32 results about "Lyase Gene" patented technology

The invention discloses a method for catalytic synthesis of malonic acid by using whole cells, and belongs to the field of bioengineering. According to the invention, escherichia coli BL21 (DE3) is taken as a host, an aspartic acid ammonia lyase gene aspA and an aspartic acid-alpha-decarboxylase gene panD, a succinate semialdehyde dehydrogenase gene yneI and a beta-alanine pyruvate transaminase gene, a beta-alanine pyruvate transaminase gene bauA and a malonyl-coenzyme A reductase gene mcr-C are expressed in modules, and recombinant escherichia coli is constructed. The malonic acid is produced by adopting a whole-cell catalysis method, so that the production period is shortened, the production efficiency of the malonic acid is improved, and the yield of the malonic acid can reach 51.0 g / L after the malonic acid is catalyzed for 24 hours.

The invention discloses a construction method of a cyanobacteria-corynebacterium glutamicum artificial photosynthetic mixed bacteria system. The construction method comprises the following steps: step S1, amplifying by taking plasmid pUC-tho as a template to obtain a theophylline inducible promoter Ptho; step S2, carrying out amplification by taking a Synechocystis sp. PCC 6803 genome as a template so as to obtain a strong promoter Pcpc560, and carrying out amplification on the strong promoter Pcpc560 so as to obtain a strong promoter Pcpc560; step S3, carrying out amplification by taking the plasmid pUC-PAL as a template to obtain an arabidopsis thaliana phenylalanine lyase gene pal; step S4, carrying out amplification by taking the plasmid pUC-cscB as a template to obtain an escherichia coli W sucrose transporter gene cscB; step S5, carrying out amplification by taking the integrated plasmid Pcp3031 as a template, so as to obtain a terminator Trbcl; and step S6, fusing the strong promoter Pcpc560, the arabidopsis phenylalanine lyase gene pal and the terminator Trbcl, and respectively connecting with an expression vector pSI-SPE to obtain the expression vector containing the gene pal. According to the invention, a'cyanobacteria-corynebacterium glutamicum 'artificial photosynthetic mixed bacteria system is constructed by simulating a mutualistic symbiotic relationship ubiquitous in nature, and negative carbon biosynthesis of cis-muconic acid is realized.

The invention discloses recombinant escherichia coli with high yield of N-acetylneuraminic acid and application of the recombinant escherichia coli, and relates to the technical field of biological genetic engineering. The invention relates to a recombinant escherichia coli, which is characterized in that the escherichia coli is taken as a host, and free expression of an N-acetylmannosamine epimerase gene yihS from Streptomyces xiamenensis or an N-acetylmannosamine epimerase gene ce3 from Bacteroides polymorpha and an exogenous N-acetylneuraminic acid lyase gene nano A is carried out; and carrying out recombinant expression on N-acetyl hexosamine 1-kinase nahK, a UDP-N-acetyl glucosamine pyrophosphorylase gene glmU and a UDP-N-acetyl glucosamine-2-epimerase gene neuC in the other synthetic route of the ManNAc. According to the recombinant escherichia coli with high yield of N-acetylneuraminic acid, the yield of N-acetylneuraminic acid can reach 23.08 g / L under a shake flask fermentation condition; a two-stage batch feeding strategy is adopted, the yield of N-acetylneuraminic acid in a 5L fermentation tank reaches 71.25 g / L, the molar conversion rate of GlcNAc reaches up to 57.60%, and the method has the potential of industrial application.

