scholarly journals Pathogen and Pest Responses Are Altered Due to RNAi-Mediated Knockdown of GLYCOALKALOID METABOLISM 4 in Solanum tuberosum

2017 ◽  
Vol 30 (11) ◽  
pp. 876-885 ◽  
Author(s):  
Jamuna Risal Paudel ◽  
Charlotte Davidson ◽  
Jun Song ◽  
Itkin Maxim ◽  
Asaph Aharoni ◽  
...  
Keyword(s):  
Solanum Tuberosum ◽  
Biosynthetic Pathway ◽  
Plant Protection ◽  
Insect Pest ◽  
Metabolite Profile ◽  
Gene Encoding ◽  
Rnai Line ◽  
Leaf Consumption ◽  
Insect Mortality ◽  
Potato Growth

Steroidal glycoalkaloids (SGAs) are major secondary metabolites constitutively produced in cultivated potato Solanum tuberosum, and α-solanine and α-chaconine are the most abundant SGAs. SGAs are toxic to humans at high levels but their role in plant protection against pests and pathogens is yet to be established. In this study, levels of SGAs in potato were reduced by RNA interference (RNAi)-mediated silencing of GLYCOALKALOID METABOLISM 4 (GAME4)—a gene encoding cytochrome P450, involved in an oxidation step in the conversion of cholesterol to SGA aglycones. Two GAME4 RNAi lines, T8 and T9, were used to investigate the effects of manipulation of the SGA biosynthetic pathway in potato. Growth and development of an insect pest, Colorado potato beetle (CPB), were affected in these lines. While no effect on CPB leaf consumption or weight gain was observed, early instar larval death and accelerated development of the insect was found while feeding on leaves of GAME4 RNAi lines. Modulation of SGA biosynthetic pathway in GAME4 RNAi plants was associated with a larger alteration to the metabolite profile, including increased levels of one or both the steroidal saponins or phytoecdysteroids, which could affect insect mortality as well as development time. Colonization by Verticillium dahliae on GAME4 RNAi plants was also tested. There were increased pathogen levels in the T8 GAME4 RNAi line but not in the T9. Metabolite differences between T8 and T9 were found and may have contributed to differences in V. dahliae infection. Drought responses created by osmotic stress were not affected by modulation of SGA biosynthetic pathway in potato.

scholarly journals Biosynthetic pathways and enzymes involved in the production of phosphonic acid natural products

2021 ◽  
Vol 85 (1) ◽  
pp. 42-52
Author(s):  
Taro Shiraishi ◽  
Tomohisa Kuzuyama
Keyword(s):  
Natural Products ◽  
Biosynthetic Pathway ◽  
Organophosphorus Compounds ◽  
Genome Mining ◽  
Biological Molecules ◽  
Antibacterial Drug ◽  
Gene Encoding ◽  
Quarter Century ◽  
Lead Compounds ◽  
Biosynthetic Machinery

Abstract Phosphonates are organophosphorus compounds possessing a characteristic C−P bond in which phosphorus is directly bonded to carbon. As phosphonates mimic the phosphates and carboxylates of biological molecules to potentially inhibit metabolic enzymes, they could be lead compounds for the development of a variety of drugs. Fosfomycin (FM) is a representative phosphonate natural product that is widely used as an antibacterial drug. Here, we review the biosynthesis of FM, which includes a recent breakthrough to find a missing link in the biosynthetic pathway that had been a mystery for a quarter-century. In addition, we describe the genome mining of phosphonate natural products using the biosynthetic gene encoding an enzyme that catalyzes C–P bond formation. We also introduce the chemoenzymatic synthesis of phosphonate derivatives. These studies expand the repertoires of phosphonates and the related biosynthetic machinery. This review mainly covers the years 2012-2020.

scholarly journals The biosynthetic pathway of potato solanidanes diverged from that of spirosolanes due to evolution of a dioxygenase

