Heterologous comparative genomics to identify candidate genes impacting fruit quality in apple (Malus x domestica Borkh.)

Fruits are an important source of healthy compounds in the human diet, such as fibers, organic acids, vitamins, and antioxidants. All these metabolites are developed during fruit ripening, a complex process characterized by dramatic physiological changes. Fruit ripening is normally distinguished as climacteric or non-climacteric, depending on the direct effect of the hormone ethylene in the control of these processes, especially on fruit softening. Variation in fruit firmness, one of the most evident phenomena, strongly influences the general fruit quality, limiting the shelf life due to a minor resistance to post-harvest diseases. To investigate the transcription dynamics over the apple ripening, two wide genomic cDNA microarrays were used: an apple specific homologous system, and a tomato heterologous platform. In this study, we assessed the potential of the heterologous array to analyze the apple ripening physiology. The normal ripening transcriptome was compared with the distorted one obtained with 1-MCP treatment (an ethylene competitor), allowing for the identification of a comprehensive gene set, developmental and ethylene dependent.