The invention discloses an escherichia coli engineering strain with high benzyl acetate yield and application thereof. The escherichia coli strain efficiently expresses a brand new biosynthetic pathway related gene of benzyl acetate; comprising a phenylalanine lyase gene, a cinnamic acid coenzyme A ligase gene, a 3-hydroxyacyl coenzyme A dehydrogenase gene, a 3-oxoacyl coenzyme A ketohydrolase gene, an enoyl coenzyme A hydratase gene, a carboxylic acid reductase gene, a phosphoric acid pantetheinyl transferase gene and an acyltransferase gene. The obtained escherichia coli engineering strain can utilize a sustainable and cheap raw material glucose as a carbon source to realize efficient synthesis of benzyl acetate. The yield of benzyl acetate synthesized by the escherichia coli benzyl acetate engineering bacteria is the highest yield of benzyl acetate synthesized by a microbial fermentation method reported at home and abroad from beginning. The benzyl acetate produced by the engineering strain has the advantages of reliable quality, economic product, green production and the like, and has important economic value and social benefit.

The invention relates to an intestinal probiotic genetically engineered bacterium as well as a construction method and application thereof, and belongs to the technical field of genetic engineering. According to the invention, Escherichia coli is used as an expression host, endogenous recessive plasmid pMUT1 gene and pMUT2 gene are knocked out, an exo-algin lyase gene and an open-loop uronic acid monomer dehydrogenase gene are subjected to heterologous expression, and a 2-keto-3-deoxy-gluconate kinase gene and a 2-keto-3-deoxy-6-phosphate-gluconate aldolase gene are subjected to overexpression. According to the invention, an endogenous recessive plasmid pMUT2 of Escherichia coli Nissle 1917 is utilized, metabolic pathways of algin and degradation products thereof are introduced, and a stable passage engineered strain EcNc-pMUT2 '-4 which can be proliferated by utilizing algin and degradation products thereof and is free of antibiotic markers is obtained, and the engineered strain has good intestinal tract probiotic performance.

The invention discloses an ergothioneine-producing recombinant engineering bacterium as well as a construction method and application thereof, and belongs to the technical field of gene recombination fermentation. The method comprises the following steps: by taking escherichia coli as a starting bacterium, carrying out recombinant expression on a histidine trimethyl inner salt cysteine sulfoxide synthetase egt1 gene, an L-histidine methyltransferase egtD gene, a histidine trimethyl inner salt cysteine sulfoxide lyase egt2 gene, a methionine adenosine transferase metK gene, an adenylate kinase adK gene and an adenine phosphoribose transferase apt gene; on this basis, supply of precursor substances including histidine, cysteine and methionine is further improved through metabolic transformation, the yield of the finally obtained recombinant engineering bacterium for producing ergothioneine reaches 2.54 g / L after 48 h of shake-flask culture, the yield of a 5L fermentation tank reaches 18 g / L after further enlarged culture, the yield of ergothioneine is guaranteed while energy consumption and cost are reduced, and the method is suitable for industrial production. The method is suitable for practical popularization.

The application provides a method for increasing the length of a main panicle of rice, the number of secondary branches of the main panicle, the number of grains on the main panicle of rice and / or improving the yield of rice, which comprises overexpressing a cystathionine beta-lyase gene OsCBL in rice by using a recombinant vector containing a CDS coding sequence of the cystathionine beta-lyase gene OsCBL as shown in SEQ ID NO: 2 to obtain a transgenic plant. The transgenic plant obtained by the method has an increased number of grains per panicle and an increased yield per plant compared with normal plants. The method can be used for treating rice plants to improve the yield of rice and provides a new gene resource and a new idea for breeding rice with increased yield.

To provide: a technique that can predict the prognosis of inflammatory bowel disease, can contribute to verifying treatment effects at that point in time, imposes less physical burden, and has high accuracy (low likelihood of missing individuals at risk of worsening disease); and a technique that can contribute to diagnosing inflammatory bowel disease, imposes less physical burden, and enables inexpensive and rapid testing of the likelihood of contracting inflammatory bowel disease.SOLUTION: A method for predicting the prognosis of inflammatory bowel disease comprises detecting the amount of an N-acetylneuraminate lyase gene derived from intestinal bacteria in a biological sample from a subject. A method for testing inflammatory bowel disease comprises detecting the amount of an N-acetylneuraminate lyase gene derived from intestinal bacteria in a biological sample from a subject.SELECTED DRAWING: Figure 6

