An EST database from saffron stigmas

BACKGROUND: Saffron (Crocus sativus L., Iridaceae) flowers have been used as a spice and medicinal plant ever since the Greek-Minoan civilization. The edible part - the stigmas - are commonly considered the most expensive spice in the world and are the site of a peculiar secondary metabolism, responsible for the characteristic color and flavor of saffron. RESULTS: We produced 6,603 high quality Expressed Sequence Tags (ESTs) from a saffron stigma cDNA library. This collection is accessible and searchable through the Saffron Genes database http://www.saffrongenes.org. The ESTs have been grouped into 1,893 Clusters, each corresponding to a different expressed gene, and annotated. The complete set of raw EST sequences, as well as of their electopherograms, are maintained in the database, allowing users to investigate sequence qualities and EST structural features (vector contamination, repeat regions). The saffron stigma transcriptome contains a series of interesting sequences (putative sex determination genes, lipid and carotenoid metabolism enzymes, transcription factors). CONCLUSION: The Saffron Genes database represents the first reference collection for the genomics of Iridaceae, for the molecular biology of stigma biogenesis, as well as for the metabolic pathways underlying saffron secondary metabolism

Silencing of beta-carotene hydroxylase increases total carotenoid and beta-carotene levels in potato tubers

BACKGROUND: Beta-carotene is the main dietary precursor of vitamin A. Potato tubers contain low levels of carotenoids, composed mainly of the xanthophylls lutein (in the beta-epsilon branch) and violaxanthin (in the beta-beta branch). None of these carotenoids have provitamin A activity. We have previously shown that tuber-specific silencing of the first step in the epsilon-beta branch, LCY-e, redirects metabolic flux towards beta-beta carotenoids, increases total carotenoids up to 2.5-fold and beta-carotene up to 14-fold. RESULTS: In this work, we silenced the non-heme beta-carotene hydroxylases CHY1 and CHY2 in the tuber. Real Time RT-PCR measurements confirmed the tuber-specific silencing of both genes . CHY silenced tubers showed more dramatic changes in carotenoid content than LCY-e silenced tubers, with beta-carotene increasing up to 38-fold and total carotenoids up to 4.5-fold. These changes were accompanied by a decrease in the immediate product of beta-carotene hydroxylation, zeaxanthin, but not of the downstream xanthophylls, viola- and neoxanthin. Changes in endogenous gene expression were extensive and partially overlapping with those of LCY-e silenced tubers: CrtISO, LCY-b and ZEP were induced in both cases, indicating that they may respond to the balance between individual carotenoid species. CONCLUSION: Together with epsilon-cyclization of lycopene, beta-carotene hydroxylation is another regulatory step in potato tuber carotenogenesis. The data are consistent with a prevalent role of CHY2, which is highly expressed in tubers, in the control of this step. Combination of different engineering strategies holds good promise for the manipulation of tuber carotenoid content

Metabolic engineering of potato tuber carotenoids through tuber-specific silencing of lycopene epsilon cyclase

BACKGROUND: Potato is a major staple food, and modification of its provitamin content is a possible means for alleviating nutritional deficiencies. beta-carotene is the main dietary precursor of vitamin A. Potato tubers contain low levels of carotenoids, composed mainly of the xanthophylls lutein, antheraxanthin, violaxanthin, and of xanthophyll esters. None of these carotenoids have provitamin A activity. RESULTS: We silenced the first dedicated step in the beta-epsilon- branch of carotenoid biosynthesis, lycopene epsilon cyclase (LCY-e), by introducing, via Agrobacterium-mediated transformation, an antisense fragment of this gene under the control of the patatin promoter. Real Time measurements confirmed the tuber-specific silencing of Lcy-e. Antisense tubers showed significant increases in beta-beta-carotenoid levels, with beta-carotene showing the maximum increase (up to 14-fold). Total carotenoids increased up to 2.5-fold. These changes were not accompanied by a decrease in lutein, suggesting that LCY-e is not rate-limiting for lutein accumulation. Tuber-specific changes in expression of several genes in the pathway were observed. CONCLUSION: The data suggest that epsilon-cyclization of lycopene is a key regulatory step in potato tuber carotenogenesis. Upon tuber-specific silencing of the corresponding gene, beta-beta-carotenoid and total carotenoid levels are increased, and expression of several other genes in the pathway is modified

