title: Isolation and characterization of 9-lipoxygenase and epoxide hydrolase 2 genes: Insight into lactone biosynthesis in mango fruit (Mangifera indica L.).
abstract: Uniqueness and diversity of mango flavour across various cultivars are well known. Among various flavour metabolites lactones form an important class of aroma volatiles in certain mango varieties due to their ripening specific appearance and lower odour detection threshold. In spite of their biological and biochemical importance, lactone biosynthetic pathway in plants remains elusive. Present study encompasses quantitative real-time analysis of 9-lipoxygenase (Mi9LOX), epoxide hydrolase 2 (MiEH2), peroxygenase, hydroperoxide lyase and acyl-CoA-oxidase genes during various developmental and ripening stages in fruit of Alphonso, Pairi and Kent cultivars with high, low and no lactone content and explains their variable lactone content. Study also covers isolation, recombinant protein characterization and transient over-expression of Mi9LOX and MiEH2 genes in mango fruits. Recombinant Mi9LOX utilized linoleic and linolenic acids, while MiEH2 utilized aromatic and fatty acid epoxides as their respective substrates depicting their role in fatty acid metabolism. Significant increase in concentration of δ-valerolactone and δ-decalactone upon Mi9LOX over-expression and that of δ-valerolactone, γ-hexalactone and δ-hexalactone upon MiEH2 over-expression further suggested probable involvement of these genes in lactone biosynthesis in mango.
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, 411 008, India.
authors.forename: Ashish B
authors.initials: AB
authors.lastname: Deshpande
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, 411 008, India.
authors.forename: Hemangi G
authors.initials: HG
authors.lastname: Chidley
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, 411 008, India.
authors.forename: Pranjali S
authors.initials: PS
authors.lastname: Oak
authors.affiliation: Dr. Balasaheb Sawant Konkan Agriculture University, Dapoli, 415712, India.
authors.forename: Keshav H
authors.initials: KH
authors.lastname: Pujari
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, 411 008, India.
authors.forename: Ashok P
authors.initials: AP
authors.lastname: Giri
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, 411 008, India. Electronic address: vs.gupta@ncl.res.in.
authors.forename: Vidya S
authors.initials: VS
authors.lastname: Gupta
mesh_terms: D000446:Aldehyde-Lyases / Q000737:chemistry; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry; D004851:Epoxide Hydrolases / Q000235:genetics*; D005227:Fatty Acids; D005638:Fruit / Q000737:chemistry; D007783:Lactones / Q000737:chemistry*; D008084:Lipoxygenase / Q000235:genetics*; D031022:Mangifera / Q000201:enzymology* / Q000235:genetics; D006899:Mixed Function Oxygenases / Q000737:chemistry; D010940:Plant Proteins / Q000235:genetics*; D011753:Pyrones / Q000737:chemistry
chemical_list: D005227:Fatty Acids; D007783:Lactones; D010940:Plant Proteins; D011753:Pyrones; C052207:delta-valerolactone; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D008084:Lipoxygenase; C022333:peroxygenase; D004851:Epoxide Hydrolases; D000446:Aldehyde-Lyases; C054540:hydroperoxide lyase
keywords: 12(13) EpOME (PubChem CID: 5356421); 9-Lipoxygenase; 9HpODE (PubChem CID: 9548877); 9HpOTrE (PubChem CID: 5282864); Anacardiaceae; Delta-decalactone (PubChem CID: 12810); Delta-hexalactone (PubChem CID: 13204); Delta-valerolactone (PubChem CID: 10953); Epoxide hydrolase 2; Gamma-hexalactone (PubChem CID: 12756); Lactone biosynthesis; Mangifera indica; Transient expression