Michail Michailidis

@agro.auth.gr

47

Scopus Publications

Scopus Publications

  • Understanding the effect of calcium in kiwifruit ripening and establishment of early and late response mechanisms through a cross-omics approach
    Chrysanthi Polychroniadou, Michail Michailidis, Martina Samiotaki, Ioannis-Dimosthenis S. Adamakis, Eleni Giannoutsou, Christina Skodra, Evangelos Karagiannis, Christos Bazakos, Athanassios Molassiotis, and Georgia Tanou

    Elsevier BV

  • Non-Destructive Quality Estimation Using a Machine Learning-Based Spectroscopic Approach in Kiwifruits
    Georgios Tziotzios, Xanthoula Eirini Pantazi, Charalambos Paraskevas, Christos Tsitsopoulos, Dimitrios Valasiadis, Elpida Nasiopoulou, Michail Michailidis, and Athanassios Molassiotis

    MDPI AG
    The current study investigates the use of a non-destructive hyperspectral imaging approach for the evaluation of kiwifruit cv. “Hayward” internal quality, focusing on physiological traits such as soluble solid concentration (SSC), dry matter (DM), firmness, and tannins, widely used as quality attributes. Regression models, including partial least squares regression (PLSR), bagged trees (BTs), and three-layered neural network (TLNN), were employed for the estimation of the above-mentioned quality attributes. Experimental procedures involving the Specim IQ hyperspectral camera utilization and software were followed for data acquisition and analysis. The effectiveness of PLSR, bagged trees, and TLNN in predicting the firmness, SSC, DM, and tannins of kiwifruit was assessed via statistical metrics, including R squared (R²) values and the root mean square error (RMSE). The obtained results indicate varying degrees of efficiency for each model in predicting kiwifruit quality parameters. The study concludes that machine learning algorithms, especially neural networks, offer substantial accuracy, surpassing traditional methods for evaluating kiwifruit quality traits. Overall, the current study highlights the potential of such non-destructive techniques in revolutionizing quality assessment during postharvest by yielding rapid and reliable predictions regarding the critical quality attributes of fruits.

  • Wide-characterization of high and low dry matter kiwifruit through spatiotemporal multi-omic approach
    Dimitrios Valasiadis, Marios Georgios Kollaros, Michail Michailidis, Chrysanthi Polychroniadou, Georgia Tanou, Christos Bazakos, and Athanassios Molassiotis

    Elsevier BV

  • Screening the Citrus Greek National Germplasm Collection for fruit quality and metabolic footprint
    Michail Michailidis, Vasileios Ziogas, Eirini Sarrou, Elpida Nasiopoulou, Vaia Styliani Titeli, Christina Skodra, Georgia Tanou, Ioannis Ganopoulos, Stefan Martens, and Athanassios Molassiotis

    Elsevier BV

  • Comparative Evaluation of Secondary Metabolite Chemodiversity of Citrus Genebank Collection in Greece: Can the Peel be More than Waste?
    Eftychia Martinidou, Michail Michailidis, Vasileios Ziogas, Domenico Masuero, Andrea Angeli, Theodoros Moysiadis, Stefan Martens, Ioannis Ganopoulos, Athanassios Molassiotis, and Eirini Sarrou

