Pre- and Post-harvest Melatonin Application Boosted Phenolic Compounds Accumulation and Altered Respiratory Characters in Sweet Cherry Fruit

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

Genetics and epigenetics of Pinus nigra populations with differential exposure to air pollution

Forest species in the course of their evolution have experienced several environmental challenges, which since historic times include anthropogenic pollution. The effects of pollution on the genetic and epigenetic diversity in black pine (Pinus nigra) forests were investigated in the Amyntaio – Ptolemais – Kozani Basin, which has been for decades the largest lignite mining and burning center of Greece, with a total installed generating capacity of about 4.5 GW, operating for more than 70 years and resulting in large amounts of primary air pollutant emissions, mainly SO2, NOx and PM10. P. nigra, a biomarker for air pollution and a keystone species of affected natural ecosystems, was examined in terms of phenology (cone and seed parameters), genetics (283 AFLP loci) and epigenetics (606 MSAP epiloci), using two populations (exposed to pollution and control) of the current (mature trees) and future (embryos) stand. It was found that cone, seed, as well as genetic diversity parameters, did not show statistically significant differences between the exposed population and the control. Nevertheless, statistically significant differences were detected at the population epigenetic level. Moreover, there was a further differentiation regarding the intergenerational comparison: while the epigenetic diversity does not substantially change in the two generations assessed in the control population, epigenetic diversity is significantly higher in the embryo population compared to the parental stand in the exposed population. This study sheds a light to genome dynamics in a forest tree population exposed to long term atmospheric pollution burden and stresses the importance of assessing both genetics and epigenetics in biomonitoring applications

Whole genome scanning of a Mediterranean basin hotspot collection provide new insights into olive tree biodiversity and biology

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. The availability of whole genome assemblies and annotations of olive tree cultivars and oleaster (O. europaea subsp. europaea var. sylvestris) has 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 for olive tree popula-tions that span the entire Mediterranean region. In the present study we developed the most complete genomic variation map and the most comprehensive catalog/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. Addi-tionally, 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 a selective sweep scan to be under selection pressure on all olive tree chromosomes. To further exploit the genomic and phenotypic resources obtained from the current work, genome-wide association analyses were performed for 23 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 olive tree biology.info:eu-repo/semantics/publishedVersio

The GenTree Platform: growth traits and tree-level environmental data in 12 European forest tree species

Background: Progress in the field of evolutionary forest ecology has been hampered by the huge challenge of phenotyping trees across their ranges in their natural environments, and the limitation in high-resolution environmental information. Findings: The GenTree Platform contains phenotypic and environmental data from 4,959 trees from 12 ecologically and economically important European forest tree species: Abies alba Mill. (silver fir), Betula pendula Roth. (silver birch), Fagus sylvatica L. (European beech), Picea abies (L.) H. Karst (Norway spruce), Pinus cembra L. (Swiss stone pine), Pinus halepensis Mill. (Aleppo pine), Pinus nigra Arnold (European black pine), Pinus pinaster Aiton (maritime pine), Pinus sylvestris L. (Scots pine), Populus nigra L. (European black poplar), Taxus baccata L. (English yew), and Quercus petraea (Matt.) Liebl. (sessile oak). Phenotypic (height, diameter at breast height, crown size, bark thickness, biomass, straightness, forking, branch angle, fructification), regeneration, environmental in situ measurements (soil depth, vegetation cover, competition indices), and environmental modeling data extracted by using bilinear interpolation accounting for surrounding conditions of each tree (precipitation, temperature, insolation, drought indices) were obtained from trees in 194 sites covering the species’ geographic ranges and reflecting local environmental gradients. Conclusion: The GenTree Platform is a new resource for investigating ecological and evolutionary processes in forest trees. The coherent phenotyping and environmental characterization across 12 species in their European ranges allow for a wide range of analyses from forest ecologists, conservationists, and macro-ecologists. Also, the data here presented can be linked to the GenTree Dendroecological collection, the GenTree Leaf Trait collection, and the GenTree Genomic collection presented elsewhere, which together build the largest evolutionary forest ecology data collection available

