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

BUSTAMANTE, CLAUDIA; BUDDE, CLAUDIO OLAF; LARA, MARÍA VALERIA; DRINCOVICH, MARÍA FABIANA

Buenos Aires

Congreso; Reunión Conjunta de Biociencias; 2017

Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB)

Peaches are highly perishable and deteriorate quicklyat ambient temperature. Cold storage is commonly used to preventfruit decay; however, it affects fruit quality causing physiological disorderscollectively termed ?chilling injury? (CI). To prevent or ameliorateCI, heat treatment (HT) is often applied prior to cold storage.In this work, we analyzed ethylene production and the expression ofenzymes and proteins involved in cell wall metabolism in ?Dixiland?peach fruits exposed to 39 °C, cold stored, or after a combined treatmentof 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 productionwas observed, meanwhile cell wall-related genes showeddifferent expression patterns. After HT (3 d at 39 ºC), fruit maintainedtheir firmness, exhibiting low PpACO1 level and significant lower levelsof the twelve cell wall-modifying genes. Once fruits were transferredto 20ºC after HT, an increase in gene expression occurredto different extent depending on the transcript analyzed, except inthe case of PpPME1. Cold storage for 3 and 5 d at 0 ºC (R3 andR5) prevented softening, the increase in the levels of PpACO1, andthe accumulation of transcripts encoding for cell wall-related genes.Fruits subjected to both heat and cold treatments (HT+R2) showedvery low ethylene production and expression of enzymes and proteinsinvolved in cell wall metabolism; however, when fruits weretransferred to 20 ºC for 2 d (HT+R2+2), softening and the levels ofPpACO1 and cell wall-modifying transcripts were similar or even higherthan fruits of the same post-harvest age maintained at ambienttemperature. Overall, our results indicate that when HT is appliedprior to cold storage, the expression of enzymes and proteins involvedin cell wall metabolism is recovered following return to ambienttemperature, in contrast to R3+2 and R5+2 samples, revealing thebenefits of applying a HT prior to refrigeration.