9 research outputs found

    Genetically engineered orange petunias on the market

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    Main conclusion Unauthorized genetically engineered orange petunias were found on the market. Genetic engineering of petunia was shown to lead to novel flower color some 20 years ago. Here we show that petunia lines with orange flowers, generated for scientific purposes, apparently found their way to petunia breeding programmes, intentionally or unintentionally. Today they are widely available, but have not been registered for commerce

    Flavonoid Metabolomics in Gerbera hybrida and Elucidation of Complexity in the Flavonoid Biosynthetic Pathway

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    The flavonoid biosynthetic pathway and flavonoid metabolites have been extensively studied because of their biological roles in plant and animal kingdoms. Flavonoid metabolites are involved in plant resistance, UV-protection, pollinator attraction and have antioxidant effects. Plant species synthesise a large number of secondary metabolites, including flavonoids, carotenoids and others. Flower colour is an important feature for marketing of the ornamental model plant gerbera (Gerbera hybrida). In gerbera, flavonoid metabolites accumulate in the adaxial epidermal layer of flower petals and lead to different flower colours and patterns. These metabolites consist of three subgroups, flavones, flavonols and anthocyanins in gerbera, which have also been used to characterize different cultivars. The cultivars show variation in flower colour according to their anthocyanin type. The acyanic gerbera cultivars have flavonoid profiles comparable to the cyanic cultivars, except for the synthesis and accumulation of specific anthocyanins. Metabolite profiles indicated that all analysed acyanic cultivars have a block in a late stage of the anthocyanin pathway. Ivory, a sport of the pelargonidin-cultivar Estelle, has white flowers. Ivory has flavones and flavonols, but no anthocyanin. Gene expression of all flavonoid pathway genes was similar in Estelle and Ivory. However, both cultivars have two different alleles encoding dihydroflavonol 4-reductase and in Ivory one of them (GDFR1-2) was found to have a point mutation resulting in inactivation of the encoded enzyme. Still, Ivory expresses the second allele (GDFR1-3) and accumulates active DFR enzyme. The cyanidin cultivar President expresses only the GDFR1-3 allele, but cannot synthesize pelargonidin. Therefore, GDFR1-2 contributes specifically to pelargonidin biosynthesis and GDFR1-3 to cyanidin biosynthesis. This could be explained by a coordinated biosynthesis of anthocyanins in multi-enzyme complexes, metabolons. Gerbera chalcone synthases (GCHSs) belong to the superfamily of Type III polyketide synthase enzymes. GCHS1, 3 and 4 have different contributions to the flavonoid pathway, according to the tissue specific and post-transcriptional regulation. RNA interference of CHS encoding genes was used in different gerbera cultivars to show that GCHS1 has the main contribution to anthocyanin accumulation in petal tissues. GCHS4 was strongly expressed in petals but did not lead to anthocyanin accumulation. Still, GCHS4 is expressed and encoded a functional enzyme in the vegetative tissues.Flavonoidit ovat kasvien fenolisia yhdisteitä, jotka voivat olla värittömiä (flavonit ja flavonolit) tai oranssin, punaisen tai sinisen sävyisiä pigmenttejä (antosyaanit). Flavonodit suojaavat kasvia UV-säteilyltä ja taudinaiheuttajilta, ja toisaalta houkuttelevat hyödyllisiä pölyttäjiä. Flavonoidit ovat ravinnossa tärkeitä antioksidantteja ja niiden biosynteesiä on tutkittu paljon. Tässä työssä tutkittiin koristekasvina tunnetun gerberan kukinnon flavonoidien kemiaa, entsymologiaa ja geeniekspressiota. Materiaalina käytettiin lajikkeita, jotka sisälsivät flavoneja (apigeniinia tai luteiinia), flavonoleja (kemferolia tai kversetiiniä) ja/tai antosyaaneja (pelargonidiineja tai syanidiineja). Punaisesta Estelle-lajikkeen sivuhaarana syntyneessä valkoisessa Ivory-lajikkeessa todettiin mutaatio antosyaanibiosynteesille tärkeässä DFR-entsyymiä koodaavassa geenissä. Toinen DFR-alleeli kuitenkin koodasi toimivaa entsyymiä, joka kasvissa ei johtanut pigmentin biosynteesiin vaikka geeni ilmeni. Samalla tavalla flavonoidireitin alkupäässä olevan CHS-entsyymin kohdalla todettiin, että kahdesta kukinnossa ilmenevästä muodosta vain toinen oli tärkeä kukinnon antosyaanien biosynteesille. Toinen vastasi lehtiruotiin muodostuvasta antosyaanista. Yhteenvetona voidaan todeta, että flavonodien biosynteesiä säädellään geberalla geenitoiminnan lisäksi myös proteiinitasolla

