.

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 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.

The present disclosure relates to Taq DNA Polymerase mutants comprising at least three mutations which are capable of high levels of DNA amplification in the presence of several PCR inhibitors and compositions comprising the same. Also disclosed are methods of performing mutagenesis on wild-type Taq DNA polymerase to obtain the disclosed Taq DNA polymerase mutants, DNA amplification using the same, and cDNA amplification using the same.

The invention discloses a method for creating new dwarf tomato germplasm by EMS mutagenesis, which comprises the following steps: selecting new dwarf tomato seeds with full grains and no damage, soaking in 84 disinfectant fluid with the ratio of 1: 1, and washing with tap water for 5 times; the dwarf tomato seeds in the step (S1) are soaked in an EMS-phosphoric acid buffer solution with the concentration being 0.4%-2% and subjected to vibration treatment in a dark place for 6-36 h; detoxicating the mutagenized seeds in the step (S2), pouring out an EMS solution, washing twice with an antidote, and washing with tap water for 2 hours; (S3) accelerating germination of the detoxified seeds in the step (S3), accelerating germination in a dark incubator, picking out the germinated seeds for planting, and observing and counting mutagenesis effects; and (S4) sowing the seeds collected in the step (S4) in the whole growth period. The EMS mutagenesis is high in point mutation frequency and relatively less in chromosome distortion, and the method has the advantages that the operation is simple and convenient, the breeding period is short, and new genes and new characters which are difficult to generate by a traditional breeding method can be generated.

The invention belongs to the technical field of biology, and particularly discloses a tryptophan production strain and application thereof. The L-tryptophan high-yield strain T29 is developed and obtained through methods of combining gene modification with mutagenesis screening and the like. The strain T29 is fermented in a 5L tank, the highest yield of L-tryptophan can reach 60.7 g / L, and the conversion rate reaches 18.6%. Therefore, the strain provided by the invention has important industrial application value for industrial production of L-tryptophan and development of an L-tryptophan production strain with higher fermentation performance.

The invention discloses a method for screening high-yield recombinant human lactoferrin through nucleic acid aptamer-assisted mutagenesis of a trichoderma reesei strain and application, and belongs to the technical field of microorganisms. The nucleic acid aptamer Lac-6a-FAM-BHQ1 capable of changing the fluorescence intensity according to the content of lactoferrin is constructed on the basis of the aptamer Lac-6a, and the nucleic acid aptamer can be used for rapidly selecting a mutant strain for producing high-titer recombinant human lactoferrin. The ARTP mutagenesis technology is combined with a nucleic acid aptamer auxiliary screening system, the mutant strain with the improved recombinant human lactoferrin yield is rapidly obtained from a large number of mutant strains, and the yield reaches 274.57 mg / L and is improved by 24.8% compared with that of an original strain. After the genes 111681 and 62716 are over-expressed in T. reesei, compared with a control strain, the yields of the recombinant human lactoferrin of the recombinant strain are respectively increased by 6.9% and 22.1%.

In traditional plant breeding approaches, chemical mutagenesis may be utilized to introduce nucleotide substitutions at random in the genome of a plant, i.e. without possibilities to control the sites of nucleotide changes. Because of genome complexities, the statistical probability is extremely little when it comes to finding a predetermined nucleotide substitution. The present invention, however, demonstrates how a novel, alternative use of digital polymerase chain reaction (dPCR), preferably droplet dPCR (ddPCR), is developed to exploit finding of specific nucleotide substitutions in mutated genes. The entire platform comprises a screening method with a library of mutagenized organisms, digital PCR-based systems and a set-up to propagate and analyze identified, mutated organisms.

The present disclosure provides compositions and methods for altering auxin accumulation in corn or maize plants. Methods and compositions are also provided for altering the expression of genes related to auxin efflux through editing or mutagenesis of a brachytic2 (br2) gene to introduce a premature stop codon or a deletion into the gene such that a truncated Br2 protein encoded by the mutant allele of the br2 gene, which may be a dominant or semi-dominant allele, has at least part of a transmembrane domain without a nucleotide binding domain or motif. Modified plant, plant parts and cells having such a mutant allele with reduced or altered expression or activity of a br2 gene product can have improved characteristics, such as reduced plant height and increased lodging resistance, but without off-types in the plant.

