Morphological,genetic and molecular characteristics of barley root hair mutants

Root hairs are tubular outgrowths of specialized epidermal cells called trichoblasts. They affect anchoring plants in soil, the uptake of water and nutrients and are the sites of the interaction between plants and microorganisms. Nineteen root hair mutants of barley representing different stages of root hair development were subjected to detailed morphological and genetic analyses. Each mutant was monogenic and recessive. An allelism test revealed that nine loci were responsible for the mutated root hair phenotypes in the collection and 1–4 mutated allelic forms were identified at each locus. Genetic relationships between the genes responsible for different stages of root hair formation were established. The linkage groups of four loci rhl1, rhp1, rhi1 and rhs1, which had previously been mapped on chromosomes 7H, 1H, 6H and 5H, respectively, were enriched with new markers that flank the genes at a distance of 0.16 cM to 4.6 cM. The chromosomal position of three new genes – two that are responsible for the development of short root hairs (rhs2 and rhs3) and the gene that controls an irregular root hair pattern (rhi2) – were mapped on chromosomes 6H, 2H and 1H, respectively. A comparative analysis of the agrobotanical parameters between some mutants and their respective parental lines showed that mutations in genes responsible for root hair development had no effect on the agrobotanical performance of plants that were grown under controlled conditions. The presented mutant collection is a valuable tool for further identification of genes controlling root hair development in barley.     

Frequencies of apolipoprotein E polymorphism in a healthy Kurdish population from Kermanshah, Iran

The molecular polymorphism displayed by apolipoprotein E (APOE) has been listed as a risk factor for susceptibility to various disorders, such as those associated with lipid metabolism, arteriosclerosis, coronary artery disease (CAD), and Alzheimer disease. To evaluate the role of APOE genotypes as risk factors for Alzheimer disease, CAD, and atherosclerosis in the Kurdish population of Kermanshah, Iran, we studied the frequencies of APOE alleles *2, *3, and *4 and genotypes in 914 healthy Kurdish subjects (514 men and 400 women). The highest frequency of APOE in the Kurdish population was found for APOE*3 (87.87%). The APOE*2 and APOE*4 allele frequencies were 6.66% and 5.45%, respectively. Distribution of APOE genotypes and alleles was not significantly different between male and female subjects (p > 0.05). Interestingly, the order of the frequency of APOE alleles (*3-->*2-->*4) in the Kurdish population was quite different from that reported for most populations in the world (*3-->*4-->*2). The findings of the present study can be used to identify individuals with high risk of CAD and atherosclerosis and suggest a preventive measure to reduce their susceptibility.     

Morphological and molecular variations in the epiphytic CAM fern Pyrrosia piloselloides

Variation in shape and size of mature sterile fronds of the epiphytic fern, Pyrrosia piloselloides (L.) Price, was observed. These morphological differences were also linked to genotypic variations of the different fern populations studied. Genetic polymorphism in different populations of P. piloselloides was investigated using random amplified polymorphic DNA markers. This revised version was published online in July 2006 with corrections to the Cover Date.     

Application of molecular markers to assess genetic relationships among accessions of wild oat,Avena sterilis

Summary The Avena sterilis collection in the National Small Grains Collection (NSGC) is an invaluable source of genetic variation to be exploited by oat breeding programs. Prior knowledge of the structure and distribution of genetic variation within the A. sterilis collection would be useful to efficiently screen the collection for valuable traits. To determine genetic structure within a subset of the collection, restriction fragment length polymorphisms were analyzed in a stratified sample of 173 accessions originating in eight countries of Africa and Southwest Asia. Of the 48 probes used for this study 43 detected polymorphism among accessions. The average number of RFLP patterns per probe ranged from 2.9 among Ethiopian accessions to 3.7 among those from Iran. Genetic variation, as measured by genetic distances and polymorphic indexes, was highest in Iran and lowest in Ethiopia. The probability of drawing a genotype from Iran or Iraq that is not present in the more western regions was high, indicating large genetic divergence of the Iran-Iraq accessions from the other regional collections surveyed. Cluster analysis of genetic distances and probabilities of unique genotypes clearly differentiated the eastern region (Iran and Iraq) from the western region (Algeria, Ethiopia, Israel, Lebanon, Morocco, and Syria). The western region could be further subdivided into two clusters, an African cluster (Algeria, Ethiopia, and Morocco) and a southwestern Asia cluster (Israel, Lebanon, and Syria). Genetic distances were generally related to but not proportional to geographical distances.     

Morphological and genetic characterization of endophytic bacteria isolated from roots of different maize genotypes

Maize is one of the most important crops worldwide, and in Brazil, the state of Paraná stands as its largest producer. The crop demands high inputs of N fertilizers, therefore all strategies aiming to optimize the grain production with lower inputs are very relevant. Endophytic bacteria have a high potential to increment maize grain yield by means of input via biological nitrogen fixation and/or plant growth promotion, in this last case increasing the absorption of water and nutrients by the plants. In this study, we established a collection of 217 endophytic bacteria, isolated from roots of four lineages and three hybrid genotypes of maize, and isolated in four different N-free culture media. Biochemical―comprising growth in different carbon sources, intrinsic tolerance to antibiotics, and biochemical tests for catalase, nitrate reductase, urease, and growth in N-free media in vitro―and genetic characterization by BOX-PCR revealed great variability among the isolates. Both commercial hybrids and homozygous lineages were broadly colonized by endophytes, and sequencing of the 16S rRNA gene revealed the presence of bacteria belonging to the genera Pantoea, Bacillus, Burkholderia, and Klebsiella. Qualitative differences in endophytic colonization were detected between lineages and hybrid genotypes.     

