Rhamnosyltransferases involved in the biosynthesis of flavone rutinosides in Chrysanthemum species

Linarin (acacetin-7-O-rutinoside), isorhoifolin (apigenin-7-O-rutinoside), and diosmin (diosmetin-7-O-rutinoside) are chemically and structurally similar flavone rutinoside (FR) compounds found in Chrysanthemum L. (Anthemideae, Asteraceae) plants. However, their biosynthetic pathways remain largely unknown. In this study, we cloned and compared FRs and genes encoding rhamnosyltransferases (RhaTs) among eight accessions of Chrysanthemum polyploids. We also biochemically characterized RhaTs of Chrysanthemum plants and Citrus (Citrus sinensis and Citrus maxima). RhaTs from these two genera are substrate-promiscuous enzymes catalyzing the rhamnosylation of flavones, flavanones, and flavonols. Substrate specificity analysis revealed that Chrysanthemum 1,6RhaTs preferred flavone glucosides (e.g. acacetin-7-O-glucoside), whereas Cs1,6RhaT preferred flavanone glucosides. The nonsynonymous substitutions of RhaTs found in some cytotypes of diploids resulted in the loss of catalytic function. Phylogenetic analysis and specialized pathways responsible for the biosynthesis of major flavonoids in Chrysanthemum and Citrus revealed that rhamnosylation activity might share a common evolutionary origin. Overexpression of RhaT in hairy roots resulted in 13-, 2-, and 5-fold increases in linarin, isorhoifolin, and diosmin contents, respectively, indicating that RhaT is mainly involved in the biosynthesis of linarin. Our findings not only suggest that the substrate promiscuity of RhaTs contributes to the diversity of FRs in Chrysanthemum species but also shed light on the evolution of flavone and flavanone rutinosides in distant taxa.

The discovery of rhamnosyltransferases in eight accessions of Chrysanthemum species contributes to the biosynthesis of flavone rutinosides and evolution of glycosyltransferases in plants.     

Lipids and sterols of Pinus sylvestris L. sapwood and heartwood

Summary The lipid and sterol content and composition of three lipid fractions (free fatty acids/ sterols, triacylglycerols and sterol/triterpenoid esters) extracted from three stem discs of Pinus sylvestris were assessed to investigate metabolic changes related to heartwood formation. The wood was separated into (1) cambial zone, (2) outer sapwood, (3) inner sapwood, (4) transition zone, (5) outer heartwood and 6) inner heart-wood. The fractions were separated by thin-layer chromatography (TLC) and analysed by gas-liquid chromatography (GLC). The amount of fatty acids of sapwood triacylglycerols was about 1.5% (dry wt.) but a large reduction occurred in the transition zone. In contrast, noticeable amounts of free fatty acids were present only in the heart-wood. The most important fatty acids in the sapwood fractions were 16:0, 18:0, 18:1, 18:2 (the dominant fatty acid in all fractions), 18:3 and 20:3. Together 18:1 and 18:2 formed about 70% of the total triacylglycerol fatty acids. Of the sterol/ triterpenoid esters, 18:2 and 18:3 were predominant. The fatty acid composition of all fractions changed in the transition zone. The sterols found were sitosterol, stigmastanol, campesterol and campestanol. The amount of sterol esters increased towards the heartwood, and the amount of free sterols was lowest in the inner sapwood. Sitosterol was the dominant sterol in both free sterols and sterol esters.     

6-Deoxotyphasterol and 3-Dehydro-6-deoxoteasterone,Possible Precursors to Brassinosteroidsin the Pollen of Cupressus arizonica