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ryota Akiyama ◽  
Bunta Watanabe ◽  
Masaru Nakayasu ◽  
Hyoung Jae Lee ◽  
Junpei Kato ◽  
...  
Keyword(s):  
Solanum Tuberosum ◽  
Solanum Lycopersicum ◽  
Biosynthetic Pathway ◽  
Potato Breeding ◽  
Chemical Diversity ◽  
Evolutionary Divergence ◽  
Food Crop ◽  
Common Pathway ◽  
Structural Differences ◽  
Key Enzyme

AbstractPotato (Solanum tuberosum), a worldwide major food crop, produces the toxic, bitter tasting solanidane glycoalkaloids α-solanine and α-chaconine. Controlling levels of glycoalkaloids is an important focus on potato breeding. Tomato (Solanum lycopersicum) contains a bitter spirosolane glycoalkaloid, α-tomatine. These glycoalkaloids are biosynthesized from cholesterol via a partly common pathway, although the mechanisms giving rise to the structural differences between solanidane and spirosolane remained elusive. Here we identify a 2-oxoglutarate dependent dioxygenase, designated as DPS (Dioxygenase for Potato Solanidane synthesis), that is a key enzyme for solanidane glycoalkaloid biosynthesis in potato. DPS catalyzes the ring-rearrangement from spirosolane to solanidane via C-16 hydroxylation. Evolutionary divergence of spirosolane-metabolizing dioxygenases contributes to the emergence of toxic solanidane glycoalkaloids in potato and the chemical diversity in Solanaceae.

scholarly journals Isolation and functional expression of human COQ2, a gene encoding a polyprenyl transferase involved in the synthesis of CoQ

2004 ◽  
Vol 382 (2) ◽  
pp. 519-526 ◽  
Author(s):  
Margareta FORSGREN ◽  
Anneli ATTERSAND ◽  
Staffan LAKE ◽  
Jacob GRÜNLER ◽  
Ewa SWIEZEWSKA ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Functional Expression ◽  
Human Muscle ◽  
Null Mutant ◽  
Human Homologue ◽  
Gene Encoding ◽  
Reading Frame ◽  
Human Enzyme ◽  
Liver Cdna Library ◽  
Mutant Cells

The COQ2 gene in Saccharomyces cerevisiae encodes a Coq2 (p-hydroxybenzoate:polyprenyl transferase), which is required in the biosynthetic pathway of CoQ (ubiquinone). This enzyme catalyses the prenylation of p-hydroxybenzoate with an all-trans polyprenyl group. We have isolated cDNA which we believe encodes the human homologue of COQ2 from a human muscle and liver cDNA library. The clone contained an open reading frame of length 1263 bp, which encodes a polypeptide that has sequence homology with the Coq2 homologues in yeast, bacteria and mammals. The human COQ2 gene, when expressed in yeast Coq2 null mutant cells, rescued the growth of this yeast strain in the absence of a non-fermentable carbon source and restored CoQ biosynthesis. However, the rate of CoQ biosynthesis in the rescued cells was lower when compared with that in cells rescued with the yeast COQ2 gene. CoQ formed when cells were incubated with labelled decaprenyl pyrophosphate and nonaprenyl pyrophosphate, showing that the human enzyme is active and that it participates in the biosynthesis of CoQ.

scholarly journals Lipidomics of Candida albicans biofilms reveals phase-dependent production of phospholipid molecular classes and role for lipid rafts in biofilm formation

Microbiology ◽  
2011 ◽  
Vol 157 (11) ◽  
pp. 3232-3242 ◽  
Author(s):  
Ali Abdul Lattif ◽  
Pranab K. Mukherjee ◽  
Jyotsna Chandra ◽  
Mary R. Roth ◽  
Ruth Welti ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Biosynthetic Pathway ◽  
Bloodstream Infections ◽  
Unsaturation Index ◽  
Lipid Profiles ◽  
Planktonic Cells ◽  
Gene Encoding ◽  
Aureobasidin A ◽  
Developmental Phases ◽  
Candida Albicans Biofilms

