Ethylene and α-Farnesene Metabolism in Green and Red Skin of Three Apple Cultivars in Response to 1-Methylcyclopropene (1-MCP) Treatment

Abstract

Relationships among alpha-farnesene synthesis and oxidation, ethylene production and perception, antioxidative enzyme activities, and superficial scald development in fruit of three commercial apple cultivars were investigated at the biochemical and gene transcriptional levels. Scald-susceptible Cortland and Law Rome and scald-resistant Idared apples were untreated or treated with the ethylene action inhibitor 1-methylcyclopropene (1-MCP) and stored for up to 25 weeks at 0.5 degrees C. Separate blushed (red) and unblushed (green) peel tissue samples were taken at harvest and after 2, 4, 6, 10, 15, 20, and 25 weeks of storage. Large increases in peel tissue concentrations of alpha-farnesene and its conjugated trienol (CTol) oxidation products occurred in untreated Cortland and Law Rome and were about 4-9-fold greater than those in Idared. In both Cortland and Law Rome, accumulation of CTols in green peel was nearly twice that in red peel. 1-MCP treatment delayed and attenuated alpha-farnesene and CTol accumulation in each cultivar. Activities of peroxidase (POX) and catalase (CAT) were lower in red peel than in green peel, with the exception of CAT in Law Rome, whereas no effects of 1-MCP on enzyme activities were detected except for Cortland. In control fruit, internal ethylene concentrations (IECs) increased during the first 4-6 weeks to reach highest levels in Cortland, intermediate levels in Law Rome, and low levels in Idared. In 1-MCP-treated fruit, IECs increased gradually to modest levels by 25 weeks in Cortland and Law Rome but were almost nil in Idared. Expression patterns of the alpha-farnesene synthase gene MdAFS1, the ethylene receptor gene MdERS1, and the ethylene biosynthetic genes MdACS1 and MdACO1 were generally in accord with the patterns of alpha-farnesene and ethylene production. In particular, MdAFS1 and MdACS1 showed similar patterns of expression in each cultivar. Among the controls, transcript levels increased more rapidly in Cortland and Law Rome than in Idared during the first few weeks of storage. In 1-MCP-treated fruit, transcript abundance in Cortland and Law Rome rose to untreated control levels after 10-15 weeks but remained low in Idared. Scald symptoms were restricted to unblushed skin, and the incidence in controls after 25 weeks was nearly 100% in Cortland and Law Rome compared with 1% in Idared. 1-MCP treatment reduced scald incidence to 14, 3, and 0% in Cortland, Law Rome, and Idared, respectively. Overall, the results support the proposed role of CTols in scald induction and indicate that alpha-farnesene synthesis is tightly regulated by ethylene. However, gene transcription alone does not account for the big differences in ethylene and alpha-farnesene production in Cortland, Law Rome, and Idared apples.

Influence of 1-Methylcyclopropene Treatment on Postharvest Quality of Four Scab (Venturia inaequalis)-Resistant Apple Cultivars

“…However, we observed significant differences in ethylene production among the five cultivars as well as differential response of these cultivars to the 1-MCP treatment in the two storage durations. Our results are in agreement with earlier observations made by Tsantili et al [34]. Additionally, Watkins et al [19] showed different sensitivity to 1-MCP among four apple cultivars, resulting in different degree of inhibition of ethylene production.…”

“…Tsantili et al [34] reported different levels of ethylene synthesis between "Cortland," "Law Rome," and "Idared" apples during 25 weeks of storage at 0.5 ∘ C. The 1-MCP effect on ethylene production also slightly differed among cultivars. Although 1-MCP reduced ethylene production in many apple cultivars, the rate of synthesis started to increase after 5 weeks of storage in "Cortland" and "Law Rome" apples, while it stayed relatively constant in "Idared" fruits after 25 weeks of storage [34]. In the present study, 1-MCP treatment reduced ethylene production in all five cultivars.…”

Effect of the Cooling System and 1-MCP on the Incidence of Superficial Scald in ‘Granny Smith’ Apples

“…This agrees with what has been reported by several studies Watkins et al, 2000;DeEll et al, 2002;Shaham et al, 2003;Zanella, 2003;DeLong et al, 2004) and reaffirms that the control is a function of an inhibition of ethylene that regulates lower AF production Watkins et al, 2000;Golding et al, 2001;Shaham Arquiza et al, 2005;Tsantili et al, 2007) and its consequent oxidation of TC, in particular TC 281.…”

Alteração da eficiência do 1-MCP com o retardo na sua aplicação após a colheita em maçãs 'Fuji suprema'

“…Todavia, menores benefícios do 1-MCP são observados em maçãs colhidas em estádio avançado de maturação (ARGENTA et al, 2005) ou tratadas depois de decorrido certo tempo de armazenamento refrigerado (ARGENTA et al, 2005;NOCK, 2005;JUNG;WATKINS, 2008). A menor eficiência do 1-MCP nestas condições é resultado do maior acúmulo de transcritos dos genes das rotas de biossíntese de etileno e de a-farneseno (PECHOUS et al, 2005;TSANTILI et al, 2007).…”