Olive mill wastes. A source of bioactive molecules for plant growth and protection against pathogens

Olive oil production generates high amounts of liquid and solid wastes. For a long time, such complex matrices were considered only as an environmental issue, due to their polluting properties. On the other hand, olive mill wastes (OMWs) exert a positive effect on plant growth when applied to soil due to the high content of organic matter and mineral nutrients. Moreover, OMWs also exhibit antimicrobial activity and protective properties against plant pathogens possibly due to the presence of bioactive molecules including phenols and polysaccharides. This review covers the recent advances made in the identification, isolation, and characterization of OMW-derived bioactive molecules able to influence important plant processes such as plant growth and defend against pathogens. Such studies are relevant from different points of view. First, basic research in plant biology may benefit from the isolation and characterization of new biomolecules to be potentially applied in crop growth and protection against diseases. Moreover, the valorization of waste materials is necessary for the development of a circular economy, which is foreseen to drive the future development of a more sustainable agriculture

An EST database from saffron stigmas

Abstract Background Saffron (Crocus sativus L., Iridaceae) flowers have been used as a spice and medicinal plant ever since the Greek-Minoan civilization. The edible part – the stigmas – are commonly considered the most expensive spice in the world and are the site of a peculiar secondary metabolism, responsible for the characteristic color and flavor of saffron. Results We produced 6,603 high quality Expressed Sequence Tags (ESTs) from a saffron stigma cDNA library. This collection is accessible and searchable through the Saffron Genes database http://www.saffrongenes.org. The ESTs have been grouped into 1,893 Clusters, each corresponding to a different expressed gene, and annotated. The complete set of raw EST sequences, as well as of their electopherograms, are maintained in the database, allowing users to investigate sequence qualities and EST structural features (vector contamination, repeat regions). The saffron stigma transcriptome contains a series of interesting sequences (putative sex determination genes, lipid and carotenoid metabolism enzymes, transcription factors). Conclusion The Saffron Genes database represents the first reference collection for the genomics of Iridaceae, for the molecular biology of stigma biogenesis, as well as for the metabolic pathways underlying saffron secondary metabolism.</p

Olive mill waste water valorization: bioactive molecules-enriched fractions recovered by tangential-flow membrane filtration (TFMF) to elicit plant defence responses

In modern olive oil extraction process (Multi-phase Leopard Decanter), in addition to oil and a kernel dehydrated fraction, a hydrated pulp named "Patè" is produced. After centrifugation, the vegetative water (VW) can be recovered from Patè as supernatant. VW is rich of bioactive molecules such as oligosaccharides and phenols effective in plant protection against pathogens. VW have been fractionated by TFMF. NMR spectroscopy analysis indicated the presence of bioactive phenols such as tyrosol, hydroxytyrosol and oleuropein with a known antimicrobial activity. The profile of TFMF fractions obtained by HPAEC-PAD indicated the presence of pectin-derived oligogalacturonides (OGs) well known elicitors of plant defence responses as the early intracellular increase of Ca2+ levels. A dose dependent elicitation of Ca2+ was induced by OG enriched TFMF fractions. Remarkably, pre-treatment with specific OG-enriched TFMF fractions reduces plant disease symptoms against microbial pathogens. The possibility that phenols cooperate with OGs in inducing plant immunity is not excluded. This finding highlights the potential of this waste as bio-stimulant of plant defense responses

