Heat treatment applied prior to cold storage restored cell wall metabolism in ?Dixiland? peach fruits

BUSTAMANTE C.; GABILONDO J.; BUDDE C.; LARA M. V.; DRINCOVICH M. F.

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Peaches are highly perishable and deteriorate quickly at ambient temperature. Cold storage is commonly used to prevent fruit decay; however, it affects fruit quality causing physiological disorders collectively termed ?chilling injury? (CI). To prevent or ameliorate CI, heat treatment (HT) is often applied prior to cold storage. In this work, we analyzed ethylene production and the expression of enzymes and proteins involved in cell wall metabolism in ?Dixiland? peach fruits exposed to 39 °C, cold stored, or after a combined treatment of heat and cold, and were compared with fruits ripening at 20 °C. For the group of fruit kept at 20 ºC, an increase in ethylene production was observed, meanwhile cell wall-related genes showed different expression patterns. After HT (3 d at 39 ºC), fruit maintained their firmness, exhibiting low PpACO1 level and significant lower levels of the twelve cell wall-modifying genes. Once fruits were transferred to 20ºC after HT, an increase in gene expression occurred to different extent depending on the transcript analyzed, except in the case of PpPME1. Cold storage for 3 and 5 d at 0 ºC (R3 and R5) prevented softening, the increase in the levels of PpACO1, and the accumulation of transcripts encoding for cell wall-related genes. Fruits subjected to both heat and cold treatments (HT+R2) showed very low ethylene production and expression of enzymes and proteins involved in cell wall metabolism; however, when fruits were transferred to 20 ºC for 2 d (HT+R2+2), softening and the levels of PpACO1 and cell wall-modifying transcripts were similar or even higher than fruits of the same post-harvest age maintained at ambient temperature. Overall, our results indicate that when HT is applied prior to cold storage, the expression of enzymes and proteins involved in cell wall metabolism is recovered following return to ambient temperature, in contrast to R3+2 and R5+2 samples, revealing the benefits of applying a HT prior to refrigeration.