Publications by authors named "Jianzhong Huang"

120 Publications

The resistance associated protein RIN4 promotes the extracellular transport of AtEXO70E2.

Biochem Biophys Res Commun 2021 Mar 31;555:40-45. Epub 2021 Mar 31.

State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, College of Life Sciences, Wuhan University, Wuhan, 430072, China. Electronic address:

RIN4 is an important immunomodulator in Arabidopsis, which is targeted by multiple pathogenic effectors, and consequently guarded by different immune receptors. Although RIN4 plays a significant role in plant immunity, its molecular function is not fully understood. We found that RIN4 interacts with the exocyst subunit EXO70E2. Transiently expressed RIN4 can recruits EXO70E2 vesicles to the plasma membrane, and promote the transport of the vesicles to the extracellular matrix. RIN4 also can decrease the protein level of EXO70E2. Base on the fact that EXO70 proteins positively mediates plant immunity, the function of RIN4 is to promote the extracellular export of defense related vesicles. Pathogens will secret effectors to modify or cleavage it to interfere this exocytosis.
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http://dx.doi.org/10.1016/j.bbrc.2021.03.072DOI Listing
March 2021

Highly Efficient Production of Menaquinone-7 from Glucose by Metabolically Engineered .

ACS Synth Biol 2021 Mar 23. Epub 2021 Mar 23.

CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.

Menaquinone-7 (MK-7) possesses wide health and medical value, and the market demand for MK-7 has increased. Metabolic engineering for MK-7 production in still remains challenging due to the characteristics of the competing quinone synthesis, and cells mainly synthesized menaquinones under anaerobic conditions. To increase the production of MK-7 in engineered strains under aerobic conditions, we divided the whole MK-7 biosynthetic pathway into three modules (MVA pathway, DHNA pathway, and MK-7 pathway) and systematically optimized each of them. First, by screening and enhancing Idi expression, the amounts of MK-7/DMK-7 increased significantly. Then, in the MK-7 pathway, by combinatorial overexpression of endogenous MenA and exogenous UbiE, and fine-tuning the expression of HepPPS, MenA, and UbiE, 70 μM MK-7 was achieved. Third, the DHNA synthetic pathway was enhanced, and 157 μM MK-7 was achieved. By the combinational metabolic engineering strategies and membrane engineering, an efficient metabolic engineered strain for MK-7 synthesis was developed, and 200 μM (129 mg/L) MK-7 was obtained in shake flask experiment, representing a 306-fold increase compared to the starting strain. In the scale-up fermentation, 2074 μM (1350 mg/L) MK-7 was achieved after 52 h fermentation with a productivity of 26 mg/L/h. This is the highest titer of MK-7 ever reported. This study offers an alternative method for MK-7 production from biorenewable feedstock (glucose) by engineered . The high titer of our process should make it a promising cost-effective resource for MK-7.
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http://dx.doi.org/10.1021/acssynbio.0c00568DOI Listing
March 2021

Pyrroloquinoline quinone protects against exercise-induced fatigue and oxidative damage via improving mitochondrial function in mice.

FASEB J 2021 Apr;35(4):e21394

Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Normal University, Fuzhou, Funjian, China.

Pyrroloquinoline quinone (PQQ) has a variety of biological functions. However, rare attention has been paid to its effects on exercise-induced damage. Here, we assessed the potential protective effects of PQQ against the fatigue and oxidative damage caused by repeated exhaustive exercise, and studied the underlying mechanism. The models for exercise-induced fatigue were established, and the parameters were measured, including the time to exhaustion (TTE), biochemical indicators, the expression of nuclear factor kappa B (NF-κB) and inflammatory cytokines and so on. Besides, the mitochondrial function was evaluated by the morphology, membrane potential, respiratory function, adenosine triphosphate (ATP) levels, and the application of the mitochondrial complex I inhibitor. The results demonstrate that PQQ prolongs TTE, causes the decrease in the activity of serum creatine kinase and lactate dehydrogenase, increases the activity of antioxidant enzymes, inhibits the production of reactive oxygen species (ROS) and malondialdehyde (MDA), and diminishes the over expression of NF-κB (p65) and inflammatory mediators. Furthermore, PQQ preserves normal mitochondrial function. Particularly, PQQ reduces the accumulation of ROS triggered by the mitochondrial complex I inhibitor. These data suggest that PQQ can significantly protect mice from exercise-induced fatigue and oxidative damage by improving mitochondrial function. These data also suggest that PQQ controls mitochondrial activity through directly affecting the NADH dehydrogenase.
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http://dx.doi.org/10.1096/fj.202001977RRDOI Listing
April 2021

Economic evaluation of variable rate nitrogen management of canola for zones based on historical yield maps and soil test recommendations.

Sci Rep 2021 Feb 24;11(1):4439. Epub 2021 Feb 24.

Agriculture and Agri-Food Canada (AAFC), Brandon Research and Development Centre, R.R. #3, PO Box 1000a, Brandon, MB, R7A 5Y3, Canada.

Canola (Brassica napus L.) is a highly valuable crop for Canada's economy, making the efficient management of canola a priority. A field-scale study was conducted at ten sites between 2014 and 2016 to evaluate the viability of site specific nitrogen (N) management zones (MZ) based on analysis of historical yield maps and soil test recommendations to improve canola productivity and profitability in western Canada. Treatments included factorial combinations of three canola yield zones (low, average, high) by four N rates, replicated four times at each site. The canola yield function had a quadratic form in each field but the effects of MZ varied between fields with positive effects in only a few fields. When ten site-years data were combined, MZ had positive effects on canola performance. On average, MZ of N fertilizer over ten fields generated between $28 to $65 ha more net revenue (NR) relative to average yield management. Site-years, which reflect farm management and other farm characteristics had significant effects on yield and NR ranging from - $91 to $352 ha compared to a baseline. Nitrogen application under MZs was only reduced by 8% compared to uniform rates. The potential for MZ does exist; however, its effectiveness is highly variable.
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http://dx.doi.org/10.1038/s41598-021-83917-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7904948PMC
February 2021

Structural Insights into the -Acting Enoyl Reductase in the Biosynthesis of Long-Chain Polyunsaturated Fatty Acids in .

J Agric Food Chem 2021 Feb 15;69(7):2316-2324. Epub 2021 Feb 15.

