Project description:Superficial scald is a major physiological disorder in apple fruit that is induced by cold storage and is mainly expressed as brown necrotic patches on peel tissue. However, a global view of the gene-protein-metabolite interactome underlying scald prevention/sensitivity is currently missing. Herein, we have found for the first time that cold storage in an atmosphere enriched with ozone (O3) induced scald symptoms in ‘Granny Smith’ apple fruits during subsequent ripening at room temperature. In contrast, treatment with the ethylene perception inhibitor 1-methylcyclopropene (1-MCP) reversed this O3-induced scald effect. Amino acids, including branched-chain amino acids, were the most strongly induced metabolites in peel tissue of 1-MCP treated fruits. Proteins involved in oxidative stress and protein trafficking were differentially accumulated prior to and during scald development. Genes involved in photosynthesis, flavonoid biosynthesis and ethylene signaling displayed significant alterations in response to 1-MCP and O3. Analysis of regulatory module networks identified putative transcription factors (TFs) that could be involved in scald. Subsequently, a transcriptional network of the genes-proteins-metabolites and the connected TFs was constructed. This approach enabled identification of several genes co-regulated by TFs, notably encoding glutathione S-transferase (GST) protein(s) with distinct signatures following 1-MCP and O3 treatments. Overall, this study is an important contribution to future functional studies and breeding programs for this fruit, aiding to the development of improved apple cultivars to superficial scald.
Project description:Apple (Malus x domestica Borkh.) is a model fruit species to study the metabolic changes occurring at the onset of ripening as well the physiological mechanism governed by the hormone ethylene. In this survey, to dissect the climacteric interplay in apple, a multidisciplinary approach was employed. To this end, a comprehensive analysis of gene expression together with the investigation of several physiological entities (texture, volatilome and polyphenolic compounds) was carried out throughout fruit development and ripening. The transcriptomic profiling was conducted with two microarray platforms, a custom array dedicated to fruit ripening pathways (iRIPE) and a whole genome array specifically enriched of ripening related genes for apple (WGAA). The transcriptomic and phenotypic changes following the application of 1-methylcyclopropene (1-MCP), an ethylene inhibitor, were also highlighted. The suppression of ethylene modified and delayed the ethylene receptors turnover, leading to important modifications in the overall fruit physiology. The integrative comparative network analysis showed both negative and positive correlations between ripening related transcripts and accumulation of specific metabolites or texture components. The ripening distortion caused by the inhibition of the ethylene perception besides affecting the ethylene and texture control, stimulated the de-repression of auxin related genes, transcription factors and photosynthethic genes. In the end, the comprehensive repertoire of results obtained here step forwards in the elucidation of the multi-layered control of ethylene, hypothesizing a possible hormonal cross-talk coupled with a transcriptional regulation. 48 samples analyzed; 8 stages have been identified over the fruit development and ripening (from flower to post harvest ripening) of apple fruit belonging to two apple cultivars (Golden Delicious and Granny Smith), ending with 16 samples (3 replacates for each sample)
Project description:Apple (Malus x domestica Borkh.) is a model fruit species to study the metabolic changes occurring at the onset of ripening as well the physiological mechanism governed by the hormone ethylene. In this survey, to dissect the climacteric interplay in apple, a multidisciplinary approach was employed. To this end, a comprehensive analysis of gene expression together with the investigation of several physiological entities (texture, volatilome and polyphenolic compounds) was carried out throughout fruit development and ripening. The transcriptomic profiling was conducted with two microarray platforms, a custom array dedicated to fruit ripening pathways (iRIPE) and a whole genome array specifically enriched of ripening related genes for apple (WGAA). The transcriptomic and phenotypic changes following the application of 1-methylcyclopropene (1-MCP), an ethylene inhibitor, were also highlighted. The suppression of ethylene modified and delayed the ethylene receptors turnover, leading to important modifications in the overall fruit physiology. The integrative comparative network analysis showed both negative and positive correlations between ripening related transcripts and accumulation of specific metabolites or texture components. The ripening distortion caused by the inhibition of the ethylene perception besides affecting the ethylene and texture control, stimulated the de-repression of auxin related genes, transcription factors and photosynthethic genes. In the end, the comprehensive repertoire of results obtained here step forwards in the elucidation of the multi-layered control of ethylene, hypothesizing a possible hormonal cross-talk coupled with a transcriptional regulation. whole genome array specifically enriched of ripening related genes for apple (WGAA) with two cultivars (Golden Delicious and Granny Smith)
Project description:Apple (Malus x domestica Borkh.) is a model fruit species to study the metabolic changes occurring at the onset of ripening as well the physiological mechanism governed by the hormone ethylene. In this survey, to dissect the climacteric interplay in apple, a multidisciplinary approach was employed. To this end, a comprehensive analysis of gene expression together with the investigation of several physiological entities (texture, volatilome and polyphenolic compounds) was carried out throughout fruit development and ripening. The transcriptomic profiling was conducted with two microarray platforms, a custom array dedicated to fruit ripening pathways (iRIPE) and a whole genome array specifically enriched of ripening related genes for apple (WGAA). The transcriptomic and phenotypic changes following the application of 1-methylcyclopropene (1-MCP), an ethylene inhibitor, were also highlighted. The suppression of ethylene modified and delayed the ethylene receptors turnover, leading to important modifications in the overall fruit physiology. The integrative comparative network analysis showed both negative and positive correlations between ripening related transcripts and accumulation of specific metabolites or texture components. The ripening distortion caused by the inhibition of the ethylene perception besides affecting the ethylene and texture control, stimulated the de-repression of auxin related genes, transcription factors and photosynthethic genes. In the end, the comprehensive repertoire of results obtained here step forwards in the elucidation of the multi-layered control of ethylene, hypothesizing a possible hormonal cross-talk coupled with a transcriptional regulation.
