title: Comparative glandular trichome transcriptome-based gene characterization reveals reasons for differential (-)-menthol biosynthesis in Mentha species.
abstract: The genes involved in menthol biosynthesis are reported earlier in Mentha × piperita. But the information on these genes is not available in Mentha arvensis. To bridge the gap in knowledge on differential biosynthesis of monoterpenes leading to compositional variation in the essential oil of these species, a comparative transcriptome analysis of the glandular trichome (GT) was carried out. In addition to the mevalonic acid (MVA) and methylerythritol phosphate (MEP) pathway genes, about 210 and 196 different terpene synthases (TPSs) transcripts were identified from annotation in M. arvensis and M. × piperita, respectively, and correlated to several monoterpenes present in the essential oil. Six isoforms of (-)-menthol dehydrogenases (MD), the last enzyme of the menthol biosynthetic pathway, were identified, cloned and characterized from the transcriptome data (three from each species). Varied expression levels and differential enzyme kinetics of these isoforms indicated the nature and composition of the product, as these isoforms generate both (-)-menthol and (+)-neomenthol from (-)-menthone and converts (-)-menthol to (-)-menthone in the reverse reaction, and hence together determine the quantity of (-)-menthol in the essential oil in these two species. Several genes for high value minor monoterpenes could also be identified from the transcriptome data.
authors.affiliation: Biotechnology Division, CSIR - Central Institute of Medicinal and Aromatic Plants, Lucknow, 226015, India.
authors.forename: Md Qussen
authors.identifier: http://orcid.org/0000-0002-5564-9961
authors.initials: MQ
authors.lastname: Akhtar
authors.affiliation: Biotechnology Division, CSIR - Central Institute of Medicinal and Aromatic Plants, Lucknow, 226015, India.
authors.forename: Nida
authors.initials: N
authors.lastname: Qamar
authors.affiliation: Biotechnology Division, CSIR - Central Institute of Medicinal and Aromatic Plants, Lucknow, 226015, India.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Yadav
authors.affiliation: Biotechnology Division, CSIR - Central Institute of Medicinal and Aromatic Plants, Lucknow, 226015, India.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Kulkarni
authors.affiliation: Biotechnology Division, CSIR - Central Institute of Medicinal and Aromatic Plants, Lucknow, 226015, India.
authors.forename: Ajay
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Biotechnology Division, CSIR - Central Institute of Medicinal and Aromatic Plants, Lucknow, 226015, India.
authors.forename: Ajit Kumar
authors.initials: AK
authors.lastname: Shasany
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D027541:Mentha / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D008610:Menthol / Q000378:metabolism*; D008798:Mevalonic Acid / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D064201:Trichomes / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D020033:Protein Isoforms; D008610:Menthol; D019883:Alkyl and Aryl Transferases; C108877:terpene synthase; D008798:Mevalonic Acid