Metabolite profiling of postharvest senescence in different strawberry cultivars

Abstract

The cultivated strawberry (Fragaria x ananassa) is the berry most consumed worldwide, being well appreciated for its flavour and nutritional characteristics. However, strawberries possess a very short postharvest shelf-life due to their high respiration rate and their susceptibility to water loss, mechanical damage and fungi deterioration (Feliziani and Romanazzi, 2016). Extension of fruit shelf-life is a major economic goal, and measures are commercially taken to delay senescence, including the use of low temperature storage alone or in combination with controlled atmosphere (Pedreschi and Lurie, 2015). To improve our understanding of the molecular and biochemical mechanisms underlying the deterioration of fruit quality attributes during senescence, we realized a metabolite profiling of five commercial strawberry cultivars under different postharvest treatments. Ripe fruits were harvested and kept at 4ºC during three, six and ten days in ambient, CO2-enriched and O3-enriched atmospheres. We used a combination of gas chromatography-mass spectrometry (GC-TOF-MS), ultra-performance liquid chromatography-Orbitrap mass/mass spectrometry (UPLC-Orbitrap-MS/MS) and headspace solid phase micro extraction (HS-SPME) coupled with GC-MS to identify and semi-quantify 49 primary metabolites (sugars, amino and organic acids), 132 polar secondary metabolites (mainly polyphenols) and 70 volatile compounds. Multivariate statistical approaches were used to characterize the variation in metabolite content during the strawberry fruit postharvest life and to identify the biochemical pathways which are most affected in the senescence processes. Preliminary analysis pointed out that changes in primary metabolism were possibly related to responses to abiotic stress.