Phytochemical profile of olive oil mill vegetative waters

Olive (Olea europaea L.) belongs to the Oleaceae family and it has been cultivated for olive oil, fine wood, olive leaf and its fruits from 2000 years ago and is one of the most diffused crops in the Mediterranean basin. Its fruits can be consumed as it is, but traditionally they are employed to produce olive oil, which is one of the cornerstones of the Mediterranean diet. It is a commercial good whose market is projected to reach a revenue of 1 billion of US dollars in 2022 worldwide and is a major contribution to Italian economy (1). The production of olive oil consists in several steps that produce, along the final product, several wastes among which pomace is a wet solid waste composed by peels, pulp residues and seed fragments. In modern implants (decanter multiphase) waste can include a dehydrated pomace containing peels and hazelnuts suitable for production of pellet for stoves and a second by-product, called "paté", consisting in hydrated pulp with a high humidity (75-80%) usually used to produce biogas. In the process for the latter, vegetative water is also produced, which is an aqueous toxic waste usually discarded (2). Olive mill wastes are toxic for both natural beneficial and pathogenic microrganisms. Nowadays, in the optic of a better employment of the natural resources, these approaches are no longer sustainable, and as such several national and international projects have been founded in order to use these waste materials for other applications. The aim of this project, which is the first step of the larger ABASA (Agricultural By-products into valuable Assets for Sustainable Agriculture) project founded by LazioInnova- Regione Lazio, is to characterize the phytochemical composition of patè and vegetative waters fractionated by various stages of membrane filtration in order to identify and quantify molecules with biological activity which could be employed in agriculture as phytopesticides, agents in crop protection, soil biofertilizers or as a source of bioactive compounds. In the present study, both pomace and vegetative waters fractions were analyzed by high-resolution NMR spectroscopy. The matrices have been treated with a multi-solvent extraction protocol, and both the hydro soluble and lyposoluble fractions have been analyzed. Mono and polyunsaturated fatty acid, triglycerides, triterpenes derived from ursolic acid, oleuropein, lingstroside and their aglycones, tyrosol and hydroxytirosol were observed in both matrices, with the major difference between them being the relative amount of triglycerides. Of great interest is the presence of oleuropein and lingstroside in waste waters since they are both seco-iridoids with a known antifungal and antimicrobical activity (3) Carbohydrate profile has been obtained for the same fractions. The presence of pectin and oligogalacturonides (OGs) were identified by anion exchange HPLC-Dionex. OGs are cell wall derived pectic fragments elicitors of plant immune responses (4). This finding highlights the high potential of these by-products as biostimulant of plant defense responses. The evaluation of the fractionation efficiency and the biological activity of the different fractions are in progress

Effects on growth and biomass production of patè olive cake for agronomic application

The cultivation of olive trees (Olea europaea L.) is very important worldwide and especially for the Mediterranean area. This crop is mainly used for the production of oil, but also of olives and precious wood. The chemical-physical characteristics of the by-products derived from the transformation of olives depend on the synergy between the soil and climatic conditions of the cultivation area, the variety, the state of ripeness of the olives and, above all, the processing system adopted. These wastes, in fact, due to their acidity, the presence of phenolic compounds, suspended substances and the high organic load, can be characterized by a high polluting and phytotoxic degree. These characteristics, combined with the seasonality of olive production, concentrated from October to March, and therefore the high concentration of potential pollutants in a short period of the year, are unable to guarantee cost-effectiveness of management in the transformation and disposal phase. The need arises for the recovery and recycling of oil waste for the production of compounds of commercial value to be reused in agriculture as an excellent combination between the enhancement of the by-product and waste management. This requires both the use of eco-sustainable separation and extraction technologies for the selective recovery of biological macromolecules of high added value, and the implementation of the agricultural use of the fractions with greater bio-stimulating potential. In this context is the study conducted within the ABASA project (Agricultural By-products into valuable Assets for Sustainable Agriculture), funded by Lazio Innova-Regione Lazio, CUP: B81G18000770002 "Green technologies for sustainable agriculture: protection from phytopathogens and fertilizers of agri-food crops using biomolecules obtained from oil waste". Object of this work is the evaluation of the effect on plant growth and biomass production of a new olive mill by-products named “Patè Olive Cake” (POC) generated by a multi-phase decanter (DMF) technology that combine an extraction technology without the addition of water. POC is an olive mill by-product consisting of olive pulp, olive skin and vegetative water. The aim of this research was to adopt protocols for the evaluation of different POC fractions through laboratory bioassays to highlight their nutritional, bio-stimulating, toxic and genotoxic properties. In the present work the first results obtained are reported and discussed. Tests in pots are being carried out in order to investigate the effects of different fractions on growth and biomass production tested on ryegrass (Lolium perenne L.) and on the chemical and microbiological characteristics on two different soils used for the experimental test