Variation of sesquiterpene lactone contents in Lactuca altaica natural populations from Armenia

In recent years we initiated extensive studies on the characterization of the population structure of wild Lactuca relatives (WLRs) originating from their center of origin and diversity in Southwest Asia. A comparative phytochemical study of nine sesquiterpene lactones in natural populations of the wild lettuce L. altaica Fisch. & C.A. Mey. (Asteraceae) was performed, based on 22 plants, representing seven original individual seed samples derived from three localities representing three regions in Armenia. The compounds were profiled and quantified in leaves and roots of the plants, grown in a controlled glasshouse. The contents of major sesquiterpene lactones, that including the following eight guaianolides: cichorioside B, lactucin, 11β,13-dihydrolactucin, crepidiaside B, 8-deoxylactucin, jacquinelin, lactucopicrin/11β,13-dihydrolactucopicrin, as well as the germacranolide glucoside – lactuside A, were estimated by HPLC/PDA. The L. altaica plants could be characterized by the occurrence of lactuside A in their roots, and the mixture of lactucopicrin/11β,13-dihydrolactucopicrin in both their roots and leaves by relatively high amounts, similarly to results obtained for three commercial cultivars of L. sativa. The total content of sesquiterpene lactones in the roots was significantly higher than that in the leaves. This study is likely the first report of detailed screening of L. altaica natural populations and individuals, even by low sample size, for any trait. Species within the primary lettuce gene pool, should be considered as an attractive source of germplasm in further research and improvement of cultivated lettuce, Lactuca sativa L. While using interspecific hybridization in order to elevate the sesquiterpene levels in cultivated lettuces, the lactones quality (profile) and quantity, as well as the cross-ability level of the wild Lactuca spp. with the crop and fertility of the obtained offspring should be considered.     

Variation of bioactive substances and morphological traits in Hypericum perforatum populations from Northern Turkey

Hypericum perforatum L. has become one of the leading plant-based dietary supplements worldwide and its biological activities have been mainly attributed to hypericin and phenolic contents. The present study was conducted to determine chemical and morphological variability of H. perforatum sampled from different locations of Northern Turkey. The populations were investigated according to the hypericin, chlorogenic acid and the flavonoids, namely rutin, hyperoside, apigenin-7-O-glucoside, quercitrin and quercetin contents and morphological characters including leaf dark gland density, leaf area, leaf length/width ratio and plant height. Significant chemical and morphological variations were detected among the populations. Hypericin content among populations ranged between 0.44 and 2.82 mg/g dry weight, chlorogenic acid between 0.0 and 1.86 mg/g dry weight, rutin between 0.0 and 8.77 mg/g dry weight, hyperoside between 5.41 and 22.28 mg/g dry weight, quercitrin between 1.64 and 3.98 mg/g dry weight and quercetin between 1.01 and 1.76 mg/g dry weight. Hypericin content was found to be correlated positively with leaf dark gland density, however, negatively with leaf area and no correlation was detected between the other morphological traits and bioactive substances examined.     

RAPD polymorphism of wild emmer wheat populations, Triticum dicoccoides, in Israel

 Genetic diversity in random amplified polymorphic DNAs (RAPDs) was studied in 110 genotypes of the tetraploid wild progenitor of wheat, Triticum dicoccoides, from 11 populations sampled in Israel and Turkey. Our results show high level of diversity of RAPD markers in wild wheat populations in Israel. The ten primers used in this study amplified 59 scorable RAPD loci of which 48 (81.4%) were polymorphic and 11 monomorphic. RAPD analysis was found to be highly effective in distinguishing genotypes of T. dicoccoides originating from diverse ecogeographical sites in Israel and Turkey, with 95.5% of the 100 genotypes correctly classified into sites of origin by discriminant analysis based on RAPD genotyping. However, interpopulation genetic distances showed no association with geographic distance between the population sites of origin, negating a simple isolation by distance model. Spatial autocorrelation of RAPD frequencies suggests that migration is not influential. Our present RAPD results are non-random and in agreement with the previously obtained allozyme patterns, although the genetic diversity values obtained with RAPDs are much higher than the allozyme values. Significant correlates of RAPD markers with various climatic and soil factors suggest that, as in the case of allozymes, natural selection causes adaptive RAPD ecogeographical differentiation. The results obtained suggest that RAPD markers are useful for the estimation of genetic diversity in wild material of T. dicoccoides and the identification of suitable parents for the development of mapping populations for the tagging of agronomically important traits derived from T. dicoccoides. Received: 13 July 1998 / Accepted: 13 August 1998     

