Project description:The self-abscising characteristic of fruit is a prominent trait for labor-saving cultivation in apple (Malus × domestica). Up to 30 days after full bloom, early abscission leaves only central fruit in a cluster, while four lateral fruits are abscised. Since fruit abscission is possibly induced during earlier phases of fruit development, samples were collected at full bloom and 10 days after full bloom. Comparative analysis between central and lateral pedicels in self-abscising apple can be used to identify the genes that trigger the abscission mechanism, as the destinies of the pedicels in a cluster are obvious. Transcriptome analysis was performed using RNA-Seq to compare expression profiles between the surviving central pedicel to be survived and abscised lateral pedicel to be abscised from self-abscising apple. A total of 797,647 ESTs were assembled into 65,876 contigs which were annotated and analyzed with using Blast2GO. A total of 1,585 differentially expressed genes in central and lateral pedicels were identified using the NOISeq software. , and these genes were were characterized using the MapMan ontology software. Transcription factors involved in vascular bundle differentiation functioned in the central pedicel, while the signaling cascade of IAA14/SLR-ARF7, which progressed during lateral root emergence from primary roots, operated in lateral pedicels. Future studies should explore associations between the mechanisms of lateral root emergence and pedicel abscission during early phases of fruit development, as well as the interconnection among hormones.
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:In tomato, the mutants that lack the abscission zone (AZ) within pedicels are called a ‘jointless’ and are agronomically significant in that they increase the tomato fruit yield for industrial processing. We have employed DNA microarray expression analysis to identify genes with the potential to play a role in development of the pedicel abscission zone of tomato, and identified several classes of differentially regulated genes between pedicels of the AZ-forming line (wild-type) and pedicels of the non AZ-forming lines (jointless mutant and MC-suppressed transformant).
Project description:In tomato, the mutants that lack the abscission zone (AZ) within pedicels are called a ‘jointless’ and are agronomically significant in that they increase the tomato fruit yield for industrial processing. We have employed DNA microarray expression analysis to identify genes with the potential to play a role in development of the pedicel abscission zone of tomato, and identified several classes of differentially regulated genes between pedicels of the AZ-forming line (wild-type) and pedicels of the non AZ-forming lines (jointless mutant and MC-suppressed transformant). Tomato flower pedicels were harvested at anthesis stage from the AZ-forming line (wild-type) and the non AZ-forming lines (jointless mutant and MC-suppressed transformant), and subjected to DNA microarray analyses. Experiments were performed twice with independently prepared samples.
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:Transcriptional profiling of apple (Malus x domestica Borkh) pedicels displaying abnormal additional amphivasal vascular bundles in the pith