1
|
Liao HS, Lee KT, Chung YH, Chen SZ, Hung YJ, Hsieh MH. Glutamine induces lateral root initiation, stress responses, and disease resistance in Arabidopsis. PLANT PHYSIOLOGY 2024; 195:2289-2308. [PMID: 38466723 DOI: 10.1093/plphys/kiae144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/06/2024] [Accepted: 02/20/2024] [Indexed: 03/13/2024]
Abstract
The production of glutamine (Gln) from NO3- and NH4+ requires ATP, reducing power, and carbon skeletons. Plants may redirect these resources to other physiological processes using Gln directly. However, feeding Gln as the sole nitrogen (N) source has complex effects on plants. Under optimal concentrations, Arabidopsis (Arabidopsis thaliana) seedlings grown on Gln have similar primary root lengths, more lateral roots, smaller leaves, and higher amounts of amino acids and proteins compared to those grown on NH4NO3. While high levels of Gln accumulate in Arabidopsis seedlings grown on Gln, the expression of GLUTAMINE SYNTHETASE1;1 (GLN1;1), GLN1;2, and GLN1;3 encoding cytosolic GS1 increases and expression of GLN2 encoding chloroplastic GS2 decreases. These results suggest that Gln has distinct effects on regulating GLN1 and GLN2 gene expression. Notably, Arabidopsis seedlings grown on Gln have an unexpected gene expression profile. Compared with NH4NO3, which activates growth-promoting genes, Gln preferentially induces stress- and defense-responsive genes. Consistent with the gene expression data, exogenous treatment with Gln enhances disease resistance in Arabidopsis. The induction of Gln-responsive genes, including PATHOGENESIS-RELATED1, SYSTEMIC ACQUIRED RESISTANCE DEFICIENT1, WRKY54, and WALL ASSOCIATED KINASE1, is compromised in salicylic acid (SA) biosynthetic and signaling mutants under Gln treatments. Together, these results suggest that Gln may partly interact with the SA pathway to trigger plant immunity.
Collapse
Affiliation(s)
- Hong-Sheng Liao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Kim-Teng Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences, The Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan
| | - Yi-Hsin Chung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Soon-Ziet Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Jie Hung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences, The Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan
- Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan
| |
Collapse
|
2
|
Chung YH, Chen TC, Yang WJ, Chen SZ, Chang JM, Hsieh WY, Hsieh MH. Ectopic expression of a bacterial thiamin monophosphate kinase enhances vitamin B1 biosynthesis in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:1330-1343. [PMID: 37996996 DOI: 10.1111/tpj.16563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 11/25/2023]
Abstract
Plants and bacteria have distinct pathways to synthesize the bioactive vitamin B1 thiamin diphosphate (TDP). In plants, thiamin monophosphate (TMP) synthesized in the TDP biosynthetic pathway is first converted to thiamin by a phosphatase, which is then pyrophosphorylated to TDP. In contrast, bacteria use a TMP kinase encoded by ThiL to phosphorylate TMP to TDP directly. The Arabidopsis THIAMIN REQUIRING2 (TH2)-encoded phosphatase is involved in TDP biosynthesis. The chlorotic th2 mutants have high TMP and low thiamin and TDP. Ectopic expression of Escherichia coli ThiL and ThiL-GFP rescued the th2-3 mutant, suggesting that the bacterial TMP kinase could directly convert TMP into TDP in Arabidopsis. These results provide direct evidence that the chlorotic phenotype of th2-3 is caused by TDP rather than thiamin deficiency. Transgenic Arabidopsis harboring engineered ThiL-GFP targeting to the cytosol, chloroplast, mitochondrion, or nucleus accumulated higher TDP than the wild type (WT). Ectopic expression of E. coli ThiL driven by the UBIQUITIN (UBI) promoter or an endosperm-specific GLUTELIN1 (GT1) promoter also enhanced TDP biosynthesis in rice. The pUBI:ThiL transgenic rice accumulated more TDP and total vitamin B1 in the leaves, and the pGT1:ThiL transgenic lines had higher TDP and total vitamin B1 in the seeds than the WT. Total vitamin B1 only increased by approximately 25-30% in the polished and unpolished seeds of the pGT1:ThiL transgenic rice compared to the WT. Nevertheless, these results suggest that genetic engineering of a bacterial vitamin B1 biosynthetic gene downstream of TMP can enhance vitamin B1 production in rice.
