Exploring the metabolic diversity of peach fruits from different varieties allowed the identification of quality metabolic biomarkers

BUSTAMANTE C. A.; FERNIE A. R.; MONTI L. L.; DRINCOVICH M. F.; LARA M. V.

Rosario

Simposio; Second Latin American Metabolic Profiling Symposium; 2016

LAMPS

The application of cold after the harvest of many fruits is used to extent shelf-life and preserve quality properties. Besides, it is well known that cold causes dramatic reconfiguration of the plant metabolome as an adaptative response to avoid cold-induced damage. In the case of fruits, it is essential to analyze the changes in metabolites due to cold storage, which may have a substantial impact on organoleptic properties, human health and wellbeing. In an earlier study, using a single peach genotype, metabolomic changes induced by short cold and heat treatment, used to prevent chilling injury (CI), allowed us to identify metabolites which are involved in priming the fruit to cope with stress situations (1). Nonetheless, further metabolomic studies revealed a great diversity in the content of key metabolites among different peach varieties (2). Thus, these studies opened the question on whether it would be possible to associate a metabolic profile of a particular genotype with differential CI susceptibility in peach. Here, a metabolite profiling study after short and long cold storage of six peach varieties with differential susceptibility to CI was performed in order to identify, among the metabolic changes induced by cold, those that may be functionally related to CI resistance. Both common and distinct metabolic responses among the six varieties were detected. Common changes include a dramatic rise in galactinol and raffinose; increase in GABA, Asp and Phe; and a decrease in 2-oxo-glutarate and succinate. No cluster separation of fruits resistant to mealiness from those sensitive was found, indicating that resistance to CI can be found in different metabolic contexts. Although a direct correlation of a multigenic trait such as CI tolerance with the concentration of only one metabolite would not be expected, the degree of mealiness resistance of the different peach fruit varieties correlated to the level of raffinose following long cold storage. Thus, raffinose emerges as candidate biomarker for mealiness resistance. Interestingly, xylose is only increased by cold treatment in peach susceptible genotypes, which indicates a particular reconfiguration of the cell wall in the most susceptible varieties while being cold-stored for long period of times. When taken together, these data indicate that peach fruit differential metabolic rearrangements due to cold, rather than differential metabolic priming before cold, are better related with CI resistance. Peach fruit metabolism plasticity renders it possible to induce a diverse array of metabolites after cold, which is successful, in some genotypes, to avoid CI and preserve fruit quality.