The invention discloses a Rogowski eutrophy alkali-producing engineering strain for producing p-coumaric acid as well as a construction method and application of the Rogowski eutrophy alkali-producing engineering strain. The preparation method comprises the following steps: by taking a chemoautotrophic microorganism Ropriavidus alcaligenes H16 as an original strain, firstly, by knocking out a synthetic route of a strain poly-3-hydroxybutyrate (PHB), introducing a tyrosine ammonia lyase gene from Rhodotorula glutinis to construct a basic engineering strain capable of producing p-coumaric acid, and then, carrying out fermentation on the basic engineering strain to obtain the p-coumaric acid. Then, endogenous 3-deoxy-7-phosphoheptanone acid synthase gene aroG1 and chorismate synthase gene aroC are overexpressed, and the total copy is increased, so that the p-coumaric acid synthetic pathway flux of the engineering strain is enhanced; and introducing NAD (P) transhydrogenase gene pntAB from Escherichia coli to improve the supply of cofactors, so as to finally obtain the eutrophy alcaligenes Rosei engineering strain capable of synthesizing p-coumaric acid by using CO2.

The present application relates to a kind of high catalytic activity artificial synthesis of ulvan lyase A21 and application, belong to functional enzyme technical field, the amino acid sequence of the artificial synthesis of ulvan lyase A21 as shown in SEQ ID NO.1, the present application also provides the enzyme preparation comprising the artificial synthesis of ulvan lyase A21, and the recombination expression vector and engineering bacteria comprising the gene of the artificial synthesis of ulvan lyase A21 coding ulvan lyase A21.The present application also provides the application of the artificial synthesis of ulvan lyase A21 in the preparation of ulvan oligosaccharide of the cleavage of ulva lactuca.The artificial synthesis of ulvan lyase A21 compared with wild ulvan lyase has better stability, and its catalytic activity compared with wild enzyme JpPL40A is increased by nearly 4.5 times.

The application belongs to the technical field of biotechnology, and particularly relates to a Clostridium perfringens bacteriophage lytic enzyme produced by Bacillus subtilis, a preparation method and application thereof, an optimized Clostridium perfringens bacteriophage lytic enzyme coding nucleic acid sequence according to the codon bias of Bacillus subtilis, and an optimized Clostridium perfringens bacteriophage lytic enzyme coding nucleic acid sequence as shown in SEQ ID NO. 1. The preparation method of the Clostridium perfringens bacteriophage lytic enzyme is as follows: firstly, a recombinant expression vector containing a Clostridium perfringens bacteriophage lytic enzyme gene is constructed, and then the vector is transferred into a Bacillus subtilis competent cell to obtain a Bacillus subtilis strain recombinant engineering bacterium. After the recombinant strain is induced to express, a fermentation liquor with Clostridium perfringens bacteriophage lytic enzyme activity can be obtained. The fermentation liquor can specifically inhibit the growth of Clostridium perfringens, and provides a safe, efficient and orally-taken preparation for treating animal diseases caused by Clostridium perfringens.

The present invention discloses a prophage lytic enzyme of Streptococcus equi subspecies equi, and its preparation method and application, which belong to the technical field of veterinary medicine. The amino acid sequence of the lytic enzyme is shown in SEQ ID NO.29. The polynucleotide encoding the prophage lytic enzyme of Streptococcus equi subspecies equi, the expression vector containing the polynucleotide, and the host bacteria containing the expression vector are also within the protection scope of the present invention. Among them, preferably, the sequence of the polynucleotide is shown in SEQ ID NO.30. The present invention compares the prophage lytic enzyme genes in the genome sequence of Streptococcus equi subspecies equi, designs specific primers, amplifies and clones the lytic enzyme genes in the Streptococcus equi strains preserved in the laboratory, performs recombinant expression, and evaluates the antibacterial effects of different lytic enzymes, and finally screens out the lytic enzyme with the best bactericidal effect, thereby providing a new technical means for the prevention and treatment of equine strep.