Collapse
Affiliation(s)
- Yi-Hsin Chung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Ting-Chieh Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Wen-Ju Yang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Soon-Ziet Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Jia-Ming Chang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Wei-Yu Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| |
Collapse
|
3
|
Hsieh WY, Wang HM, Chung YH, Lee KT, Liao HS, Hsieh MH. THIAMIN REQUIRING2 is involved in thiamin diphosphate biosynthesis and homeostasis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:1383-1396. [PMID: 35791282 DOI: 10.1111/tpj.15895] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/28/2022] [Accepted: 07/01/2022] [Indexed: 06/15/2023]
Abstract
The THIAMIN REQUIRING2 (TH2) protein comprising a mitochondrial targeting peptide followed by a transcription enhancement A and a haloacid dehalogenase domain is a thiamin monophosphate (TMP) phosphatase in the vitamin B1 biosynthetic pathway. The Arabidopsis th2-3 T-DNA insertion mutant was chlorotic and deficient in thiamin diphosphate (TDP). Complementation assays confirmed that haloacid dehalogenase domain alone was sufficient to rescue the th2-3 mutant. In pTH2:TH2-GFP/th2-3 complemented plants, the TH2-GFP was localized to the cytosol, mitochondrion, and nucleus, indicating that the vitamin B1 biosynthetic pathway extended across multi-subcellular compartments. Engineered TH2-GFP localized to the cytosol, mitochondrion, nucleus, and chloroplast, could complement the th2 mutant. Together, these results highlight the importance of intracellular TMP and thiamin trafficking in vitamin B1 biosynthesis. In an attempt to enhance the production of thiamin, we created various constructs to overexpress TH2-GFP in the cytosol, mitochondrion, chloroplast, and nucleus. Unexpectedly, overexpressing TH2-GFP resulted in an increase rather than a decrease in TMP. While studies on th2 mutants support TH2 as a TMP phosphatase, analyses of TH2-GFP overexpression lines implicating TH2 may also function as a TDP phosphatase in planta. We propose a working model that the TMP/TDP phosphatase activity of TH2 connects TMP, thiamin, and TDP into a metabolic cycle. The TMP phosphatase activity of TH2 is required for TDP biosynthesis, and the TDP phosphatase activity of TH2 may modulate TDP homeostasis in Arabidopsis.
Collapse
Affiliation(s)
- Wei-Yu Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Hsin-Mei Wang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Yi-Hsin Chung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Kim-Teng Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
- Molecular and Biological Agricultural Sciences, Taiwan International Graduate Program, Academia Sinica, Taipei, 11529, Taiwan
| | - Hong-Sheng Liao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
- Molecular and Biological Agricultural Sciences, Taiwan International Graduate Program, Academia Sinica, Taipei, 11529, Taiwan
- Department of Life Sciences, National Central University, Taoyuan, 32001, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung, 40227, Taiwan
| |
Collapse
|
4
|
Lee YJ, Kim JK, Baek SA, Yu JS, You MK, Ha SH. Differential Regulation of an OsIspH1, the Functional 4-Hydroxy-3-Methylbut-2-Enyl Diphosphate Reductase, for Photosynthetic Pigment Biosynthesis in Rice Leaves and Seeds. FRONTIERS IN PLANT SCIENCE 2022; 13:861036. [PMID: 35498655 PMCID: PMC9044040 DOI: 10.3389/fpls.2022.861036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/10/2022] [Indexed: 06/02/2023]
Abstract