Between but not within species variation in the distribution of fitness effects

New mutations provide the raw material for evolution and adaptation. The distribution of fitness effects (DFE) describes the spectrum of effects of new mutations that can occur along a genome, and is therefore of vital interest in evolutionary biology. Recent work has uncovered striking similarities in the DFE between closely related species, prompting us to ask whether there is variation in the DFE among populations of the same species, or among species with different degrees of divergence, i.e., whether there is variation in the DFE at different levels of evolution. Using exome capture data from six tree species sampled across Europe we characterised the DFE for multiple species, and for each species, multiple populations, and investigated the factors potentially influencing the DFE, such as demography, population divergence and genetic background. We find statistical support for there being variation in the DFE at the species level, even among relatively closely related species. However, we find very little difference at the population level, suggesting that differences in the DFE are primarily driven by deep features of species biology, and that evolutionarily recent events, such as demographic changes and local adaptation, have little impact

Exploring of genetic diversity, molecular identification and application of functional markers in cherry (Prunus avium L.)

Wild cherry (Prunus avium L.) is a widespread, partially asexual, noble hardwood European species characterized by a scattered distribution, small population sizes and human exploitation for its valuable wood. These characteristics, especially at the southern limits of the species natural distribution where additional varying stresses may occur render P. avium populations prone to potential stochastic, genetic and demographic events. In this study, we used dominant inter simple sequence repeats (ISSR) and co-dominant simple sequence repeats (SSR) markers to infer the genetic structure of P. avium. Five populations from northern Greece were evaluated based on 46 ISSR and 11 SSR loci. Allelic frequencies were investigated in terms of distribution and genetic structure at the gametophytic self-incompatibility locus in five wild cherry (Prunus avium L.) populations. Comparisons were also made between the differentiation at the S-locus and at the SSR loci. Theoretical expectations under balancing selection were congruent to the results observed. Nineteen Greek traditional sweet cherry cultivars and two international cultivars, which were used as controls, were grown in Greece and characterized for seventeen morpho-physiological traits, fifteen Simple Sequence Repeat (SSR) loci and ten Inter Simple Sequence Repeat (ISSR) markers. The S allele genotypes of 21 sweet cherry cultivars widely grown in Greece, including 19 not previously genotyped, were determined based on their S-RNase gene products and using PCR analysis. Eight different S alleles in ten combinations, were distinguished and two new incompatibility groups were documented. Comparison of wild cherry populations and sweet cherry cultivars showed a significant reduction of genetic diversity parameters in the cultivated germplasm compared to natural populations. Bayesian, frequency-based and MCMC analyses have revealed that the wild and cultivar groups are genetically divergent and that realized between-group gene flow is almost completely absent. The application of High-Resolution-Melting (HRM) described a recent enhancement to traditional DNA melting analysis for the characterization of polymerase chain reaction products and the identification of nine gene based SNPs for distinguishing the main Greek sweet cherry cultivars. Sweet cherries can be grafted on a wide range of rootstocks belonging to genus Prunus. High Resolution Melting (HRM) analysis, coupled with five SSR markers in order to facilitate the identification of the most popular sweet cherry rootstocks in Greece. The five SSR loci used were highly informative and generated a unique melting curve profile of microsatellites for each of the six rootstocks tested. In particular, one marker, BPPCT002, with six HRM profiles was sufficient to discriminate all sweet cherry rootstocks studied. Finally, thirteen microsatellites were tested and the combination of the amplification profiles of six of them, characterised by high polymorphism and simple electrophoretic patterns, enabled to distinguish and identify a PDO sweet cherry cultivar used for sweet cherry products.