Two new congeners (22R,23R,24S)-22,23-dihydroxy-24-methyl-5α-cholestan-3α-ol 2 and (22R,23R,24S)-22,23-dihydroxy-24-methyl-5α-cholestan-3-one 4 that are termed 6-deoxotyphasterol and 3-dehydro-6-eoxoteasterone, respectively, occur in relatively large amounts in the mature pollen of Cupressus arizonica. GC-MS, NMR spectroscopy, the reduction of 4 to 2, and the independent formation of 2 by the reduction of typhasterol were used to identify the new compounds. In the rice lamina bioassay, 2 showed weak activity. 6-Deoxocastasterone, castasterone, typha sterol, an epicastasterone-like compound, teasterone, 28-homocastasterone, 3-dehydroteasterone, brassinolide, and dolichosterone (or 24-epibrassinolide) were also present. These brassinosteroids were identified by co-chromatography with standards after being converted for an HPLC analysis of bioactive fractions. Six other peaks have not yet been assigned. 6-Deoxotyphasterol and 3-dehydro-6-deoxoteasterone should prove useful for exploring the early stages of the biosynthetic pathway(s) to brassinosteroids.     

Generalized host‐plant feeding can hide sterol‐specialized foraging behaviors in bee–plant interactions

Host‐plant selection is a key factor driving the ecology and evolution of insects. While the majority of phytophagous insects is highly host specific, generalist behavior is quite widespread among bees and presumably involves physiological adaptations that remain largely unexplored. However, floral visitation patterns suggest that generalist bees do not forage randomly on all available resources. While resource availability and accessibility as well as nectar composition have been widely explored, pollen chemistry could also have an impact on the range of suitable host‐plants. This study focuses on particular pollen nutrients that cannot be synthesized de novo by insects but are key compounds of cell membranes and the precursor for molting process: the sterols. We compared the sterol composition of pollen from the main host‐plants of three generalist bees: Anthophora plumipes, Colletes cunicularius, and Osmia cornuta, as well as one specialist bee Andrena vaga. We also analyzed the sterols of their brood cell provisions, the tissues of larvae and nonemerged females to determine which sterols are used by the different species. Our results show that sterols are not used accordingly to foraging strategy: Both the specialist species A. vaga and the generalist species C. cunicularius might metabolize a rare C₂₇ sterol, while the two generalist species A. plumipes and O. cornuta might rather use a very common C₂₈ sterol. Our results suggest that shared sterolic compounds among plant species could facilitate the exploitation of multiple host‐plants by A. plumipes and O. cornuta whereas the generalist C. cunicularius might be more constrained due to its physiological requirements of a more uncommon dietary sterol. Our findings suggest that a bee displaying a generalist foraging behavior may sometimes hide a sterol‐specialized species. This evidence challenges the hypothesis that all generalist free‐living bee species are all able to develop on a wide range of different pollen types.     

The diseases of ornamental plants caused by aphelenchoides ritzemabosi in association with fungi

A great importance of Aphelenchoides ritzemahosi in a disease of Callistephus chinensis, Chrysanthemum spp. and Zinnia violaceae was found. In the disease process caused by the nematode, fungi of different parasitic abilities participated, e.g., Septoria chrysanthemella frequently attacked varieties of the genus Chrysanthemum, whereas Fusarium spp. affected C. chinensis. Longer rainy periods stimulated the development of higher epidemics of gray mold. Aphelenchoides ritzemabosi occasionally fed on hyphae that along with metabolities excreted into a medium differently influenced the nematode. Aphelenchoides ritzemabosi survived up to some years in a plant material. The phylloplane mycoflora population increased quantitatively and qualitatively when the plants aged. Filamentous fungi increased the necrosis of plants affected by the nematode. Fungi testing Botrytis cinerea showed a different potential of an antagonistic influence. Gonatobotrys simplex parasitized on Alternaria zinniae.     

