Project description:Molecular events regulating apple fruit ripening and sensory quality are largely unknown. Such knowledge is essential for genomic-assisted apple breeding and postharvest quality management. In this study, a parallel transcriptome profile analysis, scanning electron microscopic (SEM) examination and systematic physiological characterization were performed on two apple cultivars, Honeycrisp (HC) and Cripps Pink (CP), which have distinct ripening features and texture attributes. Systematic physiological characterization of fruit ripening based on weekly maturity data indicated substantial differences in fruit crispness and firmness at comparable ripening stages. SEM images of fruit cortex tissues prepared from fruits with equivalent maturity suggested that the cell wall thickness may contribute to the observed phenotypes of fruit firmness and crispness. A high-density long-oligo apple microarray consisting of duplex 190,135 cross-hybridization-free 50-70-mer isothermal probes, and representing 23,997 UniGene clusters, was manufactured on a Nimblegen array platform. Transcriptome profiling identified a total of 1793 and 1209 UniGene clusters differentially expressed during ripening from cortex tissues of HC and CP, respectively. UniGenes implicated in hormone metabolism and response, cell wall biosynthesis and modification and those encoding transcription factors were among the prominent functional groups. Between the two cultivars, most of the identified UniGenes were similarly regulated during fruit ripening; however, a short list of gene families or specific family members exhibited distinct expression patterns between the two cultivars, which may represent candidate genes regulating cultivar-specific apple fruit ripening patterns and quality attributes. Using a single color labeling system, a total of 24 microarray slides were utilized, one for each cortex tissue sample, for transcriptome profiling analysis. 2 cultivars x 3 developmental stages x 4 biological replicates.
Project description:Molecular events regulating apple fruit ripening and sensory quality are largely unknown. Such knowledge is essential for genomic-assisted apple breeding and postharvest quality management. In this study, a parallel transcriptome profile analysis, scanning electron microscopic (SEM) examination and systematic physiological characterization were performed on two apple cultivars, Honeycrisp (HC) and Cripps Pink (CP), which have distinct ripening features and texture attributes. Systematic physiological characterization of fruit ripening based on weekly maturity data indicated substantial differences in fruit crispness and firmness at comparable ripening stages. SEM images of fruit cortex tissues prepared from fruits with equivalent maturity suggested that the cell wall thickness may contribute to the observed phenotypes of fruit firmness and crispness. A high-density long-oligo apple microarray consisting of duplex 190,135 cross-hybridization-free 50-70-mer isothermal probes, and representing 23,997 UniGene clusters, was manufactured on a Nimblegen array platform. Transcriptome profiling identified a total of 1793 and 1209 UniGene clusters differentially expressed during ripening from cortex tissues of HC and CP, respectively. UniGenes implicated in hormone metabolism and response, cell wall biosynthesis and modification and those encoding transcription factors were among the prominent functional groups. Between the two cultivars, most of the identified UniGenes were similarly regulated during fruit ripening; however, a short list of gene families or specific family members exhibited distinct expression patterns between the two cultivars, which may represent candidate genes regulating cultivar-specific apple fruit ripening patterns and quality attributes.
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:Here, we conducted an tandem mass tag (TMT)-based proteomics analysis of apple fruit development over five growth stages. Our objective was to gain a global overview of the dynamics of apple fruit development and identify key regulatory networks and proteins that contribute to fruit development and the metabolism and accumulation of sugars and acids for fruit quality improvement.
Project description:Russeting of apple fruit is a non-invasive physiological disorder. It occurs mainly in 'Golden Delicious' apple and its hybrids, while understanding of its molecular mechanism is still limited. In this study, we used mRNA sequencing and an isobaric tag for relative and absolute quantitation-based quantitative (iTRAQ) proteomic analysis to detect changes in the expression levels of genes and proteins during russeting formation in russeted and non-russeted skin of 'Golden Delicious' apple. We set up three comparison groups representing the three developmental stages in the russeting formation process. With the formation of fruit russeting, there were 2856 differentially expressed genes and 942 differentially expressed proteins in the comparison groups as detected at the transcript level and protein level, respectively. A correlation analysis of the transcriptome and proteome data revealed related-genes involved in lignin biosynthesis are significant changes at different developmental stages during apple russeting formation. Some other transcription factors, such as MYBs, NACs and LIMs were also involved in apple russeting formation. In this study, one LIM transcription factor was preliminarily determined to be involved in lignin biosynthesis by combining to PAL-box element. Studying the identified genes and proteins will provide further insights into the molecular mechanisms controlling apple russeting formation.
