Conversion of hydroxylated and methylated dihydroflavonols into anthocyanins in a white flowering mutant of Petunia hybrida

A 3′, 4′-dihydroxy or a 3′, 4′, 5′-trihydroxy substitution pattern of dihydroflavonols is required for their conversion into the corresponding anthocyanins in a white flower of Petunia hybrida. The presence of a 5-hydroxyl group is not required. B-ring methylated dihydroflavonols were not converted into the corresponding anthocyanins. In case of a 4′-methoxy substituted dihydroflavonol a 4′-hydroxyanthocyanin is obtained, suggesting demethylation of this compound. The conversion of synthetic (±)-trans-2,3-dihydroflavonols into anthocyanins proceeded almost as well as with natural compounds. The results demonstrate that the cinnamic acid starter hypothesis for the origin of B-ring substituents is not correct for B-ring methylation.     

Partial purification and characterization of a ribonuclease from Petunia hybrida

A crude extract from leaves of Petunia hybrida contains three ribonucleases (RNases) as revealed by polyacrylamide gel electrophoresis (PAGE). One     

Differences in the incorporation pattern of labelled cinnamic acid and l-phenylalanine into the anthocyanins of Petunia hybrida

The incorporation of phenylalanine-[¹⁴C] into anthocyanins of petals of Petunia hybrida is greater than that of cinnamic acid-[¹⁴C]. Moreover, there is a preferential incorporation of phenylalanine-[¹⁴C] into delphinidin 3-monoglucoside, as compared with the incorporation into cyanidin and peonidin 3-monoglucosides.     

Der substitutionsspezifische einfluss von chalkonen auf die anthocyanbiosynthese bei Petunia hybrida

The effect of two chalcones, 3,4,2′,4′,6′-pentahydroxy- and the 4, 2 ′,4′,6′ -tetrahydroxy- 3-methoxy-chalcone- 4′-glucoside, on the synthesis of different flower anthocyanins in isolated petals of Petunia hybrida has been investigated. The results show that the synthesis of those anthocyanins, which have the same substitution pattern as the chalcone used was increased. This suggests that the chalcones are incorporated into the anthocyanins concerned. When the chalcones were fed together with acetic acid-[1-¹⁴C], this specific substitution effect was detectable only for the 3,4,2′,4′,6′-pentahydroxy-chalcone-4′-glucoside.     

Beyerene derivatives and other constituents from Petunia patagonica

Two new diterpenes of the beyerene type, ent-19-hydroxy-1 7-acetoxybeyer-15-ene and ent-beyer-15-en-17-oic acid, and two previously characterized kauranoids, ent-16β-hydroxy-17-acetoxykaurane and ent-16β,1 7-dihydroxy-kaurane, as well as two known flavonoids, luteolin-7,3′,4′-trimethyl ether and luteolin-7,3′-dimethyl ether, and a triterpenoid, oleanoic acid, were obtained from a chloroform extract of Petunia patagonica. The new structures were elucidated by spectral data and chemical transformations.     

Time-course tracer studies on the metabolism of cinnamic acid in Cestrum poeppigii

Time-course tracer studies were performed on the metabolism of trans-cinnamic acid-[3-¹⁴C] and trans-p-coumaric acid-[2-¹⁴C] in the     

Floral anthocyanins of some malesian Hibiscus species

In 14 Malesian species of Hibiscus (sensu lato) the most common floral anthocyanin was cyanidin 3-sambubioside. Cyanidin 3-glucoside was found     

Acylated anthocyanins in inflorescence of spider flower (Cleome hassleriana)