Phylogeny of the Genus Chrysanthemum L.: Evidence from Single-Copy Nuclear Gene and Chloroplast DNA Sequences

Chrysanthemum L. (Asteraceae-Anthemideae) is a genus with rapid speciation. It comprises about 40 species, most of which are distributed in East Asia. Many of these are narrowly distributed and habitat-specific. Considerable variations in morphology and ploidy are found in this genus. Some species have been the subjects of many studies, but the relationships between Chrysanthemum and its allies and the phylogeny of this genus remain poorly understood. In the present study, 32 species/varieties from Chrysanthemum and 11 from the allied genera were analyzed using DNA sequences of the single-copy nuclear CDS gene and seven cpDNA loci (psbA-trnH, trnC-ycf6, ycf6-psbM, trnY-rpoB, rpS4-trnT, trnL-F, and rpL16). The cpDNA and nuclear CDS gene trees both suggest that 1) Chrysanthemum is not a monophyletic taxon, and the affinity between Chrysanthemum and Ajania is so close that these two genera should be incorporated taxonomically; 2) Phaeostigma is more closely related to the Chrysanthemum+Ajania than other generic allies. According to pollen morphology and to the present cpDNA and CDS data, Ajania purpurea is a member of Phaeostigma. Species differentiation in Chrysanthemum appears to be correlated with geographic and environmental conditions. The Chinese Chrysanthemum species can be divided into two groups, the C. zawadskii group and the C. indicum group. The former is distributed in northern China and the latter in southern China. Many polyploid species, such as C. argyrophyllum, may have originated from allopolyploidization involving divergent progenitors. Considering all the evidence from present and previous studies, we conclude that geographic and ecological factors as well as hybridization and polyploidy play important roles in the divergence and speciation of the genus Chrysanthemum.     

Volatile and Non-volatile Forms of Aroma Compounds in Tea Leaves and Their Changes due to Injury

Fresh tea leaves were homogenized in a chloroform-methanol mixture (1:1, v/v), and separated into chloroform-soluble and methanol-water-soluble fractions after addition of water. From the chloroform-soluble fraction, the volatile forms of the aroma compounds were obtained. The non-volatile forms of the aroma compounds were associated with the methanol-water-soluble fraction, and were converted to volatile forms by hydrolysis with dilute acid.

The amount of the aroma compounds in the free form, such as cis-3-pentenol, hexanol, cis-3-hexenol, trans-2-hexenol, linalool, linalool oxide (cis, 5-membered), linalool oxide (trans, 5-membered), linalool oxide (trans, 6-rnembered), linalool oxide (cis, 6-membered), nerol, geraniol, phenylmethanol, and 2-phenylethanol, markedly increased during black tea manufacture. However, those in the bound form, showed a slight decrease during the manufacture. The increases in the former were also brought about by maceration, or treatment of the tea leaves with monoiodoacetate or malonate.     

UNUSUAL DIHYDROXYSTEROLS AS CHEMOTAXONOMIC MARKERS FOR MICROALGAE FROM THE ORDER PAVLOVALES (HAPTOPHYCEAE)1

Recent studies have led to the identification of an unusual class of dihydroxysterols (steroidal diols termed “pavlovols”)in a few species of microalgae from the genus Pavlova (family Pavlovaceae, class Haptophyceae = Prymnesiophyceae). These compounds have an additional hydroxyl group at G-4 in the sterol A ring, which appears to be very rare in sterol biosynthetic pathways. The sterol compositions of many other haptophytes from different orders have been analyzed, but to date all have lacked pavlovols. We now report the occurrence of these compounds in Diacronema vlkianum Prauser and two strains of Pavlova pinguis Green. This is the first report of the lipid composition of these species. Both microalgae contained “24-methylpavlovol” (4α, 24-dimethyl-5α-cholestan-3β, 4β-diol), P. pinguis also contained “24-ethylpavlovol” (4α-methyl-24-ethyl-5α-cholestan-3β, 4β-diol), and D. vlkianum contained a diol identified from its mass spectrum as 4α, 24β-dimethyl-5α-cholest-22E-en-3β,4β-diol. Both species contained structurally analogous 4-desmethyl sterols and 4-methyl sterols, although there were major differences in the proportions in each series. The major 4-desmethyl sterol in both species was 24-ethylcholesta-5, 22E-dien-3β-ol and the major 4-methyl sterol was 4α-methyl-24-ethyl-5α-cholest-22E-en-3β-ol. The presence of pavlovols in P. pinguis, combined with earlier data, suggests that all Pavlova species might have this distinguishing lipid feature. However, their identtjication in D. vlkianum extends the occurrence of these compounds to another genus and shows that they are not unique to the genus Pavlova. However, they are probably restricted to species from the order Pavlov ales. The modes of biosynthesis and functions of pavlovols remain unknown.     

