title: Cloning and functional characterization of quinolinic acid phosphoribosyl transferase (QPT) gene of Nicotiana tabacum.
abstract: The quinolinate phosphoribosyl transferase (QPT) is a key enzyme that converts quinolinic acid into nicotinic acid mononucleotide. The QPT gene plays an essential role in the pyridine nucleotide cycle as well as in the biosynthetic pathway of the alkaloid nicotine. However, a clear role for QPT is yet to be characterized to validate the actual function of this gene in planta. In this study, an RNA interference (RNAi) approach was used to reveal the functional role of QPT. Transformation and analysis of the hairy roots (HRs) of the Nicotiana leaf explants was used, followed by plant regeneration and analysis. High-performance liquid chromatography (HPLC) analysis of the HRs and of the regenerated plants both revealed altered alkaloid biosynthetic cycle, with a substantially reduced content of nicotine and anabasine. The transgenic plants exhibited a significantly altered phenotype and growth pattern. Also, silencing of QPT led to a decrease in chlorophyll content, maximum quantum efficiency of PSII, net CO2assimilation and starch content. Results clearly demonstrated that QPT was not only involved in the biosynthetic pathway of the alkaloids but also affected plant growth and development. Our results provide information to be considered when trying to engineer the secondary metabolite quality and quantity.
authors.affiliation: Plant Biotechnology Division, Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Lucknow 226015, India.
authors.forename: Sana
authors.initials: S
authors.lastname: Khan
authors.affiliation: Microbial Technology Department, Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Lucknow 226015, India.
authors.forename: Shiv Shanker
authors.initials: SS
authors.lastname: Pandey
authors.affiliation: Analytical Chemistry Department, Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Lucknow 226015, India.
authors.lastname: Jyotshna
authors.affiliation: Analytical Chemistry Department, Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Lucknow 226015, India.
authors.forename: Karuna
authors.initials: K
authors.lastname: Shanker
authors.affiliation: Metabolic and Structural Biology Department, Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Lucknow 226015, India.
authors.forename: Feroz
authors.initials: F
authors.lastname: Khan
authors.affiliation: Plant Biotechnology Division, Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Lucknow 226015, India.
authors.forename: Laiq Ur
authors.initials: LU
authors.lastname: Rahman
mesh_terms: D010430:Pentosyltransferases / Q000235:genetics* / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D014026:Nicotiana / Q000201:enzymology* / Q000235:genetics*; D000098553:Nicotinate-Nucleotide Diphosphorylase (Carboxylating)
chemical_list: D010940:Plant Proteins; D010430:Pentosyltransferases; D000098553:Nicotinate-Nucleotide Diphosphorylase (Carboxylating)