Five anthocyanins, cyanidin 3-(2′′-(6′′′-caffeoyl-β-glucopyranosyl)-6′′-(E-p-coumaroyl)-β-glucopyranoside)-5-β-glucopyranoside, cyanidin 3-(2′′-(6′′′-E-sinapoyl-β-glucopyranosyl)-6′′-(E-p-coumaroyl)-β-glucopyranoside)-5-β-glucopyranoside, cyanidin 3-(2′′-(6′′′-feroyl-β-glucopyranosyl)-6′′-(E-p-coumaroyl)-β-glucopyranoside)-5-β-glucopyranoside, pelargonidin 3-(2′′-(6′′′-E-sinapoyl-β-glucopyranosyl)-6′′-(E-p-coumaroyl)-β-glucopyranoside)-5-β-glucopyranoside, and pelargonidin 3-(2′′-(6′′′-E-p-coumaroyl-β-glucopyranosyl)-6′′-(E-p-coumaroyl)-β-glucopyranoside)-5-β-glucopyranoside, together with five known anthocyanins have been identified in flowers of Cleome hassleriana Queen line. One monoacylated and four diacylated cyanidin 3-sophoroside-5-glucosides were identified as the main anthocyanins in flowers with mauve colouration, while a homologous glycosidic pattern based on pelargonidin was found in the five main anthocyanins from flowers with pink colouration. The anthocyanins identified in C. hassleriana share the same glycosidic pattern as anthocyanins isolated from the genera Raphanus, Brassica and Iberis in the sister family Brassicaceae.     

Effect of phenolic compounds in Lycopersicon esculeutum on the synthesis of ethylene

Caffeic, coumaric, sinapic and ferulic acids and naringenin were found in green tomato fruit, Chlorogenic acid accounted for 75% of the total phenolics in mature green fruit but only 35% in ripe fruit. There was very little change in the phenolic composition of the flesh of the fruit during ripening, whereas in the skin, naringenin increased markedly at the onset of the climacteric and three unidentified compounds increased during the climacteric rise. The increase in the concentration of naringenin was accompanied by an increase in the production of ethylene in the skin. Investigation of three systems producing ethylene from 4-methylmercapto-2-oxobutyric acid in the presence of peroxidase, showed that only p`-coumaric acid or naringenin were capable of acting as phenolic substrates, the other phenolic compounds being inhibitory.     

Characterization of PhPRP1, a histidine domain arabinogalactan protein from Petunia hybrida pistils

An arabinogalactan protein, PhPRP1, was purified from Petunia hybrida pistils and shown to be orthologous to TTS-1 and TTS-2 from Nicotiana tabacum and NaTTS from Nicotiana alata. Sequence comparisons among these proteins, and CaPRP1 from Capsicum annuum, reveal a conserved histidine-rich domain and two hypervariable domains. Immunoblots show that TTS-1 and PhPRP1 are also expressed in vegetative tissues of tobacco and petunia respectively. In contrast to the molecular mass heterogeneity displayed by the pistil proteins, the different isoforms found in seedlings, roots, and leaves each has a discrete size (37, 80, 160, and 200 kDa) on SDS-PAGE gels. On the basis of their chemistry, distinctive domain architecture, and the unique pattern of expression, we have named this group of proteins HD-AGPs (histidine domain-arabinogalactan proteins).     

Complex anthocyanins from Ipomoea congesta

Six acylated anthocyanins have been isolated from the flowers of Ipomoea congesta R. Brown. One has been previously described as an acylated peonidin derivative. Three others are isomers, derived from peonidin-3-(caffeylsophoroside)-5-glucoside. The fifth was characterised as peonidin-3-(p-coumarylcaffeylsophoroside)-5-glucoside and the last as peonidin-3-(coumarylsophoroside)-5-glucoside. It is noteworthy that the anthocyanins found in this species have the same glycosidic pattern, 3-sophoroside-5-glucoside, as those reported for the cyanidin derivatives in Ipomoea cairica flowers. Acylated anthocyanin occurrence in Tubiflorae order is of chemotaxonomical value.     