    Within leaf variation is the largest source of variation in agroinfiltration of Nicotiana benthamiana

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    Abstract Background: Transient gene expression utilizing syringe agroinfiltration offers a simple and efficient technique for different transgenic applications. Leaves of Nicotiana benthamiana show reliable and high transformation efficiency, but in quantitative assays also a certain degree of variation. We used a nested design in our agroinfiltration experiments to dissect the sources of this variation. Results: An intron containing firefly luciferase gene was used as a reporter for agroinfiltration. A number of 6 week old tobacco plants were infiltrated for their top leaves, several samples were punched from the leaves after 2 days of transient expression, and protein extracts from the samples were repeatedly measured for luciferase activity. Interestingly, most of the variation was due to differences between the sampling spots in the leaves, the next important source being the different leaves on each plant. Variation between similar experiments, between plants and between repetitive measurements of the extracts could be easily minimized. Conclusions: Efforts and expenditure of agroinfiltration experiments can be optimized when sources of variation are known. In summary, infiltrate more plants but less leaves, sample more positions on the leaf but run only few technical replicates.Peer reviewe

    Functional characterization and expression of GASCL1 and GASCL2, two anther-specific chalcone synthase like enzymes from Gerbera hybrida

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    The chalcone synthase superfamily consists of type III polyketidesynthases (PKSs), enzymes responsible for producing plant secondary metabolites with various biological and pharmacological activities. Anther-specific chalcone synthase-like enzymes (ASCLs) represent an ancient group of type III PKSs involved in the biosynthesis of sporopollenin, the main component of the exine layer of moss spores and mature pollen grains of seed plants. In the latter, ASCL proteins are localized in the tapetal cells of the anther where they participate in sporopollenin biosynthesis and exine formation within the locule. It is thought that the enzymes responsible for sporopollenin biosynthesis are highly conserved, and thus far, each angiosperm species with a genome sequenced has possessed two ASCL genes, which in Arabidopsis thaliana are PKSA and PKSB. The Gerbera hybrida (gerbera) PKS protein family consists of three chalcone synthases (GCHS1, GCHS3 and GCHS4) and three 2-pyrone synthases (G2PS1, G2PS2 and G2PS3). In previous studies we have demonstrated the functions of chalcone synthases in flavonoid biosynthesis, and the involvement of 2-pyrone synthases in the biosynthesis of antimicrobial compounds found in gerbera. In this study we expanded the gerbera PKS-family by functionally characterizing two gerbera ASCL proteins. In vitro enzymatic studies using purified recombinant proteins showed that both GASCL1 and GASCL2 were able to use medium and long-chain acyl-CoA starters and perform two to three condensation reactions of malonyl-CoA to produce tri- and tetraketide 2-pyrones, usually referred to as alpha-pyrones in sporopollenin literature. Both GASCL1 and GASCL2 genes were expressed only floral organs, with most expression observed in anthers. In the anthers, transcripts of both genes showed strict tapetum-specific localization. (C) 2016 Elsevier Ltd. All rights reserved.Peer reviewe

    MOESM1 of Within leaf variation is the largest source of variation in agroinfiltration of Nicotiana benthamiana

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    Additional file 1: Table S1. Measurements of luciferase activity from the first experiment and calculation of variance components. Table S2. Measurements of luciferase activity from the second experiment and calculation of variance components
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