Molecular Bases of Fruit Quality in Prunus Species: An Integrated Genomic, Transcriptomic, and Metabolic Review with a Breeding Perspective.

In plants, fruit ripening is a coordinated developmental process that requires the change in expression of hundreds to thousands of genes to modify many biochemical and physiological signal cascades such as carbohydrate and organic acid metabolism, cell wall restructuring, ethylene production, stress response, and organoleptic compound formation. In Prunus species (including peaches, apricots, plums, and cherries), fruit ripening leads to the breakdown of complex carbohydrates into sugars, fruit firmness reductions (softening by cell wall degradation and cuticle properties alteration), color changes (loss of green color by chlorophylls degradation and increase in non-photosynthetic pigments like anthocyanins and carotenoids), acidity decreases, and aroma increases (the production and release of organic volatile compounds). Actually, the level of information of molecular events at the transcriptional, biochemical, hormonal, and metabolite levels underlying ripening in Prunus fruits has increased considerably. However, we still poorly understand the molecular switch that occurs during the transition from unripe to ripe fruits. The objective of this review was to analyze of the molecular bases of fruit quality in Prunus species through an integrated metabolic, genomic, transcriptomic, and epigenetic approach to better understand the molecular switch involved in the ripening process with important consequences from a breeding point of view.

Physico-chemical and physiological changes during fruit development and on-tree ripening of two Spanish jujube cultivars (Ziziphus jujuba Mill.).

BACKGROUND: Few studies have been performed on changes in organoleptic, nutritive, functional, and physiological properties during jujube fruit development and on-tree ripening. In this work, a comparative study on the evolution of physical, chemical, nutritive, and physiological parameters and bioactive compounds of two Spanish jujube cultivars was performed. RESULTS: Both cultivars showed a non-climacteric ripening pattern, although the JM cultivar was smaller, sweeter, softer, and more highly coloured than the JG, which was characterised by having larger and firmer fruits, although less sweet and coloured. Both cultivars showed high TAA, which was highly correlated with the concentration of total phenols, giving them great functional properties. CONCLUSION: This fruit has little economic importance in Spain and it is just marginally grown for self-consumption or for ornamental purposes. Given the excellent properties of these fruits, it could be considered a fruit species of great interest, and commercial growth of these cultivars with high yields and fruits with high functional properties should be promoted. © 2016 Society of Chemical Industry.