Capability of wild Rosa rugosa and its varieties and hybrids to produce sesquiterpene components in leaf glandular trichomes.
The sesquiterpene contents in leaves of wild Rosa rugosa and of sixty-one hybrid rugosas were quantitatively measured by a GC analysis. In this group of samples, the greater the number of glandular trichomes the hybrid rugosas possessed on their leaves, the larger the amount of sesquiterpenes they accumulated. In contrast, those having no leaf glandular hairs contained only a trace amount of sesquiterpene components. The concentrations of bisaborosaol A (1) and carota-1,4-dienaldehyde (2) as representative sesquiterpenes of R. rugosa were positively correlated with the density of the glandular trichomes. Furthermore, an approximately regular correlation was observed between the concentrations of 1 and 2 in most of the sesquiterpene-producing hybrid rugosas, regardless of their productivity. This suggests that a major part of these hybrid rugosas have inherited from R. rugosa the ability to produce two skeletally different sesquiterpenes in parallel with a phenotype to develop leaf glandular trichomes. This investigation also led to discovering 1-dominant (e.g., Amelie Gravereaux and Purple Pavement), 2-dominant (e.g., David Thompson), and other-dominant (e.g., Martin Frobisher) types of sesquiterpene-producing hybrid rugosas. (+info)
Molecular comparison of pathogenic bacteria from pear trees in Japan and the fire blight pathogen Erwinia amylovora.
Several strains of the genus Erwinia, which were isolated in Japan from pear trees with necrotic symptoms that resembled fire blight, and tentatively identified as Erwinia amylovora, were reinvestigated for their relationship to the fire blight pathogen. These isolates produced ooze on slices of immature pears and were mucoid on MM2Cu agar plates, but did not synthesize levan and did not give the expected PCR signals with several primer pairs specific for Erwinia amylovora. The isolates tested positive with PCR primers designed to detect the novel pear pathogen Erwinia pyrifoliae, which was isolated from Nashi pear trees in South Korea. The nucleotide sequence analysis of a DNA fragment preceding the gene cluster for exopolysaccharide synthesis revealed a closer relationship to Erwinia pyrifoliae than to Erwinia amylovora. Plasmid profiles, protein patterns and genomic DNA analysed by PFGE after XbaI and SpeI digestion were different than Erwinia amylovora. Experiments with strains of Erwinia amylovora isolated from raspberry (Rubus sp.), Erwinia mallotivora and Enterobacter pyrinus also did not reveal a relationship between these bacteria and the Japanese Erwinia strains. The latter are not identical to Erwinia pyrifoliae, but possess many similar features to this pathogen that causes Asian pear blight. It is concluded that pathogenic bacteria isolated in Japan from pear trees with symptoms resembling fire blight are possibly different from Erwinia amylovora. (+info)
Quantitative determination of flavonoids in the flowers and leaves of Prunus spinosa L.
The content of flavonoids in the flowers and leaves of Prunus spinosa L. was determined by spectrophotometric and RP-HPLC method. Determinations included hydrolysis of flavonoid glycosides in extracts from raw materials and then quantitative analysis of the obtained aglycones. Results were calculated for the content of glycosides and statistical analysis of the obtained data was performed. (+info)
Characterization and complete nucleotide sequence of Strawberry mottle virus: a tentative member of a new family of bipartite plant picorna-like viruses.
An isolate of Strawberry mottle virus (SMoV) was transferred from Fragaria vesca to Nicotiana occidentalis and Chenopodium quinoa by mechanical inoculation. Electron micrographs of infected tissues showed the presence of isometric particles of approximately 28 nm in diameter. SMoV-associated tubular structures were also conspicuous, particularly in the plasmodesmata of C. quinoa. DsRNA extraction of SMoV-infected N. occidentalis yielded two bands of 6.3 and 7.8 kbp which were cloned and sequenced. Gaps in the sequence, including the 5' and 3' ends, were filled using RT-PCR and RACE. The genome of SMoV was found to consist of RNA1 and RNA2 of 7036 and 5619 nt, respectively, excluding a poly(A) tail. Each RNA encodes one polyprotein and has a 3' non-coding region of approximately 1150 nt. The polyprotein of RNA1 contains regions with identities to helicase, viral genome-linked protein, protease and polymerase (RdRp), and shares its closest similarity with RNA1 of the tentative nepovirus Satsuma dwarf virus (SDV). The polyprotein of RNA2 displayed some similarity to the large coat protein domain of SDV and related viruses. Phylogenetic analysis of the RdRp region showed that SMoV falls into a separate group containing SDV, Apple latent spherical virus, Naval orange infectious mottling virus and Rice tungro spherical virus. Given the size of RNA2 and the presence of a long 3' non-coding region, SMoV is more typical of a nepovirus, although atypically for a nepovirus it is aphid transmissible. We propose that SMoV is a tentative member of an SDV-like lineage of picorna-like viruses. (+info)
Hawthorn fruit is hypolipidemic in rabbits fed a high cholesterol diet.