The invention discloses an SNP (Single Nucleotide Polymorphism) molecular marker related to mummy number on a porcine chromosome 5. SNP loci of the SNP molecular marker correspond to 22th, 452nd and 453rd Cgt on a chromosome 5 of a reference sequence of an international porcine genome version 11.1; and the polymorphism of the basic group at the site leads to the difference of the mutagenesis of the pigs. By verifying the influence effect of the molecular marker on the mummy number of sows, an efficient and accurate molecular marker-assisted breeding technology is finally established, and the molecular marker is applied to genetic improvement of reducing the mummy number of boars, so that the reproductive performance of offspring pigs is improved, and the economic profit of enterprises is increased. Accordingly, a corresponding genetic improvement method is established, and by optimizing the dominant alleles of the SNP, the dominant alleles frequency can be increased generation by generation, the number of mugs produced by sows can be reduced, and the progress of genetic improvement of pigs can be accelerated, so that the economic benefit of breeding of the boars can be effectively improved. Besides, a primer pair for amplifying a nucleotide sequence of the SNP molecular marker is further researched and designed, breeding traits can be rapidly and accurately bred through the primer pair, and the breeding process is accelerated.

The invention discloses a mutant and a genetically engineered bacterium for catalytic synthesis of D-chiral inositol by using the mutant, and relates to the technical field of biology, inositol dehydrogenase is subjected to site-directed saturation mutagenesis at N154 and C269 sites and then is subjected to combined mutagenesis at M123, V157, A171 and Y277 to obtain the inositol dehydrogenase mutant, so that a conversion reaction is carried out in a forward direction, and the conversion rate of D-chiral inositol is greatly improved.

The invention relates to the technical field of hard rock excavation, in particular to hard rock multi-source mutagenesis cutting increase and multi-mode non-explosive mechanical excavation equipment and a hard rock multi-source mutagenesis cutting increase and multi-mode non-explosive mechanical excavation process. The excavation equipment comprises a walking device, and a cutting device, an excavation device, a recovery device and a cutting increase device which are all mounted on the walking device; a digging head of the digging device comprises a multi-stage cutter head telescopic structure, an impact rock breaking structure is arranged on an inner cutter head, a rolling rock breaking structure is arranged on an outer cutter head, and the multi-stage cutter head telescopic structure stretches out and draws back to achieve alternate protruding of the impact rock breaking structure and the rolling rock breaking structure. The driving mechanism drives the excavating arm to move to achieve three-dimensional movement of the excavating head and rotation around the axis of the excavating arm. According to the cutting device, the pre-cutting groove extending transversely is pre-cut in the bottom of the tunnel face, the overall strength of the tunnel face rock mass is remarkably reduced, pre-cracking weakening is conducted on the tunnel face rock mass through the cutting increasing device, the hard rock cuttable performance is improved, hard rock crushing is achieved through the rolling and impacting combined rock breaking effect, and the cutting strength of the tunnel face rock mass is improved. The device is suitable for hard rock excavation.

The invention provides Saccharomyces cerevisiae for producing squalene as well as a screening method and application of the Saccharomyces cerevisiae. The method comprises the following steps: culturing a Saccharomyces cerevisiae engineering strain ySC782 for synthesizing squalene to obtain a to-be-mutagenized bacterial solution, carrying out ARTP mutagenesis on the to-be-mutagenized bacterial solution, adding the to-be-mutagenized bacterial solution into a YPD liquid culture medium, culturing to obtain a resuscitation bacterial solution, adding the resuscitation bacterial solution into a sucrose solution with gradient concentration distribution, screening, and repeating the ARTP mutagenesis-sucrose solution screening step to obtain the squalene mutant strain. And finally, the saccharomyces cerevisiae strain ySC782-M5 is obtained through screening, and the saccharomyces cerevisiae strain ySC782-M5 is obtained through screening. The yield of squalene produced by the saccharomyces cerevisiae ySC782-M5 reaches 49.83 g / L, so that a solution is provided for breaking through the yield bottleneck of squalene synthesized by yeast.

