1,721,019 research outputs found

    The ethylene biosynthetic and transduction pathways are differently affected by 1-MCP in apple and peach fruit

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    1-Methylcyclopropene (1-MCP) is an antagonist of ethylene for receptor binding sites and the effects of its application differ in relation to a number of factors including genotype and ripening physiology. Peach (Prunus persica L. Batsch cv. ‘Summer Rich’) and apple (Malus domestica L. Borkh cv. ‘Golden Delicious’) fruits were incubated with 1-MCP (1 microLL−1) for 24 h at 20 ◦C and respiration rate, ethylene production and fruit firmness, together with ACC synthase, ACC oxidase, ETR1, ERS1, and CTR1 gene expression patterns were assessed throughout the post-treatment phase. 1-MCP was confirmed to be effective in delaying ripening in apples while in peaches only a limited effect of the chemical was observed. A dramatic inhibition of ethylene biosynthesis and ACS gene expression was induced by 1-MCP in apples whereas no marked difference was observed in peaches between the two controls (in air and in sealed jars without 1-MCP) and the treated fruit. In apples, Md-ETR1 and Md-ERS1 gene expression was down-regulated by 1-MCP starting from the end of the treatment, while Md-CTR1 appeared negatively affected by the chemical at a later stage. Transcription of Pp-ETR1, Pp-ERS1 and Pp-CTR1 genes appeared unaffected in 1-MCP treated peaches. Differences in receptor transcript levels between control fruit maintained in air and those enclosed in sealed jars without 1-MCP may be due to an effect of CO2 that rapidly accumulates following incubation of ripening peaches. Results support the hypothesis that the different behaviour of peaches and apples in response to 1-MCP application might be related to differences in terms of ratio, expression patterns and/or turn-over of the ethylene receptors

    Postharvest water loss induces marked changes in transcript profiling in skins of wine grape berries

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    A large-scale transcriptome analysis was conducted using an oligo-based microarray (14,562 probes) on skins of wine grape (Vitis vinifera L.) berries dehydrated at different rates (slow, S and rapid, R) after harvest up to 10 and 30% of weight loss (WL). At 10% WL, a total of 84 and 68 probes were differentially expressed following S and R dehydration, respectively. At 30% WL, 309 and 262 differentially expressed probes were detected in S and R samples, respectively, indicating that grape berries are still reactive at advanced stages of postharvest dehydration. Bioinformatic analysis revealed that about 70% of the differentially expressed probes could be annotated and putative functions were assigned. Functional characterization highlighted that, independently of the rate and intensity of dehydration, differential expression occurred in particular for genes associated with general metabolism, regulatory processes, and responses to biotic and abiotic stimuli. A total of 16 (induced) and 10 (repressed) probes, common to all four dehydrated samples, were associated with hormone (ethylene) metabolism, transcription factors, carbohydrate and secondary (polyphenols) metabolism, transport and stress responses. Together with the total number of differentially expressed probes, enhancing the dehydration level from 10 to 30% WL also affected the distribution of genes within functional categories: this behaviour was observed in particular for R samples. A higher level of water stress in grapes appears to be associated with modification to the expression of genes mainly involved in hormone and sugar metabolism, and defence mechanisms. Besides the intensity of dehydration, a significant effect on gene expression was also associated with rate of water loss: an increase in the percentage incidence of differentially expressed probes was present for categories involved in defence and environmental stress when comparing R and S samples. The microarray data, validated by RT-PCR analyses, represent robust evidence for the marked effects of postharvest water loss on metabolic processes in fruit tissues
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