Genetic relationships among Arachis hypogaea L. (AABB) and diploid Arachis species with AA and BB genomes

The cultivated peanut (Arachis hypogaea L.) is an allotetraploid, with two types of genomes, classified as AA and BB, according to cytogenetic characters. Similar genomes to those of A. hypogaea are found in the wild diploid species of section Arachis, which is one of the nine Arachis sections. The wild species have resistances to pests and diseases that affect the cultivated peanut and are a potential source of genes to increase the resistance levels in peanut. The aim of this study was to analyze the genetic variability within AA and BB genome species and to evaluate how they are related to each other and to A. hypogaea, using RAPD markers. Eighty-seven polymorphic bands amplified by ten 10-mer primers were analyzed. The species were divided into two major groups, and the AA and the BB genome species were, in general, separated from each other. The results showed that high variation is available within species that have genomes similar to the AA and the BB genomes of A. hypogaea.     

Genetic diversity in wild Tunisian populations of Mentha pulegium L. (Lamiaceae)

The allozyme variation of 15 Tunisian wild populations of Mentha pulegium L. threatened by human activities (clearing, hard-grazing, ploughing, traditional uses) was surveyed by the analysis of 14 isozyme loci using horizontal gel starch electrophoresis. The species exhibited a high level of genetic variation within populations (the mean Ap = 2.20, P = 72%, Ho = 0.349 and He = 0.229), which indicates a predominately outcrossing mating system and the recruitment of new genotypes via dispersal seeds. The genetic structure analysis of the populations using F statistics indicates no inbreeding, and showed an excess of heterozygosity for few loci. The moderate differentiation of populations (F_ST = 0.110) and the low rate of gene flow between them (Nm = 2.02) might been caused by recent isolation of the populations through biotope disturbances. The value of Nei's genetic identity varied from 0.839 to 0.999 reflecting a relatively low genetic divergence between populations. Cluster analysis using UPGMA method and Nei's genetic identity values, showed that populations geographically close didn't always cluster together. However, populations within the same bioclimatic stage generally subclustered together indicating that differentiation between bioclimatic regions occurred.     

Antimicrobial and antioxidant activities of Melissa officinalis L. (Lamiaceae) essential oil

The present study describes antimicrobial and free radical scavenging capacity (RSC) together with the effects on lipid peroxidation (LP) of Melissa officinalis essential oil. The chemical profile of essential oil was evaluated by the means of gas chromatography-mass spectrometry (GC-MS) and thin-layer chromatography (TLC). RSC was assessed measuring the scavenging activity of essential oil on the 2,2-diphenyl-1-picrylhydrazyl (DPPH(*)) and OH(*) radicals. The effect on LP was evaluated following the activities on Fe(2+)/ascorbate and Fe(2+)/H(2)O(2) systems of induction. The antimicrobial activity was tested against 13 bacterial strains and six fungi. The examined essential oil exhibited very strong RSC, reducing the DPPH radical formation (IC(50) = 7.58 microg/mL) and OH radical generation (IC(50) = 1.74 microg/mL) in a dose-dependent manner. According to the GC-MS and TLC (dot-blot techniques), the most powerful scavenging compounds were monoterpene aldehydes and ketones (neral/geranial, citronellal, isomenthone, and menthone) and mono- and sesquiterpene hydrocarbons (E-caryophyllene). Very strong inhibition of LP, particularly in the Fe(2+)/H(2)O(2) system of induction (94.59% for 2.13 microg/mL), was observed in both cases, also in a dose-dependent manner. The most effective antibacterial activity was expressed on a multiresistant strain of Shigella sonei. A significant rate of antifungal activity was exhibited on Trichophyton species.     

Genetic diversity and population structure in medicinal plant Melissa officinalis L. (Lamiaceae)

Genetic Resources and Crop Evolution - Melissa officinalis is an important medicinal plant and is extensively used by locals. This species is growing in different regions of Iran and forms several...     