Engineering Research Center of Industrial Microbiology, Ministry of Education; Collaborative Innovation Center of Haixi Green Bio-Manufacturing Technology, Ministry of Education; National & Local Joint Engineering Research Center of Industrial Microbiology and Fermentation Technology, National Development and Reform Commission; College of Life Sciences, Fujian Normal University, Fuzhou, 350117, P. R. China.

Two long-chain polyunsaturated fatty acids (LC-PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), play vital roles in human health. Similarly, two biosynthetic pathways, based on desaturase/elongase and polyketide synthase, have been implicated in the synthesis of microbial LC-PUFA. Up to now, only several microalgae, no bacteria, have been used in the commercial production of oils rich in DHA and/or EPA. Fully understanding the enzymatic mechanism in the biosynthesis of LC-PUFA would contribute significantly to produce EPA and/or DHA by the bacteria. In this study, we report a 1.998 Å-resolution crystal structure of -acting enoyl reductase (ER), SpPfaD, from . The SpPfaD model consists of one homodimer in the asymmetric unit, and each subunit contains three domains. These include an N-terminal, a central domain forming a classic TIM barrel with a single FMN cofactor molecule bound atop the barrel, and a C-terminal domain with a lid above the TIM barrel. Furthermore, we docked oxidized nicotinamide adenine dinucleotide phosphate (NADP) and an inhibitor 2-(4-(2-((3-(5-(pyridin-2-ylthio)thiazol-2-yl)ureido)methyl)-1-imidazole-4-yl)phenoxy)acetic acid (TUI) molecule into the active site and analyzed the inhibition and catalytic mechanisms of the enoyl reductase SpPfaD. To the best of our knowledge, this is the first crystal structure of -ER in the biosynthesis of bacterial polyketides.
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http://dx.doi.org/10.1021/acs.jafc.0c07386DOI Listing
February 2021

High-Level Production of Indole-3-acetic Acid in the Metabolically Engineered .

J Agric Food Chem 2021 Feb 4;69(6):1916-1924. Epub 2021 Feb 4.

Engineering Research Center of Industrial Microbiology of Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou 350117, Fujian, China.

Indole-3-acetic acid (IAA) is a critical plant hormone that regulates cell division, development, and metabolism. IAA synthesis in plants and plant-associated microorganisms cannot fulfill the requirement for large-scale agricultural production. Here, two novel IAA biosynthesis pathways, tryptamine (TAM) and indole-3-acetamide (IAM), were developed for IAA production by whole-cell catalysis and biosynthesis in an engineered MG1655. When 10 g/L l-tryptophan was used as a substrate, an MIA-6 strain containing a heterologous IAM pathway had the highest IAA titer of 7.10 g/L (1.34 × 10 mg/g DCW), which was 98.4 times more than MTAI-5 containing the TAM pathway by whole-cell catalysis. IAA biosynthesis was optimized by improving NAD(P)H availability, resulting in an increased IAA titer of 906 mg/L obtained by the MGΔadhE::icd strain, which is 29.7% higher than the control These strategies exhibit the potential for IAA production in engineered and possible industrial applications.
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http://dx.doi.org/10.1021/acs.jafc.0c08141DOI Listing
February 2021

Screening of perhydrolases to optimize glucose oxidase-perhydrolase-in situ chemical oxidation cascade reaction system and its application in melanin decolorization.

J Biotechnol 2021 Feb 21;328:106-114. Epub 2021 Jan 21.

National & Local United Engineering Research Center of Industrial Microbiology and Fermentation Technology, Ministry of Education, Fujian Normal University, Fuzhou, 350117, China; College of Life Sciences, Fujian Normal University (Qishan Campus), Fuzhou, 350117, China; Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Fujian Normal University, Fuzhou, 350117, China. Electronic address:

A novel glucose oxidase (GOD)-perhydrolase-in situ chemical oxidation (ISCO) cascade reaction system was designed, optimized, and verified the operation feasibility in this research. Among the determined four perhydrolases, acyltransferase from Mycobacterium smegmatis (MsAcT) displayed the highest specific activity for perhydrolysis reaction (76.4 U/mg) and the lowest K value to hydrogen peroxide (13.9 mmol/L). GOD-MsAcT cascade reaction system also displayed high catalytic efficiency. Under the optimal parameters (50:1 activity unit ratio of GOD to MsAcT, pH 8.0, 50 mmol/L of β-d-glucose, and 15 mmol/L of glyceryl triacetate), the melanin decolorization rate using GOD-MsAcT-ISCO cascade reaction system reached 86.8 %. Kinetics of GOD-MsAcT-ISCO cascade reaction system for melanin decolorization fitted the kinetic model of Boltzmann sigmoid. As a substitutive skin whitening technology, GOD-MsAcT-ISCO cascade reaction system displayed an excellent application prospect.
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http://dx.doi.org/10.1016/j.jbiotec.2021.01.013DOI Listing
February 2021

An ,,,, Mutant with a 33-nt Deletion Showed Enhanced Tolerance to Salt and Drought Stress in Rice.

Plants (Basel) 2020 Dec 24;10(1). Epub 2020 Dec 24.

National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang University, Hangzhou 310058, China.

encodes inositol 1,3,4,5,6-pentaphosphate 2-kinase, which catalyzes the conversion of -inositol-1,3,4,5,6-pentaphosphate to -inositol-1,2,3,4,5,6-hexaphosphate (IP) in rice. By clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein (Cas9)-mediated mutagenesis in the 3rd exon of the gene, three mutations, i.e., (a 33-nt deletion), (a 1-nt deletion), and (a 2-nt deletion) were identified in T plants of the rice line Xidao #1 (wild type, WT). A transfer DNA free line with the homozygous mutation was developed; however, no homozygous mutant lines could be developed for the other two mutations. The comparative assay showed that the mutant line had a significantly lower level of phytic acid (PA, IP; -19.5%) in rice grain and agronomic traits comparable to the WT. However, the mutant was more tolerant to salt and drought stresses than the WT, with significantly lower levels of inositol triphosphate (IP), reactive oxygen species (ROS) and induced IP, and higher activities of antioxidant enzymes in seedlings subjected to these stresses. Further analyses showed that the transcription of stress response genes was significantly upregulated in the mutant under stress. Thus, the low phytic acid mutant should have potential applications in rice breeding and production.
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http://dx.doi.org/10.3390/plants10010023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7824669PMC
December 2020

Structure and function analysis of a CC-NBS-LRR protein AT1G12290.