Microsatellite polymorphism in natural populations of wild emmer wheat,Triticum dicoccoides,in Israel

Diversity in 20 microsatellite loci of wild emmer wheat, Triticum dicoccoides, was examined in 15 populations (135 genotypes) representing a wide range of ecological conditions of soil, temperature, and water availability, in Israel and Turkey. An extensive amount of diversity at microsatellite loci was observed despite the predominantly selfing nature of this plant species. The 20 Gatersleben wheat microsatellites (GWM), representing 13 chromosomes of genomes A and B of wheat, revealed a total of 364 alleles, with an average of 18 alleles per GWM marker (range: 5–26). The proportion of polymorphic loci per population averaged 0.90 (range: 0.45– 1.00); genic diversity, He, averaged 0.50 (range 0.094– 0.736); and Shannon’s information index averaged 0.84 (range 0.166–1.307). The coefficients of genetic distance between populations were high and averaged D=1.862 (range 0.876–3.320), an indication of sharp genetic divergence over short distances. Interpopulation genetic distances showed no association with geographic distance between the population sites of origin, which ruled out a simple isolation by distance model. Genetic dissimilarity values between genotypes were used to produce a dendrogram of the relationships among wild wheat populations by the unweighted pair-group method with arithmetic averages (UPGMA). The results showed that all the wild emmer wheat populations could be distinguished. Microsatellite analysis was found to be highly effective in distinguishing genotypes of T. dicoccoides, originating from diverse ecogeographical sites in Israel and Turkey, with 88% of the 135 genotypes correctly classified into sites of origin by discriminant analysis. Our present microsatellite results are non-random and in agreement with the previously obtained allozyme and RAPD patterns, although the genetic-diversity values obtained with microsatellites are much higher. Significant correlates of microsatellite markers with various climatic and soil factors suggest that, as in allozymes and RAPDs, natural selection causes adaptive microsatellite ecogeographical differentiation, not only in coding, but most importantly in non-coding genomic regions. Hence, the concept of ”junk DNA” needs to be replaced by at least partly regulatory DNA. The obtained results suggest that microsatellite markers are useful for the estimation of genetic diversity in natural populations of T. dicoccoides and for the tagging of agronomically important traits derived from wild emmer wheat. Received: 27 February 2001 / Accepted: 22 March 2001     

锥栗自然居群遗传多样性的ISSR分析

采用20条ISSR分子标记对栗属中国特有种-锥栗(Castanea henryi)的16个自然居群进行了遗传多样性与遗传关系分析。在449份试材上共扩增得到379个位点,其中多态性位点378个,多态性位点百分率(PPL)达99.74%,平均期望杂合度(He)为0.2950,Shannon信息指数(I)为0.4522;居群水平遗传多样性为46.09%,且不同居群遗传多样性水平有较大差异,16个自然居群中以湘西居群的遗传多样性水平最高(PPL=53.30%,He=0.1861,I=0.2781),其次为靖州、庆元、昭通及都江堰居群,南平居群最低(PPL=36.94%,He=0.1202,I=0.1817)。Nei’s遗传多样性和AMOVA分析表明,居群间产生了较大的遗传分化(Gst=0.4466),锥栗自然居群内的遗传变异稍占优势(52.51%)。UPGMA聚类分析将16个锥栗居群分为2大类5亚类。湘西地区可能是锥栗的次生分布中心和现代遗传多样性分布中心,是锥栗研究的资源中心,也是最有价值的基因库,需要重点保护。     

The frequency distribution of Hymenolepis diminuta cysticercoids in natural,sympatric populations of Tenebrio molitor and T. obscurus

Rau M. E. 1979. The frequency distribution of Hymenolepis diminuta cysticercoids in natural, sympatric populations of Tenebrio molitor and T. obscurus. International Journal for Parasitology9: 85–87. Natural, sympatric populations of Tenebrio molitor and T. obscurus were examined for cysticercoids of Hymemlepis diminuta. The distribution of cysticeroids in both species and both sexes conformed to the negative binomial. Cysticeroids were more prevalent and the mean intensity of infection was higher in T. obscurus than in T. molitor. No differences in the intensity of infection were detected between the sexes. Larvae of both beetle species were always very lightly infected. The significance of these factors in the transmission of the infection to the rat definitive host is discussed.     

