title: Role of ethylene in the biosynthetic pathway of aliphatic ester aroma volatiles in Charentais Cantaloupe melons.
abstract: Compared to other melon types, Cantaloupe Charentais melons are highly aromatic with a major contribution to the aroma being made by aliphatic and branched esters. Using a transgenic line in which the synthesis of the plant hormone ethylene has been considerably lowered by antisense ACC oxidase mRNA (AS), the aliphatic ester pathway steps at which ethylene exerts its regulatory role were found. The data show that the production of aliphatic esters such as hexyl and butyl acetate was blocked in AS fruit and could be reversed by ethylene. Using fruit discs incubated in the presence of various precursors, the steps at which ester formation was inhibited in AS fruit was shown to be the reduction of fatty acids and aldehydes, the last step of acetyl transfer to alcohols being unaffected. However, treating AS fruit with the ethylene antagonist 1-methylcyclopropene resulted in about 50% inhibition of acetyl transfer activity, indicating that this portion of activity was ethylene-dependent and this was supported by the low residual ethylene concentration of AS fruit discs (around 2 microl l(-1)). In conclusion, the reduction of fatty acids and aldehydes appears essentially to be ethylene-dependent, whilst the last step of alcohol acetylation has ethylene-dependent and ethylene-independent components, probably corresponding to differentially regulated alcohol acetyltransferases.
authors.affiliation: UMR INRA-INP/ENSAT, Av. de l'Agrobiopole, BP 107, Auzeville, F-31326 Castanet-Tolosan, France.
authors.forename: Francisco
authors.initials: F
authors.lastname: Flores
authors.forename: Fikri
authors.initials: F
authors.lastname: El Yahyaoui
authors.forename: Gustavo
authors.initials: G
authors.lastname: de Billerbeck
authors.forename: Felix
authors.initials: F
authors.lastname: Romojaro
authors.forename: Alain
authors.initials: A
authors.lastname: Latché
authors.forename: Mondher
authors.initials: M
authors.lastname: Bouzayen
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Pech
authors.forename: Christian
authors.initials: C
authors.lastname: Ambid
mesh_terms: D000085:Acetates / Q000378:metabolism*; D000447:Aldehydes / Q000378:metabolism; D000594:Amino Acid Oxidoreductases / Q000378:metabolism; D016375:Antisense Elements (Genetics); D000440:Butanols / Q000378:metabolism; D028462:Cucumis / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D003521:Cyclopropanes / Q000494:pharmacology; D004952:Esters / Q000378:metabolism; D005030:Ethylenes / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D005227:Fatty Acids / Q000378:metabolism; D005638:Fruit / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D000441:Hexanols / Q000378:metabolism; D009812:Odorants / Q000032:analysis*; D010937:Plant Growth Regulators / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D030821:Plants, Genetically Modified; D014835:Volatilization
chemical_list: D000085:Acetates; D000447:Aldehydes; D016375:Antisense Elements (Genetics); D000440:Butanols; D003521:Cyclopropanes; D004952:Esters; D005030:Ethylenes; D005227:Fatty Acids; D000441:Hexanols; D010937:Plant Growth Regulators; C006848:butyl acetate; C036216:ethylene; D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase; C412563:1-methylcyclopropene