Biochem Biophys Res Commun 2021 01 1;534:206-211. Epub 2020 Dec 1.

State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, College of Life Sciences, Wuhan University, Wuhan, 430072, China. Electronic address:

Nucleotide-binding site (NBS) and leucine-rich repeat (LRR) receptors (NLRs) play important roles in plant immunity. The genome of Arabidopsis thaliana contains about 150 genes encoding NLR proteins, but few of them have been studied. We transiently expressed a series of NBS-LRR proteins in the leaves of Nicotiana benthamiana, and found that the CC-NBS-LRR protein (AT1G12290) was able to trigger cell death, a characterized function for the activation of an NLR protein. We observed that the YFP-tagged AT1G12290 was localized on the plasma membrane (PM), and the predicted myristoylation site Gly2 is required for the localization and function of the protein. Further structure dissection revealed that the CC domain was enough to activate cell death, and the N-terminal 1-100 amino acid fragment was the minimal region to induce cell death and self-association. Our research provides important clues to elucidate the activation mechanism of AT1G12290.
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http://dx.doi.org/10.1016/j.bbrc.2020.11.111DOI Listing
January 2021

The Enigmatic Thelebolaceae (Thelebolales, Leotiomycetes): One New Genus and Five New Species.

Front Microbiol 2020 29;11:572596. Epub 2020 Oct 29.

Institute of Fungus Resources, Department of Ecology, College of Life Sciences, Guizhou University, Guiyang, China.

The family Thelebolaceae belongs to the order Thelebolales, class Leotiomycetes, and contains 22 genera. In this study, we introduce a new genus gen. nov. in the family Thelebolaceae, which is supported by morphological observation and multilocus-based [internal transcribed spacers (ITS) + and ITS + + + + ] phylogenetic analysis. Maximum-likelihood and Bayesian phylogenetic inference analyses indicated that is a distinct genus within this family. The new genus is compared against related Thelebolaceae genera, and its description and illustration are provided. This genus comprises one new species and one unnamed species (including two strains). We also report the addition of four new species - , , , and - in the family Thelebolaceae and present their morphological and phylogenetic characterizations.
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http://dx.doi.org/10.3389/fmicb.2020.572596DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7658094PMC
October 2020

A bi-enzymatic cascade to yield pyruvate as co-substrate for L-tyrosine production.

Appl Microbiol Biotechnol 2020 Dec 31;104(23):10005-10018. Epub 2020 Oct 31.

College of Life Science, Fujian Normal University, Fuzhou, 350117, Fujian, China.

L-Tyrosine is a versatile compound used in the fine chemical, pharmaceutical, and functional food industries. Here, we report a bi-enzymatic cascade involving alanine racemase (ALR) and D-amino acid oxidase (DAAO) to produce pyruvate, as co-substrate for L-tyrosine production, from the cheap substrate L-alanine. The BpALR (ALR from Bacillus pseudofirmus) was used as a whole-cell biocatalyst, converting L-alanine to D, L-alanine. The FsDAAO (DAAO from Fusarium solani) was immobilized to oxidize the D-alanine generated in the first step to pyruvate. Both systems were combined as a continuous-flow reactor for maximized L-alanine-to-pyruvate conversion rates. The optimal parameters and appropriate conditions for FsDAAO immobilization were investigated. The pyruvate concentration of 86.6 g/L was achieved within 17 h. Subsequently, a whole-cell biocatalyst system for L-tyrosine production, catalyzed by the tyrosine phenol-lyase (TPL) from Erwinia herbicola (EhTPL), was developed, and a fed-batch approach was applied with phenol and the pyruvate produced with the ALR/DAAO system mentioned above. The concentration of phenol and pyruvate in the reactor should not exceed 7.5 g/L and 10 g/L, respectively. Significantly, the L-tyrosine concentration of 152.5 g/L was achieved within 10 h, demonstrating the great potential for high-efficiency production of L-tyrosine through the approach we established in this paper. Graphical abstract KEY POINTS: • A specific bioreactor system for pyruvate produced from l-alanine was developed • The appropriate condition for immobilization of FsDAAO was investigated • A fed-batch process was established to produce l-tyrosine with recombinant E. coli • The bi-enzymatic cascade was successfully used for l-tyrosine production at low cost.
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http://dx.doi.org/10.1007/s00253-020-10975-4DOI Listing
December 2020

Structure and Function of Bacterial Microbiota in Eucommia ulmoides Bark.

Curr Microbiol 2020 Nov 7;77(11):3623-3632. Epub 2020 Aug 7.

Institute of Fungus Resources, Department of Ecology, College of Life Sciences, Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Guizhou University, Guiyang, 550025, Guizhou, China.

The study aimed to explore the bacterial community composition and the functions of core microbiota in Eucommia ulmoides bark. The bark samples of E. ulmoides were collected from Wangcang Sichuan Province, Cili Hunan Province, and Zunyi Guizhou Province, in China, respectively. Through the high-throughput sequencing methods and techniques, the community composition, core microbiota, and function of the bacteria were studied. The bacterial community of E. ulmoides bark consisted of 9 phyla, 11 classes, 22 orders, 28 families, 31 genera, and 37 OTUs. At the genus level, the dominant genus was the unclassified bacteria of Cyanobacteria, with a relative abundance of 97.01%. The bacterial communities of E. ulmoides bark from different areas have their unique units except for the common microbiota. The core microbiota of bacteria included an unclassified genus of Cyanobacteria, an unclassified genus of Mitochondria, Pseudomonas, Sphingobium, Rhizobium, Novosphingobium, Enterobacter, Rhodococcus, Curtobacterium, and Ralstonia. FAPROTAX function prediction suggested that the core microbiota has a substantial potential for photoautotrophy, phototrophy, aerobic chemoheterotrophy, chemoheterotrophy. Ten taxa composed the core microbiota, and the majority of them were related to the pharmacologically active ingredients of E. ulmoides bark. The research provides a scientific basis for the biological marker of genuineness and microbial technology for improving the content of medicinal ingredients of E. ulmoides.
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http://dx.doi.org/10.1007/s00284-020-02157-2DOI Listing
November 2020

Improved Production of Majority Cellulases in by Integration of Gene From .