Disclosed herein are methods and systems for aligning sequence reads based on reduced sequence representations. The methods and systems may include receiving sequence reads generated from nucleic acids; encoding sequence reads with a reduced sequence representation, thereby generating transformed sequence reads; generating seeds from the transformed sequence reads; and matching the seeds, thereby aligning the transformed sequence reads. The methods and systems may improve alignment efficiency and accuracy, for example when used with sequence reads which include mutations or sequencing errors, such as in sequencing aided by mutagenesis (SAM) or long-read sequencing applications.

The application provides a Torulopsis glbrata TS-73 and application thereof in fermented fruit juice, and belongs to the technical field of microbial fermentation.The application adopts a composite mutagenesis method combining ARTP mutagenesis and ultraviolet mutagenesis to obtain a Torulopsis glbrata TS-73 capable of high yield of ethyl hexanoate;when the application is used for preparing fermented cherry juice and raspberry juice, the content of ethyl hexanoate in the cherry juice and the raspberry juice is increased by 44.01% and 54.19% respectively compared with the original strain Torulopsis glbrata G4.The Torulopsis glbrata TS-73 has the advantages of increasing the content of aroma substance ethyl hexanoate and stable performance.

The invention discloses a corynebacterium glutamicum whole genome random mutation tool and application thereof, and belongs to the technical field of genetic engineering and biological mutagenesis. DsDNA is unwound in the transcription process based on DNA helicase, DNA adenine deaminase and the DNA helicase are fused, and whole-genome random mutation of corynebacterium glutamicum is achieved. The whole genome random mutation method disclosed by the invention is applied to mutagenesis of an original strain of Corynebacterium glutamicum ATCC 13032, and a mutant strain of which the biomass is 1.95 times of that of WT (OD600 is 2.2) and 1.99 times of that of WT / pXMJ19 (OD600 is 2.16) when being cultured under the condition that the pH value is 5.5 is obtained. The corynebacterium glutamicum whole genome random mutation method disclosed by the invention has important guiding significance for screening other mutation strains with enhanced robustness.

The invention discloses a cordyceps militaris strain with high yield of ergothioneine and application of the cordyceps militaris strain, and belongs to the technical field of microorganisms and fermentation engineering. On the basis of the screened cordyceps militaris strain with high-yield ergothioneine potential, the cordyceps militaris strain is subjected to ultraviolet mutagenesis treatment, and a cordyceps militaris mutant strain which can be stably inherited and has high-yield ergothioneine is obtained through screening. According to the method, the yield of ergothioneine, cordycepin and cordyceps adenosine in the cordyceps militaris strain is synergistically improved on the basis of precursor directional metabolism remodeling by optimizing and screening precursor substances. The extracting solution of the cordyceps militaris strain can improve the survival rate of lactobacillus reuteri at the high temperature of 50 DEG C and has a protection effect on cells, and the active ingredients of the cordyceps militaris strain can provide an antioxidant protection effect to improve the viability of the cells in an extreme environment.