The invention provides a method for enhancing methyl mercury degradation capacity of phytoplankton, and belongs to the field of biotechnology. The method for enhancing the methyl mercury degrading capacity of the phytoplankton comprises the step of enabling the phytoplankton to overexpress a methyl mercury lyase gene merB. The organic mercury lyase coded by the merB gene, namely the MerB protein, can decompose high-toxicity methyl mercury into low-toxicity Hg and methane (CH), so that the tolerance of phytoplankton expressing the merB gene to the methyl mercury can be enhanced. Meanwhile, the phytoplankton can enrich methyl mercury in the water environment, the phytoplankton serves as a primary producer in a food chain and is a source of substances and energy, the content of methyl mercury can be reduced from the source by reducing the methyl mercury in the phytoplankton, and therefore the ecological health risk that the methyl mercury is transmitted along the food chain is reduced. The mercury metabolic pathway of phytoplankton is enhanced through genetic engineering, and an efficient and sustainable method is provided for bioremediation of mercury pollution.

The invention relates to the technical field of bioengineering, and discloses a construction method and application of recombinant Escherichia coli engineering bacteria with high yield of ergothioneine, and the method comprises the following steps: by taking Escherichia coli as a chassis, integrating a mycobacterium smegmatis egtABCDE gene cluster at an ldhA site; a repressor protein gene metJ and a cysteine lyase gene yhaM are knocked out, a methionine adenosine transferase gene metK and a serine acetyltransferase gene cysE are overexpressed by using a strong promoter, and mutant metA, thrA, serA and hisG genes for relieving feedback inhibition are introduced, so that metabolic inhibition of methionine, cysteine and histidine pathways is systematically relieved; the invention also establishes a matched fermentation process. According to the invention, endogenous precursor supply and exogenous synthesis pathways are synergistically enhanced, the precursor supply bottleneck is solved, the yield of ergothioneine is increased, and the method is suitable for industrial production.

The invention discloses a mucus type pseudomonas aeruginosa bacteriophage separation method based on recombinant alginate lyase, according to the separation method, mucus type pseudomonas aeruginosa bacteriophage is obtained based on recombinant alginate lyase separation, and the amino acid sequence of the recombinant alginate lyase is shown as SEQ ID NO.2. An alginate lyase gene algL in genomic DNA of a pseudomonas aeruginosa standard strain PAO1 is used as a target gene, a recombinant plasmid is constructed, induced expression is completed in escherichia coli, and the recombinant alginate lyase with high purity and high alginate degradation activity is obtained. Based on the recombinant alginate lyase, the bacteriophage which shows a high splitting effect on the mucus type pseudomonas aeruginosa is screened, the problem that the mucus type pseudomonas aeruginosa bacteriophage is difficult to separate is solved, and a technical basis is provided for development of drugs for treating infectious diseases caused by the mucus type pseudomonas aeruginosa.

The application discloses a phenylalanine ammonia-lyase gene RkPAL , which is separated from red yeast (Rhodotorula rubra) Rhodosporidium kratochvilovae , has a nucleotide sequence as shown in SEQ ID NO:1, and encodes an amino acid sequence as shown in SEQ ID NO:2. The gene is connected with a carrier and is transferred into red yeast cells, and experimental results show that RkPAL overexpression of the gene can promote the red yeast to synthesize carotenoids and oil; and the application provides a reference for large-scale commercial production of carotenoids and oil.