Effects of treatment with phenylthiosemicarbazide and 4'-chlorophenylthiosemicarbazide on Fusarium wilt of pea and tomato plants

Effects of treatment with phenylthiosemicarbazide (PTS) and its 4′-chloro-derivative (4′-chloro-PTS) on Fusarium wilt of pea and tomato plants were investigated. Depending on pH and availability of oxygen, PTS and 4′-chloro-PTS are converted to their corresponding phenylazothioformamides and phenylazothioformamide-S-oxides, which are the actual fungitoxic compounds. PTS and 4′-chloro-PTS were shown to inhibit growth of Fusarium oxysporum f. pisi and F. oxysporum f. lycopersici in liquid media as well as on agar plates at concentrations of 50–100 mg/1. Inhibition was greater at pH 7 than at pH 5. When administered to pea and tomato plants, both compounds caused severe phytotoxic effects, especially at temperatures favouring Fusarium wilt, thus almost entirely obscuring any protective activity against the diseases. All compounds were strongly adsorbed to loam, but readily released from sand. Neither in pea nor in tomato plants were PTS and 4′-chloro-PTS converted to any fungitoxic substance, not already present in the aqueous solutions administered.     

Identification of anti-inflammatory constituents in Hypericum perforatum and Hypericum gentianoides extracts using RAW 264.7 mouse macrophages

Hypericum perforatum (St. John’s wort) is an herb widely used as supplement for mild to moderate depression. Our prior studies established synergistic anti-inflammatory activity associated with 4 bioactive compounds in a fraction of a H. perforatum ethanol extract. Whether these 4 compounds also contributed to the ethanol extract activity was addressed in the research reported here. Despite the popularity of H. perforatum, other Hypericum species with different phytochemical profiles could have their anti-inflammatory potentials attributed to these or other compounds. In the current study, ethanol extracts of different Hypericum species were compared for their inhibitory effect on LPS-induced prostaglandin E2 (PGE2) and nitric oxide (NO) production in RAW 264.7 mouse macrophages. Among these extracts, those made from H. perforatum and H. gentianoides demonstrated stronger overall efficacy. LC–MS analysis established the 4 compounds were present in the H. perforatum extract and pseudohypericin in all active fractions. The 4 compounds accounted for a significant part of the extract’s inhibitory activity on PGE2, NO, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in RAW 264.7 as well as peritoneal macrophages. Pseudohypericin was the most important contributor of the anti-inflammatory potential among the 4 compounds. The lipophilic fractions of H. gentianoides extract, which did not contain the previously identified active constituents, decreased PGE2 and NO potently. These fractions were rich in acylphloroglucinols, including uliginosin A that accounted for a proportion of the anti-inflammatory activity observed with the active fractions. Overall, the current study established that a different group of major anti-inflammatory constituents were present in H. gentianoides, while showing that the previously identified 4 compound combination was important for H. perforatum’s anti-inflammatory potential.     

The chemical world of crucivores: lures, treats and traps

Papilio polytes utilizes only a few plant species of Rutaceae as hosts in the field. We examined in detail the acceptability of Toddalia asiatica (a major host plant) and three other potential rutaceous hosts, Murraya paniculata, Melicope triphylla, and Phellodendron amurense, for ovipositing females of the butterfly. Female responses to the foliage, methanol extracts, and partitioned fractions from these plants were assayed for the presence of oviposition stimulants and/or deterrents. Larval survivorship on these plant species was also compared as an estimate of fitness. The foliage and a methanol extract of T. asiatica readily induced egg-laying, while females responded moderately to the foliage and a methanol extract of P. amurense. By contrast, ovipositing females only marginally accepted Me. triphylla and completely rejected Mu. paniculata. Further experiments to test the biological activity of fractions derived from the respective plant species revealed that T. asiatica contains potent oviposition stimulant(s) and that weak stimulant(s) are present in P. amurense. Poor or negative oviposition responses to both Me. triphylla and Mu. paniculata proved to be attributable to strong deterrent(s) present in these plants. Larvae performed very well on T. asiatica and P. amurense, whereas larval mortality was much higher on Mu. paniculata and Me. triphylla, suggesting the involvement of antifeedant(s) or toxic substance(s) in these plants.     