Chemical analysis of Teucrium species (Lamiaceae) growing on serpentine soils in Bulgaria

Trace elemental concentrations (Fe, Ni, Mn, Cr, Co, Cu, Zn, Pb, Cd, and As) in aerial biomass (stems, leaves, and flowers) of the medicinal plants Teucrium chamaedrys, T. montanum, and T. polium growing on serpentine soils in Bulgaria were examined in relation to the total element contents in their respective rhizospheric soils. The objectives of the study were to evaluate: (1) elemental concentrations in plant tissues and associated soil samples together with the plants ability to tolerate/accumulate metal concentrations; (2) correlations between total metal concentrations in plants and their rhizospheric soils. Metal concentrations varied across species and sites. Their levels in plant tissues from nonserpentine sites were always lower compared to those from serpentine ones. The highest concentrations for Fe, Ni, Mn, Cr, As, Cu, and Pb were found in T. polium. Positive correlation coefficients were established between Ni, Cr, Fe, Co, and Cu in plants and Ca in the soil. None of the species tested hyperaccumulated metals although the metal concentration in some of them exceeded the range naturally found in plants. The Teucrium species can be considered as “excluders”, containing relatively low metal concentrations in their aerial parts (stems, leaves, and flowers) even in cases of high elemental concentrations in the rhizospheric soil. In all three medicinal plants, metal concentrations for toxic elements were above the permissible limits for pharmaceutical purposes. Therefore, plants found on serpentine bedrock are not recommended to be collected for pharmaceutical purposes.     

Inter-MITE polymorphisms of a newly identified MITE show relationships among sugarcane (Saccharum) species

Sugarcane, one of the most important tropical crops, belongs the genus Saccharum. This genus consists of six species, four cultivated and two wild. The domestication histories of the four cultivated Saccharum species is an interesting and important topic of study. Previous studies have categorized the four cultivated species into two groups, one consisting only of S. edule and the other comprising S. officinarum, S. sinense and S. barberi. All four species have inherited the genomic DNA of S. robustum, one of two wild relative species. Saccharum species have large genomes with complex structures, as evidenced by chromosomes with a high degree of polyploidy, alloploidy and aneuploidy. Miniature inverted-repeat transposable elements (MITEs) are class II (DNA) transposons that disperse throughout the plant genome. In this study, a Tourist family MITE sequence with 18/19-bp terminal inverted repeats and a 2-bp target site duplication was newly identified from genomic DNA of S. robustum. The abundant accumulation of this MITE sequence in the sugarcane genome enabled the application of inter-MITE polymorphism (IMP) analysis to Saccharum. IMP analysis revealed the genetic relationships among all six Saccharum species and the domestication histories of the four cultivated species.     

Phylogenetic relationships among Triticum L. and Aegilops L. species as genome progenitors of bread wheat based on sequence diversity in trnT-F region of chloroplast DNA

Cultivated wheat, (Triticum aestivum L.), is one of the most important food crops in the world. The Aegilops L. genus is frequently utilized by plant breeders for improving the current wheat cultivars due to their close relationships. Therefore, understanding the phylogenetic relationships among the species of these genera is not only valuable for plant taxonomy, but also for plant breeding efforts. The presented phylogenetic analysis was based on the sequences of trnT-F chloroplast DNA containing three non-coding sub-regions. Twelve genotypes belonging to four species of Triticum L. genus and twenty-four genotypes belonging to eight species of Aegilops genus were used in the current study. The results postulated a close genetic relationship between diploid Aegilops species containing the BB genome and polyploid Triticum species. With the exception of Aegilops cylindrica Host (CCDD), all other Aegilops species having the CC genome were alienated from Aegilops speltoides Tausch (BB) and clustered together. These two clusters joined by a third cluster including the AA genome containing diploid Triticum species.     

Antimicrobial and antioxidant properties of rosemary and sage (Rosmarinus officinalis L. and Salvia officinalis L., Lamiaceae) essential oils