Project description:Apple (Malus domestica Borkh) is an important fruit crop cultivated in a broad range of environmental conditions. Apple fruit, and specifically peel tissue, ripening is a physiological process whose molecular regulatory networks response to different environments are still not sufficiently investigated. In this study, the influence of low (20 m) and high (750 m) altitude environmental conditions in peel tissue was assessed by physiological measurements combined with global metabolite and protein expression profiling during apple fruit development and ripening. Although apple fruit ripening was unaffected by the different environmental conditions, however several key color parameters, such as redness and the color percentage index, were induced by high altitude. Consistent with this, increased level of anthocyanin and other phenolic compounds, including cyanidin-3-O-galactoside, quercetin-3-O-rhamnoside, quercetin-3-O-rutinoside and chlorogenic acid were identified in apple peel at high altitude. Also, high altitude environment, particularly, at the ripening period, up-accumulated various carbohydrates (eg., arabinose, xylose and sucrose) while repressed glutamic acid and several related proteins such as glycine hydroxymethyltransferase and glutamate���glyoxylate aminotransferase. Other processes affected by high altitude concerned the TCA cycle, the synthesis of oxidative/defense enzymes, and the accumulation of photosynthetic proteins. Finally, we constructed a metabolite-protein network depicting the impact of altitude on peel ripening. These data provide insights into physiological processes linked to apple peel ripening across different climatic conditions and will assist in efforts to improve apple fruit appeal and quality.
Project description:Apple (Malus domestica Borkh) is an important fruit crop cultivated in a broad range of environmental conditions. Apple fruit, and specifically peel tissue, ripening is a physiological process whose molecular regulatory networks response to different environments are still not sufficiently investigated. In this study, the influence of low (20 m) and high (750 m) altitude environmental conditions in peel tissue was assessed by physiological measurements combined with global metabolite and protein expression profiling during apple fruit development and ripening. Although apple fruit ripening was unaffected by the different environmental conditions, however several key color parameters, such as redness and the color percentage index, were induced by high altitude. Consistent with this, increased level of anthocyanin and other phenolic compounds, including cyanidin-3-O-galactoside, quercetin-3-O-rhamnoside, quercetin-3-O-rutinoside and chlorogenic acid were identified in apple peel at high altitude. Also, high altitude environment, particularly, at the ripening period, up-accumulated various carbohydrates (eg., arabinose, xylose and sucrose) while repressed glutamic acid and several related proteins such as glycine hydroxymethyltransferase and glutamate–glyoxylate aminotransferase. Other processes affected by high altitude concerned the TCA cycle, the synthesis of oxidative/defense enzymes, and the accumulation of photosynthetic proteins. Finally, we constructed a metabolite-protein network depicting the impact of altitude on peel ripening. These data provide insights into physiological processes linked to apple peel ripening across different climatic conditions and will assist in efforts to improve apple fruit appeal and quality.
Project description:Bull’s eye rot is one of the most severe diseases that may affect apples during storage. It is caused by the fungus Neofabraea vagabunda, and the mechanism by which the pathogen infects the fruits is only partially understood. In particular, very little is known about the molecular mechanisms regulating the interaction between the pathogen and the host during symptoms development. Despite different apple cultivars show different levels of resistance to the pathogen, the genetic basis of these responses are unknown. In order to understand the molecular mechanisms occurring in the apple fruit during N. vagabunda infection, a large-scale transcriptome study by RNA-Seq analysis was performed, comparing fruits of the sensitive ‘Roho’ cultivar and the resistant cultivar ‘Ariane’ after artificial infection with N. vagabunda and a storage period of 4 months.
Project description:Anthocyanins are colorful plant pigments with antioxidant properties, and a diet rich in these flavonoids bears health benefits. Therefore, a strong anthocyanin accumulation in edible plant parts is of significant interest, and in Malus domestica, the domesticated apple, certain red-fleshed apple varieties exhibit this trait. Enhanced anthocyanin accumulation in the flesh of apple fruits is attributed to the hyperactivation of the MYB transcription factor MdMYB10, which act as a key regulators of anthocyanin biosynthesis by inducing the expression of multiple biosynthetic genes. While several studies have explored the underlying genetic mutations and resulting transcriptome changes, there is a lack of research on proteome alterations that cause the red-fleshed apple phenotype. To address this gap, a mass spectrometry-based proteomics approach was employed. Comparative proteomics identified differentially abundant proteins in young and mature fruits of the red-fleshed ‘Bay13645’ variety compared to the white-fleshed ‘Royal Gala’. Whereas several MYB transcription factors were enriched during early fruit development, they were no longer among the hyper-abundant proteins in ripe fruits of the red-fleshed genotype. In contrast, anthocyanin biosynthetic enzymes were enriched more strongly in ripe fruits of the red-fleshed cultivar, indicating developmental stage-specific differences in the control of the pigmentation process. The proteomic approach also identified novel regulatory factors and enzymes that may contribute to the red-fleshed apple phenotype, including a BAHD acyltransferase, Mal d proteins, and transcription factors of diverse families, and their potential relevance for the exhibition of this trait is discussed.
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)