Η αγριοκερασιά (Prunus avium L.) είναι ένα ευρέως διαδεδομένο, ευγενές πλατύφυλλο ευρωπαϊκό είδος που χαρακτηρίζεται από την διάσπαρτη κατανομή, το μικρό μέγεθος πληθυσμού και την ανθρωπογενή εκμετάλλευση για την πολύτιμη και ανθεκτική ξυλεία του. Αυτά τα χαρακτηριστικά, ειδικά στα νότια όρια της φυσικής εξάπλωσης του είδους, όπου μπορεί να υφίστανται ποικίλες πρόσθετες περιβαλλοντικές πιέσεις, καθιστούν τους πληθυσμούς του P. avium επιρρεπείς σε πιθανά στοχαστικά, γενετικά και δημογραφικά γεγονότα. Στην παρούσα μελέτη, χρησιμοποιήθηκαν κυρίαρχοι ISSR και συγκυρίαρχοι SSR δείκτες για να διερευνηθεί η γενετική δομή του P. avium. Πέντε πληθυσμοί από τη βόρεια Ελλάδα αξιολογήθηκαν με βάση 46 ISSR και 11 SSR γονιδιακές θέσεις. Το αυτοασυμβίβαστο, ένα κοινό χαρακτηριστικό της ανάπτυξης των φυτών, είναι ένα κλασσικό παράδειγμα της εξισορροπητικής επιλογής σε φυσικούς πληθυσμούς, ιδιαίτερα της αρνητικής επιλογής της εξαρτώμενης από την συχνότητα. Σύμφωνα με την εξαρτώμενη από τη γονιδιακή συχνότητα αρνητική επιλογή, η γενετική θεωρία προβλέπει ότι η S-γονιδιακή θέση, που ελέγχει το αυτοασυμβίβαστο εμπεριέχει πολλά αλληλόμορφα σε ισομερείς συχνότητες που αποδεικνύουν ένα ευρύ φάσμα αλληλομόρφων. Ερευνήθηκαν οι συχνότητες των αλληλομόρφων όσον αφορά τη κατανομή τους και την γενετική δομή τους, στην γονιδιακή θέση που ελέγχει το γαμετοφυτικό αυτοασυμβίβαστο, σε πέντε πληθυσμούς αγριοκερασιάς (Prunus avium L.). Επίσης, έγιναν συγκρίσεις μεταξύ της διαφοροποίησης της S-γενετικής θέσης και των SSR γονιδιακών θέσεων. Δεκαεννιά ελληνικές παραδοσιακές ποικιλίες καλλιεργούμενης κερασιάς καθώς και δύο διεθνείς ποικιλίες που χρησιμοποιήθηκαν ως μάρτυρες χαρακτηρίστηκαν χρησιμοποιώντας δεκαπέντε SSR και δέκα ISSR μοριακούς δείκτες. Επιπλέον, προσδιορίστηκαν οι γενότυποι των S-αλληλομόρφων από 21 ποικιλίες κερασιάς συμπεριλαμβανομένων και 19 που δεν έχουν γενοτυπηθεί αλλά καλλιεργούνται ευρέως στην Ελλάδα, με βάση τα S-RNase γονιδιακά προϊόντα τους καθώς και τη χρήση της PCR ανάλυσης. Ακόμη, χρησιμοποιήθηκαν 9 γονιδιακές θέσεις SSR για την ανάλυση της γενετικής ποικιλότητας σε 93 άτομα άγριας και 21 άτομα καλλιεργούμενης κερασιάς που αντιπροσωπεύουν το τοπικό γενετικό υλικό. Τα αποτελέσματα έδειξαν σημαντική μείωση των γενετικών παραμέτρων στο καλλιεργούμενο γενετικό υλικό σε σύγκριση με τους φυσικούς πληθυσμούς. Οι βιο-στατιστικές προσεγγίσεις των δεδομένων της μοριακής γενετικής ανάλυσης έδειξαν ότι η ομάδα των ατόμων της αγριοκερασιάς είναι γενετικά διαφοροποιημένη από την ομάδα των καλλιεργούμενων ποικιλιών κάτι που συνεπάγεται ότι η ροή γονιδίων μεταξύ των δύο τύπων πληθυσμών είναι ασήμαντη. Περιγράφηκε η εφαρμογή της Σύγκρισης Καμπυλών Τήξης σε Υψηλή ανάλυση (HRM), που είναι μια πρόσφατη ενίσχυση στην παραδοσιακή ανάλυση τήξης DNA με σκοπό τον χαρακτηρισμό των προϊόντων της PCR και τον εντοπισμό εννέα εντοπισμένων σε γονίδια μοριακούς δείκτες SNP για τη διάκριση των κυριότερων ελληνικών ποικιλιών καλλιεργούμενης κερασιάς. Πραγματοποιήθηκε η μοριακή ταυτοποίηση των περισσότερο διαδεδομένων υποκειμένων καλλιεργούμενης κερασιάς του ελλαδικού χώρου με HRM ανάλυση πέντε μικροδορυφορικών θέσεων (SSR-HRM). Δημιουργήθηκε μια μέθοδος με βάση τους μικροδορυφορικούς δείκτες για να διακρίνει τις ποικιλίες κερασιάς ώστε να πιστοποιηθεί η ΠΟΠ ‘Τραγανά Εδέσσης’ στο επίπεδο της ποικιλίας, αλλά και στα μεταποιημένα προϊόντα στην κερασιά. Δοκιμάστηκαν δεκατρείς μικροδορυφορικοί δείκτες και ο συνδυασμός των, που χαρακτηρίζεται από υψηλό πολυμορφισμό και απλά ηλεκτροφορητικά πρότυπα, επέτρεψε την διάκριση και τον προσδιορισμό μιας ΠΟΠ ποικιλίας κερασιάς η οποία χρησιμοποιείται για παραγωγή προϊόντων