The essential oils of rosemary ( Rosmarinus officinalis L.) and sage ( Salvia officinalis L.) were analyzed by means of gas chromatography-mass spectrometry and assayed for their antimicrobial and antioxidant activities. Antimicrobial activity was tested against 13 bacterial strains and 6 fungi, including Candida albicans and 5 dermatomycetes. The most important antibacterial activity of both essential oils was expressed on Escherichia coli, Salmonella typhi, S. enteritidis, and Shigella sonei. A significant rate of antifungal activity, especially of essential oil of rosemary, was also exhibited. Antioxidant activity was evaluated as a free radical scavenging capacity (RSC), together with the effect on lipid peroxidation (LP). RSC was assessed by measuring the scavenging activity of essential oils on 2,2-diphenyl-1-picrylhydrazil (DPPH) and hydroxyl radicals. Effects on LP were evaluated following the activities of essential oils in Fe(2+)/ascorbate and Fe(2+)/H2O2 systems of induction. Investigated essential oils reduced the DPPH radical formation (IC50 = 3.82 microg/mL for rosemary and 1.78 microg/mL for sage) in a dose-dependent manner. Strong inhibition of LP in both systems of induction was especially observed for the essential oil of rosemary.     

Morphological relationships among 15 species of Trifolium occurring in Poland

Populations of 15 Trifolium species were morphologically assayed to elucidate species relationships and taxonomic arrangements in the genus. Twenty-one characters were scored and analyzed by numerical methods. All species proved to be heterogenous. The levels of dissimilarity among populations of the same species ranged from around 0.05 to around 0.6. Cluster analysis divided all taxa into two major groups of species which were joined at D (Euclidean Distance) around 0.9. Within the first group three major sub-groups were revealed, comprising T. hybridum L., T. repens L., T. strepens Cr., T. dubium Sibth., T. campestre Schreb., T. patens Schreb. and T. fragiferum L. The second major group consisted of T. pannonicum L., T. arvense L., T. montanum L., T. incarnatum L., T. alpestre L., T. rubens L., T. pratense L. and T. medium L. The present results proved that the genus is very heterogenous, and support the hypothesis that the section Lotoidea was probably the stock from which other sections derived. Morphological relationships among 15 Trifolium species support their taxonomic arrangements proposed by Zohary & Heller (1984), with some exceptions. Sectional positions of T. montanum and T. strepens should be reexamined. Conspecific ranks for three species of section Chronosemum – T. dubium, T. campestre and T. patens – should be considered.     

Genetic variation within and among species of five sections of the genus Arachis L. (Leguminosae) using RAPDs

Some Arachis species are widely used as commercial plants, e.g. the groundnut A. hypogaea, an important source of good quality protein and oil, and A. pintoi and A. glabrata, that are utilized as forage species. Germplasm of most Arachis species is available in germplasm banks. However, little it is known about the genetic attributes of this germplasm, and mainly about its genetic variability, which is very important for its maintenance. In the present study RAPDs were used to assay the genetic variation within and among 48 accessions of five sections of the genus Arachis and to establish the genetic relationships among these accessions. Ten of 34 primers tested were selected for DNA amplification reactions since they yielded the largest numbers of polymorphic loci. A dendrogram was constructed based on data from the 10 primers selected. Eighty RAPD polymorphic bands were analyzed among the accessions studied. The relationships among species based on RAPDs were similar to those previously reported based on morphological, cytological and crossability data; demonstrating that RAPDs can be used to determine the genetic relationships among species of the different sections of the genus Arachis. In general, wide variation was found among accessions and low variation was found within the accessions that had two or more plants analyzed. However, higher polymorphism was found in the section Trierectoides and in one accession of A. major, indicating that generalizations should be avoided and each species should be analyzed in order to establish collection and maintenance strategies.     

Genetic diversity among sumac (Rhus coriaria L.) accessions collected from five areas of Iran

Genetic Resources and Crop Evolution - Sumac (Rhus coriaria L.) has been used in human nutrition as an herbal drug to treat different diseases for centuries. In recent years, the genetic...     

Relationships among species of Hystrix Moench and Elymus L. assessed by RAPDs

To assess the generic delimitation and the interspecific relationships between Hystrix and Elymus, three Hystrix and 10 Elymus species were used for random amplified polymorphic DNA(RAPD) assay. Of the 54 primers tested, 26 (48%) produced polymorphic products. A total of 167 products amplified from 16 primers were selected for RAPD analysis, among which 156 (93.4%) amplified products were found to be polymorphic among the 13 species. The polymorphism produced by each primer ranged from 4 to 13, with an average of 9.8. Data were used to generate Jaccard's similarity coefficients and to construct a dendrogram using UPGMA in the NTSYS computer programs. It is concluded from this study that: (1) there were clear differences between Hystrix and Elymus, which possibly suggest that Hystrix is a valid genus; (2) great diversity existed among the species of Hystrix and Elymus; (3) the species similar to each other in morphological characters were grouped together; (4) the species from neighboring geographical regions were clustered; (5) the species with the same genomes and polyploidy level were clustered together; (6) RAPD results are comparable with those obtained from studies on morphology and cytology. It is a useful additional method for assessing the relationships among genera and species in Triticeae.     