Front Microbiol 2020 14;11:1633. Epub 2020 Jul 14.

National Joint Engineering Research Center of Industrial Microbiology and Fermentation Technology, College of Life Sciences, Fujian Normal University, Fuzhou, China.

Lignocellulose is an abundant waste resource and has been considered as a promising material for production of biofuels or other valuable bio-products. Currently, one of the major bottlenecks in the economic utilization of lignocellulosic materials is the cost-efficiency of converting lignocellulose into soluble sugars for fermentation. One way to address this problem is to seek superior lignocellulose degradation enzymes or further improve current production yields of lignocellulases. In the present study, the lignocellulose degradation capacity of a thermophilic fungus was firstly evaluated and compared to that of the biotechnological workhorse The data demonstrated that compared to displayed substantially higher cellulose-utilizing efficiency with relatively lower production of cellulases, indicating that better cellulases might exist in . Comparison of the protein secretome between and showed that the secreted protein categories were quite different in these two species. In addition, to prove that cellulases in had better enzymatic properties, the major cellulase cellobiohydrolase I (CBH1) from and were firstly characterized, respectively. The data showed that the specific activity of CBH1 was about 4.5-fold higher than CBH1 in a wide range of temperatures and pH. To explore whether increasing CBH1 activity in could contribute to improving the overall cellulose-utilizing efficiency of , gene was replaced with gene by integration of gene into gene locus. The data surprisingly showed that this gene replacement not only increased the cellobiohydrolase activities by around 4.1-fold, but also resulted in stronger induction of other cellulases genes, which caused the filter paper activities, Azo-CMC activities and β-glucosidase activities increased by about 2.2, 1.9, and 2.3-fold, respectively. The study here not only provided new resources of superior cellulases genes and new strategy to improve the cellulase production in , but also contribute to opening the path for fundamental research on
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http://dx.doi.org/10.3389/fmicb.2020.01633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7381231PMC
July 2020

Menaquinone-7 production in engineered Escherichia coli.

World J Microbiol Biotechnol 2020 Aug 1;36(9):132. Epub 2020 Aug 1.

CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.

Menaquinone-7 (MK-7), a highly valuable member of the vitamin K2 series, is an essential nutrient for humans. In this study, to develop engineered Escherichia coli strains for MK-7 production, heterogeneous heptaprenyl pyrophosphate synthetase (HepPPS) was introduced, and MK-7 production was first achieved in engineered E. coli by overexpression of Bacillus subtilis-derived HepPPS (BsHepPPS). Then, by optimizing the enzyme expression of the heterogenous mevalonic acid (MVA) pathway and the BsHepPPS, the titre of MK-7 increased to 2.3 μM, which was 22-fold higher than that of the original strain. The competitive pathways of MK-7 were further investigated by deletion of ubiCA or ispB. Finally, the scale-up fermentation of the engineered E. coli in a 5-L fermenter was studied under aerobic conditions using glucose, and 13.6 μM (8.8 mg/L) MK-7 was achieved. Additionally, metabolite analysis revealed a new bottleneck in the MK-7 pathway at ubiE, suggesting an avenue for further optimization. This report is the first to describe the metabolic engineering of MK-7 in E. coli, which provides a new perspective for MK-7 production.
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http://dx.doi.org/10.1007/s11274-020-02880-9DOI Listing
August 2020

Relationship between Gepotidacin Exposure and Prevention of On-Therapy Resistance Amplification in a Neisseria gonorrhoeae Hollow-Fiber Infection Model.

Antimicrob Agents Chemother 2020 09 21;64(10). Epub 2020 Sep 21.

Institute for Clinical Pharmacodynamics, Inc., Schenectady, New York, USA.

Multidrug-resistant has emerged as a threat to global health. The relationship between gepotidacin exposure and prevention of on-therapy amplification of drug-resistant was examined using a 7-day hollow-fiber infection model. The study design included both inactive (no-treatment and ciprofloxacin) and active (ceftriaxone) control regimens. Study drug concentration-time profiles were simulated in the system for a single oral 0.5 g ciprofloxacin dose, a single intramuscular 0.25 g ceftriaxone dose, and single or two (8 to 12 h apart) oral gepotidacin doses ranging from 0.75 to 12 g. The initial bacterial burden inoculated in the model was 10 CFU/ml. The gepotidacin, ciprofloxacin, and ceftriaxone broth MIC values for the challenge isolate ( GSK #8) were 0.5, 2, and 0.002 mg/liter, respectively. Samples were collected for enumeration of total and drug-resistant bacterial populations and drug concentrations. The no-treatment control reached a bacterial density greater than 10 CFU/ml over 24 h and remained consistent over the 7-day study period. The bacterial density in the model system of the ciprofloxacin regimen matched that of the growth control throughout the study duration, while the ceftriaxone regimen sterilized the model system by the end of day 1. For gepotidacin, a full dose-response relationship was observed. While failure was observed for the 0.75-, 1.5-, and 3-g single-dose regimens, all gepotidacin single- or divided-dose regimens totaling at least 4.5 g prevented resistance amplification and sterilized the model system. These data are useful to provide gepotidacin dose selection support for treating patients with gonorrhea infections.
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http://dx.doi.org/10.1128/AAC.00521-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7508576PMC
September 2020

Exploring the role and mechanisms of diallyl trisulfide and diallyl disulfide in chronic constriction-induced neuropathic pain in rats.

Korean J Pain 2020 Jul;33(3):216-225

Department of Anesthesiology, LinFen City Central Hospital of Shanxi Province, Linfen, Shanxi, China.

Background: Garlic oil is a rich source of organosulfur compounds including diallyl disulfide and diallyl trisulfide. There have been studies showing the neuroprotective actions of these organosulfur compounds. However, the potential of these organosulfur compounds in neuropathic pain has not been explored. The present study was aimed at investigating the pain attenuating potential of diallyl disulfide and diallyl trisulfide in chronic constriction injury (CCI)-induced neuropathic pain in rats. The study also explored their pain-attenuating mechanisms through modulation of HS, brain-derived neurotrophin factor (BDNF) and nuclear factor erythroid 2-related factor 2 (Nrf2).

Methods: The rats were subjected to CCI injury by ligating the sciatic nerve in four places. The development of neuropathic pain was measured by assessing mechanical hyperalgesia (Randall-Selittotest), mechanical allodynia (Von Frey test), and cold allodynia (acetone drop test) on 14th day after surgery.