The methylerythritol 4-phosphate (MEP) pathway is responsible for providing common precursors for the biosynthesis of diverse plastidial terpenoids, including chlorophylls, carotenoids, and phytohormones, in plants. In rice (Oryza sativa), the last-step genes encoding 4-hydroxy-3-methylbut-2-enyl diphosphate reductase [HDR/isoprenoid synthesis H (IspH)] have been annotated in two genes (OsIspH1 and OsIspH2) in the rice genome. The spatial transcript levels indicated that OsIspH1 is highly expressed in all tissues at different developmental stages, whereas OsIspH2 is barely expressed due to an early stop in exon 1 caused by splicing error. OsIspH1 localized into plastids and osisph1, a T-DNA inserted knockout mutant, showed an albino phenotype, indicating that OsIspH1 is the only functional gene. To elucidate the role of OsIspH1 in the MEP pathway, we created two single (H145P and K407R) and double (H145P/K407R) mutations and performed complementation tests in two hdr mutants, including Escherichia coli DLYT1 strains and osisph1 rice plants. The results showed that every single mutation retained HDR function, but a double mutation lost it, proposing that the complementary relations of two residues might be important for enzyme activity but not each residue. When overexpressed in rice plants, the double-mutated gene, OsIspH1MUT , reduced chlorophyll and carotenoid biosynthesis in the leaves and seeds. It confirmed the crucial role of OsIspH1 in plastidic terpenoid biosynthesis, revealing organ-specific differential regulation of OsIspH1 in rice plants.
Collapse
Affiliation(s)
- Yeo Jin Lee
- Department of Genetics and Biotechnology, Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, South Korea
| | - Jae Kwang Kim
- Division of Life Sciences, Bio-Resource and Environmental Center, Incheon National University, Incheon, South Korea
| | - Seung-A Baek
- Division of Life Sciences, Bio-Resource and Environmental Center, Incheon National University, Incheon, South Korea
| | - Ji-Su Yu
- Department of Genetics and Biotechnology, Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, South Korea
| | - Min Kyoung You
- Department of Genetics and Biotechnology, Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, South Korea
| | - Sun-Hwa Ha
- Department of Genetics and Biotechnology, Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, South Korea
| |
Collapse
|
5
|
Shailaja A, Srinath M, Bindu BVB, Giri CC. Isolation of 4-hydroxy 3-methyl 2-butenyl 4-diphosphate reductase ( ApHDR) gene of methyl erythritol diphosphate (MEP) pathway, in silico analysis and differential tissue specific ApHDR expression in Andrographis paniculata (Burm. f) Nees. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2021; 27:223-235. [PMID: 33707865 PMCID: PMC7907293 DOI: 10.1007/s12298-021-00952-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/23/2021] [Accepted: 02/10/2021] [Indexed: 06/12/2023]
Abstract
UNLABELLED The full length Andrographis paniculate 4-hydroxy 3-methyl 2-butenyl 4-diphosphate reductase (ApHDR) gene of MEP pathway was isolated for the first time. The ApHDR ORF with 1404 bp flanked by 100 bp 5'UTR and 235 bp 3'UTR encoding 467 amino acids (NCBI accession number: MK503970) and cloned in pET 102, transformed and expressed in E. coli BL21. The ApHDR protein physico-chemical properties, secondary and tertiary structure were analyzed. The Ramachandran plot showed 93.8% amino acids in the allowed regions, suggesting high reliability. The cluster of 16 ligands for binding site in ApHDR involved six amino acid residues having 5-8 ligands. The Fe-S cluster binding site was formed with three conserved residues of cysteine at positions C123, C214, C251 of ApHDR. The substrate HMBPP and inhibitors clomazone, paraquat, benzyl viologen's interactions with ApHDR were also assessed using docking. The affinity of Fe-S cluster binding to the cleft was found similar to HMBPP. The HPLC analysis of different type of tissue (plant parts) revealed highest andrographolide content in young leaves followed by mature leaves, stems and roots. The differential expression profile of ApHDR suggested a significant variation in the expression pattern among different tissues such as mature leaves, young leaves, stem and roots. A 16-fold higher expression of ApHDR was observed in the mature leaves of A. paniculata as compared to roots. The young leaves and stem showed 5.5 fold and fourfold higher expression than roots of A. paniculata. Our result generated new genomic information on ApHDR which may open up prospects of manipulation for enhanced diterpene lactone andrographolide production in A. paniculata. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s12298-021-00952-0.