Metabolic engineering of soybean affords improved phytosterol seed traits

Different combinations of three rate‐limiting enzymes in phytosterol biosynthesis, the Arabidopsis thaliana hydroxyl methylglutaryl CoA1 (HMGR1) catalytic subunit linked to either constitutive or seed‐specific β‐conglycinin promoter, and the Glycine max sterol methyltransferase1 (SMT1) and sterol methyltransferase2‐2 (SMT2‐2) genes, under the control of seed‐specific Glycinin‐1 and Beta‐phaseolin promoters, respectively, were engineered in soybean plants. Mature seeds of transgenic plants displayed modest increases in total sterol content, which points towards a tight control of phytosterol biosynthesis. However, in contrast to wild‐type seeds that accumulated about 35% of the total sterol in the form of intermediates, in the engineered seeds driven by a seed‐specific promoter, metabolic flux was directed to Δ⁵‐24‐alkyl sterol formation (99% of total sterol). The engineered effect of end‐product sterol (sitosterol, campesterol, and stigmasterol) over‐production in soybean seeds resulted in an approximately 30% increase in overall sitosterol synthesis, a desirable trait for oilseeds and human health. In contradistinction, increased accumulation of cycloartenol and 24(28)‐methylencylartanol (55% of the total sterol) was detected in plants harbouring the constitutive t‐HMGR1 gene, consistent with the previous studies. Our results support the possibility that metabolic flux of the phytosterol family pathway is differentially regulated in leaves and seeds.     

Food attractants and a pheromone as trail-following substances for the Saintonge termite multiplicity of the trail-following substances in L. Trabea-infected wood

Column chromatography of the unsaponifiable lipids from pine wood, on which the fungus Lenzites trabea was cultured, yielded two well-separated fractions, which were highly active in choice tests as well as in a trail-following test with the termite Reticulitermes lucifugus var. santonensis (Feytaud).Thin layer and gas chromatography confirmed that these fractions contained distinctly different active compounds. Column chromatography of the non-saponifiable lipids of the worker termites yielded only one active fraction, which corresponded to one of the fractions obtained from the wood. These results are in agreement with the opinion of Smythe et al., (1967), that a trail-following pheromone may at the same time be a food attractant. Our data show, however, that the food contains more than one highly active trail-following substance. Comparison of gas chromatographic data showed that cis-3, cis-6, trans-8-dodecatrien-1-ol, described by Matsumura et al. in 1968, may be present in one of these fractions.

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Résumé Le champignon Lenzites trabea a été cultivé sur le bois de Pinus silvestris, qui, en conséquence, devient attractif pour le termite de Saintonge, Reticulitermes lucifugus var. santonensis.Le bois attaqué est soumis à une distillation par la vapeur d'eau et le distillat est extrait avec l'hexane. La saponification de cet extrait et la séparation des lipides non-saponifiables donnent un produit très actif dans des tests de choix et dans un essai quantitatif pour des substances de pistage. Par la chromatographie sur colonne de ces lipides on a obtenu deux fractions très actives. Une de celles-ci est semblable à la fraction active obtenue par une méthode analogue, à partir d'extraits d'ouvriers du Termite de Saintonge. La chromatographie en phase gazeuse démontre qu'une des fractions des lipides du bois peut contenir la substance de pistage, cis-3, cis-6, trans-8-dodecatrièn-1-ol, qui a été décrite par Matsumura en 1968.L'autre fraction se comporte différemment, non seulement en chromatographie sur colonne, mais aussi en chromatographie en phase gazeuse et sur couche mince. Néanmoins elle aussi est fort active dans des tests de choix et dans l'essai de pistage.Les résultats indiquent que la phéromone de pistage du termite de Saintonge est aussi présente dans le bois attaqué par le champignon, qui peut être considéré comme une source de nourriture du termite. En outre les résultats démontrent que ce bois contient au moins une autre substance très active.

