Project description:Apple pedicel vascular development array Twelvet apple samples. Biological replicates: 2 for each sample, independently grown and harvested.
Project description:Apple pedicel vascular development array Eight apple samples. Biological replicates: 2 for each sample, independently grown and harvested.
Project description:Abscission is the regulated process of detachment of an organ from a plant. In apple the abscission of fruits occurs during their early development to control the fruit load depending on the nutritional state of the plant. In order to control production and obtain fruits with optimal market qualities, the horticultural procedure of thinning is performed to further reduce the number of fruitlets. In this study we have conducted a transcriptomic profiling of seeds from two different types of fruitlets, according to size and position in the fruit cluster. Transcriptomic profiles of central and lateral fruit seeds were obtained by RNAseq. Comparative analysis was performed by the functional categorization of differentially expressed genes by means of Gene Ontology (GO) annotation of the apple genome. Our results revealed the overexpression of genes involved in responses to stress, hormone biosynthesis and also the response and/or transport of auxin and ethylene. A smaller set of genes, mainly related to ion transport and homeostasis, were found to be down-regulated. The transcriptome characterization described in this manuscript contributes to unravelling the molecular mechanisms and pathways involved in the physiological abscission of apple fruits and suggests a role for seeds in this process.
Project description:Effect of the presence of fruits on the expression of genes possibly involved in floral induction in the terminal meristem of spur bourse shoot. Investigation on mecanisms involved in Biennial Bearing in mature apple trees cultivar Royal Gala.
Project description:Effect of the presence of fruits on the expression of genes possibly involved in floral induction in the terminal meristem of spur bourse shoot. Investigation on mecanisms involved in Biennial Bearing in mature apple trees cultivar Royal Gala. Two-condition experiment : 'ON' trees (unthinned control) & 'OFF' trees (deflowered) for comparison. Three comparisons at sampling dates : 28, 48 and 119 days after full bloom (DAFB). Two dye switch biological replicates for each treatment and sampling date.
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: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:Freezing tolerance is a significant trait in plants that grow in cold environments and survive through the winter. Apple (Malus domestica Borkh.) is a cold-tolerant fruit tree, and the cold tolerance of its bark is important for its survival at low temperatures. However, little is known about the gene activity related to its freezing tolerance. To better understand the gene expression and regulation properties of freezing tolerance in dormant apple trees, we analyzed the transcriptomic divergences in the bark from 1-year-old branches of two apple cultivars, "Golden Delicious" (G) and "Jinhong" (H), which have different levels of cold resistance, under chilling and freezing treatments. "H" can safely overwinter below -30?°C in extremely low-temperature regions, whereas "G" experiences severe freezing damage and death in similar environments. Based on 28 bark transcriptomes (from the epidermis, phloem, and cambium) from 1-year-old branches under seven temperature treatments (from 4 to -29?°C), we identified 4173 and 7734 differentially expressed genes (DEGs) in "G" and "H", respectively, between the chilling and freezing treatments. A gene coexpression network was constructed according to this expression information using weighted gene correlation network analysis (WGCNA), and seven biologically meaningful coexpression modules were identified from the network. The expression profiles of the genes from these modules suggested the gene regulatory pathways that are responsible for the chilling and freezing stress responses of "G" and/or "H." Module 7 was probably related to freezing acclimation and freezing damage in "H" at the lower temperatures. This module contained more interconnected hub transcription factors (TFs) and cold-responsive genes (CORs). Modules 6 and 7 contained C-repeat binding factor (CBF) TFs, and many CBF-dependent homologs were identified as hub genes. We also found that some hub TFs had higher intramodular connectivity (KME) and gene significance (GS) than CBFs. Specifically, most hub TFs in modules 6 and 7 were activated at the beginning of the early freezing stress phase and maintained upregulated expression during the whole freezing stress period in "G" and "H". The upregulation of DEGs related to methionine and carbohydrate biosynthetic processes in "H" under more severe freezing stress supported the maintenance of homeostasis in the cellular membrane. This study improves our understanding of the transcriptional regulation patterns underlying freezing tolerance in the bark of apple branches.
Project description:BackgroundIndividual plants adapt to their immediate environment using a combination of biochemical, morphological and life cycle strategies. Because woody plants are long-lived perennials, they cannot rely on annual life cycle strategies alone to survive abiotic stresses. In this study we used suppression subtractive hybridization to identify genes both up- and down-regulated in roots during water deficit treatment and recovery. In addition we followed the expression of select genes in the roots, leaves, bark and xylem of 'Royal Gala' apple subjected to a simulated drought and subsequent recovery.ResultsIn agreement with studies from both herbaceous and woody plants, a number of common drought-responsive genes were identified, as well as a few not previously reported. Three genes were selected for more in depth analysis: a high affinity nitrate transporter (MdNRT2.4), a mitochondrial outer membrane translocase (MdTOM7.1), and a gene encoding an NPR1 homolog (MpNPR1-2). Quantitative expression of these genes in apple roots, bark and leaves was consistent with their roles in nutrition and defense.ConclusionsAdditional genes from apple roots responding to drought were identified using suppression subtraction hybridization compared to a previous EST analysis from the same organ. Genes up- and down-regulated during drought recovery in roots were also identified. Elevated levels of a high affinity nitrate transporter were found in roots suggesting that nitrogen uptake shifted from low affinity transport due to the predicted reduction in nitrate concentration in drought-treated roots. Suppression of a NPR1 gene in leaves of drought-treated apple trees may explain in part the increased disease susceptibility of trees subjected to dehydrative conditions.