Molecular characterization of pathogenic Fusarium species in cucurbit plants from Kermanshah province, Iran

Fusarium is one of the important phytopathogenic genera of microfungi causing serious losses on cucurbit plants in Kermanshah province, the largest area of cucurbits plantation in Iran. Therefore, the objectives in this study were to isolate and identify disease-causing Fusarium spp. from infected cucurbit plants, to ascertain their pathogenicity, and to determine their phylogenetic relationships. A total of 100 Fusarium isolates were obtained from diseased cucurbit plants collected from fields in different geographic regions in Kermanshah province, Iran. According to morphological characters, all isolates were identified as Fusarium oxysporum, Fusarium proliferatum, Fusarium equiseti, Fusarium semitectum and Fusarium solani. All isolates of the five Fusarium spp. were evaluated for their pathogenicity on healthy cucumber (Cucumis sativus) and honeydew melon (Cucumis melo) seedlings in the glasshouse. F. oxysporum caused damping-off in 20–35 days on both cucurbit seedlings tested. Typical stem rot symptoms were observed within 15 days after inoculation with F. solani on both seedlings. Based on the internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA) restriction fragment length polymorphism (RFLP) analysis, the five Fusarium species were divided into two major groups. In particular, isolates belonging to the F. solani species complex (FSSC) were separated into two RFLP types. Grouping among Fusarium strains derived from restriction analysis was in agreement with criteria used in morphological classification. Therefore, the PCR-ITS-RFLP method provides a simple and rapid procedure for the differentiation of Fusarium strains at species level. This is the first report on identification and pathogenicity of major plant pathogenic Fusarium spp. causing root and stem rot on cucurbits in Iran.     

Morphological, physiological and molecular genetic characterization ofArabidopsis himalaica, with reference toA. thaliana

Arabidopsis himalaica (Edgeworth) O.E. Schulz, a poorly characterized species typical of HimalayanArabidopsis, was analyzed in terms of its morphology, physiology, chromosome number and molecular genetics, in comparison withA. thaliana which is the standard species in the genusArabidopsis. From view point of developmental genetics, several features which are specific toA. himalaica seem not to be derived by single-gene mutations inA. thaliana. Phylogenetic analyses based onrbcL sequences suggested that genusArabidopsis is not monophyletic. The detailed characterization ofA. himalaica should provide clues to understand the trait of evolution of particular features of Himalayan species ofArabidopsis and their genetic basis.     

Genetic diversity of superior Persian walnut genotypes in Azadshahr,Iran

Persian walnut (Juglans regia L.) is known to have originated in central and eastern Asia. Remnants of these wild populations can still be found in the Hyrcanian forest in north-eastern Iran. In this study, 102 individual walnut trees from four geographic populations in the Azadshahr province (Vamenan, Kashidar, Rudbar and Saidabad) were sampled. We characterized individual trees using 28 standard morphological traits. The range of traits varied widely for some economically important characteristics including nut weight (6.1–19.79 g), kernel weight (2.9–9.4 g), and kernel fill percentage (26.51–60.34%). After morphological evaluation, 39 superior individuals based on nut quality and kernel fill percentage were selected for further genetic analysis. Individual superior trees were genotyped using 10 simple sequence repeat markers (SSR) and genetic diversity. Number of alleles per locus ranged from 3 (WGA005) to 12 (WGA054). Clustering analysis of 10 SSR loci divided the genotypes into three main groups. PCoA analysis clearly sorted genotypes into one of four distinctive groups which aligned with the cluster analysis. All analyses showed that individuals from Saidabad were genetically distinct. Likewise, results indicated that the high level of genetic diversity in Azadshahr region walnuts may provide a diverse source for superior walnuts in walnut breeding programs.     

Detection of responsible mutations for beta thalassemia in the Kermanshah Province of Iran using PCR-based techniques

Beta Thalassemia has been reported to be a common genetic disorder in Iran. To establish the molecular spectrum of the beta thalassemias in the Kermanshah Province of Iran, 185 unrelated beta thalassemia patients with Kurdish ethnic background were studied (181 β-thalassemia major and 4 β-thalassemia intermedia). Using polymerase chain reaction-amplification refractory mutation system (PCR-ARMS), restriction fragment length polymorphism (RFLP) and direct genomic sequencing twenty different mutations were identified accounting for 98.1% of the alleles. Approximately 80.8% of β-thalassemia chromosomes had β⁰ mutation. The most prevalent mutation was the IVSII-1 (G→A) (32.97%), followed by CD8/9 +G (13.51%), IVSI-110 (C→T) (8.38%), CD 36/37 −T (7.84%), CD8 −AA (5.94%), CD15 (G→A) (4.86%) and IVSI-1 (G→A) (4.59%). All of these mutations accounted for 78.1% of the alleles. The results described here will be of valuable help in the development of successful prevention programs for the population of Kermanshah.     