The disease resistance gene Dm3 is infrequent in natural populations of Lactuca serriola due to deletions and frequent gene conversions at the RGC2 locus

Resistance genes can exhibit heterogeneous patterns of variation. However, there are few data on their frequency and variation in natural populations. We analysed the frequency and variation of the resistance gene Dm3, which confers resistance to Bremia lactucae (downy mildew) in 1033 accessions of Lactuca serriola (prickly lettuce) from 49 natural populations. Inoculations with an isolate of Bremia lactucae carrying avirulence gene Avr3 indicated that the frequency of Dm3 in natural populations of L. serriola was very low. Molecular analysis demonstrated that Dm3 was present in only one of the 1033 wild accessions analysed. The sequence of the 5' region of Dm3 was either highly conserved among accessions, or absent. In contrast, frequent chimeras were detected in the 3' leucine-rich repeat-encoding region. Therefore low frequency of the Dm3 specificity in natural populations was due to either the recent evolution of Dm3 specificity, or deletions of the whole gene as well as variation in 3' region caused by frequent gene conversions. This is the most extensive analysis of the prevalence of a known disease resistance gene to date, and indicates that the total number of resistance genes in a species may be very high. This has implications for the scales of germplasm conservation and exploitation of sources of resistance.     

Flavones,sesquiterpene lactones and glycosides isolated from Centaurea aspera var. Stenophylla

From the alcoholic extract of Centaurea aspera var. stenophylla benzoic acid, p-hydroxybenzoic acid, apigenin, 6-methoxyluteolin, 11,13-dehydromelitensin, melitensin, stenophyliolide, ethyl-7-O-apigenin-glucuronate and the glucosides of sitosterol and stigmasterol were isolated and characterized. Stenophyllolide was shown to be 9,15-dihydroxygermacra-1(10),4,11-trien-12,6-olide.     

Biodiversity of Lactuca aculeata germplasm assessed by SSR and AFLP markers,and resistance variation to Bremia lactucae

In total, seventy two Lactuca aculeata and three Lactuca serriola samples originating from natural populations of these species in Turkey, Jordan, and Israel were analysed by eight microsatellite and 287 amplified fragment length polymorphism (AFLP) markers. Neighbor–Network and Bayesian clustering were used for visualisation of the differences among the analysed L. aculeata and L. serriola samples, and to confirm hybrid origin (L. aculeata × L. serriola) of three samples (343-8A, 343-8B, 54/07) previously indicated by their morphological traits. Molecular data reflect the geographical origin, i.e., the clustering of samples according to their country of origin. Samples from neighbouring parts of Jordan and Israel expressed similar genetic characteristics, indicating the possibility of migration or artificial introduction of plant material. Forty-one L. aculeata samples were screened for their response to five Bremia lactucae races (Bl: 17, Bl: 18, Bl: 24, Bl: 27, and Bl: 28). Susceptible reactions of L. aculeata prevailed. L. aculeata samples were most frequently susceptible to races Bl: 18, Bl: 24, Bl: 27, Bl: 28; and least susceptible to Bl: 17. No highly efficient source of resistance was detected; however, race-specific reaction patterns were frequently recorded, indicating the possible presence of some race-specific resistance factors/genes in the studied samples of L. aculeata. Conservation and exploitation of this material in lettuce breeding is discussed.     

Phylogeny of an Albugo sp. infecting Barbarea vulgaris in Denmark and its frequency of symptom development in natural populations of two evolutionary divergent plant types

The oomycete Albugo candida has long been considered a broad spectrum generalist pathogen, but recent studies suggest that it is diverged into several more specialized species in addition to the generalist Albugo candida sensu stricto. Whereas these species cause the disease white blister rust in many crucifer plants, asymptomatic endophytic infections may be important in the epidemiology of others. One of the plant species attacked by Albugo sp. is the wild crucifer Barbarea vulgaris ssp. arcuata, which is diverged into two phytochemically and genetically different types with different geographical distributions in Europe. These were previously shown to differ strongly in propensity to develop white rust upon controlled infections in the greenhouse. Here, we analyse the phylogenetic relatedness of this local Albugo sp. field isolate to other species and lines of Albugo spp., including others collected on B. vulgaris. We further ask whether the difference in incidence of white rust between the two types of B. vulgaris are also expressed in natural populations.     

