Quinic acids from Aster caucasicus and from transgenic callus expressing a beta-amyrin synthase.

Several different classes of secondary metabolites, including flavonoids, triterpenoid saponins and quinic acid derivatives, are found in Aster spp. (Fam. Asteraceae). Several Aster compounds revealed biological as well as pharmacological activities. In this work, a phytochemical investigation of A. caucasicus evidenced the presence of quinic acid derivatives, as well as the absence of triterpene saponins. To combine in one species the production of different phytochemicals, including triterpenes, an Agrobacterium-mediated transformation of A. caucasicus was set up to introduce A. sedifolius β-amyrin synthase (AsOXA1)-encoding gene under the control of the constitutive promoter CaMV35S. The quali-quantitative analysis of transgenic calli with ectopic expression of AsOXA1 showed, in one sample, a negligible amount of triterpene saponins combined with higher amount of quinic acid derivatives as compared with the wild type callus

Genome-wide analysis of histone modifiers in tomato: gaining an insight into their developmental roles

BACKGROUND: Histone post-translational modifications (HPTMs) including acetylation and methylation have been recognized as playing a crucial role in epigenetic regulation of plant growth and development. Although Solanum lycopersicum is a dicot model plant as well as an important crop, systematic analysis and expression profiling of histone modifier genes (HMs) in tomato are sketchy. RESULTS: Based on recently released tomato whole-genome sequences, we identified in silico 32 histone acetyltransferases (HATs), 15 histone deacetylases (HDACs), 52 histone methytransferases (HMTs) and 26 histone demethylases (HDMs), and compared them with those detected in Arabidopsis (Arabidopsis thaliana), maize (Zea mays) and rice (Oryza sativa) orthologs. Comprehensive analysis of the protein domain architecture and phylogeny revealed the presence of non-canonical motifs and new domain combinations, thereby suggesting for HATs the existence of a new family in plants. Due to species-specific diversification during evolutionary history tomato has fewer HMs than Arabidopsis. The transcription profiles of HMs within tomato organs revealed a broad functional role for some HMs and a more specific activity for others, suggesting key HM regulators in tomato development. Finally, we explored S. pennellii introgression lines (ILs) and integrated the map position of HMs, their expression profiles and the phenotype of ILs. We thereby proved that the strategy was useful to identify HM candidates involved in carotenoid biosynthesis in tomato fruits. CONCLUSIONS: In this study, we reveal the structure, phylogeny and spatial expression of members belonging to the classical families of HMs in tomato. We provide a framework for gene discovery and functional investigation of HMs in other Solanaceae species

Multi-omics data integration provides insights into the post-harvest biology of a long shelf-life tomato landrace

In this study we investigated the transcriptome and epigenome dynamics of the tomato fruit during post-harvest in a landrace belonging to a group of tomatoes (Solanum lycopersicum L.) collectively known as "Piennolo del Vesuvio", all characterized by a long shelf-life. Expression of protein-coding genes and microRNAs as well as DNA methylation patterns and histone modifications were analysed in distinct post-harvest phases. Multi-omics data integration contributed to the elucidation of the molecular mechanisms underlying processes leading to long shelf-life. We unveiled global changes in transcriptome and epigenome. DNA methylation increased and the repressive histone mark H3K27me3 was lost as the fruit progressed from red ripe to 150 days post-harvest. Thousands of genes were differentially expressed, about half of which were potentially epi-regulated as they were engaged in at least one epi-mark change in addition to being microRNA targets in ~5% of cases. Down-regulation of the ripening regulator MADS-RIN and of genes involved in ethylene response and cell wall degradation was consistent with the delayed fruit softening. Large-scale epigenome reprogramming that occurred in the fruit during post-harvest likely contributed to delayed fruit senescence

Whole-genome re-sequencing of two Italian tomato landraces reveals sequence variations in genes associated with stress tolerance, fruit quality and long shelf-life traits

Tomato is a high value crop and the primary model for fleshy fruit development and ripening. Breeding priorities include increased fruit quality, shelf life and tolerance to stresses. To contribute towards this goal, we re-sequenced the genomes of Corbarino (COR) and Lucariello (LUC) landraces, which both possess the traits of plant adaptation to water deficit, prolonged fruit shelf-life and good fruit quality. Through the newly developed pipeline Reconstructor, we generated the genome sequences of COR and LUC using datasets of 65.8M and 56.4M of 30–150bp paired-end reads, respectively. New contigs including reads that could not be mapped to the tomato reference genome were assembled, and a total of 43, 054 and 44, 579 gene loci were annotated in COR and LUC. Both genomes showed novel regions with similarity to Solanum pimpinellifolium and Solanum pennellii. In addition to small deletions and insertions, 2, 000 and 1, 700 single nucleotide polymorphisms (SNPs) could exert potentially disruptive effects on 1, 371 and 1, 201 genes in COR and LUC, respectively. A detailed survey of the SNPs occurring in fruit quality, shelf life and stress tolerance related-genes identified several candidates of potential relevance. Variations in ethylene response components may concur in determining peculiar phenotypes of COR and LUC

Learning and playing in Web 3.0: Evidence from Serious Games in Higher Education

Educational institutions are rapidly rethinking their pedagogical models and approaches to teaching and learning, increasingly adapting to traits and characteristics of learners. Personalization of learning, participative activities, and online interaction are changing learning models and approaches. In this chapter we will look at the phenomenon of learning through the lens of the participatory paradigm through which we interpret new paths of learning. Evidences from two Serious Games will be presented, arguing that the playful aspect embodied in these games is key to learners’ engagement. Implications for teaching and learning practices will be discussed in relation to potential directions that participatory approaches might take

Molecular characterization of β-amyrin synthase from Aster sedifolius L. and triterpenoid saponin analysis

Triterpenoid saponins are secondary metabolites showing a remarkable structural variety, as well as notable biological activities. They are synthesised via the isoprenoid pathway by 2,3-oxidosqualene cyclization mediated by oxidosqualene cyclase (OSC) enzymes. In our previous work, three new oleanane-type triterpene saponins (astersedifolioside A-C) were isolated from the aerial tissues of Aster sedifolius L. In this work, the full-length cDNA of a new OSC, designated AsOXA1, was isolated from A. sedifolius. The AsOXA1 open reading frame consisting of 2286 bp was predicted to encode a protein of 761 amino acid residues. The deduced amino acid sequence of AsOXA1 showed QW and DCTAE motifs which are highly conserved among the known triterpene synthases. In addition, the comparative and phylogenetic analysis evidenced that AsOXA1 was closely related to other plant OSCs, and particularly, β-amyrin synthases including that one of Panax ginseng with which it shared a high degree of identity (79%). Recombinant AsOXA1 has been shown to produce β-amyrin in yeast. RT-PCR analysis evidenced that AsOXA1 was a tissue-specific gene differentially expressed during plant development. Transcripts of AsOXA1 accumulated strongly in leaf at the early reproductive stage but were deficient in root. On the contrary, the accumulation of astersedifoliosides resulted 10-fold higher in roots than in aerial tissues. Molecular and biochemical results have been discussed