The invention relates to an artificially synthesized ulva polysaccharide lyase A21 with high catalytic activity and application thereof, and belongs to the technical field of functional enzymes, and the amino acid sequence of the artificially synthesized ulva polysaccharide lyase A21 is shown as SEQ ID NO.1. The invention also provides an enzyme preparation containing the artificially synthesized ulva polysaccharide lyase A21. The invention also discloses a recombinant expression vector and engineering bacteria for coding the artificially synthesized ulva polysaccharide lyase A21 gene. The invention also provides application of the artificially synthesized ulva polysaccharide lyase A21 in preparation of ulva oligosaccharide by cracking ulva. Compared with wild ulva polysaccharide lyase, the artificially synthesized ulva polysaccharide lyase A21 has better stability, and the catalytic activity of the artificially synthesized ulva polysaccharide lyase A21 is nearly 4.5 times higher than that of wild enzyme JpPL40A.

The invention relates to a genetically engineered bacterium for producing (-)-limonene, (-)-carvol and (-)-carvone and application of the genetically engineered bacterium. According to the method, endogenous ATP-citrate lyase genes ACL and CarYB genes are knocked out, endogenous mevalonic acid pathway key genes HMGR, ACCT and IDI are overexpressed, a mevalonic acid kinase gene MmMK sourced from methanosarcina martensii and mevalonic acid pathway key genes EfMvaS and EfMvaE sourced from enterococcus faecalis are introduced, and the (-)-limonene, (-)-carvol and (-)-carvone are synthesized into the genetically engineered strain. The method is realized in a platform strain for regulating and controlling the balance of the cofactor NADPHP. And the yield of the (-)-limonene in a bioreactor of 500-mL reaches 608.5 mg / L. The yield of the (-)-carveol reaches 667.6 mg / L when the (-)-carveol is fermented in a 500-mL bioreactor. The fermentation yield of the recombinant strain for producing the (-)-carvone in a 500-mL bioreactor reaches 67.1 mg / L.

The invention relates to a construction method of an engineering strain of Rhodosporidium toruloides capable of producing high yield of Ergothioneine, and a preparation method of the engineering strain of the Rhodosporidium toruloides. The preparation method comprises the following steps: overexpressing an ergothioneine synthetase gene NcEGT1 from Neurospora crassa, an ergothioneine synthetase gene CpEGT2 from Clavipis purpurea, an ATP (adenosine triphosphate) transphosphoribose kinase gene HIS1, an S-adenosylmethionine synthetase-2 gene SAM2, a sulfate kinase gene MET14 and a cystathionine gamma-lyase gene CYS3 from the Rhodosporidium toruloides in a Rhodosporidium toruloides chassis; the production level of ergothioneine is remarkably improved by two or more than two genes in the cystathionine beta-synthetase gene CYS4. The rhodosporidium toruloides engineering strain constructed by the invention can be used for producing ergothioneine through fermentation by taking glucose or molasses or acetate and glucose as carbon sources, expensive raw materials such as precursor amino acid do not need to be added, and the economic benefit is remarkable.

The invention discloses an application of a soybean cystathionine beta-lyase gene GmCBL2 in soybean resistance to soybean mosaic virus diseases. The invention also discloses application of the soybean cystathionine beta-lyase gene GmCBL2 as shown in SEQ ID NO.1 and SEQ ID NO.2 in genetic engineering modification of soybean mosaic virus resistance. The soybean cystathionine beta-lyase gene GmCBL2 can negatively regulate the resistance of soybeans to diseased soybean mosaic virus diseases, and the antiviral reaction of the soybeans can be activated due to function deficiency of the soybean cystathionine beta-lyase gene GmCBL2. The gene is knocked out through a CRISPR / Cas9 gene editing technology, so that the resistance of soybeans to the soybean mosaic virus disease can be remarkably improved.

