ARS | Publication request: Differential suppression of ethylene biosynthesis and receptor genes in 'Golden Delicious' apple by preharvest and postharvest 1-MCP treatments

Submitted to: Journal of Plant Growth Regulation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 7, 2013
Publication Date: March 12, 2013
Citation: Varanasi, V., Shin, S.B., Johnson, F., Mattheis, J.P., Zhu, Y. 2013. Differential suppression of ethylene biosynthesis and receptor genes in 'Golden Delicious' apple by preharvest and postharvest 1-MCP treatments. Journal of Plant Growth Regulation. DOI 10.1007/s00344-013-9326-8.

Interpretive Summary: Ethylene is a very simple molecule by its chemical nature, but its impacts on the ripening behaviors and quality attributes of climacteric fruit such as apple can never be underestimated. 1-Methylcyclopropene (1-MCP) with the commercial name of SmartFresh™ is an ethylene action inhibitor, and it has been used in postharvest management for better storability of fresh fruit and vegetables. Harvista™ is a foliar spray formulation of 1-MCP and it was designed to use at preharvest stages to influence the ripening behavior and quality management even to on-tree maturing fruit. In the current study, the timing of pre-harvest application and its effects on fruit ripening progress and fruit firmness was studied; both physiological change and molecular alteration were characterized. The timing of pre-harvest application of Harvista™ resulted in evident differences in ripening parameters, while the Harvista™ application in the starch pattern index of 2.5 resulted in the best results of at-harvest firmness. Pre-harvest Harvista™ application led to better postharvest fruit firmness retention and reduced ethylene production. As expected, additional application of SmartFresh™ resulted in further fruit firmness retention and longer ethylene suppression. Both preharvest and postharvest treatments resulted in contrasting responses on two ethylene biosynthesis genes and differential suppressing effects on four ethylene receptor genes. Using weekly samples, the expression profiles of these genes during on-tree fruit maturation and before Harvista™ application were also characterized to explore the potential molecular mechanisms leading to differential suppression by 1-MCP treatments. Our results support the potential roles of Harvista™ in manipulating the ripening process and the molecular characterization suggest their influencing on 1-MCP treatment efficacy.

Technical Abstract: Harvista™, a spraying formulation of 1-MCP, is a recently available tool for managing preharvest on-tree fruit maturation whereas SmartFresh™ is the widely-used treatment for postharvest handling and storage. In the current study, the timing of pre-harvest application and its effects on fruit ripening progress and fruit firmness was investigated; the expression profiles of ethylene biosynthesis and receptor genes were characterized during regular air cold storage for 24 weeks. The timing of pre-harvest application of Harvista™ resulted in evident differences in ripening parameters, while the Harvista™ application in the starch pattern index of 2.5 resulted in the best results of at-harvest firmness. Pre-harvest Harvista™ application led to better postharvest fruit firmness retention and reduced ethylene production. As expected, additional application of SmartFresh™ resulted in further fruit firmness retention and longer ethylene suppression. Both preharvest and postharvest treatments resulted in contrasting responses on two ethylene biosynthesis genes and differential suppressing effects on four ethylene receptor genes. Using weekly samples, the expression profiles of these genes during on-tree fruit maturation and before Harvista™ application were also characterized to explore the potential molecular mechanisms leading to differential suppression by 1-MCP treatments. The potential roles of Harvista™ to manipulate the ripening process and the molecular mechanism influencing 1-MCP treatment efficacy are discussed.