Ethylene synthesis, ripening capacity, and superficial scald inhibition in 1-MCP treated ‘d’Anjou’ pears are affected by storage temperature

This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/postharvest-biology-and-technology/A continuing challenge for commercializing 1-methylcyclopropene (1-MCP) to extend the storage life and control superficial scald of ‘d’Anjou’ pear (Pyrus communis L.) is how to initiate ripening in 1-MCP treated fruit. ‘D’Anjou’ pears harvested at commercial and late maturity were treated with 1-MCP at 0.15 μL L⁻¹ and stored either at the commercial storage temperature -1.1 °C (1-MCP@-1.1°C), or at 1.1 °C (1-MCP@1.1°C) or 2.2 °C (1-MCP@2.2°C) for 8 months. Control fruit stored at -1.1 °C ripened and developed significant scald within 7 d at 20 °C following 3-5 months of storage. While 1-MCP@-1.1°C fruit did not develop ripening capacity due to extremely low internal ethylene concentration (IEC) and ethylene production rate for 8 months, 1-MCP@1.1°C fruit produced significant amounts of IEC during storage and developed ripening capacity with relatively low levels of scald within 7 d at 20 °C following 6-8 months of storage. 1-MCP@2.2°C fruit lost quality quickly during storage. Compared to the control, the expression of ethylene synthesis (PcACS1, PcACO1) and signal (PcETR1, PcETR2) genes was stable at extremely low levels in 1-MCP@-1.1°C fruit. In contrast, they increased expression after 4 or 5 months of storage in 1-MCP@1.1 °C fruit. Other genes (PcCTR1, PcACS2, PcACS4 and PcACS5) remained at very low expression regardless of fruit capacity to ripen. A storage temperature of 1.1 °C can facilitate initiation of ripening capacity in 1-MCP treated ‘d’Anjou’ pears with relatively low scald incidence following 6-8 months storage through recovering the expression of certain ethylene synthesis and signal genes