Project description:Escherichia coli O157:H7 has caused serious outbreaks of foodborne illness via transmission in a variety of food vehicles, including unpasteurized apple juice, dried salami, and spinach. To understand how this pathogen responds to the multiple stresses of the food environment, we compared global transcription patterns after exposure to apple juice. Transcriptomes of mid-exponential and stationary phase cells were evaluated after 10 minutes in model apple juice (pH3.5) using microarrays probing 4,886 ORFs. Significant changes in gene expression were determined using R/MAANOVA and the Fs test. A total of 331 ORFs were significantly induced upon exposure of cells to model apple juice and included genes involved in the acid and osmotic stress responses as well as the oxidative stress response and envelope stress. Genes involved in the acid and osmotic stress responses, including asr, osmC, osmB, and osmY were significantly induced in response to model apple juice. Genes involved in the envelope stress response, known to be controlled by CpxR (cpxP, degP, and htpX), were significantly induced 2 to 15 fold upon exposure to apple juice, independent of growth phase. Inactivation of CpxRA resulted in a significant decrease in survival of O157:H7 in model apple juice compared to the isogenic parent strain. Of the 331 ORFs induced in model apple juice, 104 are O157-specific ORFs, including those encoding type three secretion effectors espJ, espB, espM2, espL3 and espZ. By elucidating the response of O157:H7 to acidic foods, we hope to gain insights into how this pathogen is able to survive in food matrices and how exposure to foods affects subsequent transmission and virulence. Keywords: stress The results are based on O157:H7 Sakai exponential and stationary phase cultures grown in MOPS minimal medium and then exposed to model apple juice (pH 3.5, 37C) for 10 minutes. Differences in transcript levels were determined using a mixed model ANOVA in R/MAANOVA which tested for significant differences due to growth phase (exponential or stationary), treatment (MOPS or MAJ) and the interaction of these two factors using the following linear model: array+dye+sample (biological replicate)+ phase+treatment+phase*treatment. We incorporated the dye-swaps among the biological replicates.
Project description:Based on sensorial analysis over 4 years, 6 apple genotypes with contrasted fruit texture (mealy or not) were selected among a progeny. Apple samples were collected at 100 days after flowering (100 DAF), harvest (H), after 2 and 4 months of cold storage (60DAH and 120DAH respectively).
Project description:Based on sensorial analysis, 8 apple genotypes with contrasted fruit texture for mealiness were selected among a progeny. Apple samples were collected at 60 days after flowering (60DAF), 110 days after flowering (110DAF), harvest (Rec), and after 1 or 2 months of cold storage (1M and 2M respectively).
Project description:Escherichia coli O157:H7 has caused serious outbreaks of foodborne illness via transmission in a variety of food vehicles, including unpasteurized apple juice, dried salami, and spinach. To understand how this pathogen responds to the multiple stresses of the food environment, we compared global transcription patterns after exposure to apple juice. Transcriptomes of mid-exponential and stationary phase cells were evaluated after 10 minutes in model apple juice (pH3.5) using microarrays probing 4,886 ORFs. Significant changes in gene expression were determined using R/MAANOVA and the Fs test. A total of 331 ORFs were significantly induced upon exposure of cells to model apple juice and included genes involved in the acid and osmotic stress responses as well as the oxidative stress response and envelope stress. Genes involved in the acid and osmotic stress responses, including asr, osmC, osmB, and osmY were significantly induced in response to model apple juice. Genes involved in the envelope stress response, known to be controlled by CpxR (cpxP, degP, and htpX), were significantly induced 2 to 15 fold upon exposure to apple juice, independent of growth phase. Inactivation of CpxRA resulted in a significant decrease in survival of O157:H7 in model apple juice compared to the isogenic parent strain. Of the 331 ORFs induced in model apple juice, 104 are O157-specific ORFs, including those encoding type three secretion effectors espJ, espB, espM2, espL3 and espZ. By elucidating the response of O157:H7 to acidic foods, we hope to gain insights into how this pathogen is able to survive in food matrices and how exposure to foods affects subsequent transmission and virulence. Keywords: stress
Project description:Based on sensorial analysis over 4 years, 6 apple genotypes with contrasted fruit texture (mealy or not) were selected among a progeny. Apple samples were collected at 100 days after flowering (100 DAF), harvest (H), after 2 and 4 months of cold storage (60DAH and 120DAH respectively). 6 apple hybrids were analysed in dye-switch. Biological replicates are fruits from 2 to 4 different harvest years. Each mealy hybrid was compared to a non-mealy hybrid from the same harvest year in 12 dye-swap 3 pairs at 4 four time points).