This invention relates to the field of biotechnology, and discloses an engineered *Yarrowia lipolytica* strain that produces p-coumaric acid using glucose as a substrate, its construction method, and its applications. Construction method: A tyrosine ammonia-lyase gene is integrated using a CRISPR / Cas9 localization and integration method. TAL In *Yarrowia lipophila* strains, the DAHP synthase gene was enhanced. ARO4 , DHS1 and AROG Overexpression of tyrosine synthase TYR Genes and histidine phosphotransferases HIS5 The protease gene was further integrated to synthesize exogenous phenylalanine deamination and hydroxylation pathway genes for p-coumaric acid, including phenylalanine ammonia-lyase gene, cinnamate hydroxylase gene, and P450 reductase gene. The p-coumaric acid produced by the engineered *Yarrowia lipolytica* strain of this invention can reach a maximum yield of 1.7 g / L in shake flasks, and a yield of 30 g / L in a 5 L fed-batch fermentation tank, demonstrating significant industrial application value.

To provide a technique capable of contributing to the diagnosis of pancreatic cancer, reducing a physical burden, and inexpensively and quickly examining the possibility of suffering from pancreatic cancer.SOLUTION: The method for examining pancreatic cancer includes detecting the amount of N-acetylneuraminic acid lyase gene derived from bacteria in a sample from a subject. Advantageous Effects of Invention According to the present invention, pancreatic cancer can be tested using a biological sample obtained noninvasively, such as feces, saliva, blood, or body fluid, without imposing a hospital visit burden or a physical burden related to the test on a subject. Since the amount of the nanA gene derived from bacteria can be measured by PCR and the comprehensive analysis of intestinal bacterial flora is unnecessary in the present invention, pancreatic cancer can be rapidly and inexpensively examined.SELECTED DRAWING: Figure 4

The application discloses an endolytic alginate lyase AlgC2m and application thereof. The biological enzyme is derived from a Paenibacillus-like bacterium enriched in a seaside soil sample. The application also discloses a recombinant expression vector and a recombinant host containing the alginate lyase AlgC2m gene. The application clones a new alginate lyase gene AlgC2m, which is 1320 bp in size, encodes 439 amino acids, and is classified into the PL-7 family. The similarity of the alginate lyase to alginate lyases in the same family is only 38%. The alginate lyase AlgC2m provided by the application has the function of degrading sodium alginate to prepare alginate oligosaccharide, and the main degradation product is unsaturated alginate disaccharide and trisaccharide, and has certain industrial application value.

The present invention relates to a co-oxygen protein VHb, its recombinant bacterium X33-pPICZαA-102C300C-Vgb and applications, belonging to the technical field of genetic engineering. The nucleotide sequence of the gene of the co-oxygen protein VHb is as shown in SEQ ID N0.1, and the gene of the co-oxygen protein VHb can be used to improve the efficiency of the secretion of alginate lyase by the Pichia pastoris engineering bacterium. The present invention also provides that the amino acid sequence of the co-oxygen protein VHb is as shown in SEQ ID N0.2. The present invention also provides a recombinant expression vector and a recombinant bacterium X33-pPICZαA-102C300C-Vgb comprising an alginate lyase gene and the gene of the co-oxygen protein VHb. The recombinant bacterium improves the utilization rate of oxygen by the bacterial cells in a low-oxygen environment in the later stage of fermentation, and finally improves the yield of alginate lyase.

The invention provides a preparation method of L-cysteine hydrochloride, and relates to the field of chemical processes. According to the preparation method of the L-cysteine hydrochloride, escherichia coli BL21 is adopted as an original host strain, and site-directed mutagenesis is performed on serine transacetylase in the escherichia coli original strain through feedback inhibition mutation, threonine synthetase gene deletion and serine transacetylase gene overexpression, so that the L-cysteine hydrochloride is obtained. By overexpressing the O-acetylserine sulfydryl lyase gene, promoting the combination of hydrogen sulfide and OAS to generate L-cysteine and removing the feedback inhibition of threonine, the method overcomes the defects that a large amount of hydrochloric acid is used and acidic waste is discharged in the preparation of a traditional process, reduces the discharge of waste acid by 80% or more, is renewable in raw materials, meets the requirements of green chemistry, and is suitable for industrial production. The future trend of a green and environment-friendly preparation process is achieved.