     

Evidence for the existence of a universal crown-gall tumor initiation enhancer

Tumor initiation of different dicotyledonous plant species inoculated with Agrobacterium tumefaciens B₆ has been studied in vivo and in vitro. The tumor formation in weakly susceptible plants can be strongly enhanced by exogenously applied active extract fractions derived from highly susceptible Helianthus cotyledons. It is found that highly susceptible plants (Kalanchoë, Lycopersicon and Pinto beans) contain an active tumor initiation enhancer which is clearly similar to the compound(s) found in Helianthus cotyledons. No activity can be detected in extracts derived from weakly susceptible plants (Coleus, Phaseolus) or in those obtained from crown-gall tumor tissues.Abbreviations HS high susceptibility for tumor initiation - LS low susceptibility for tumor initiation - PEF purified active extract fraction     

GENETIC DIVERGENCE AMONG MEDITERRANEAN AND MACARONESIAN GENERA OF THE SUBTRIBE CHRYSANTHEMINAE (ASTERACEAE)

Genetic variation at 17 isozyme loci was used to assess divergence among the four genera comprising subtribe Chrysantheminae (Anthemideae: Asteraceae). The Macaronesian endemic genus Argyranthemum is supported as monophyletic and is about equally divergent at isozyme loci from the other three genera of the Chrysantheminae, Chrysanthemum, Heteranthemis, and Ismelia. Chrysanthemum is native to the Mediterranean whereas Heteranthemis occurs in southern Iberia and Morocco, and Ismelia is endemic to Morocco. The genera Chrysanthemum and Ismelia have a genetic identity of 0.9283, which is comparable to values often seen for congeneric species and indicates that they should be treated as one genus. The isozyme data indicate that three lines consisting of Argyranthemum, Chrysanthemum-Ismelia, and Heteranthemis radiated rapidly from a common ancestor. Divergence times estimated from isozyme data suggest that the initial radiation of the three lines occurred 2.5–3.0 mya. If this is so, then Argyranthemum or its ancestor arrived in Macaronesia after all the islands except La Palma and El Hierro were formed. The evolutionary history of the subtribe is discussed in relation to the climatic and geological events that took place in the Western Mediterranean between the Tertiary and Quaternary, i.e., the first Northern Hemisphere glaciation and desertification of the Sahara region. The high mean genetic identities between species of Argyranthemum suggest that it might have subsequently undergone a second more recent radiation in the Macaronesian Islands. Also, the high mean identity (0.860) between populations in Chrysanthemum and Ismelia suggest that these continental genera might be in the early stages of secondary speciation.     

Characterization of antifungal glycoprotein in red-light-irradiated broadbean leaflets

 Red-light treatment of broadbean leaflets resulted in the production of antifungal substance(s) against Botrytis cinerea. The antifungal substance(s) was positively charged, as the antifungal constituent was removed by the cation exchanger CM cellulose. Treatment of infection droplets with glycosidases (α-mannosidase, β-galactosidase, β-glucosidase), glycol-specific reagent periodate (NaIO₄), and proteinase K completely eliminated antifungal activity, suggesting that both protein and carbohydrate are active components. The protein content of infection droplets was 0.148 mg/ml. The HPLC gel column analysis of infection droplets resulted in four fractions; all the fractions showed antifungal activity. Received: June 14, 2002 / Accepted: August 12, 2002 Correspondence to:Y. Honda     

Mapping of multiple mouse loci related to the farnesyl pyrophosphate synthetase gene