New,noteworthy, and rare species of the genus Boletus in Israel

This paper presents information about Boletus poikilochromus, B. pulchrotinctus, and B. pulverulentus in Israel. These species are reported for the first time in Israel, and also B. pulchrotinctus and B. poikilochromus are reported for the first time in Asia. Furthermore, these three species are reported for the first time in association with Quercus calliprinos. Macro- and microscopical characteristics, distribution, ecology, and illustrations related to morphology and anatomy of the species are provided.     

Morphological variation and relationships of Georgian populations of Vitis vinifera L. subsp. sylvestris (C.C. Gmel.) Hegi

Georgia is considered as one of the regions where for the first time wild growing grapevine plants were used and taken into cultivation by men. An ampelographic and ampelometric study of leaf characters and flower landmark morphometrics was carried out in seven populations of wild grapevine located in four river basins of three geographic regions – Western (1 popul.), Eastern (5 popul.) and Southern (1 popul.) Georgia, and then compared using principal component analysis and multivariate discriminant analysis allowing the populations to be distinguished. Lengths of main leaf veins and nectaries in male flowers were the variables, which allowed the best discrimination among populations. A mutation leading to white-fruited grapevine is found in one population. Pubescence varies within populations and even within an individual genome and could be used as a discriminant trait only in combination with shapes and sizes of leaves and other morphological characters. The results revealed significant differences among populations located in different geographic regions of the Southern Caucasus area, but the five investigated populations from Eastern Georgia differ only insignificantly. The high morphological variability of wild grapevine in Georgia might be considered as characterizing the large gene pool that contributed to the domestication process of grapevine.     

Stereostructures of inunal and isoalloalantolactone,two biologically active sesquiterpene lactones from Inula racemosa

Two new sesquiterpene lactones, inunal and isoalloalantolactone, have been isolated from Inula racemosa. Inunal, an aldehydolactone, displays considerable biological activity as a plant growth regulator. Structures have been assigned to these compounds on the basis of spectral data and chemical correlation with alantolactone and isotelekin.     

The stereochemistry of matricin and 4-epimatricin,proazulene sesquiterpene lactones from Artemisia arborescens

An investigation of Artemisia arborescens afforded, in addition to the known compounds matricin, artabsin and artemetin, the new guaianolide 4-epimatricin. The stereostructures of 4-epimatricin and matricin were assigned on the basis of spectroscopic evidence.     

Diversity and evolution of polyketide biosynthesis gene clusters in the Ceratocystidaceae

Polyketides are secondary metabolites with diverse biological activities. Polyketide synthases (PKS) are often encoded from genes clustered in the same genomic region. Functional analyses and genomic studies show that most fungi are capable of producing a repertoire of polyketides. We considered the potential of Ceratocystidaceae for producing polyketides using a comparative genomics approach. Our aims were to identify the putative polyketide biosynthesis gene clusters, to characterize them and predict the types of polyketide compounds they might produce. We used sequences from nineteen species in the genera, Ceratocystis, Endoconidiophora, Davidsoniella, Huntiella, Thielaviopsis and Bretziella, to identify and characterize PKS gene clusters, by employing a range of bioinformatics and phylogenetic tools. We showed that the genomes contained putative clusters containing a non-reducing type I PKS and a type III PKS. Phylogenetic analyses suggested that these genes were already present in the ancestor of the Ceratocystidaceae. By contrast, the various reducing type I PKS-containing clusters identified in these genomes appeared to have distinct evolutionary origins. Although one of the identified clusters potentially allows for the production of melanin, their functional characterization will undoubtedly reveal many novel and important compounds implicated in the biology of the Ceratocystidaceae.     