    American Chemical Society (ACS)
    Citrus fruits are among the most economically important crops in the world. In the global market, the Citrus peel is often considered a byproduct but substitutes an important phenotypic characteristic of the fruit and a valuable source of essential oils, flavonoids, carotenoids, and phenolic acids with variable concentrations. The Mediterranean basin is a particularly dense area of autochthonous genotypes of Citrus that are known for being a source of healthy foods, which can be repertoires of valuable genes for molecular breeding with the focus on plant resistance and quality improvement. The scope of this study was to characterize and compare the main phenotypic parameters (i.e., peel thickness, fruit volume, and area) and levels of bioactive compounds in the peel of fruits from the local germplasm of Citrus in Greece, to assess their chemodiversity regarding their polyphenolic, volatile, and carotenoid profiles. A targeted liquid chromatographic approach revealed hesperidin, tangeretin, narirutin, eriocitrin, and quercetin glycosides as the major polyphenolic compounds identified in orange, lemon, and mandarin peels. The content of tangeretin and narirutin followed the tendency mandarin > orange > lemon. Eriocitrin was a predominant metabolite of lemon peel, following its identification in lower amounts in mandarin and at least in the orange peel. For these citrus-specific metabolites, high intra- but also interspecies chemodiversity was monitored. Significant diversity was found in the essential oil content, which varied between 1.2 and 3% in orange, 0.2 and 1.4% in mandarin, and 0.9 and 1.9% in lemon peel. Limonene was the predominant compound in all Citrus species peel essential oils, ranging between 88 and 93% among the orange, 64 and 93% in mandarin, and 55 and 63% in lemon cultivars. Carotenoid analysis revealed different compositions among the Citrus species and accessions studied, with β-cryptoxanthin being the most predominant metabolite. This large-scale metabolic investigation will enhance the knowledge of Citrus peel secondary metabolite chemodiversity supported by the ample availability of Citrus genetic resources to further expand their exploitation in future breeding programs and potential applications in the global functional food and pharmaceutical industries.

  • Exploring the Robustness of Causal Structures in Omics Data: A Sweet Cherry Proteogenomic Perspective
    Maria Ganopoulou, Aliki Xanthopoulou, Michail Michailidis, Lefteris Angelis, Ioannis Ganopoulos, and Theodoros Moysiadis

    MDPI AG
    Causal discovery is a highly promising tool with a broad perspective in the field of biology. In this study, a causal structure robustness assessment algorithm is proposed and employed on the causal structures obtained, based on transcriptomic, proteomic, and the combined datasets, emerging from a quantitative proteogenomic atlas of 15 sweet cherry (Prunus avium L.) cv. ‘Tragana Edessis’ tissues. The algorithm assesses the impact of intervening in the datasets of the causal structures, using various criteria. The results showed that specific tissues exhibited an intense impact on the causal structures that were considered. In addition, the proteogenomic case demonstrated that biologically related tissues that referred to the same organ induced a similar impact on the causal structures considered, as was biologically expected. However, this result was subtler in both the transcriptomic and the proteomic cases. Furthermore, the causal structures based on a single omic analysis were found to be impacted to a larger extent, compared to the proteogenomic case, probably due to the distinctive biological features related to the proteome or the transcriptome. This study showcases the significance and perspective of assessing the causal structure robustness based on omic databases, in conjunction with causal discovery, and reveals advantages when employing a multiomics (proteogenomic) analysis compared to a single-omic (transcriptomic, proteomic) analysis.

  • Whole genome scanning of a Mediterranean basin hotspot collection provides new insights into olive tree biodiversity and biology
    Christos Bazakos, Konstantinos G. Alexiou, Sebastián Ramos‐Onsins, Georgios Koubouris, Nikolaos Tourvas, Aliki Xanthopoulou, Ifigeneia Mellidou, Theodoros Moysiadis, Ioanna‐Theoni Vourlaki, Ioannis Metzidakis,et al.

    Wiley
    Olive tree (Olea europaea L. subsp. europaea var. europaea) is one of the most important species of the Mediterranean region and one of the most ancient species domesticated. Τhe availability of whole genome assemblies and annotations of olive tree cultivars and oleasters have contributed to a better understanding of genetic and genomic differences between olive tree cultivars. However, compared to other plant species there is still a lack of genomic resources with olive tree populations that span across the entire Mediterranean region. This study has developed the most complete genomic variation map and comprehensive catalogue/resource of molecular variation to date for 89 olive tree genotypes originating from the entire Mediterranean basin, revealing the genetic diversity of this commercially significant crop tree and explaining the divergence/similarity among different variants. Additionally, the monumental ancient tree "Throuba Naxos" was studied to characterize the potential origin or routes of olive tree domestication. Several candidate genes, known to be associated with key agronomic traits, including olive oil quality and fruit yield, were uncovered by selective sweep scan to be under selection pressure on all olive tree chromosomes. To exploit further the genomic and phenotypic resources obtained from the current work, Genome Wide Association Analyses were performed for twenty-three morphological and two agronomic traits. Significant associations were detected for eight traits that provide valuable candidates for fruit tree breeding and for deeper understanding of the olive tree biology.