Phylogenetic relationships among species of Citrullus and the placement of C. rehmii De Winter as determined by Internal Transcribed Spacer (ITS) sequence heterogeneity

The internal transcribed spacer regions (ITS1 and ITS2) of the 18S-25S nuclear ribosomal DNA from the four recognized species of Citrullus (C. lanatus var. lanatus (Thunb.) Matsum. & Nakai., C. lanatus var. citroides (Bailey) Mansf., C. colocynthis (L.) Schrad., C. ecirrhosus Cogn., and C. rehmii De Winter) and Acanthosicycos naudinianus (Sond.) C. Jeffrey were amplified by PCR, and direct sequenced. Within the taxa examined, the length of ITS1 varied from 216 bp to 219 bp, and ITS2 varied from 239 bp to 249 bp. The average %CG content ranged from 59 to 64% and from 62 to 66% for ITS1 and ITS2, respectively. The greater length variation observed in ITS2 was primarily attributable to the occurrence of a (CC)_n microsatellite. Cladistic (PAUP) and phenetic (MEGA) analyses resulted in highly resolutive trees. ITS sequence analysis placed the recently described C. rehmii adjacent to the cultivated watermelon and supported the validity of the species classification of this taxa.     

Weed flora survey in alfalfa (Medicago sativa L.) fields of Shabestar (northwest of Iran)

Alfalfa is one of the most widely grown forage crops in Iran, especially in Shabestar county. Weeds play a significant role in reducing the feeding value of alfalfa. Weed survey was done in order to determine environmental factors on weed species distribution in alfalfa fields at Shabestar, Iran (2010–2011). The family dominance index (FDI) and relative dominance (RD) were used to find dominant families and species for infestation of Shabestar's alfalfa fields. Data were analyzed by principal component analysis (PCA) and canonical correspondence analysis (CCA). A total of 130 weed species belonging to 28 families were observed. The most dominant families, based on the FDI, were Asteraceae, Poaceae, and Brassicaceae with 66.3, 61.8, and 41.1 FDI, respectively. Alopecurus myosuroides and Convolvulus arvensis were the most dominant species according to the RD index, measuring 26.4 and 21.8, respectively. PCA showed that some weed species only infested specific areas, but a few species with broader environmental tolerances were found near origin. Most variation in species distribution was explained by altitude, which was followed by soil potassium and salinity content of the soil. Our results suggest that the effect of altitude was more important than other environmental factors.     

The genus Amygdalus L. (Rosaceae): Species relationships, distribution and evolution under domestication

Summary The paper reviews the taxonomic relationships, morphological distinction, geographical distribution and ecological specificities of the twenty six species recognized (by us) in Amygdalus L. It also surveys the intra-genetic structure in this genus stressing the fact that they fall into five groups of closely related vicarious species: (i) Communis group (9 species), (ii) Orientalis group (6 species), (iii) Sect. Chamaeamygdalus (4 species), (iv) Sect. Spartioides (2 species), and (v) Subgenus Dodecandara (5 species). Within each group, species are separated from one another geographically (in few cases by altitude). The only major exception to such allopatric distribution is found in A. communis L., and this is interpreted as an outcome of domestication. Interspecific sterility barriers are absent, or only weakly developed in Amygdalus, and numerous inter-specific hybrids (particularly between the crop and various wild almond species) have been detected. Therefore most (may be all) wild almond species constitute the primary gene-pool of the cultivated nut crop.The combined botanical and archaeological evidene points to the Levant countries as the place where the almond was taken into cultivation. Wild forms of A. communis are very likely native only to this area. Also the earliest archaeological signs of almond domestication come from this area.