Investigating physicochemical, volatile and sensory parameters playing a positive or a negative role on tomato liking

This study aimed at providing further insights into the positive and negative drivers of tomato liking. For this purpose, 13 tomato cultivars representing different typologies were characterized for physicochemical parameters and aroma volatiles, and were assessed by a trained panel for sensory descriptors, and by Italian consumers for liking. The relationships among the different parameters and their effects on consumer liking were studied by Partial Least Squares (PLS) analysis. Among physicochemical traits and sensory descriptors, seeds, reducing sugars, firmness, thick epicarp, soluble solids, sour taste, total acidity, citrate, herbaceous aroma and brightness were found to be drivers of liking, whereas pulp thickness, humidity, fruit weight, diacetyl-like odor and mealiness showed an opposite influence. For the aroma volatiles, 2-isobutylthiazole played a key role on liking and its positive contribution seemed to be supported by (Z)-3-hexen-1-ol, but suppressed by 6-methyl-5-hepten-2-ol, especially when tomatoes had a poor volatile fraction. These results represent a contribution to the knowledge that could lead to more effective breeding strategies aimed at improving tomato sensory quality. (c) 2012 Elsevier Ltd. All rights reserved

Arabidopsis thaliana response to extracellular dna: Self versus nonself exposure

The inhibitory effect of extracellular DNA (exDNA) on the growth of conspecific individuals was demonstrated in different kingdoms. In plants, the inhibition has been observed on root growth and seed germination, demonstrating its role in plant\u2013soil negative feedback. Several hypotheses have been proposed to explain the early response to exDNA and the inhibitory effect of conspecific exDNA. We here contribute with a whole-plant transcriptome profiling in the model species Arabidopsis thaliana exposed to extracellular self-(conspecific) and nonself-(heterologous) DNA. The results highlight that cells distinguish self-from nonself-DNA. Moreover, confocal microscopy analyses reveal that nonself-DNA enters root tissues and cells, while self-DNA remains outside. Specifically, exposure to self-DNA limits cell permeability, affecting chloroplast functioning and reactive oxygen species (ROS) production, eventually causing cell cycle arrest, consistently with macroscopic observations of root apex necrosis, increased root hair density and leaf chlorosis. In contrast, nonself-DNA enters the cells triggering the activation of a hypersensitive response and evolving into systemic acquired resistance. Complex and different cascades of events emerge from exposure to extracellular selfor nonself-DNA and are discussed in the context of Damage-and Pathogen-Associated Molecular Patterns (DAMP and PAMP, respectively) responses

WHOLE-GENOME RE-SEQUENCING OF TWO TOMATO LANDRACES REVEALS SEQUENCE VARIATIONS UNDERPINNING KEY ECONOMICALLY IMPORTANT TRAITS

In the post-genomic era, one of the major challenges is the identification of alleles directly responsible for phenotype variation among different genotypes within the same species. Tomato is a model crop for understanding the development and ripening of climacteric fleshy fruits, and it is also known to be an important source of health-promoting compounds. In addition, cultivated tomato germplasm shows a high phenotypic variation despite its very low genetic diversity. Toward the identification of sequence variations responsible for stress tolerance, high fruit quality and long shelf life, we re-sequenced the genomes of two traditional landraces grown in the Campania region (Southern Italy). Crovarese, belonging to the Corbarino type (COR), and Lucariello (LUC) are typically grown under low water regimes and produce highly appreciated fruits, which can be stored up to 4-8 months. We generated 65.8M and 56.4M of paired-end 30-150 bp reads with an average insert size of 380 bp (± 52bp) and 364 bp (± 49bp) for COR and LUC, respectively. A referenceguided assembly was performed using 'Heinz 1706' as a reference genome. We estimated a mean coverage depth of ~15X for COR and 13X for LUC. Comparing the genomes of COR and LUC with that of 'Heinz 1706' we found a similar distribution of SNPs (68.8% vs. 69.9%, respectively), small deletions (8.9% vs. 8.6%) and small insertions (22.1% vs. 21.3%). Through a de novo assembly of the unmapped reads we identified 29 and 36 new contigs in COR and LUC, respectively. The new contigs could be assigned to the chromosomes thanks to the use of a splitread approach. On average, the contigs inserted in COR were 654bp, whereas those inserted in LUC were 616bp. Using custom RNA-seq data, a total of 43054 and 44576 gene loci were annotated in COR and LUC, corresponding to 62369 and 65094 transcripts, respectively. Among the genes showing a similar structure in COR and LUC compared to 'Heinz 1706', we identified ~2000 and 1700 SNPs causing potentially disruptive effects on the function of 1371 and 1201 genes in COR and LUC, respectively. Interesting GO categories highly represented in genes affected by sequence changes were identified. Major variations were present in stress-responsive genes as well as in fruit quality and development-related genes. From a practical perspective, the identified SNPs and InDels are candidate polymorphisms to track DNA variations associated to key traits of economic interest

