Carbon metabolism of peach fruit after harvest: changes in enzymes involved in organic acid and sugar level modifications

BORSANI, JULIA; BUDDE, CLAUDIO OLAF; PORRINI, LUCÍA; LAUXMANN, MARTÍN ALEXANDER; LOMBARDO, VERONICA; MURRAY, RICARDO; ANDREO, CARLOS SANTIAGO; DRINCOVICH, MARÍA FABIANA; LARA, MARÍA VALERIA

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Año: 2009 vol. 60 p. 1823 - 1837

0022-0957

Peach (Prunus persica L. Batsch) is a climacteric fruit that ripens after harvest, prior to human consumption. Organicacids and soluble sugars contribute to the overall organoleptic quality of fresh peach; thus, the integrated study ofthe metabolic pathways controlling the levels of these compounds is of great relevance. Therefore, in this work,several metabolites and enzymes involved in carbon metabolism were analysed during the post-harvest ripening ofpeach fruit cv ?Dixiland?. Depending on the enzyme studied, activity, protein level by western blot, or transcript levelby quantitative real time-PCR were analysed. Even though sorbitol did not accumulate at a high level in relation tosucrose at harvest, it was rapidly consumed once the fruit was separated from the tree. During the ripening process,sucrose degradation was accompanied by an increase of glucose and fructose. Specific transcripts encodingneutral invertases (NIs) were up-regulated or down-regulated, indicating differential functions for each putative NIisoform. Phosphoenolpyruvate carboxylase was markedly induced, and may participate as a glycolytic shunt, sincethe malate level did not increase during post-harvest ripening. The fermentative pathway was highly induced, withincreases in both the acetaldehyde level and the enzymes involved in this process. In addition, proteins differentiallyexpressed during the post-harvest ripening process were also analysed. Overall, the present study identifiedenzymes and pathways operating during the post-harvest ripening of peach fruit, which may contribute to furtheridentification of varieties with altered levels of enzymes/metabolites or in the evaluation of post-harvest treatmentsto produce fruit of better organoleptic attributes.