Results: Administration of diallyl disulfide (25 and 50 mg/kg) and diallyl trisulfide (20 and 40 mg/kg) for 14 days led to a significant reduction in pain in CCI-subjected rats. Moreover, treatment with these organosulfur compounds led to the restoration of HS, BDNF and Nrf2 levels in the sciatic nerve and dorsal root ganglia. Coadministration of ANA-12 (BDNF blocker) abolished pain attenuating actions as well as BDNF and the Nrf2 restorative actions of diallyl disulfide and diallyl trisulfide, without modulating HS levels.

Conclusions: Diallyl disulfide and diallyl trisulfide have the potential to attenuate neuropathic pain in CCI-subjected rats possibly through activation of HS-BDNF-Nrf2 signaling pathway.
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http://dx.doi.org/10.3344/kjp.2020.33.3.216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7336342PMC
July 2020

Two-stage oxygen supply strategy for enhancing fed-batch production of pyrroloquinoline quinone in Hyphomicrobium denitrificans FJNU-6.

Appl Microbiol Biotechnol 2020 Aug 12;104(15):6615-6622. Epub 2020 Jun 12.

National and Local United Engineering Research Center of Industrial Microbiology and Fermentation Technology; College of Life Sciences, Fujian Normal University, Fuzhou, 350117, Fujian, People's Republic of China.

Oxygen is a vital parameter for pyrroloquinoline quinone (PQQ) biosynthesis. In this study, the effects of oxygen supply on the biosynthesis of PQQ were first investigated systematically with Hyphomicrobium denitrificans FJNU-6. Following a kinetic analysis of the specific cell growth rate (μ) and specific PQQ formation rate (μ) in 5 L benchtop fermentation systems at various oxygen supply levels ranging from 0 to 60%, a novel, two-stage oxygen supply strategy was developed for enhancing PQQ production and productivity. Moreover, the transcription of genes involved in methanol oxidation and PQQ biosynthesis was analyzed throughout the process to outline the effect of oxygen supply on cell metabolism. Furthermore, with constant feeding of methanol at 0-1 g/L after the initial methanol was consumed completely, the PQQ concentration and productivity reached 1070 mg/L and 7.64 mg/L/h, respectively, after 140 h in a 5-L fermenter. The two-stage oxygen supply strategy developed in this study provides an effective and economical strategy for the industrial production of PQQ.Key Points• A novel, two-stage oxygen supply strategy was developed for enhancing PQQ production and productivity.•The transcription of genes involved in methanol oxidation and PQQ biosynthesis was regulated by changes in oxygen supply.• This study offers an effective and economical strategy for industrial or large-scale production of PQQ.
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http://dx.doi.org/10.1007/s00253-020-10690-0DOI Listing
August 2020

Metabolic engineering of Escherichia coli for efficient production of L-alanyl-L-glutamine.

Microb Cell Fact 2020 Jun 11;19(1):129. Epub 2020 Jun 11.

Chinese Academy of Sciences Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.

Background: L-Alanyl-L-glutamine (AQ) is a functional dipeptide with high water solubility, good thermal stability and high bioavailability. It is widely used in clinical treatment, post-operative rehabilitation, sports health care and other fields. AQ is mainly produced via chemical synthesis which is complicated, time-consuming, labor-intensive, and have a low yield accompanied with the generation of by-products. It is therefore highly desirable to develop an efficient biotechnological process for the industrial production of AQ.

Results: A metabolically engineered E. coli strain for AQ production was developed by over-expressing L-amino acid α-ligase (BacD) from Bacillus subtilis, and inactivating the peptidases PepA, PepB, PepD, and PepN, as well as the dipeptide transport system Dpp. In order to use the more readily available substrate glutamic acid, a module for glutamine synthesis from glutamic acid was constructed by introducing glutamine synthetase (GlnA). Additionally, we knocked out glsA-glsB to block the first step in glutamine metabolism, and glnE-glnB involved in the ATP-dependent addition of AMP/UMP to a subunit of glutamine synthetase, which resulted in increased glutamine supply. Then the glutamine synthesis module was combined with the AQ synthesis module to develop the engineered strain that uses glutamic acid and alanine for AQ production. The expression of BacD and GlnA was further balanced to improve AQ production. Using the final engineered strain p15/AQ10 as a whole-cell biocatalyst, 71.7 mM AQ was produced with a productivity of 3.98 mM/h and conversion rate of 71.7%.

Conclusion: A metabolically engineered strain for AQ production was successfully developed via inactivation of peptidases, screening of BacD, introduction of glutamine synthesis module, and balancing the glutamine and AQ synthesis modules to improve the yield of AQ. This work provides a microbial cell factory for efficient production of AQ with industrial potential.
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http://dx.doi.org/10.1186/s12934-020-01369-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7291740PMC
June 2020

Mutagenic Effect of Three Ion Beams on Rice and Identification of Heritable Mutations by Whole Genome Sequencing.

Plants (Basel) 2020 Apr 26;9(5). Epub 2020 Apr 26.

National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang University, Hangzhou 310058, China.

High-energy ion beams are known to be an effective and unique type of physical mutagen in plants. However, no study on the mutagenic effect of argon (Ar) ion beam radiation on rice has been reported. Genome-wide studies on induced mutations are important to comprehend their characteristics for establishing knowledge-based protocols for mutation induction and breeding, which are still very limited in rice. The present study aimed to investigate the mutagenic effect of three ion beams, i.e., Ar, carbon (C) and neon (Ne) on rice and identify and characterize heritable induced mutations by the whole genome sequencing of six M plants. Dose-dependent damage effects were observed on M plants, which were developed from ion beam irradiated dry seeds of two (LH15, T23) and two (DS551, DS48) rice lines. High frequencies of chlorophyll-deficient seedlings and male-sterile plants were observed in all M populations (up to ~30% on M plant basis); plants from the seeds of different panicles of a common M plant appeared to have different mutations; the whole genome-sequencing demonstrated that there were 236-453 mutations in each of the six M plants, including single base substitutions (SBSs) and small insertion/deletions (InDels), with the number of SBSs ~ 4-8 times greater than that of InDels; SBS and InDel mutations were distributed across different genomic regions of all 12 chromosomes, however, only a small number of mutations (0-6) were present in exonic regions that might have an impact on gene function. In summary, the present study demonstrates that Ar, C and Ne ion beam radiation are all effective for mutation induction in rice and has revealed at the genome level the characteristics of the mutations induced by the three ion beams. The findings are of importance to the efficient use of ion beam radiation for the generation and utilization of mutants in rice.
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http://dx.doi.org/10.3390/plants9050551DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7284785PMC
April 2020

Carotenoids and lipid production from cultured in tea waste hydrolysate.