Candida albicans-associated bloodstream infections are linked to the ability of this yeast to form biofilms. In this study, we used lipidomics to compare the lipid profiles of C. albicans biofilms and planktonic cells, in early and mature developmental phases. Our results showed that significant differences exist in lipid composition in both developmental phases. Biofilms contained higher levels of phospholipid and sphingolipids than planktonic cells (nmol per g biomass, P<0.05 for all comparisons). In the early phase, levels of lipid in most classes were significantly higher in biofilms compared to planktonic cells (P≤0.05). The ratio of phosphatidylcholine to phosphatidylethanolamine was lower in biofilms compared to planktonic cells in both early (1.17 vs 2.52, P≤0.001) and late (2.34 vs 3.81, P≤0.001) developmental phases. The unsaturation index of phospholipids decreased with time, with this effect being particularly strong for biofilms. Inhibition of the biosynthetic pathway for sphingolipid [mannosyl diinositolphosphoryl ceramide, M(IP)2C] by myriocin or aureobasidin A, and disruption of the gene encoding inositolphosphotransferase (Ipt1p), abrogated the ability of C. albicans to form biofilms. The differences in lipid profiles between biofilms and planktonic Candida cells may have important implications for the biology and antifungal resistance of biofilms.

scholarly journals Identification and characterization of the gene encoding the human phosphopantetheine adenylyltransferase and dephospho-CoA kinase bifunctional enzyme (CoA synthase)

2002 ◽  
Vol 365 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Suren AGHAJANIAN ◽  
D.Margaret WORRALL
Keyword(s):  
Biosynthetic Pathway ◽  
Sequence Similarity ◽  
Kinetic Properties ◽  
Sequence Information ◽  
Bifunctional Enzyme ◽  
Gene Encoding ◽  
Pig Liver ◽  
Identification And Characterization ◽  
Similar Kinetic

The final two enzymes in the CoA biosynthetic pathway, phosphopantetheine adenylyltransferase (PPAT; EC 2.7.7.3) and dephospho-CoA kinase (DPCK; EC 2.7.1.24), are separate proteins in prokaryotes, but exist as a bifunctional enzyme in pig liver. In the present study we have obtained sequence information from purified pig-liver enzyme, and identified the corresponding cDNA in a number of species. The human gene localizes to chromosome 17q12-21 and contains regions with sequence similarity to the monofunctional Escherichia coli DPCK and PPAT. The recombinant 564-amino-acid human protein confirmed the associated transferase and kinase activities, and gave similar kinetic properties to the wild-type pig enzyme.

Increased L-Ornithine Production in Corynebacterium glutamicum by Overexpression of a Gene Encoding a Putative Aminotransferase

2015 ◽  
Vol 25 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Dai-Joong Kim ◽  
Gui-Hye Hwang ◽  
Ji-Na Um ◽  
Jae-Yong Cho
Keyword(s):  
Biosynthetic Pathway ◽  
Gene Promoter ◽  
Open Reading Frame ◽  
Aminotransferase Activity ◽  
Wild Type ◽  
Gene Encoding ◽  
Reading Frame ◽  
Dehydrogenase Gene ◽  
Putative Aminotransferase ◽  
Combined Overexpression

Overexpression of the NCgl0462 open reading frame, encoding a class II aminotransferase, was studied in conjunction with other enzymes in <smlcap>L</smlcap>-ornithine biosynthesis in an <smlcap>L</smlcap>-ornithine-producing strain. Expression of the wild-type NCgl0462 open reading frame, which displayed aminotransferase activity, was amplified by placing it under the control of the glyceraldehyde 3-phosphate dehydrogenase gene promoter in the pEK0 plasmid and in the genome. <smlcap>L</smlcap>-Ornithine production in <i>Corynebacterium</i><i>glutamicum</i> SJC8260 harboring plasmid and the genomic NCgl0462 open reading frame was increased by 8.8 and 21.6%, respectively. In addition, the combined overexpression of the NCgl0462 open reading frame within the genome along with the mutated <smlcap>L</smlcap>-ornithine biosynthesis genes <i>(argCJBD)</i> placed in the pEK0 plasmid in <i>C</i>. <i>glutamicum</i> SJC8260 resulted in significant improvement in <smlcap>L</smlcap>-ornithine production (12.48 g/l for combined overexpression compared with 8.42 g/l for the control). These results suggest that overexpression of the aminotransferase-encoding NCgl0462 open reading frame plays an unequivocal role in the <smlcap>L</smlcap>-ornithine biosynthetic pathway, with overlapping substrate specificity in <i>C</i>. <i>glutamicum</i>.