The present study examined the hypolipidemic activity of hawthorn fruit. New Zealand white rabbits were fed one of three diets, a reference diet with no cholesterol added (NC), a high cholesterol diet (1 g/100 g, HC) and a HC diet supplemented with 2 g/100 g hawthorn fruit powder (HC-H). After 12 wk, serum total cholesterol (TC) and triacylglycerols (TG) were 23.4 and 22.2% lower, respectively, in the hawthorn fruit group compared with the HC rabbits (P < 0.05). Hawthorn supplementation led to 50.6% less cholesterol accumulation in aorta (P < 0.05) and 23-95% greater excretion of neutral and acidic sterols (P < 0.05). Supplementation of hawthorn fruit did not affect the activities of hepatic 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMG-CoA-R) or cholesterol 7alpha-hydroxylase (CH) but it suppressed the activity of intestinal acyl CoA:cholesterol acyltransferase (ACAT, P < 0.05). The results suggest that the mechanism by which hawthorn fruit decreases serum cholesterol involves, at least in part, the inhibition of cholesterol absorption mediated by down-regulation of intestinal ACAT activity. (+info)
Manipulation of strawberry fruit softening by antisense expression of a pectate lyase gene.
Strawberry (Fragaria x ananassa, Duch., cv Chandler) is a soft fruit with a short postharvest life, mainly due to a rapid lost of firm texture. To control the strawberry fruit softening, we obtained transgenic plants that incorporate an antisense sequence of a strawberry pectate lyase gene under the control of the 35S promoter. Forty-one independent transgenic lines (Apel lines) were obtained, propagated in the greenhouse for agronomical analysis, and compared with control plants, non-transformed plants, and transgenic lines transformed with the pGUSINT plasmid. Total yield was significantly reduced in 33 of the 41 Apel lines. At the stage of full ripen, no differences in color, size, shape, and weight were observed between Apel and control fruit. However, in most of the Apel lines, ripened fruits were significantly firmer than controls. Six Apel lines were selected for further analysis. In all these lines, the pectate lyase gene expression in ripened fruit was 30% lower than in control, being totally suppressed in three of them. Cell wall material isolated from ripened Apel fruit showed a lower degree of in vitro swelling and a lower amount of ionically bound pectins than control fruit. An analysis of firmness at three different stages of fruit development (green, white, and red) showed that the highest reduction of softening in Apel fruit occurred during the transition from the white to the red stage. The postharvest softening of Apel fruit was also diminished. Our results indicate that pectate lyase gene is an excellent candidate for biotechnological improvement of fruit softening in strawberry. (+info)
A systematic screening of total antioxidants in dietary plants.
A predominantly plant-based diet reduces the risk for development of several chronic diseases. It is often assumed that antioxidants contribute to this protection, but results from intervention trials with single antioxidants administered as supplements quite consistently do not support any benefit. Because dietary plants contain several hundred different antioxidants, it would be useful to know the total concentration of electron-donating antioxidants (i.e., reductants) in individual items. Such data might be useful in the identification of the most beneficial dietary plants. We have assessed systematically total antioxidants in a variety of dietary plants used worldwide, including various fruits, berries, vegetables, cereals, nuts and pulses. When possible, we analyzed three or more samples of dietary plants from three different geographic regions in the world. Total antioxidants was assessed by the reduction of Fe(3+) to Fe(2+) (i.e., the FRAP assay), which occurred rapidly with all reductants with half-reaction reduction potentials above that of Fe(3+)/Fe(2+). The values, therefore, expressed the corresponding concentration of electron-donating antioxidants. Our results demonstrated that there is more than a 1000-fold difference among total antioxidants in various dietary plants. Plants that contain most antioxidants included members of several families, such as Rosaceae (dog rose, sour cherry, blackberry, strawberry, raspberry), Empetraceae (crowberry), Ericaceae (blueberry), Grossulariaceae (black currant), Juglandaceae (walnut), Asteraceae (sunflower seed), Punicaceae (pomegranate) and Zingiberaceae (ginger). In a Norwegian diet, fruits, berries and cereals contributed 43.6%, 27.1% and 11.7%, respectively, of the total intake of plant antioxidants. Vegetables contributed only 8.9%. The systematic analysis presented here will facilitate research into the nutritional role of the combined effect of antioxidants in dietary plants. (+info)
Inheritance of the chloroplast genome in Sorbus aucuparia L. (Rosaceae).
Chloroplast DNA (cpDNA) inheritance was investigated in Sorbus aucuparia using progenies obtained from six controlled crosses between individuals of known haplotype. Polymerase chain reaction (PCR) amplification, followed by restriction analysis, was used to characterize 248 offspring for either of two polymorphic cpDNA fragments. All offspring exhibited the maternal haplotype, which indicates maternal inheritance of chloroplasts in S. aucuparia. Power analysis of the test showed that the frequency of paternal transmission of chloroplasts, if any, should not exceed 1.84% (with 99% confidence). (+info)