Résumé
Pineapple (Ananas comosus(L.) Merr.) is a non-climacteric tropical fruit whose ripening could be accompaniedby oxidative processes and the concurrent activation of enzymatic and non-enzymatic reactive oxygen species(ROS) scavenging systems. To better understand the variability of these processes among climatic environmentsor genotypes in pineapple, the temporal expression dynamics for genes encoding oxidative and antioxidativestress enzymes were analyzed by real-time RT-PCR during fruit development and ripening, among three culti-vars: Queen Victoria, Flhoran 41 and MD-2 hybrid, and in two climatic areas. Pineapple development andripening involved changes in the levels of transcripts encoding for polyphenol oxidase and transcripts involvedin thefirst steps of the phenylpropanoid pathway and in the balance of ROS, especially those encoding forascorbate peroxydase and metallothioneins, regardless of the cultivar. Our results confirm the same dynamic ingene expression from the two environmental crop areas, however climatic conditions influenced the level of theexpression of the major transcripts studied that were linked to these oxidative and antioxidant metabolisms.MT3a and MT3b transcripts were not influenced by genetic factor. The genetic effect was not significant on thevarious transcripts linked to thefirst steps of the phenylpropanoid pathway and to phenol oxidation, except 4CLones. In ripe pineapple, highly significant relationships were found between the contents in antioxidant meta-bolites, i.e., ascorbic acid and total phenolic compounds, and the transcript levels of genes involved in theenzymatic ROS-scavenging system and in the biosynthesis or regeneration of ROS-scavenging compounds, likephenylpropanoids, ascorbic acid, metallothioneins