Depression of enzyme activities and gene expression of ACC synthase and ACC oxidase in cut carnation flowers under high-temperature conditions

Abstract

High-temperature depression of ethylene production in cut carnation flowers cv. 'Excerea' can occur because of inhibition of ACC synthase (ACS) and ACC oxidase (ACO) activities in flowers. Large differences were apparent between ACS activity in petals at 24°C and 32°C. These ACC-accumulationrelated activities were markedly decreased in petals at 32°C, indicating that a low ACS activity and ACC accumulation in petals are a factor of ethylene biosynthesis inhibition under high-temperature conditions. In addition, the respective expressions of DC-ACO1 and DC-ACS1 were low in both gynoecia and petals of flowers kept at 32°C. Results indicate that low ACS and ACO activities under high-temperature conditions were transcriptionally regulated.

Depression of Autocatalytic Ethylene Production by High-temperature Treatment in Carnation Flowers

“…These results contrast with results in carnation flowers in which ethylene production is not initiated; that is, high temperature suppresses petal wilting (Yangkhamman et al, 2005(Yangkhamman et al, , 2007. Taken together, the results from these studies indicate that high temperature needs to be applied before autocatalytic ethylene production to suppress or delay petal wilting in carnation flowers.…”

“…Depression of ethylene production is known to be a result of suppressing DC-ACS1 and DC-ACO1 expressions in carnation flowers kept under continuous hightemperature conditions (Verlinden and Woodson, 1998;Yangkhamman et al, 2007). In petals of flowers transferred to high temperature after initiation of autocatalytic ethylene production, ACS and ACO activities were depressed with greater depression in ACS activity.…”

“…In the petals of flowers held at 32°C, upregulation of DC-ACS1 and DC-ACO1 was not induced, resulting in lower ACS and ACO activities. These results indicate that ethylene production under high-temperature conditions is inhibited at the transcriptional level (Yangkhamman et al, 2007). Verlinden and Woodson (1998) reported that cut carnation flowers exposed to 44°C for 24 h at the full-opening stage showed a delayed increase in ethylene production and transcript levels of DC-ACS1 and DC-ACO1, suggesting that high temperature affects transcriptional regulation of DC-ACS1 and DC-ACO1.…”

“…ACS and ACO activities were measured according to the procedure described in Yangkhamman et al (2007) with 0.5 g petal tissue from each control and hightemperature-treated flowers.…”

Molecular Mechanisms of Petal Senescence in Ornamental Plants

“…Ethylene is synthesized through the following pathway: L-methionine → S-adenosyl-L-methionine → 1-aminocyclopropane-1-carboxylic acid (ACC) → ethylene. The last two reactions are catalyzed by ACC synthase and ACC oxidase, which have been shown to be encoded by multi-gene families with spatial and temporal regulation by various endogenous cues and environmental stimuli (Fluhr and Mattoo, 1996;Jones and Woodson, 1999a;Nakatsuka et al, 1998;Shibuya and Ichimura, 2010;Yangkhamman et al, 2007). Recent reports suggest that ACC synthase activity is also regulated post-translationally (Lin et al, 2009;Tatsuki, 2010).…”