A multi-scale analysis of bull sperm methylome revealed both species peculiarities and conserved tissue-specific

peer-reviewedBackground: Spermatozoa have a remarkable epigenome in line with their degree of specialization, their unique nature and different requirements for successful fertilization. Accordingly, perturbations in the establishment of DNA methylation patterns during male germ cell differentiation have been associated with infertility in several species.Background: Spermatozoa have a remarkable epigenResults: The quantification of DNA methylation at CCGG sites using luminometric methylation assay (LUMA) highlighted the undermethylation of bull sperm compared to the sperm of rams, stallions, mice, goats and men. Total blood cells displayed a similarly high level of methylation in bulls and rams, suggesting that undermethylation of the bovine genome was specific to sperm. Annotation of CCGG sites in different species revealed no striking bias in the distribution of genome features targeted by LUMA that could explain undermethylation of bull sperm. To map DNA methylation at a genome-wide scale, bull sperm was compared with bovine liver, fibroblasts and monocytes using reduced representation bisulfite sequencing (RRBS) and immunoprecipitation of methylated DNA followed by microarray hybridization (MeDIP-chip). These two methods exhibited differences in terms of genome coverage, and consistently, two independent sets of sequences differentially methylated in sperm and somatic cells were identified for RRBS and MeDIP-chip. Remarkably, in the two sets most of the differentially methylated sequences were hypomethylated in sperm. In agreement with previous studies in other species, the sequences that were specifically hypomethylated in bull sperm targeted processes relevant to the germline differentiation program (piRNA metabolism, meiosis, spermatogenesis) and sperm functions (cell adhesion, fertilization), as well as satellites and rDNA repeats. Conclusions: These results highlight the undermethylation of bull spermatozoa when compared with both bovine somatic cells and the sperm of other mammals, and raise questions regarding the dynamics of DNA methylation in bovine male germline. Whether sperm undermethylation has potential interactions with structural variation in the cattle genome may deserve further attention. While bull semen is widely used in artificial insemination, the literature describing DNA methylation in bull spermatozoa is still scarce. The purpose of this study was therefore to characterize the bull sperm methylome relative to both bovine somatic cells and the sperm of other mammals through a multiscale analysis

Paviosides A-H, eight new oleane type saponins from Aesculus pavia with cytotoxic activity

A phytochemical analysis of Aesculus pavia has led to the isolation of eight novel triterpenoid saponins, based on oleane type skeleton and named paviosides A-H (1a, 1b-4a, 4b). On the basis of chemical, and 2D NMR and mass spectrometry data, the structures of the new compounds were elucidated as 3-O-[beta-D-xylopyranosyl(1 -> 2)] [-beta-D-glucopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (1a), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-glucopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (1b), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-galactopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (2a), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-galactopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (2b), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl barringtogenol C (3a), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl barringtogenol C (3b), 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-tigloyl-22-acetyl protoaescigenin (4a), and 3-O-[beta-D-xylopyranosyl (1 -> 2)] [-beta-D-xylopyranosyl (1 -> 4)]-beta-D-glucopyranosiduronic acid 21-angeloyl-22-acetyl protoaescigenin (4b). The compounds showed cytotoxic activity on J-774, murinemonocyte/macrophage, and WEHI-164, murine fibrosarcoma, cell lines. Among them, paviosides E-H (3a, 3b and 4a, 4b) showed higher activity with values ranging from 2.1 to 3.6 mu g/mL. Structure-activity relationship studies indicated the positive effect on the activity of xylose unit in the place of glucose, while a little detrimental effect is observed when glucose is substituted by galactose. The aglycone structure and the presence of a tigloyl or an angeloyl group at C-21 do not affect significantly the inhibitory activity on both tested cell lines. (C) 2012 Elsevier Ltd. All rights reserved

Metabolomic fingerprinting using nuclear magnetic resonance and multivariate data analysis as a tool for biodiversity informatics: A case study on the classification of Rosa x damascena

Metabolomics is the comprehensive and simultaneous identification and quantification of metabolites in living cells. The term metabolome is used to describe the observable chemical profile or fingerprint of the metabolites in a whole tissue. Although being a new approach to study natural compounds, metabolomics uses traditional analytical techniques, including extraction methods, which can be followed by nuclear magnetic resonance (NMR) spectroscopy and multivariate data analysis. Although metabolomics has been successfully applied to quality control issues, the examples of its use for chemosystematics are few. Thus, the analysis of four taxa of Rosa x damascena (R. damascena Mill., R. damascenasemperflorens, R. damascenatrigintipetala and R. duchesse of Portland) was carried out by NMR spectroscopy as a tool for their classification. A principal component analysis of the H-1 NMR spectra, based on the metabolites found in organic and aqueous fractions, showed a clear similarity of the samples. In particular, the major contributions from the aqueous fraction, preliminarily considered as a biomarker of R. x damascena group, are the flavonoids kaempferol and quercetin, glycosilated with glucose and rhamnose units. Our analysis demonstrated a close chemotaxonomic correlation among the four taxa, making this method a reliable tool for chemosystematics

Fire occurrence and tussock size modulate facilitation by Ampelodesmos mauritanicus

Facilitation has been reported for a wide range of plant communities, with evidence of interactions between protégé and nurse plants shifting during their ontogenetic cycles. This study showed that large Ampelodesmos mauritanicus tussocks can act as nurse for different species, but only after fire occurrence. Large tussocks are typically composed by an external belt of living tillers surrounding dead standing tillers in the inner area, thus being arranged as a “ring” shape. A low plant diversity in unburned sites, dominated by intact Ampelodesmos tussocks, was related to the intense aboveground competition due to space physical limitation by standing tillers, as well as to the reduction of light availability at ground level. In contrast, after burning, tussocks resprouted only in their external belts, leaving empty inner areas. During post-fire recovery, several species (e.g. Plantago spp., Trifolium spp., Carlina spp.) recolonize the bare soil among different tussocks. On the other hand, a moss (Funaria hygrometrica) and several herbaceous and woody plants (e.g. Spartium junceum, Calicotome villosa, Quercus pubescens subsp. pubescens) were selectively distributed within the ash-full central areas of burned Ampelodesmos tus- socks. In summary, the study reported evidence of changing prevalence in the interplay of competition and facilitation effects between small and large Ampelodesmos tussocks, respectively. These results suggest a broad significance of the interactions between fire occurrence and ontogenetic phases of the dominant species in affecting the restoration dynamics of natural plant communities