Unravelling the biochemical basis of fruit chilling injury: proteomic and metabolomics differences between mealy and nonmealy peach fruit

DRINCOVICH M.; MONTI L.; GABILONDO J.; BUSTAMANTE C.; LARA M.; BUDDE C.

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). One of the principal phenotypic expressions of CI in peach is flesh mealiness or lack of juiciness. In the present work, the differences between mealy and non-mealy fruits of Springlady cultivar, were assessed using proteomic and metabolomics analysis. Harvested fruits were stored at 0 ºC and 90% relative humidity for 21 days followed by 4 days (time required for ripeness) at 20 ºC. The apparent juice content was evaluated using a visual scale of 0 to 5 (0 = Healthy and 5 Maximum mealiness). Individual fruits with contrasting flesh mealiness were selected for proteomic and metabolomic studies. Quantitative proteomic profiling, performed using the Orbitrap technology, revealed drastic differences in the amount of 213 proteins between mealy and non-mealy fruits. The differentially expressed proteins were identified and classified considering their biological role. Significant differences were found in proteins involved in lipid, cell wall and protein metabolism; as well as in enzymes involved in secondary metabolism, such as chalcone-flavone isomerase and carotene desaturase. A marked decrease in the levels of enzymes involved in the control of the redox state, such as superoxide dismutase and a glutathione peroxidase, was detected in mealy with respect to non-mealy fruits. Metabolomic analyzes, performed by GC-MS, showed a decrease in the level of sugars, such as sucrose, galactose and raffinose, in mealy with respect with non-mealy fruits, as well as in most of the amino acids detected, with no significant changes in organic acids content. Overall, the present work identifies the biochemical basis of mealiness in peach fruits, and reveals that an altered redox state may be key in mediating many of such biochemical alterations.