Proteomic analysis of prickly pear

Fruit ripening involves a series of physiological, biochemical, and organoleptic changes that lead to the development of a soft and edible ripe fruit with desirable quality attributes. Due to its nutritional value and economic potential, and unique physiological characteristics, prickly pear is considered to be a model for the study of fruit ripening. In order to understand prickly pear fruit ripening, integration of physicochemical, biochemical and molecular studies are necessary. Knowledge of whole protein content will allow us to understand the different metabolic pathways involved in fruit ripening. In this work, we analyze protein differential expression and identify the proteins associated with ripening of prickly pears at different stages of development (early, intermediate and late ripening). Fruits from different morphospecies were harvested at green, middle-ripe and ripe stages. The proteins were extracted from the peel and resolved on 2-DE gel, analyzed with the Image master 2D Platinum 6.0 software (Amersham Biosciences) and grouped in Venn diagrams. Differential spots were analyzed by mass spectrometry approaches. There was differential expression and a high synthesis of proteins during ripening, the highest differential expression was obtained at the ripe stage of all materials. 1689 proteins were associated with ripening. We identified proteins associated with fruit ripening and with specific activities, i.e., photosynthesis, respiration, fatty acid and anthocyanins synthesis. This investigation provides the first proteomic approach for ripening of prickly pear fruits and allowed the analysis of the diversity of peptides and proteins that could be key to understanding and subsequent practical application for controlling ripening of this important fruit.