Development of genomics-guided physiological solutions in biological systems lacking significant genomic resources is challenging. Utilization of controlled physiological models with time course gene expression analysis can address these challenges. Harboring unique ripening biology and responses to the ethylene signaling inhibitor 1-MCP, pear is an ideal model for investigation of the molecular underpinnings of System 2 ethylene induction. Induction of autocatalytic ethylene biosynthesis in climacteric fruits acts as a powerful indicator of – and trigger of –ripening. We identified differential expression of genes in a ripening-related pathway during postharvest conditioning in peel tissue of two pear varieties: Anjou and Bartlett. Anjou requires 60-day cold at 0-5°C to gain competency for ripening and System 2 ethylene biosynthesis, while Bartlett requires 15 days. Further, pear exhibits variable recovery from 1-MCP treatments, with some fruit ‘locked’ permanently in an unripe state. We developed ripening-stimulating compounds (RCs) thought to increase the activity of the pathway we previously identified in comparison of Anjou and Bartlett tissue. Initial tests of mature unconditioned, 1-MCP treated fruit have shown accelerated ethylene biosynthesis, respiration rate and development of fruit quality traits from RC exposure. Future work will seek to characterize global transcriptomic responses to exposure of these RCs in 1-MCP treated and control Anjou and Bartlett fruit, as well as identify means to enhance RC penetration into fruit interior. This work demonstrates a unique means of accelerating pear ripening, and can help facilitate the use of 1-MCP in the pear postharvest management chain.