  • Physiological and Metabolic Traits Linked to Kiwifruit Quality
    Vaia Styliani Titeli, Michail Michailidis, Georgia Tanou, and Athanassios Molassiotis

    MDPI AG
    The assessment of fruit quality traits is a key factor in increasing consumer acceptance of kiwifruit. Here, an experiment was performed to evaluate the relationship between dry matter (DM) and soluble solids concentration (SSC), evaluated by both destructive (D) and non-destructive (ND) approaches, with acidity content and sensory evaluation, particularly taste, in fully ripened ‘Hayward’ kiwifruits from 20 orchards. Nutrient content and metabolomic analysis were also performed in ripened kiwifruit tissues (pericarp, placenta, and seeds) from four selected orchards of kiwifruits of high taste scores (HTS) and four orchards of low taste scores (LTS). The results suggest that ND-DM measurement positively correlated with D-DM and may serve as an indicator of kiwifruit taste. Moreover, the taste of kiwifruit was affected by both SSC and acidity. Based on the nutrient content of the pericarp and the primary metabolites of the pericarp and placenta, a clear separation was observed between kiwifruits with HTS and those with LTS, while no differences were found in seed samples. Metabolites such as fructose, maltose, mannobiose, tagatose, and citrate were accumulated in kiwifruits with a strong taste in the pericarp, whereas others, such as serine in the pericarp and placenta, have a negative impact on taste. The current study contributes to a greater understanding of the influence of dry matter, ripening characteristics, primary metabolites, and nutrient content on the taste of kiwifruits.

  • Boron stimulates fruit formation and reprograms developmental metabolism in sweet cherry
    Michail Michailidis, Christos Bazakos, Marios Kollaros, Ioannis‐Dimosthenis S. Adamakis, Ioannis Ganopoulos, Athanassios Molassiotis, and Georgia Tanou

    Wiley
    Boron modulates a wide range of plant developmental processes; however, the regulation of early fruit development by boron remains poorly defined. We report here the physiological, anatomical, metabolic, and transcriptomic impact of pre-flowering boron supply on the sweet cherry fruit set and development (S1-S5 stages). Our findings revealed that endogenous boron content increased in early growth stages (S1 and S2 stages) following pre-flowering boron exogenous application. Boron treatment resulted in increased fruit set (S1 and S2 stages) and mesocarp cell enlargement (S2 stage). Various sugars (e.g., fructose, glucose), alcohols (e.g., myo-inositol, maltitol), organic acids (e.g., malic acid, citric acid), amino acids (e.g., valine, serine) accumulated in response to boron application during the various developmental stages (S1-S5 stages). Transcriptomic analysis at early growth (S1 and S2 stages) identified boron-responsive genes that are mainly related to secondary metabolism, amino acid metabolism, calcium-binding, ribosome biogenesis, sugar homeostasis and especially to photosynthesis. We found various boron-induced/repressed genes, including those specifically involved in growth. Several heat shock proteins displayed distinct patterns during the initial growth in boron-exposed fruit. Gene analysis also discovered several putative candidate genes like PavPIP5K9, PavWAT1, PavMIOX, PavCAD1, PavPAL1 and PavSNRK2.7, which could facilitate the investigation of the molecular rationale underlying boron function in early fruit growth. Substantial changes in the expression of numerous transcription factors, including PavbHLH25, PavATHB.12L and PavZAT10.1,.2 were noticed in fruits exposed to boron. The current study provides a baseline of information for understanding the metabolic processes regulated by boron during sweet cherry fruit early growth and fruit development in general.

  • Evaluation of a dill (Anethum graveolens L.) gene bank germplasm collection using multivariate analysis of morphological traits, molecular genotyping and chemical composition to identify novel genotypes for plant breeding
    Kalliopi Kadoglidou, Catherine Cook, Anastasia Boutsika, Eirini Sarrou, Ifigeneia Mellidou, Christina Aidonidou, Ioannis Grigoriadis, Andrea Angeli, Stefan Martens, Vasiliki Georgiadou,et al.