Methylation analysis of extracellular polysaccharides from suspension-cultured cells of Nicotiana tabacum

The soluble extracellular polysaccharides (ECP) of suspension-cultured tobacco cells were fractionated by DEAE-Sephadex CC into seven sub-fractions. Su     

Lignans in flower buds of Magnolia fargesii

Four lignans were isolated from the flower buds of Magnolia fargesii Cheng, two of which were known lignans, pinoresinol dimethyl ether and lirioresinol-B dimethyl ether; the other two were new lignans, magnolin and fargesin, and their structures have been determined by spectroscopic studies.     

Structure and properties of the acylated anthocyanins from Vitis species

The acylated anthocyanins of Ives grapes have been isolated using column chromatography on polyamide and polyvinylpyrrolidone. Controlled hydrolysis with Dowex 50W-X8 ion exchange resin, KOH. peroxide oxidation and speciroscopic characterization revealed their tructure as the 3-(6-O-p-coumarylglucoside)-5-glucosides of cyanidin, peonidin, delphinidin, petunidin, and malvidin and the 3-(6-O-p-coumary lglucoside)s of delphinidin, petunidin and malvidin. On cellulose TLCs in the five solvent systems used, no clear-cut separation of these pigments could be obtained without their preliminary separation on polyamide and polyvinylpyrrolidone columns.     

Ribonucleases in Nicotiana tabacum leaf extracts treated with phenol

When tobacco leaf extracts are treated with phenol, ca 20% of the ribonuclease (RNase) activity survives and can be measured when the phenol is removed. After purification, the resistant RNase is inactivated by phenol; this suggests that tobacco leaves contain material that protects the RNase. Phenol-resistant RNase may be one of the TMV-RNA inactivating systems present in phenol extracts of tobacco leaves.     

Gamma irradiation with different dose rates induces different DNA damage responses in Petunia x hybrida cells

In plants, there is evidence that different dose rate exposures to gamma (γ) rays can cause different biological effects. The dynamics of DNA damage accumulation and molecular mechanisms that regulate recovery from radiation injury as a function of dose rate are poorly explored. To highlight dose-rate dependent differences in DNA damage, single cell gel electrophoresis was carried out on regenerating Petunia x hybrida leaf discs exposed to LDR (total dose 50 Gy, delivered at 0.33 Gy min⁻¹) and HDR (total doses 50 and 100 Gy, delivered at 5.15 Gy min⁻¹) γ-ray in the 0–24 h time period after treatments. Significant fluctuations of double strand breaks and different repair capacities were observed between treatments in the 0–4 h time period following irradiation. Dose-rate-dependent changes in the expression of the PhMT2 and PhAPX genes encoding a type 2 metallothionein and the cytosolic isoform of ascorbate peroxidase, respectively, were detected by Quantitative RealTime-Polymerase Chain Reaction. The PhMT2 and PhAPX genes were significantly up-regulated (3.0- and 0.7-fold) in response to HDR. The results are discussed in light of the potential practical applications of LDR-based treatments in mutation breeding.     

Stereochemistry of C-methylation in the biosynthesis of rhododendrin in Alnus and Betula

Using differently labelled precursors, it was established that rhododendrin (3-(4-hydroxyphenyl)-1-methylpropyl-β-D-glucopyranoside) is formed through the phenylpropane pathway via p-coumaryl alcohol, dihydro-p-coumaryl alcohol and C-methylation of the γ-C-atom of the C₆C₃ unit with methionine supplying the methyl group. It was demonstrated that the pro-(S)-hydrogen atom of dihydro-p-coumaryl alcohol is replaced stereospecifically by the methyl group.     

Hydroxytropane tiglates in the roots of Mandragora species

Roots of Mandragora autumnalis and M. vernalis contain hyoscyamine, hyoscine, cuscohygrine, apoatropine 3α-tigloyloxytropane and 3,6-ditigloyloxytropane. Belladonnine is present in the dried roots but could not be detected in fresh roots. No major differences were found in the alkaloids present in the two species. This is the first time the presence of tiglic acid esters has been reported in Mandragora species and the significance of this in the chemotaxonomy of the genus is indicated.