Biotechnol Biofuels 2020 16;13:74. Epub 2020 Apr 16.

1Engineering Research Center of Industrial Microbiology of Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117 Fujian China.

Background: In this study, renewable tea waste hydrolysate was used as a sole carbon source for carotenoids and lipid production. A novel mutant strain, RM18, was isolated through atmospheric and room-temperature plasma mutagenesis and continuous domestication in tea waste hydrolysate from ACCC20341.

Results: RM18 produced a larger biomass and more carotenoids and α-linolenic acid compared with the control strain cultured in tea waste hydrolysate. The highest yields of torularhodin (481.92 μg/g DCW) and torulene (501 μg/g DCW) from RM18 cultured in tea waste hydrolysate were 12.86- and 1.5-fold higher, respectively, than that of the control strain. In addition, α-linolenic acid production from RM18 in TWH accounted for 5.5% of total lipids, which was 1.58 times more than that of the control strain. Transcriptomic profiling indicated that enhanced central metabolism and terpene biosynthesis led to improved carotenoids production, whereas aromatic amino acid synthesis and DNA damage checkpoint and sensing were probably relevant to tea waste hydrolysate tolerance.

Conclusion: Tea waste is suitable for the hydrolysis of microbial cell culture mediums. The mutant RM18 showed considerable carotenoids and lipid production cultured in tea waste hydrolysate, which makes it viable for industrial applications.
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http://dx.doi.org/10.1186/s13068-020-01712-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7161300PMC
April 2020

Identification and Characterization of γ-Ray-Induced Mutations in Rice Cytoplasmic Genomes by Whole-Genome Sequencing.

Cytogenet Genome Res 2020 7;160(2):100-109. Epub 2020 Mar 7.

Chloroplasts and mitochondria are semi-autonomous organelles and have their own genomes (cytoplasmic genomes). Physical radiations (e.g., γ-rays) have been widely used in artificial mutation induction for plant germplasm enhancement and for breeding new cultivars. However, little is known at the genomic level about which kind of cytoplasmic mutations and/or characteristics could be induced in plants. The present study aimed to investigate the type, number, and distribution of inheritable cytoplasmic mutations induced by γ-rays in rice (Oryza sativa L.). Six plants were selected from the 2nd generation (M2) populations after γ-ray (137Cs) irradiation of the rice cultivar Nipponbare, 2 each for the 3 irradiation doses (150, 250, and 350 Gy), and their genomes were sequenced on an Illumina platform. Together with the whole-genome sequencing data of 3 external Nipponbare control plants, single-base substitutions (SBSs) and insertions/deletions (InDels) in chloroplast (cp) and mitochondrial (mt) genomes were identified and analyzed in-depth using bioinformatic tools. The majority of SBSs and InDels identified were background mutations in the 6 M2 plants, and the number of induced mutations varied greatly among the plants. Most induced mutations were present in a heterogeneous state, reflecting the fact that multiple cp and mt copies existed in the progenitor cells. The induced mutations were distributed in different genomic regions in the 6 M2 plants, including exonic regions, but none of them was predicted to cause nonsynonymous mutations or frameshifts. Our study thus revealed, at the genomic level, characteristics of cytoplasmic mutations induced by γ-rays in rice.
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http://dx.doi.org/10.1159/000506033DOI Listing
April 2020

[Reinforcement of Rhodobacter sphaeroides cofactor NADPH to increase the production of farnesol].

Sheng Wu Gong Cheng Xue Bao 2020 Jan;36(1):90-99

Engineering Research Center of Industrial Microbiology, Ministry of Education, Fujian Normal University, Fuzhou 350108, Fujian, China.

Farnesol (FOH) is produced by dephosphorylation of farnesyl diphosphate (FPP) derived from two universal building blocks, dimethylallyl diphosphate (DMAPP) and isopentenyl diphosphate (IPP). In Rhodobacter sphaeroides these building blocks are generated by MEP pathway, however, many of the biosynthetic reactions and biotransformations in the MEP pathway are limited by low availability of NADPH. Improvement of the amount of intracellular NADPH may enhance the synthesis of FOH. In this study, we utilized the strategies of increasing the production of NADPH and decreasing the consumption of NADPH. The expression of glucose 6-phosphate isomerase (pgi) and glutamate dehydrogenase (gdhA) were inhibited by RNA interference, respectively, and overexpression of 6-glucose phosphate dehydrogenase (zwf) and 6-glucose phosphate dehydrogenase (gnd) in the pentose phosphate pathway were carried out. The results showed that the content of NADPH in the recombinant strains increased significantly, the highest FOH production of RSpgii in the RNA interfered strain was 3.91 mg/g, and the FOH production increased to 3.43 mg/g after zwf gene and gnd gene has been overexpressed. In order to obtain strains with higher FOH production, we used RSpgii as the starting strain, and zwf, gnd and co-overexpressed zwf + gnd gene were overexpressed in RSpgii, respectively. The highest FOH production of the strain RSzgpi reached to 4.48 mg/g which was 2.24 times that of the starting strain RS-GY2.
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http://dx.doi.org/10.13345/j.cjb.190165DOI Listing
January 2020

Enhancement of NADPH availability for coproduction of coenzyme Q and farnesol from Rhodobacter sphaeroides.

J Ind Microbiol Biotechnol 2020 Feb 28;47(2):263-274. Epub 2020 Jan 28.

Engineering Research Center of Industrial Microbiology of Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, Fujian, China.