    PeerJ
    Dill (Anethum graveolens L.) is an aromatic herb widely used in the food industry, with several commercial cultivars available with different qualitative characteristics. Commercial cultivars are usually preferred over landraces due to their higher yield and also the lack of improved landraces than can be commercialized. In Greece, however, traditional dill landraces are cultivated by local communities. Many are conserved in the Greek Gene Bank and the aim here was to investigate and compare the morphological, genetic, and chemical biodiversity of twenty-two Greek landraces and nine modern/commercial cultivars. Multivariate analysis of the morphological descriptors, molecular markers, and essential oil and polyphenol composition revealed that the Greek landraces were clearly distinguished compared with modern cultivars at the level of phenological, molecular and chemical traits. Landraces were typically taller, with larger umbels, denser foliage, and larger leaves. Plant height, density of foliage, density of feathering as well as aroma characteristics were desirable traits observed for some landraces, such as T538/06 and GRC-1348/04, which were similar or superior to those of some commercial cultivars. Polymorphic loci for inter-simple sequence repeat (ISSR) and start codon targeted (SCoT) molecular markers were 76.47% and 72.41% for landraces, and 68.24% and 43.10% for the modern cultivars, respectively. Genetic divergence was shown, but not complete isolation, indicating that some gene flow may have occurred between landraces and cultivars. The major constituent in all dill leaf essential oils was α-phellandrene (54.42–70.25%). Landraces had a higher α-phellandrene and dill ether content than cultivars. Two dill landraces were rich in chlorogenic acid, the main polyphenolic compound determined. The study highlighted for the first-time Greek landraces with desirable characteristics regarding quality, yield, and harvest time suitable for breeding programs to develop new dill cultivars with superior features.

  • Disclosing the molecular basis of salinity priming in olive trees using proteogenomic model discovery
    Christina Skodra, Michail Michailidis, Theodoros Moysiadis, George Stamatakis, Maria Ganopoulou, Ioannis-Dimosthenis S Adamakis, Lefteris Angelis, Ioannis Ganopoulos, Georgia Tanou, Martina Samiotaki,et al.

    Oxford University Press (OUP)
    Abstract Plant responses to salinity are becoming increasingly understood, however, salt priming mechanisms remain unclear, especially in perennial fruit trees. Herein, we showed that low-salt pre-exposure primes olive (Olea europaea) plants against high salinity stress. We then performed a proteogenomic study to characterize priming responses in olive roots and leaves. Integration of transcriptomic and proteomic data along with metabolic data revealed robust salinity changes that exhibit distinct or overlapping patterns in olive tissues, among which we focused on sugar regulation. Using the multi-crossed -omics data set, we showed that major differences between primed and nonprimed tissues are mainly associated with hormone signaling and defense-related interactions. We identified multiple genes and proteins, including known and putative regulators, that reported significant proteomic and transcriptomic changes between primed and nonprimed plants. Evidence also supported the notion that protein post-translational modifications, notably phosphorylations, carbonylations and S-nitrosylations, promote salt priming. The proteome and transcriptome abundance atlas uncovered alterations between mRNA and protein quantities within tissues and salinity conditions. Proteogenomic-driven causal model discovery also unveiled key interaction networks involved in salt priming. Data generated in this study are important resources for understanding salt priming in olive tree and facilitating proteogenomic research in plant physiology.

  • A wide foodomics approach coupled with metagenomics elucidates the environmental signature of potatoes
    Anastasia Boutsika, Michail Michailidis, Maria Ganopoulou, Athanasios Dalakouras, Christina Skodra, Aliki Xanthopoulou, George Stamatakis, Martina Samiotaki, Georgia Tanou, Theodoros Moysiadis,et al.

    Elsevier BV

  • Improving Quality of Fruit
    Michail Michailidis and Georgia Tanou

    MDPI AG
    Fruits are necessary for a balanced diet, and they are consumed for their vitamins, fiber, and other beneficial compounds [...]