Collapse
Affiliation(s)
- Aayeti Shailaja
- Centre for Plant Molecular Biology (CPMB), Osmania University, Hyderabad, Telangana 500007 India
| | - Mote Srinath
- Centre for Plant Molecular Biology (CPMB), Osmania University, Hyderabad, Telangana 500007 India
| | | | - Charu Chandra Giri
- Centre for Plant Molecular Biology (CPMB), Osmania University, Hyderabad, Telangana 500007 India
| |
Collapse
|
6
|
Krause T, Reichelt M, Gershenzon J, Schmidt A. Analysis of the isoprenoid pathway intermediates, dimethylallyl diphosphate and isopentenyl diphosphate, from crude plant extracts by liquid chromatography tandem mass spectrometry. PHYTOCHEMICAL ANALYSIS : PCA 2020; 31:770-777. [PMID: 32337807 DOI: 10.1002/pca.2941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/10/2020] [Accepted: 03/12/2020] [Indexed: 06/11/2023]
Abstract
OBJECTIVE We sought to develop a sensitive and accurate analytical method for the detection and quantification of IDP and DMADP as well as their monophosphate derivatives in crude plant extracts. METHODS A liquid chromatography method coupled to tandem mass spectrometry (LC-MS/MS) with multiple reaction monitoring (MRM) was established to measure the amounts of IDP and DMADP down to low picogram levels, which was linear over at least three orders of magnitude. Extracts were enriched using an anion exchanger, and chromatographic separation was achieved using a β-cyclodextrin column. A S-thiolodiphosphate analog of DMADP was employed as an internal standard. RESULTS Dilution series of authentic compounds were used to determine the limits of detection and quantification for IDP, DMADP and their corresponding monophosphates. A survey of plant species producing varying amounts of isoprenoids showed a corresponding variation in IDP and DMADP with the ratio of DMADP/IDP ranging from 4:1 to 2:1. Trace levels of isopentenyl monophosphate (IP) and dimethylallyl monophosphate (DMAP) were also detected. CONCLUSION The LC-MS/MS method described enables absolute quantification of in planta levels of IDP and DMADP for the first time. The method is also suitable for analysing bacterial and animal samples as well as enzyme assays.
Collapse
Affiliation(s)
- Toni Krause
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Michael Reichelt
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Jonathan Gershenzon
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Axel Schmidt
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Jena, Germany
| |
Collapse
|
7
|
Hsieh WY, Liao JC, Wang HT, Hung TH, Tseng CC, Chung TY, Hsieh MH. The Arabidopsis thiamin-deficient mutant pale green1 lacks thiamin monophosphate phosphatase of the vitamin B 1 biosynthesis pathway. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:145-157. [PMID: 28346710 DOI: 10.1111/tpj.13552] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/20/2017] [Accepted: 03/21/2017] [Indexed: 05/24/2023]
Abstract
Thiamin diphosphate (TPP, vitamin B1 ) is an essential coenzyme present in all organisms. Animals obtain TPP from their diets, but plants synthesize TPPde novo. We isolated and characterized an Arabidopsis pale green1 (pale1) mutant that contained higher concentrations of thiamin monophosphate (TMP) and less thiamin and TPP than the wild type. Supplementation with thiamin, but not the thiazole and pyrimidine precursors, rescued the mutant phenotype, indicating that the pale1 mutant is a thiamin-deficient mutant. Map-based cloning and whole-genome sequencing revealed that the pale1 mutant has a mutation in At5g32470 encoding a TMP phosphatase of the TPP biosynthesis pathway. We further confirmed that the mutation of At5g32470 is responsible for the mutant phenotypes by complementing the pale1 mutant with constructs overexpressing full-length At5g32470. Most plant TPP biosynthetic enzymes are located in the chloroplasts and cytosol, but At5g32470-GFP localized to the mitochondrion of the root, hypocotyl, mesophyll and guard cells of the 35S:At5g32470-GFP complemented plants. The subcellular localization of a functional TMP phosphatase suggests that the complete vitamin B1 biosynthesis pathway may involve the chloroplasts, mitochondria and cytosol in plants. Analysis of PALE1 promoter-uidA activity revealed that PALE1 is mainly expressed in vascular tissues of Arabidopsis seedlings. Quantitative RT-PCR analysis of TPP biosynthesis genes and genes encoding the TPP-dependent enzymes pyruvate dehydrogenase, α-ketoglutarate dehydrogenase and transketolase revealed that the transcript levels of these genes were upregulated in the pale1 mutant. These results suggest that endogenous levels of TPP may affect the expression of genes involved in TPP biosynthesis and TPP-dependent enzymes.