The invention discloses a recombinant vector for expressing bacteriophage lyase and a construction method and application of the recombinant vector. The recombinant vector for expressing the bacteriophage lyase is based on a pichia pastoris expression system. The recombinant vector for expressing the bacteriophage lyase comprises a bacteriophage lyase gene, a multiple cloning site, a replication start site, a promoter, a terminator, an alpha-factor signal peptide and a resistance selection marker. According to the recombinant vector of the bacteriophage lyase provided by the invention, the lyase gene is recombined onto the vector, so that the expressed lyase can be used for developing a novel feed additive for preventing necrotic enteritis of poultry directly or after being prepared into a preparation, and a food preservative for controlling clostridium perfringens pollution in meat; or as a therapeutic drug for local or systemic infections.

This invention discloses a chemoautotrophic alkaloid-producing strain of *Alcaligenes rocheborella*, its construction method, and its application. The strain is based on the chemoautotrophic microorganism *Alcaligenes rocheborella* H16 (… Cupriavidus necator Using H16 as the starting strain, the poly-3-hydroxybutyrate (PHB) synthesis pathway of the strain was first knocked out, and then a strain from Rhodotorula glutinis (H16) was introduced. Rhodotorula glutinis ) tyrosine ammonia lyase gene tal A basic engineered strain capable of producing p-coumaric acid was constructed. Subsequently, the throughput of the p-coumaric acid synthesis pathway in the engineered strain was enhanced by overexpressing the endogenous 3-deoxy-7-phosphate heptanulate synthase gene aroG1 and the branching acid synthase gene aroC, and by increasing the tal copy number. Further enhancement was achieved by introducing strains from *Escherichia coli* (…). Escherichia coli By improving the supply of cofactors through the NAD(P) transhydrogenase gene pntAB, a strain of Alcaligenes roximatelye that can synthesize p-coumaric acid using CO2 was finally obtained.

Provided is a transformant produced by introducing a specific salicylate synthase gene or introducing a specific isochorismate synthase gene and a specific isochorismate-pyruvate lyase gene into a bacterium belonging to the genus Hydrogenophilus. The transformant can efficiently produce salicylic acid by using carbon dioxide as a sole carbon source.

This invention relates to the field of biotechnology, and more particularly to the tobacco pectin lyase NtPL gene and its applications. This invention is the first to experimentally demonstrate that mutants lacking pectin lyase function (as shown in SEQ ID NO:2) exhibit reduced petiole stress tolerance and increased leaf drop, while overexpressed mutants show increased petiole stress tolerance and reduced leaf drop. This provides a new means to regulate the mechanical strength of tobacco petioles and offers a new strategy for tobacco molecular breeding, which is of great significance for stabilizing tobacco yield and quality.

This invention discloses a recombinant engineered bacterium producing ergothioneine, its construction method, and its application, belonging to the field of gene recombination fermentation technology. This invention uses *Escherichia coli* as the starting bacterium to recombinantly express histidine trimethylammonium cysteine ​​sulfoxide synthase. egt1 Gene, L-histidine methyltransferase egtD Gene, histidine trimethyl inner salt cysteine ​​sulfoxide lyase egt2 Gene, methionine adenosine transferase metK Gene, adenosine kinase adK Genes and adenine phosphoribosyltransferase apt The gene was modified, and further metabolic modification was used to increase the supply of precursor substances histidine, cysteine, and methionine. The resulting recombinant engineered ergothionein-producing bacteria achieved a yield of 2.54 g / L after 48 h of shake-flask culture, and a yield of 18 g / L after further expansion to a 5L fermenter. This method reduces energy consumption and costs while ensuring ergothionein production, making it suitable for practical application.