  • Mechanical stress elicits kiwifruit ripening changes in gene expression and metabolic status
    Chrysanthi Polychroniadou, Michail Michailidis, Ioannis-Dimosthenis S. Adamakis, Evangelos Karagiannis, Ioannis Ganopoulos, Georgia Tanou, Christos Bazakos, and Athanassios Molassiotis

    Elsevier BV

  • Tissue-specific transcriptional analysis outlines calcium-induced core metabolic changes in sweet cherry fruit
    Michail Michailidis, Vaia Styliani Titeli, Evangelos Karagiannis, Kyriaki Feidaki, Ioannis Ganopoulos, Georgia Tanou, Anagnostis Argiriou, and Athanassios Molassiotis

    Elsevier BV

  • Identification of genes and metabolic pathways involved in wounding-induced kiwifruit ripening
    Chrysanthi Polychroniadou, Evangelos Karagiannis, Michail Michailidis, Ioannis-Dimosthenis S. Adamakis, Ioannis Ganopoulos, Georgia Tanou, Christos Bazakos, and Athanassios Molassiotis

    Elsevier BV

  • The perennial fruit tree proteogenomics atlas: a spatial map of the sweet cherry proteome and transcriptome
    Aliki Xanthopoulou, Theodoros Moysiadis, Christos Bazakos, Evangelos Karagiannis, Ioanna Karamichali, George Stamatakis, Martina Samiotaki, Maria Manioudaki, Michail Michailidis, Panagiotis Madesis,et al.

    Wiley
    Genome-wide transcriptome analysis provides systems-level insights into plant biology. Due to the limited depth of quantitative proteomics our understanding of gene-protein-complex stoichiometry is largely unknown in plants. Recently, the complexity of the proteome and its cell/tissue specific distribution boost the research community to the integration of transcriptomics and proteomics landscapes in a proteogenomic approach. Herein, we generated a quantitative proteome and transcriptome abundance atlas of 15 major sweet cherry tissues represented by 29,247 genes and 7,584 proteins. Additionally, 199,984 alternative splicing events, particularly exon skipping and alternative 3' splice site, were identified in 23,383 transcribed regions of the analyzed tissues. Common signatures as well as differences between mRNA and protein quantities, including genes encoding transcription factors and allergens, within and across the different tissues are reported. Using our integrated data set, we identified key putative regulators of fruit development, notably genes involved in the biosynthesis of the anthocyanins and flavonoids. We also provide proteogenomic-based evidence for the involvement of ethylene signaling and pectin degradation in cherry fruit ripening. Moreover, clusters of genes and proteins with similar and different expression and suppression trends across diverse tissues and developmental stages revealed a relatively low RNA abundance-to-protein correlation. The present proteogenomic analysis allows us to identify 17 novel sweet cherry proteins without prior protein-level annotation evidenced in the currently available databases. To facilitate use by the community, we also developed the Sweet Cherry Atlas Database (https://grcherrydb.com/) for viewing and data-mining these resources. This work provides new insights into the proteogenomics workflow in plants and a rich knowledge resource for future investigation of gene and protein functions in Prunus species.

  • Could causal discovery in proteogenomics assist in understanding gene–protein relations? A perennial fruit tree case study using sweet cherry as a model
    Maria Ganopoulou, Michail Michailidis, Lefteris Angelis, Ioannis Ganopoulos, Athanassios Molassiotis, Aliki Xanthopoulou, and Theodoros Moysiadis

    MDPI AG
    Genome-wide transcriptome analysis is a method that produces important data on plant biology at a systemic level. The lack of understanding of the relationships between proteins and genes in plants necessitates a further thorough analysis at the proteogenomic level. Recently, our group generated a quantitative proteogenomic atlas of 15 sweet cherry (Prunus avium L.) cv. ‘Tragana Edessis’ tissues represented by 29,247 genes and 7584 proteins. The aim of the current study was to perform a targeted analysis at the gene/protein level to assess the structure of their relation, and the biological implications. Weighted correlation network analysis and causal modeling were employed to, respectively, cluster the gene/protein pairs, and reveal their cause–effect relations, aiming to assess the associated biological functions. To the best of our knowledge, this is the first time that causal modeling has been employed within the proteogenomics concept in plants. The analysis revealed the complex nature of causal relations among genes/proteins that are important for traits of interest in perennial fruit trees, particularly regarding the fruit softening and ripening process in sweet cherry. Causal discovery could be used to highlight persistent relations at the gene/protein level, stimulating biological interpretation and facilitating further study of the proteogenomic atlas in plants.