Project description:Apple (Malus x domestica Borkh.) is a model fruit species to study the metabolic changes occurring at the onset of ripening as well the physiological mechanism governed by the hormone ethylene. In this survey, to dissect the climacteric interplay in apple, a multidisciplinary approach was employed. To this end, a comprehensive analysis of gene expression together with the investigation of several physiological entities (texture, volatilome and polyphenolic compounds) was carried out throughout fruit development and ripening. The transcriptomic profiling was conducted with two microarray platforms, a custom array dedicated to fruit ripening pathways (iRIPE) and a whole genome array specifically enriched of ripening related genes for apple (WGAA). The transcriptomic and phenotypic changes following the application of 1-methylcyclopropene (1-MCP), an ethylene inhibitor, were also highlighted. The suppression of ethylene modified and delayed the ethylene receptors turnover, leading to important modifications in the overall fruit physiology. The integrative comparative network analysis showed both negative and positive correlations between ripening related transcripts and accumulation of specific metabolites or texture components. The ripening distortion caused by the inhibition of the ethylene perception besides affecting the ethylene and texture control, stimulated the de-repression of auxin related genes, transcription factors and photosynthethic genes. In the end, the comprehensive repertoire of results obtained here step forwards in the elucidation of the multi-layered control of ethylene, hypothesizing a possible hormonal cross-talk coupled with a transcriptional regulation.
Project description:Apple is typically stored under low temperature and controlled atmospheric conditions to ensure a year round supply of high quality fruit for the consumer. During storage, losses in quality and quantity occur due to spoilage by postharvest pathogens. One important postharvest pathogen of apple is Botrytis cinerea. The fungus is a broad host necrotroph with a large arsenal of infection strategies able to infect over 1,400 different plant species. We studied the apple-B. cinerea interaction to get a better understanding of the defense response in apple. We conducted an RNAseq experiment in which the transcriptome of inoculated and non-inoculated (control and mock) apples was analyzed at 0, 1, 12 and 28 h post inoculation. Our results show extensive reprogramming of the apple's transcriptome with about 28.9 % of expressed genes exhibiting significant differential regulation in the inoculated samples. We demonstrate the transcriptional activation of pathogen-triggered immunity and a reprogramming of the fruit’s metabolism. We demonstrate a clear transcriptional activation of secondary metabolism and a correlation between the early transcriptional activation of the mevalonate pathway and reduced susceptibility, expressed as a reduction in resulting lesion diameters. This pathway produces the building blocks for terpenoids, a large class of compounds with diverging functions including defense. 1-MCP and hot water dip treatment are used to further evidence the key role of terpenoids in the defense and demonstrate that ethylene modulates this response.
Project description:Granny Smith apples (Malus x domestica Borkh) were harvested at early physiological mature stage in 2014, 2015 and 2017 and phenotyped for scald incidence after long time cold storage. Differential analyses were set-up for peel samples collected at harvest between fruit batches with low or high scald incidence.
Project description:Fruits stored at low temperature for long time can undergo to different type of chilling injuries. In apple, superficial scald represents one of the most serious physiopathy. The typical symptoms of this disorder are represented by the development of important discoloration and black patches on the fruit exocarp. Although this phenomenon has been historically related to α-farnesene, its etiology and physiology are not yet fully disclosed. In the attempt to elucidate the regulating mechanism of its development and prevention, a multidisciplinary survey was performed, integrating different level of metabolite screening (volatiles, polyphenols and lipids) with a large-scale transcriptomic analysis. The comparison between scalded and non-scalded apples (treated with an ethylene competitor) revealed that the prevention of superficial scald is associated with the triggering of cold acclimation-related processes. The interference at the ethylene receptor level stimulates the production of antioxidant compounds to scavenge reactive oxygen species (ROS), the synthesis of unsaturated fatty acids to stabilize plastid and vacuole membranes against cold temperature and the accumulation of sugar alcohols with important cryoprotectant roles, such as sorbitol. The accumulation pattern of this polyalcohol was also consistent with the expression profile of MdS6PDH. Moreover, the overexpression of this gene in transgenic line of Arabidopsis thaliana plants provided functional validation of its involvement in the biosynthetic pathway of sorbitol and elucidated its role in the cold acclimation and freezing tolerance process.