Coenzyme Q (CoQ)-an essential cofactor in the respiratory electron transport chain-has important pharmaceutical and healthcare applications. Farnesol (FOH)-an acyclic sesquiterpene alcohol-has garnered interest owing to its valuable clinical and medical benefits. Here, the coproduction of CoQ and FOH in Rhodobacter sphaeroides GY-2 was greatly improved through the enhancement of intracellular NADPH availability. Transcription of pgi, gdhA, and nuocd was, respectively, inhibited using RNA interference to reduce intracellular NAD(P)H consumption. Moreover, zwf, gnd, and zwf + gnd were overexpressed to enhance the pentose phosphate pathway, resulting in improved NADPH availability in most metabolically engineered R. sphaeroides strains. RSg-pgi with RNAi of pgi combined with overexpression of gnd produced 55.05 mg/L FOH that is twofold higher than the parental strain GY-2, and 185.5 mg/L CoQ can be coproduced at the same time. In conclusion, improved carbon flux can be redirected toward NADPH-dependent biosynthesis through the enhancement of NADPH availability.
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http://dx.doi.org/10.1007/s10295-020-02261-zDOI Listing
February 2020

Activity and Microbiological Efficacy of Gepotidacin from a Phase 2, Randomized, Multicenter, Dose-Ranging Study in Patients with Acute Bacterial Skin and Skin Structure Infections.

Antimicrob Agents Chemother 2020 02 21;64(3). Epub 2020 Feb 21.

Medicine Opportunities Research Unit, GlaxoSmithKline, Collegeville, Pennsylvania, USA.

A phase 2 study of gepotidacin demonstrated the safety and efficacy of 3 gepotidacin doses (750 mg every 12 h [q12h], 1,000 mg q12h, and 1,000 mg every 8 h [q8h]) in hospitalized patients with suspected/confirmed Gram-positive acute bacterial skin and skin structure infections (ABSSSIs). Evaluating microbiology outcomes and responses were secondary endpoints. Pretreatment isolates recovered from infected lesions underwent susceptibility testing per Clinical and Laboratory Standards Institute guidelines. accounted for 78/102 (76%) of Gram-positive isolates; 54/78 (69%) were methicillin-resistant (MRSA), and 24/78 (31%) were methicillin-susceptible (MSSA). Posttherapy microbiological success (culture-confirmed eradication of the pretreatment pathogen or presumed eradication based on a clinical outcome of success) for was 90% for the gepotidacin 750-mg q12h group, 89% for the 1,000-mg q12h, and 73% in the 1000-mg q8h group. For 78 isolates obtained from pretreatment lesions, gepotidacin MIC/MIC values were 0.25/0.5 μg/ml against both MRSA and MSSA. Isolates recovered from the few patients with posttreatment cultures showed no significant reduction in gepotidacin susceptibility (≥4-fold MIC increase) between pretreatment and posttreatment isolates. Two of the 78 isolates from pretreatment lesions had elevated gepotidacin MICs and had mutations known to occur in quinolone-resistant (GyrA S84L, ParC S80Y, and ParE D422E) or to confer elevated MICs to novel bacterial topoisomerase inhibitors (GyrA D83N, both isolates; ParC V67A, one isolate). This first report of microbiological outcomes and responses of gepotidacin in patients with ABSSSIs supports further evaluation of gepotidacin as a novel first-in-class antibacterial agent. (This study has been registered at ClinicalTrials.gov under identifier NCT02045797.).
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http://dx.doi.org/10.1128/AAC.01302-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7038298PMC
February 2020

Glutamate alleviates cadmium toxicity in rice via suppressing cadmium uptake and translocation.

J Hazard Mater 2020 02 28;384:121319. Epub 2019 Sep 28.

National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang University, Hangzhou, 310058, China; Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou, 310058, China. Electronic address:

Cadmium (Cd), a naturally occurring heavy metal, is toxic to animals and plants. Minimization of Cd in rice grain is important to human health since rice is the main source of Cd intake for human populations feeding on it as staple food. Glutamate (Glu) is reportedly involved in plant abiotic stress responses, whereas the underlying molecular mechanism remains poorly understood. In this study, we showed that supplement of Glu, but not glutamine, significantly alleviated Cd toxicity in hydroponically grown rice plants. Cd accumulation was reduced by 44.1% and 65.6% in root and shoot of rice plants respectively, after Glu supplementation (3 mM). Glu supplement restored chlorophyll biosynthesis and significantly ameliorated Cd-induced oxidative stress with reduced levels of HO, O, MDA, and increased activities of major anti-oxidant enzymes, catalase, peroxidase and glutathione S-transferase. Levels of stress-associated free amino acids proline, arginine and γ-aminobutyric acid were also reduced after Glu supplement. We further demonstrated that Glu supplement suppressed the Cd-induced expression of metal transporter genes OsNramp1, OsNramp5, OsIRT1, OsIRT2, OsHMA2 and OsHMA3 in roots of Cd-treated plants. Taken together, our results suggest that Glu supplement could alleviate Cd toxicity in rice by suppressing Cd uptake and translocation.
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http://dx.doi.org/10.1016/j.jhazmat.2019.121319DOI Listing
February 2020

A Suppressor Mutation Partially Reverts the Trait Lowered Methylation in the Promoter of in Rice.

Front Plant Sci 2019 2;10:1003. Epub 2019 Aug 2.

National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang University, Hangzhou, China.

The trait of a yellow leaf rice mutant (HYB), controlled epigenetically by elevated CHG methylation of the () promoter, has reduced chlorophyll content, altered tetrapyrrole biosynthesis, and deregulated transcription of photosynthesis-associated nuclear genes (PhANGs) compared to its wild-type progenitor Longtefu B (LTB). In the present study, we identified a suppressor mutant (CYB) of HYB and characterized its genetic, molecular, and physiological basis of the mutant phenotype. We found that the light-green phenotype of CYB was caused by a suppressor mutation in an unknown gene other than . Compared to HYB, the CHG methylation in the promoter was reduced, while OsGUN4 transcript and protein abundance levels were increased in CYB. The contents of total chlorophyll and its intermediate metabolites (except protoporphyrin IX) in CYB plants were intermediate between HYB and LTB. The expression levels of 30 genes involved in tetrapyrrole biosynthesis in CYB were all partially reverted to those of LTB, so were the PhANGs. In summary, a suppressor mutation caused the reversion of the trait reducing CHG methylation in promoter.
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http://dx.doi.org/10.3389/fpls.2019.01003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6688194PMC
August 2019

Co-production of farnesol and coenzyme Q from metabolically engineered Rhodobacter sphaeroides.

Microb Cell Fact 2019 May 31;18(1):98. Epub 2019 May 31.