  • Unraveling salt-responsive tissue-specific metabolic pathways in olive tree
    Christina Skodra, Michail Michailidis, Marilena Dasenaki, Ioannis Ganopoulos, Nikolaos S. Thomaidis, Georgia Tanou, and Athanassios Molassiotis

    Wiley
    Salinity is a serious constraint that reduces olive crop productivity. Here, we defined metabolite and gene expression changes in various tissues of olive trees (cv. 'Chondrolia Chalkidikis') exposed to 75 mM NaCl for 45 days. Results showed that salinity induced foliar symptoms and impaired growth and photosynthetic parameters. The content of Na+ and Cl- in roots, xylem, phloem and leaves increased, although the Na+ levels in old leaves and Cl- in young leaves remained unaffected. Mannitol was accumulated in roots and old leaves challenged by salinity. NaCl-treated trees have a decreased TCA-associated metabolites, such as citric and malic acid, as well as changes in phenylpropanoid-associated metabolites (i.e. pinoresinol and vanillic acid) and genes (OePLRTp2 and OeCA4H). Salt treatment resulted in hydroxyl-decarboxylmethyl eleuropein aglycone accumulation and OeGTF up-regulation in new leaves, possibly suggesting that oleuropein metabolism was modified by NaCl. Tyrosine metabolism, particularly verbascoside levels and OePPO and OehisC expressions, was modulated by salinity. Both genes (e.g., OeAtF3H and OeFNSII) and metabolites (e.g., apigenin and luteolin) involved in flavonoid biosynthesis were induced in old leaves exposed to NaCl. Based on these data, we constructed an interaction scheme of changes in metabolites and transcripts across olive tissues upon salinity. Particularly, several metabolites involved in carbohydrate metabolism were reduced in roots, while many sugars, carbohydrates and flavonoids were increased in leaves. This study provided a framework for better understanding the possible mechanisms that govern the tissue-specific response of olive tree to salinity stress, with insights into molecules that can be used for olive crop improvement projects. This article is protected by copyright. All rights reserved.

  • Proteo-metabolomic journey across olive drupe development and maturation
    Evangelos Karagiannis, Michail Michailidis, Christina Skodra, George Stamatakis, Marilena Dasenaki, Ioannis Ganopoulos, Martina Samiotaki, Nikolaos S. Thomaidis, Athanassios Molassiotis, and Georgia Tanou

    Elsevier BV

  • Silicon influenced ripening metabolism and improved fruit quality traits in apples
    Evangelos Karagiannis, Michail Michailidis, Christina Skodra, Athanassios Molassiotis, and Georgia Tanou

    Elsevier BV

  • Pre- and Post-harvest Melatonin Application Boosted Phenolic Compounds Accumulation and Altered Respiratory Characters in Sweet Cherry Fruit
    Michail Michailidis, Georgia Tanou, Eirini Sarrou, Evangelos Karagiannis, Ioannis Ganopoulos, Stefan Martens, and Athanassios Molassiotis

    Frontiers Media SA
    The aim of the present study was to investigate the impact of exogenous melatonin (0. 5 mM) application through pre-harvest foliar spray and postharvest immersion, alone or in combination, on ripening parameters of sweet cherry (cv. Ferrovia) fruit and their relationship with bioactive compounds and gene expression at harvest as well after cold storage (0°C) for 12 days and subsequent room temperature (20°C) exposure for 8 h. Although several ripening traits were not influenced by melatonin, the combining pre- and post-harvest treatments delayed fruit softening at post-cold period. Preharvest spray with melatonin depressed fruit respiration at time of harvest while all applied treatments induced respiratory activity following cold, indicating that this anti-ripening action of melatonin is reversed by cold. Several genes related to the tricarboxylic acid cycle, such as PaFUM, PaOGDH, PaIDH, and PaPDHA1 were upregulated in fruit exposed to melatonin, particularly following combined pre- and post-harvest application. The accumulation of phenolic compounds, such as neochlorogenic acid, chlorogenic acid, epicatechin, procyanidin B1, procyanidin B2+B4, cyanidin-3-O-galactoside, and cyanidin-3-O-rutinoside along with the expression of several genes involved in phenols biosynthesis, such as PaSK, PaPAL, Pa4CL, PaC4H, and PaFNR were at higher levels in melatonin-treated cherries at harvest and after cold exposure, the highest effects being observed in fruits subjected to both pre- and post-harvest treatments. This study provides a comprehensive understanding of melatonin-responsive ripening framework at different melatonin application conditions and sweet cherry stages, thereby helps to understand the action of this molecule in fruit physiology.