Induction of Promoter DNA Methylation Upon High-Pressure Spraying of Double-Stranded RNA in Plants

Exogenous application of RNA molecules is a potent method to trigger RNA interference (RNAi) in plants in a transgene-free manner. So far, all exogenous RNAi (exo-RNAi) applications have aimed to trigger mRNA degradation of a given target. However, the issue of concomitant epigenetic changes was never addressed. Here, we report for the first time that high-pressure spraying of dsRNAs can trigger de novo methylation of promoter sequences in plants

High Resolution Melting (HRM) analysis on <em>VviDXS</em> to reveal muscats or non-muscats among autochthonous Greek wine producing grape varieties

Muscat flavor in grapes is associated with a substitution of a Single Nucleotide Polymorphism (SNP) located at position 1822 (SNP1822G>T) within the coding sequence of the VviDXS gene. Various methods, including the use of High Resolution Melting (HRM) analysis, have been suggested to discriminate different SNP allelic states including the molecular discrimination of the muscat from the non-muscat grape varieties, thus providing the ability to minimize lengthy grape breeding programs when selecting for grape muscat flavor before the fruit maturity stage. HRM analysis on the SNP1822 was performed on a group of 128 wine producing grape varieties in order to separate the muscat from the non-muscat genotypes before they are used for further breeding activities. This approach could be used either as a single-step prescreening method or in accordance with recently published methodology to elucidate on varietal characterization and authentication as these are important requirements concerning nurseries, growers and winemakers

Micropropagation of guava (Psidium guajava) seedlings, a plant with interest in cool subtropics, using an innovative BB culture medium

AbstractPsidium guajava is a new crop cultivated in Greece, with a potential pharmaceutical and ornamental uses. An efficient and reliable protocol for in vitro clonal propagation of P. guajava from seeds was used. Five different media were examined. Shoot proliferation succeeded on a new basal medium (BB) supplemented with a modified vitamin solution (vit BB), without plant growth regulators. In addition, shoots on media supplemented with BB vitamin solution performed better than in Murashige and Scoog (MS) and Woody Plant (WP) media. When BB medium was used, the greatest shoot number resulted in 4 mg L−1 6-benzyladenine (BA) with a score of 2.8. Regenerated single shoots were rooted in the BB medium, supplemented with 0.1 ΝΑΑ (mg L−1) and producing 2.2 roots of 4.6 cm, along with 3.1 cm of adventitious shoots. Acclimatization was accomplished in three phases, using peat-moss, vermiculite and perlite (1:1:1), with a total survival of 83.3%. To examine the genetic diversity of the plant material, Inter Simple Sequence Repeat (ISSR) and Start Codon Targeted (SCoT) molecular markers were used. The results indicated a low diversity, along with high percentage of polymorphism for both ISSR and SCoT analyzes