Collapse
Affiliation(s)
- Wei-Yu Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Jo-Chien Liao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Hsin-Tzu Wang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Tzu-Huan Hung
- Biotechnology Division, Taiwan Agricultural Research Institute, Taichung, 41362, Taiwan
| | - Ching-Chih Tseng
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Tsui-Yun Chung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| |
Collapse
|
8
|
Cheng Q, Tong Y, Wang Z, Su P, Gao W, Huang L. Molecular cloning and functional identification of a cDNA encoding 4-hydroxy-3-methylbut-2-enyl diphosphate reductase from Tripterygium wilfordii. Acta Pharm Sin B 2017; 7:208-214. [PMID: 28303228 PMCID: PMC5343154 DOI: 10.1016/j.apsb.2016.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/20/2016] [Accepted: 12/12/2016] [Indexed: 01/27/2023] Open
Abstract
The 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR) is the last step key enzyme of the methylerythritol phosphate (MEP) pathway, synthesizing isopentenyl diphosphate and its allyl isomer dimethylallyl diphosphate, which is important for regulation of isoprenoid biosynthesis. Here the full-length cDNA of HDR, designated TwHDR (GenBank Accession No. KJ933412.1), was isolated from Tripterygium wilfordii for the first time. TwHDR has an open reading frame (ORF) of 1386 bp encoding 461 amino acids. TwHDR exhibits high homology with HDRs of other plants, with an N-terminal conserved domain and three conserved cysteine residues. TwHDR cDNA was cloned into an expression vector and transformed into an Escherichia coli hdr mutant. Since loss-of-function E.coli hdr mutant is lethal, the result showed that transformation of TwHDR cDNA rescued the E.coli hdr mutant. This complementation assay suggests that the TwHDR cDNA encodes a functional HDR enzyme. The expression of TwHDR was induced by methyl-jasmonate (MJ) in T. wilfordii suspension cells. The expression of TwHDR reached the highest level after 1 h of MJ treatment. These results indicate that we have identified a functional TwHDR enzyme, which may play a pivotal role in the biosynthesis of diterpenoid triptolide in T. wilfordii.
Collapse
Affiliation(s)
- Qiqing Cheng
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China
- National Resource Center for Chinese Materia Medica, Academy of Chinese Medical Sciences, Beijing 100700, China
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, China
| | - Yuru Tong
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China
- National Resource Center for Chinese Materia Medica, Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Zihao Wang
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China
| | - Ping Su
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China
- National Resource Center for Chinese Materia Medica, Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Wei Gao
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China
- Corresponding author. Tel.: +86 10 83911671; Fex: +86 10 83911627 (Wei Gao).
| | - Luqi Huang
- National Resource Center for Chinese Materia Medica, Academy of Chinese Medical Sciences, Beijing 100700, China
- Corresponding author. Tel.: +86 10 83911671; Fex: +86 10 83911627 (Wei Gao).