Engineering Research Center of Industrial Microbiology of Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, Fujian, China.

Background: Farnesol is an acyclic sesquiterpene alcohol present in the essential oils of various plants in nature. It has been reported to be valuable in medical applications, such as alleviation of allergic asthma, gliosis, and edema as well as anti-cancerous and anti-inflammatory effects. Coenzyme Q (CoQ), an essential cofactor in the aerobic respiratory electron transport chain, has attracted growing interest owing to its clinical benefits and important applications in the pharmaceutical, food, and health industries. In this work, co-production of (E,E)-farnesol (FOH) and CoQ was achieved by combining 3 different exogenous terpenes or sesquiterpene synthase with the RNA interference of psy (responsible for phytoene synthesis in Rhodobacter sphaeroides GY-2).

Results: FOH production was significantly increased by overexpressing exogenous terpene synthase (TPS), phosphatidylglycerophosphatase B (PgpB), and sesquiterpene synthase (ATPS), as well as RNAi-mediated silencing of psy coding phytoene synthase (PSY) in R. sphaeroides strains. Rs-TPS, Rs-ATPS, and Rs-PgpB respectively produced 68.2%, 43.4%, and 21.9% higher FOH titers than that of the control strain. Interestingly, the CoQ production of these 3 recombinant R. sphaeroides strains was exactly opposite to that of FOH. However, CoQ production was almost unaffected in R. sphaeroides strains modified by psy RNA interference. The highest FOH production of 40.45 mg/L, which was twice as high as that of the control, was obtained from the TPS-PSYi strain, where the exogenous TPS was combined with the weakening of the phytoene synthesis pathway via psy RNA interference. CoQ production in TPS-PSYi, ATPS-PSYi, and PgpB-PSYi was decreased and lower than that of the control strain.

Conclusions: The original flux that contributed to phytoene synthesis was effectively redirected to provide precursors toward FOH or CoQ synthesis via psy RNA interference, which led to weakened carotenoid synthesis. The improved flux that was originally involved in CoQ production and phytoene synthesis was redirected toward FOH synthesis via metabolic modification. This is the first reported instance of FOH and CoQ co-production in R. sphaeroides using a metabolic engineering strategy.
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http://dx.doi.org/10.1186/s12934-019-1145-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6544981PMC
May 2019

Mutation of Impairs Plant Growth and Phytic Acid Synthesis in Rice.

Plants (Basel) 2019 Apr 29;8(5). Epub 2019 Apr 29.

National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang University, Hangzhou 310058, China.

Inositol 1,3,4-trisphosphate 5/6-kinase (ITPK) is encoded by six genes in rice (). A previous study had shown that nucleotide substitutions of could significantly lower the phytic acid content in rice grains. In the present study, the possibility of establishing a genome editing-based method for breeding low-phytic acid cultivars in rice was explored, in conjunction with the functional determination of OsITPK6. Four mutant lines were generated by targeted mutagenesis of the gene's first exon using the CRISPR/Cas9 method, one () with a 6-bp in-frame deletion, and other three with frameshift mutations (, _, and _). The frameshift mutations severely impaired plant growth and reproduction, while the effect of was relatively limited. The mutant lines and _ had significantly lower levels (-10.1% and -32.1%) of phytic acid and higher levels (4.12- and 5.18-fold) of inorganic phosphorus compared with the wild-type (WT) line. The line also showed less tolerance to osmotic stresses. Our research demonstrates that mutations of , while effectively reducing phytic acid biosynthesis in rice grain, could significantly impair plant growth and reproduction.
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http://dx.doi.org/10.3390/plants8050114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6572258PMC
April 2019

Overexpression of Nucleotide-Binding and Leucine-Rich Repeat Genes and () Confers Broad-Spectrum Disease Resistance in Rice.

Front Plant Sci 2019 5;10:417. Epub 2019 Apr 5.

State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, College of Life Sciences, Wuhan University, Wuhan, China.

The nucleotide-binding domain leucine-rich repeat (NLR) immune receptors play important roles in innate plant immunity. The activation of NLRs is specifically induced by their cognate effectors released from pathogens. Autoactive NLRs are expected to confer broad-spectrum resistance because they do not need cognate effectors to activate their immune responses. In this study, we demonstrated that the genes and () from were autoactive in and conferred broad-spectrum resistance to fungal pathogen , bacterial pathogen (), and pest brown planthopper (BPH, Stål). These results revealed that interfamily transfer of dicot NLRs to monocot species could be functional. The transgenic plants displayed early and strong induction of reactive oxygen species (ROS), callose deposition, and expression of defense-related genes after challenged with . The transcriptome analysis showed that the expressions of some defense-related genes were primed to adapt the transformed autoactive NLRs in the transgenic plants. This study indicates that autoactive NLRs are a promising resource for breeding crops with broad-spectrum resistance and provides new insights for engineering disease resistance.
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http://dx.doi.org/10.3389/fpls.2019.00417DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6459959PMC
April 2019

Phospholipidase Dδ Negatively Regulates the Function of to . (RPM1).

Front Plant Sci 2018 18;9:1991. Epub 2019 Jan 18.

State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, College of Life Sciences, Wuhan University, Wuhan, China.

RPM1 is a plant immune receptor that specially recognizes pathogen-released effectors to activate effector-triggered immunity (ETI) in . RPM1 triggers ETI and hypersensitive response (HR) for disease resistance. Previous reports indicated that Phospholipase D (PLD) positively regulated RPM1-mediated HR. However, single, double, and triple mutants of 12 members of the PLD family in did not show suppressed RPM1-mediated HR, indicating the functional redundancy among PLD members. In this study, we revealed that PLD could negatively regulate the function of RPM1. We found that RPM1 interacted with PLDδ, but did not interact with PLDβ1, PLDβ2, and PLDγ3. Overexpression of δ conducted to a reduction of protein level and corresponding activity of RPM1. We found that abscisic acid (ABA) reduced the protein level of RPM1, and the ABA-induced RPM1 reduction required PLD activity and PLD-derived phosphatidic acid (PA). Our study shows that PLD plays both negative and positive roles regulating the protein level and activity of RPM1 during stress responses in plants. PLD proteins are regulating points to integrate the abiotic and biotic responses of plants.
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http://dx.doi.org/10.3389/fpls.2018.01991DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6345720PMC
January 2019