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Molecular and biochemical characteristics of a gene encoding an alcohol acyl-transferase involved in the generation of aroma volatile esters during melon ripening

Yahyaoui, Fikri E. and Wongs-Aree, Chalermchai and Latché, Alain and Hackett, Rachel and Grierson, Donald and Pech, Jean-Claude Molecular and biochemical characteristics of a gene encoding an alcohol acyl-transferase involved in the generation of aroma volatile esters during melon ripening. (2002) European Journal Of Biochemistry, vol. 2 . pp. 2359-2366. ISSN 0014-2956

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Official URL: http://dx.doi.org/10.1046/j.1432-1033.2002.02892.x

Abstract

Two genes (CM-AAT1 and CM-AAT2) with strong sequence homology (87% identity at the protein level) putatively involved in the formation of aroma volatile esters have been isolated from Charentais melon fruit.They belong to a large and highly divergent family of multifunctional plant acyl-transferases and show at most 21% identity to the only other fruit acyl-transferase characterized so far in strawberry.RT-PCR studies indicated that both genes were specifically expressed in fruit at increasing rates in the early and mid phases of ripening.Expression was severely reduced in ethylene-suppressed antisense ACC oxidase (AS) fruit and in wild-type (WT) fruit treated with the ethylene antagonist 1-MCP.Cloning of the two genes in yeast revealed that the CM-AAT1 protein exhibited alcohol acyl-transferase activity while no such activity could be detected for CM-AAT2 despite the strong homology between the two sequences.CM-AAT 1 was capable of producing esters from a wide range of combinations of alcohols and acyl-CoAs.The higher the carbon chain of aliphatic alcohols, the higher the activity.Branched alcohols were esterified at differential rates depending on the position of the methyl group and the nature of the acyl donor. Phenyl and benzoyl alcohols were also good substrates, but activity varied with the position and size of the aromatic residue.The cis/trans configuration influenced activity either positively (2-hexenol) or negatively (3-hexenol).Because ripening melons evolve the whole range of esters generated by the recombinant CM-AAT1 protein, we conclude that CM-AAT1 plays a major role in aroma volatiles formation in the melon.

Item Type:Article
Additional Information:The definitive version is available at http://www3.interscience.wiley.comThe original PDF of the article can be found at European Journal Of Biochemistry website : http://www3.interscience.wiley.com/journal/118906851/abstract
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Institut National de la Recherche Agronomique - INRA
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Other partners > University of Nottingham (UNITED KINGDOM)
Laboratory name:
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Deposited By: Dabernat Séverine

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