The prenyltransferases are a class of enzymes involved in the synthesis of sterol and nonsterol isoprene compounds. We report here the chromosomal mapping of nine loci in the mouse that hybridize to the cDNA for the enzyme farnesyl pyrophosphate synthetase (FPS), a prenyltransferase that catalyzes the synthesis of an intermediate common to both the sterol and nonsterol branches of the isoprene biosynthetic pathway. Mapping was performed with genomic DNA from a mouse-hamster somatic cell hybrid panel, and by linkage analysis with recombinant inbred strains and the progeny of an interspecific backcross. The mapped loci have been designated farnesyl pyrophosphate synthetase-like-1 (Fpsl-1) on mouse Chromosome (Chr) 3; Fpsl-2 on Chr 4; Fpsl-3, Fpsl-4, and Fpsl-5, dispersed on Chr 10; Fpsl-6 on Chr 12; Fpsl-7 on Chr 13; Fpsl-8 on Chr 17; and Fpsl-9 on Chr X. It is presently unclear which of these loci encode active prenyltransferases and which may correspond to pseudogenes. The strongly hybridizing loci provide convenient genetic markers for seven mouse chromosomes.     

Genes encoding chimeras of<Emphasis Type="Italic">Neurospora crassa erg-3</Emphasis> and human TM7SF2 proteins fail to complement Neurospora and yeast sterol C-14 reductase mutants

The human gene TM7SF2 encodes a polypeptide (SR-1) with high sequence similarity to sterol C-14 reductase, a key sterol biosynthetic enzyme in fungi, plants and mammals. In Neurospora and yeast this enzyme is encoded by theerg-3 anderg24 genes respectively. In an effort to demonstrate sterol C-14 reductase activity for SR-1 we constructed six recombinant genes coding for chimeras of the Neurosporaerg-3 and SR-1 protein sequences and tested them for complementation of the Neurosporaerg-3 mutant. To our surprise, all the chimeras failed to complementerg-3. A few of the chimeric proteins were also tested against the yeasterg24 mutant, but again there was no complementation. We discuss some reasons that might account for these unexpected findings     

A sterol biosynthetic geneAtCYP51A2 promoter for constitutive and ectopic expression of a transgene in plants

Arabidopsis CYP51A2 (AtCYP51A2) mediates the sterol 14α-demethylation step inde novo sterol biosynthesis, and is constitutively and highly expressed in all plant tissues (Kim et al., 2005). We exploited the molecular features of its expression and the fundamental role of sterol biosynthesis in cells to develop a plant-derived promoter. Our GUS expression analysis between transgenicArabidopsis lines forAtCYP51A2::GUS and35S::GUS revealed that activity of theAtCYP51A2 promoter was comparable to that of the35S promoter, based on enzymatic activities and protein levels. TheAtCYP51A2 promoter was also constitutively active in transgenic tobacco, indicating that 5′ regulatory elements could be conserved amongCYP51 promoters in dicot plants. A homologue ofAtCYP51A2 was identified from rape seed, a crop species closely related toArabidopsis. Its constitutive tissue expression pattern implies that the application of thisAtCYP51A2 promoter is possible for that species. Based on these results, we present a new binary vector system with the plant-derivedAtCYP51A2 promoter, which is able to constitutively and ectopically drive a transgene in various dicotyledonous plants. These two authors are equally contributed to this work.     

Peroxidasemuster und Systematik vonArgyranthemum undChrysanthemum s. str. (Asteraceae-Anthemideae)

Leaf extracts of several taxa ofArgyranthemum (nanophaneroand chamaephytes endemic to the Macaronesian Islands) andChrysanthemum s. str. (therophytes of the West Mediterranean region) were subjected to polyacrylamide disc gel electrophoresis and analysis of peroxidase isoenzymes. The differences between the two genera are small; this points to their close affinity. The taxonomic subdivision ofChrysanthemum s. str. is confirmed. ForArgyranthemum the inclusion ofA. callichrysum andA. ochroleucum into sect.Ismelia is suggested.A. foeniculaceum may fit better into the otherwise isolated sect.Monoptera but somewhat approaches sect.Ismelia. Isoenzyme patterns inA. frutescens s. l. seem to reflect a geographical differentiation of the group on 5 Canary Islands.