Heat treatment of peach fruit: modifications in the extracellular compartment and identification of novel extracellular proteins

BUSTAMANTE, CLAUDIA; BUDDE, CLAUDIO OLAF; BORSANI, JULIA; LOMBARDO, VERONICA; LAUXMANN, MARTÍN ALEXANDER; ANDREO, CARLOS S.; LARA, MARÍA VALERIA; DRINCOVICH, MARÍA FABIANA

PLANT PHYSIOLOGY AND BIOCHEMISTRY

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Lugar: Paris; Año: 2012 p. 35 - 45

0981-9428

Ripening of peach (Prunus persica L. Batsch) fruit is accompanied by dramatic cell wall changes that leadto softening. Post-harvest heat treatment is effective in delaying softening and preventing some chillinginjury symptoms that this fruit exhibits after storage at low temperatures. In the present work, the levelsof twelve transcripts encoding proteins involved in cell wall metabolism, as well as the differentialextracellular proteome, were examined after a post-harvest heat treatment (HT; 39 C for 3 days) of?Dixiland? peach fruit. A typical softening behaviour, in correlation with an increase in 1-aminocyclopropane-1-carboxylic acid oxidase-1 (PpACO1), was observed for peach maintained at 20 Cfor 3 days (R3). Six transcripts encoding proteins involved in cell wall metabolism significantly increasedin R3 with respect to peach at harvest, while six showed no modification or even decreased. In contrast,after HT, fruit maintained their firmness, exhibiting low PpACO1 level and significant lower levels of thetwelve cell wall-modifying genes than in R3. Differential proteomic analysis of apoplastic proteins duringsoftening and after HT revealed a significant decrease of DUF642 proteins after HT; as well as an increaseof glyceraldehyde-3-phosphate dehydrogenase (GAPC) after softening. The presence of GAPC in thepeach extracellular matrix was further confirmed by in situ immunolocalization and transient expressionin tomato fruit. Though further studies are required to establish the function of DUF642 and GAPC in theapoplast, this study contributes to a deeper understanding of the events during peach softening and afterHT with a focus on this key compartment.