Project description:We performed Illumina sequencing of sRNA libraries prepared from juvenile and reproductive phase buds from the apple trees. A large number of sRNAs exemplified by 33 previously annotated miRNAs and 6 novel members displayed significant differential expression (DE) patterns in juvenile and reproductive stages. The study provides new insight into our understanding of fundamental mechanism of poorly studied phase transitions in apple and other woody plants and important resource for future in-depth research in the apple development.
Project description:Background miRNAs and their regulatory functions have been extensively characterized in model species but whether apple has evolved similar or unique regulatory features remains unknown. Results We performed deep sRNA-seq and identified 23 conserved, 10 less-conserved and 42 apple-specific miRNAs or families with distinct expression patterns. The identified miRNAs target 118 genes representing a wide range of enzymatic and regulatory activities. Apple also conserves two TAS gene families with similar but unique tasiRNA biogenesis profiles and target specificities. Importantly, we found that miR159, miR828 and miR858 can collectively target up to 81 MYB genes potentially involved in diverse aspects of plant growth and development. These miRNA target sites are differentially conserved among MYBs, which is largely influenced by the location and conservation of the encoded amino acid residues in MYB factors. Finally, we found that ten of the 19 miR828-targeted MYBs undergo siRNA biogenesis at the 3' cleaved, highly divergent transcript regions, generating over 100 sequence-distinct siRNAs that potentially target over 70 diverse genes as confirmed by degradome analysis. Conclusion Our work identified and characterized apple miRNAs, their expression patterns, targets and regulatory functions. We also discovered that three miRNAs and the ensuing siRNAs exploit both conserved and divergent sequence features of MYB genes to initiate distinct regulatory networks targeting a multitude of genes inside and outside the MYB family.
Project description:Transcriptional profiling of various apple (Malus x domestica Borkh) organ systems using probes complementary to both sense and anti-sense transcripts. Eight apple organs/samples. Biological replicates: 2 for each sample, independently grown and harvested.
Project description:Apple is one of the most popular fruit crops world-wide and its skin color is an important quality consideration essential for commercial value. However, the strategy on genetic breeding for red skin apple and the genetic basis of skin color differentiation is very limited and still largely unknown. Here, we reported a bud sport mutant of Fuji apple with red skin color and enhanced anthocyanins accumulation. Quantitative SWATH-MS (sequential window acquisition of all theoretical spectra-mass spectrometry) proteomics investigations revealed proteome changes in the apple red skin bud mutation and a total of 411 differentially expressed proteins were identified in apple skin. The mutant showed significantly increased expression levels of photosynthesis-related proteins, stress-related proteins as well as anthocyanins biosynthesis pathway. On the other hand, substanial downregulation of mitogen-activated protein kinase 4 (MAPK4) and mevalonate kinase (MVK) were detected. We also hypothesize that a post-transcriptional regulation of the skin color formation occurs in the mutant through the advanced SWATH-MS analysis. Overall, our work provide important information on the application of proteomic methods for analysing proteomes changes in Fuji apple and highlights a clade of regulatory proteins potentially contributed to the fruit skin color formation.
Project description:Background miRNAs and their regulatory functions have been extensively characterized in model species but whether apple has evolved similar or unique regulatory features remains unknown. Results We performed deep sRNA-seq and identified 23 conserved, 10 less-conserved and 42 apple-specific miRNAs or families with distinct expression patterns. The identified miRNAs target 118 genes representing a wide range of enzymatic and regulatory activities. Apple also conserves two TAS gene families with similar but unique tasiRNA biogenesis profiles and target specificities. Importantly, we found that miR159, miR828 and miR858 can collectively target up to 81 MYB genes potentially involved in diverse aspects of plant growth and development. These miRNA target sites are differentially conserved among MYBs, which is largely influenced by the location and conservation of the encoded amino acid residues in MYB factors. Finally, we found that ten of the 19 miR828-targeted MYBs undergo siRNA biogenesis at the 3' cleaved, highly divergent transcript regions, generating over 100 sequence-distinct siRNAs that potentially target over 70 diverse genes as confirmed by degradome analysis. Conclusion Our work identified and characterized apple miRNAs, their expression patterns, targets and regulatory functions. We also discovered that three miRNAs and the ensuing siRNAs exploit both conserved and divergent sequence features of MYB genes to initiate distinct regulatory networks targeting a multitude of genes inside and outside the MYB family. Identification of apple miRNAs and their targets from four different tissues