The invention belongs to the field of microbial breeding and fermentation engineering, and particularly relates to a saccharomyces cerevisiae mutagenesis strain with high yield of S-adenosyl-L-methionine as well as a mutagenesis method and application of the saccharomyces cerevisiae mutagenesis strain. Saccharomyces cerevisiae is induced to generate genetic diversity through multiple rounds of ultraviolet mutagenesis, and high-throughput screening is performed in combination with strain color phenotypic difference; and the mutant strain HY2402-Z18 with high yield of S-adenosine-L-methionine and genetic stability is obtained. The SAM yield of the mutagenic strain is increased by 40.1% compared with that of an original strain, the SAM yield reaches 13.44 g / L when the mutagenic strain is fermented for 60 h in a 5 L fermentation tank system, the unit yield reaches 0.156 g / L / OD, and the methionine conversion rate is 75%. After thalli are collected through centrifugation of fermentation liquor, an S-adenosine-L-methionine product with the purity of 98%-100% can be obtained through purification of ion exchange resin, no by-products are accumulated, the yield, the substrate conversion rate and the production efficiency of the S-adenosine-L-methionine can be remarkably improved when the mutagenesis strain is used for fermentation production, and the production cost is reduced. The production cost is effectively reduced, the product purity and quality are improved, and the method is suitable for industrial large-scale production of SAM.

The invention discloses a preparation method of ganoderma lucidum mutant strain active polysaccharide and application of the ganoderma lucidum mutant strain active polysaccharide in oxidation resistance, and relates to the technical field of biology. The ganoderma lucidum mutant strain active polysaccharide is prepared by taking mycelium of a ganoderma lucidum mutant strain CGMCC No.23283 as a raw material and adopting a water extraction and alcohol precipitation method. The invention develops a novel ganoderma lucidum active polysaccharide, and a ganoderma lucidum strain adopted by the ganoderma lucidum active polysaccharide is cultured by a space mutation technology. Compared with common ganoderma lucidum strain polysaccharide, the polysaccharide provided by the invention is more prominent in antioxidant activity, and is more excellent in key indexes such as total antioxidant capacity and free radical scavenging. The invention provides a new biological material resource for the preparation of antioxidant products.

The invention belongs to the field of crop genetic breeding, and relates to a method for efficiently creating brown glume rice and application thereof. According to the application, a stably inherited brown glume mutant hcm is created through radiation mutagenesis, and a molecular marker of brown glume characters is developed; a restorer line Huazhan is used as a recurrent parent for recurrent breeding with a mutant hcm, and the brown glume rice is efficiently created by combining molecular marker-assisted selection. And matching the rice sterile line Yunnan 165S with brown glume rice to obtain F1 hybrids, and planting the F1 hybrids to obtain brown glume hybrid rice grains. According to the invention, the brown character of the hcm glume of the mutant is directionally introduced into the restoring line Huazhan and the hybrid thereof, and when the improved restoring line is used for carrying out hybrid rice seed production, the hybrid and the selfing seed of the restoring line can be distinguished by utilizing the color difference of the glume of the male and female parent seeds, so that the large-scale mixed planting, mixed harvesting and color sorting separation of the hybrid are realized; the seed production efficiency of the hybrid rice is favorably improved.

This invention discloses a method for directed evolution of antibiotic-resistant Escherichia coli strains based on cytidine deaminase, belonging to the field of microbial directed evolution and genetic engineering technology. This method uses E. coli as the host, introducing a recombinant plasmid expressing an optimized double-stranded cytidine deaminase mutant. Utilizing the low toxicity and high mutagenicity of this mutant, continuous passage evolution is carried out under gradient concentrations of aminoglycoside antibiotics (kanamycin and streptomycin). Combined with whole-genome sequencing, molecular docking, and reverse genetics verification, the A145T missense mutation in the wcaE gene is identified as the core functional site. This invention overcomes the shortcomings of traditional spontaneous and chemical mutagenesis, which suffer from low efficiency and significant strain damage. The mutation type is controllable, the evolutionary cycle is short, and the obtained engineered strains can tolerate up to 300 mg / L kanamycin while exhibiting streptomycin cross-resistance, and the genetic stability of the tolerance trait is strong. This method is simple, highly reproducible, and suitable for industrial breeding of stress-resistant E. coli, and can be widely applied in antibiotic fermentation, industrial microbial culture, and other scenarios.

The disclosure provides Moloney murine leukemia virus (MMLV) reverse transcriptase (RTase) mutants. The disclosure as provides suitable amino acid positions in MMLV RTase for mutagenesis and methods and kits for using MMLV RTase mutants to synthesize cDNA from RNA templates.