  • An early calcium loading during cherry tree dormancy improves fruit quality features at harvest
    Michail Michailidis, Chrysanthi Polychroniadou, Maria-Anastasia Kosmidou, Dafni Petraki-Katsoulaki, Evangelos Karagiannis, Athanassios Molassiotis, and Georgia Tanou

    MDPI AG
    The possible role of an early calcium application via sprays (0.25, 0.5 and 1M CaCl2) on dormant buds to improve sweet cherry (cv. Ferrovia) fruit quality at harvest was investigated. Fruit quality characteristics were also investigated in response to the age of spurs, the ripening stage, and their interactions. Results indicate that calcium enters the dormant flower buds and the phloem but not to the dormant vegetative buds. At harvest, the levels of Zn, Mn, and Cu were declined in fruits by increasing CaCl2 doses of sprays. Fruit respiratory activity was higher and on–tree fruit cracking was lower in red-colour (unripe) cherries as well as in fruit that was produced by 2-year-old short spurs or by Ca-treated buds. Differences in the sweet cherry skin metabolic profiles were identified. Fruit produced from Ca-exposed spurs exhibited lower levels of ribose and other cell-wall-related sugars and higher sucrose, maltose, and quininic acid levels. Nutrient shift was increased in red cherries, while anthocyanins were boosted in the black ones. PCA analysis was performed between the high dose of calcium spray and a control for mineral element content and cherry quality traits. This study illustrates that the high dose of calcium application during bud dormancy can effectively improve sweet cherry fruit characteristics, in terms of calcium content, cracking incidence, and fruit set. Overall, the present study contributes to a better understanding of the impact of calcium nutrition in fruit crops, which will provide references for alternative nutrient management and quality control in sweet cherry production.

  • Olive fruit development and ripening: Break on through to the “‐omics” side
    Christina Skodra, Vaia Styliani Titeli, Michail Michailidis, Christos Bazakos, Ioannis Ganopoulos, Athanassios Molassiotis, and Georgia Tanou

    MDPI AG
    The olive tree (Olea europaea L. subsp. europaea) is the most important perennial crop in the Mediterranean region, producing table olives and oil, both appreciated for their nutraceutical value. Although olive oil quality traits have been extensively studied, much less attention has been paid to olive drupe. Olive drupe ripening is an extremely complex process involving numerous physiological and molecular changes that are unique in this fruit crop species. This review underlines the contribution of “-omics” techniques and of the recent advances in bioinformatics and analytical tools, notably next-generation sequencing and mass spectrometry, for the characterization of the olive ripening syndrome. The usage of high-dimensional datasets, such as transcriptomics, proteomics, and metabolomics, will provide a systematical description of the molecular-specific processes regulating olive fruit development and ripening. However, the incomplete sequence of the O. europaea L. reference genome has largely hampered the utilization of omics tools towards olive drupe research. Due to this disadvantage, the most reported -omics studies on fruit trees concern metabolomics and only a few transcriptomics and proteomics. In this review, up-to-date applications of -omics technologies towards olive drupe biology are addressed, and future perspectives in olive fruit research are highlighted.

  • Fruit quality trait discovery and metabolic profiling in sweet cherry genebank collection in Greece
    Evangelos Karagiannis, Eirini Sarrou, Michail Michailidis, Georgia Tanou, Ioannis Ganopoulos, Christos Bazakos, Konstantinos Kazantzis, Stefan Martens, Aliki Xanthopoulou, and Athanassios Molassiotis

    Elsevier BV