scholarly journals Lysine Represses Transcription of the Escherichia coli dapB Gene by Preventing Its Activation by the ArgP Activator

2008 ◽  
Vol 190 (15) ◽  
pp. 5224-5229 ◽  
Author(s):  
Jean Bouvier ◽  
Patrick Stragier ◽  
Violette Morales ◽  
Elisabeth Rémy ◽  
Claude Gutierrez
Keyword(s):  
Escherichia Coli ◽  
Transcription Start Site ◽  
Biosynthetic Pathway ◽  
Genomic Library ◽  
Regulatory Region ◽  
Null Mutation ◽  
Start Site ◽  
Transcription Start ◽  
Gene Encoding ◽  
Gel Retardation Assay

ABSTRACT The Escherichia coli dapB gene encodes one of the enzymes of the biosynthetic pathway leading to lysine and its immediate precursor, diaminopimelate. Expression of dapB is repressed by lysine, but no trans-acting regulator has been identified so far. Our analysis of the dapB regulatory region shows that sequences located in the −81/−118 interval upstream of the transcription start site are essential for full expression of dapB, as well as for lysine repression. Screening a genomic library for a gene that could alleviate lysine repression when present in multicopy led to the recovery of argP, a gene encoding an activating protein of the LysR-type family, known to use lysine as an effector. An argP null mutation strongly decreases dapB transcription that becomes insensitive to lysine. Purified His6-tagged ArgP protein binds with an apparent K d of 35 nM to the dapB promoter in a gel retardation assay, provided that sequences up to −103 are present. In the presence of l-lysine and l-arginine, the binding of ArgP to dapB is partly relieved. These results fit with a model in which ArgP contributes to enhanced transcription of dapB when lysine becomes limiting.

scholarly journals Involvement of Quinolinate Phosphoribosyl Transferase in Promotion of Potato Growth by a Burkholderia Strain

2006 ◽  
Vol 72 (1) ◽  
pp. 760-768 ◽  
Author(s):  
Keri Wang ◽  
Kenneth Conn ◽  
George Lazarovits
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
De Novo ◽  
Growth Promotion ◽  
Amino Acid Level ◽  
Growth Stimulation ◽  
Wild Type ◽  
Gene Encoding ◽  
Burkholderia Strain ◽  
Potato Growth

ABSTRACT Burkholderia sp. strain PsJN stimulates root growth of potato explants compared to uninoculated controls under gnotobiotic conditions. In order to determine the mechanism by which this growth stimulation occurs, we used Tn5 mutagenesis to produce a mutant, H41, which exhibited no growth-promoting activity but was able to colonize potato plants as well as the wild-type strain. The gene associated with the loss of growth promotion in H41 was shown to exhibit 65% identity at the amino acid level to the nadC gene encoding quinolinate phosphoribosyltransferase (QAPRTase) in Ralstonia solanacearum. Complementation of H41 with QAPRTase restored growth promotion of potato explants by this mutant. Expression of the gene identified in Escherichia coli yielded a protein with QAPRTase activities that catalyzed the de novo formation of nicotinic acid mononucleotide (NaMN). Two other genes involved in the same enzymatic pathway, nadA and nadB, were physically linked to nadC. The nadA gene was cotranscribed with nadC as an operon in wild-type strain PsJN, while the nadB gene was located downstream of the nadA-nadC operon. Growth promotion by H41 was fully restored by addition of NaMN to the tissue culture medium. These data suggested that QAPRTase may play a role in the signal pathway for promotion of plant growth by PsJN.

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