Genetic diversity of four esterase loci in natural populations of Hordeum spontaneum C. Koch from Jordan

Summary The diversity of four esterase loci was studied electrophoretically in 690 individual spikes representing 12 populations of wild barley (Hordeum spontaneum C. Koch.) collected from central, peripheral and marginal regions of its distribution in Jordan. A minimum of 6, 10, 5 and 5 alleles were observed at the Est-1, Est-2, Est-4 and Est-5 loci, respectively. Est-2 and Est-4 were the most diverse loci (H_c=0.53±0.05 and 0.46±0.07, respectively). Est-5 was intermediate (H_c=0.33+0.07) and Est-1 was the lowest (H_c=0.22±0.04). Polymorphism was highest in the central populations (H_e=0.52±0.04), followed by the peripheral (H_e=0.40±0.05) and the marginal (H_e=0.22±0.05) populations. Average allelic diversity between (G_st=0.49) and within (H_s=0.51) populations reflects a high allelic differentiation among these populations. Log-linear analyses revealed that four two-locus terms and two three-locus terms were significantly associated (P<0.05). Geographical distances between populations were not significantly correlated with Nei's genetic similarity index (r=0.16; P<0.19). It is postulated that diversifying selection is a major factor in the population genetic differentiation of these esterase loci.     

Mitochondrial DNA diversity and male sterility in natural populations of Daucus carota ssp carota

Mitochondrial variability was investigated in natural populations of wild carrot (Daucus carota ssp carota) in different regions: South of France, Greece, and various sites in the Mediterranean Basin and Asia. Total DNA was digested with two restriction endonucleases (EcoRV and HindIII) and probed with three mitochondrial DMA-specific genes (coxI, atp6, and coxII). Twenty-five different mitochondrial types were found in 80 analyzed individuals. Thirteen mitotypes were found among the 7 French populations studied. On average, 4.4 different mitotypes were observed per population, and these mitotypes were well-distributed among the populations. All of the mitochondrial types were specific to a single region. However, the proportion of shared restriction fragments between 2 mitotypes from different regions was not particularly lower than that which occurred among mitotypes from a single region. On the basis of the sexual phenotype [male-sterile (MS) or hermaphrodite] of the plants studied in situ and that of their progeny, 2 mitotypes were found to be highly associated with male sterility. Eighty percent of the plants bearing these mitotypes were MS in situ, and all of these plants produced more than 30% MS plants in their progeny. This association with male sterility was consistent in several populations, suggesting an association with a cytoplasmic male-sterility system. Moreover, these two mitotypes had very similar mitochondrial DNA restriction patterns and were well-differentiated from the other mitotypes observed in wild plants and also from those observed in the two CMS types already known in the cultivated carrot. This suggests that they correspond to a third cytoplasmic sterility.     

Cancer burden in four countries of the Middle East Cancer Consortium (Cyprus; Jordan; Israel; Izmir (Turkey)) with comparison to the United States surveillance; epidemiology and end results program

It is important that population-based cancer registries provide accurate and reliable data for public health purposes. These data are essential data for planning of cancer control and prevention. In this study, we examined cancer incidence rates (year 2005–2010) in four MECC registries (Cyprus, Jordan, Israel, Izmir (Turkey)) and compared with the rates in the US. The overall age-standardized incidence rates for males were highest in the US followed by Israeli Jews, Izmir (Turkey), Cyprus, Israeli Arabs, and lowest in Jordan. In women the rates of cancer of all sites were also highest in US women followed by Israeli Jews, Cyprus, Israeli Arabs, Izmir (Turkey), and lowest in Jordan. It is of interest that although site-specific cancer rates differ between the countries studied, prostate, lung and colorectal cancers are within the five most common cancers males in all countries studied. In females, breast colorectal and endometrium cancers are three of the five most common cancers in females in all countries studied. The results presented in this paper can have implications for opportunities in cancer control and prevention in these countries. Future studies on individual cancer sites with highest rates in these Countries are currently underway.     

Sequence-related amplified polymorphism (SRAP) of wild emmer wheat (Triticum dicoccoides) in Israel and its ecological association

Genetic diversity and population structure of 15 wild emmer wheat (Triticum dicoccoides) populations from Israel were detected by 30 sequence-related amplified polymorphism (SRAP) primer pairs. Two hundred and forty four fragments out of 438 were polymorphic. The proportion of polymorphic loci (P), the genetic diversity (He), and Shannon's information index were 0.557, 0.198, and 0.295, respectively. The population Amirim had the highest genetic variation, whereas the population of Tabigha had the lowest genetic variation. The hierarchical analysis of molecular variance (AMOVA) revealed that most of the variation was presented within populations. The value of genetic distance (D) between the populations varied from 0.027 to 0.165 with an average of 0.079, and the estimates of genetic distance were geographically independent based on the Mantel test (r = 0.105, P = 0.168). A total of 30 significant (P < 0.05) correlations were detected between 14 SRAP loci and 12 ecogeographic factors.