| |
Collapse
|
9
|
Brown AC, Kokoczka R, Parish T. LytB1 and LytB2 of Mycobacterium tuberculosis Are Not Genetically Redundant. PLoS One 2015; 10:e0135638. [PMID: 26309039 PMCID: PMC4550268 DOI: 10.1371/journal.pone.0135638] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/23/2015] [Indexed: 11/26/2022] Open
Abstract
Mycobacterium tuberculosis synthesises isoprenoid precursors via the MEP/DOXP pathway and at least five enzymes in the pathway (Dxs1, Dxr/IspC, IspD, IspF, and GcpE/IspG) are required for growth in vitro. We investigated the role of LytB (IspH) in M. tuberculosis; M. tuberculosis is unusual in that it has two homologs–LytB1 and LytB2. We were unable to delete the lytB2 gene unless we provided an additional copy elsewhere, demonstrating that this is the essential homolog. We expressed lytB1 from the lytB2 promoter and confirmed that this could not complement for loss of function of lytB2, despite LytB1 possessing all the previously described conserved critical residues. Interestingly the sole LytB homolog of Mycobacterium smegmatis was able to compensate for loss of LytB2 in M. tuberculosis. We tested translational fusions of LytB1 and LytB2 for functionality in M. tuberculosis, but only a fusion with 90% N-terminal LytB2 and 10% C-terminal LytB1 was functional. In order to identify the key difference between the two proteins, site directed mutagenesis was used to change LytB2 residues into their counterparts in LytB1. None of these amino acid substitutions was essential for function and all lytB2 mutant alleles were functional. In contrast, mutation of the key residues for [Fe4S4] cluster formation, as well as a catalytic residue in LytB1 did not result in functional complementation. Thus, although LytB1 and LytB2 are not genetically redundant, this is not dependent on small amino acid changes, but is likely to be a result of major overall structural differences.
Collapse
Affiliation(s)
- Amanda Claire Brown
- Queen Mary University of London, London, E1 2AD, United Kingdom
- Barts & the London School of Medicine and Dentistry, London, E1 2AD, United Kingdom
| | - Rachel Kokoczka
- TB Discovery Research, Infectious Disease Research Institute, Seattle, WA, 98102, United States of America
| | - Tanya Parish
- Queen Mary University of London, London, E1 2AD, United Kingdom
- Barts & the London School of Medicine and Dentistry, London, E1 2AD, United Kingdom
- TB Discovery Research, Infectious Disease Research Institute, Seattle, WA, 98102, United States of America
- * E-mail:
| |
Collapse
|
10
|
Hsieh WY, Hsieh MH. The amino-terminal conserved domain of 4-hydroxy-3-methylbut-2-enyl diphosphate reductase is critical for its function in oxygen-evolving photosynthetic organisms. PLANT SIGNALING & BEHAVIOR 2015; 10:e988072. [PMID: 25723575 PMCID: PMC4622703 DOI: 10.4161/15592324.2014.988072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 09/17/2014] [Accepted: 09/17/2014] [Indexed: 05/22/2023]
Abstract
4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR), also known as isoprenoid synthesis H (IspH) or lysis-tolerant B (LytB), catalyzes the last step of the methylerythritol phosphate pathway to synthesize isopentenyl diphosphate and dimethylallyl diphosphate. The structure and reaction mechanism of IspH have been actively investigated in Escherichia coli but little is known in plants. Compared with the bacterial IspH, cyanobacterial and plant HDRs all contain an extra N-terminal conserved domain (NCD) that is essential for their function. Tyr72 in the NCD and several plant-specific residues around the central active site are critical for Arabidopsis HDR function. These results suggest that the structure and reaction mechanism of HDR/IspH may be different between plants and bacteria. The E. coli IspH is an iron-sulfur protein that is sensitive to oxygen. It is possible that the cyanobacterial HDR may independently evolve from the common ancestor of prokaryotes to obtain the NCD, which may protect the enzyme from high concentration of oxygen during photosynthesis.
Collapse
Affiliation(s)
- Wei-Yu Hsieh
- Institute of Plant and Microbial Biology; Academia Sinica; Taipei, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology; Academia Sinica; Taipei, Taiwan
- Correspondence to: Ming-Hsiun Hsieh;
| |
Collapse
|