Assessment of genetic diversity among faba bean genotypes using agro-morphological and molecular markers

Forty faba bean (Vicia faba L.) genotypes were evaluated for their agro-morphological performance and molecular diversity under Central Region of Saudi Arabia conditions during 2010–11 and 2011–12 seasons. Field performance results showed that faba genotypes exhibited a significant amount of variation for their agro-morphological studied parameters. Giza40 recorded the tallest genotype (139.5 cm), highest number of seeds per plants (100.8), and the highest seed yield per plant (70.8 g). The best performing genotypes were Giza40, FLIP03-014FB, Gazira1 and Goff1. Genetic variability among genotypes was determined using Sequence Related Amplified Polymorphism (SRAP) and Amplified Fragment Length Polymorphism (AFLP) markers. A total of 183 amplified fragments (alleles) and 1758 polymorphic fragments (bands) in SRAP and 202 alleles and 716 bands in AFLP were obtained using six SRAP and four AFLP primer combinations respectively. Polymorphism information content (PIC) values for AFLP and SRAP markers were higher than 0.8, indicating the existence of a considerable amount of genetic diversity among faba tested genotypes. The UPGMA based clustering of faba genotypes was largely based on origin and/or genetic background. Result of cluster analysis based on SRAP showed weak and not significant correlation while, it was highly significant based on AFLP analysis with agro-morphological characters (r = 0.01, p > 0.54 and r = 0.26, p < 0.004 respectively). Combined SRAP and AFLP markers proved to be significantly useful for genetic diversity assessment at molecular level. They exhibited high discrimination power, and were able to distinguish the faba bean genotypes with high efficiency and accuracy levels.     

Morphological and molecular identification of Leptosphaeria maculans in canola seeds and flowers collected from the North Iran

Blackleg disease, caused by Leptosphaeria maculans, is one of the most important diseases of rapeseed Brassica napus in Iran as in other regions of the world. The samples including canola petals and seeds were collected during 2014–2015 from canola field in North Iran. Isolates characteristics of fungus were assessed based on the colony growth rate and pycnidia in Potato Dextrose Agar. The pycnidia of the fungus were black, globose to subglobose in shape, the single-celled conidia, hyaline and fusiform with diameters of 4–5 × 1.5–2 μm. Most of the isolates were produced pigment in the liquid culture in variable color brown to black. Thirteen isolates were then separated into pathogenicity groups based on the interactions on B. napus differential cultivars. For the direct detection of seed contamination with L. maculans, PCR was developed using specific primers pair (LmacF, LmacR) which can amplify ITS1 and ITS2 along with the 5.8S rRNA region of L. maculans genome. Based on the followed information and sequence analysis, the fungal isolates from these samples were identified as L. maculans. The findings of this research showed that the disease was aggressive and highly distributed from infested seeds to oilseed rape fields.     

Morphological variations and climatic differences

As it has been shown long ago by physicists, the volume/surface ratio influences the cooling of bodies. Unfortunately, the volume of living things in most cases is difficult to assess. Therefore it can be reasonably replaced by body-weight, as it is usual in biological work. A second ratio, total limbs length/body weight, also plays an obvious role in body-heat regulation.Both ratios were studied experimentally on more than 100 men, in a hot room or on a tread-mill. On the other hand they were studied statistically on many different populations belonging to all the major divisions of the human species. These ratios are not the cornerstone of body-heat regulation, but both influence it. As a general tendency, body-weight/body-surface ratio decreases in warm climates, whereas limbs-length/body weight ratio increases. These geographical differences may be considered as ecological gradients related to body-heat regulation.These gradients do not exactly follow latitudes, because other factors, such as altitude, must be also taken into account. Perhaps there are several similar gradients, represented by different figures in different branches of human species. Some small gradient irrégularities can probably be explained by sampling errors: adaptation is a statistical phenomenon and small samples may sometimes distort a gradient's orderliness. Finally, body-weight/body-surface ratio is to some extent related to age. As we have shown it elsewhere, some numerical “inconsistencies” disappear if the age influence is statistically eliminated. Unfortunately, this correction is often impossible because in many populations the exact age of adult subjects is unknown.     

Morphological and genetic variations of Potentilla matsumurae (Rosaceae) between fellfield and snowbed populations

Identifying ecological factors associated with local differentiation of populations is important for understanding microevolutionary processes. Alpine environments offer a unique opportunity to investigate the effects of habitat-specific selective forces and gene flow limitations among populations at a microscale on local adaptation because the heterogeneous snowmelt patterns in alpine ecosystems provide steep environmental changes. We investigated the variation in morphological traits and enzyme loci between fellfield and snowbed populations of Potentilla matsumurae, a common alpine herb with a wide distribution along snowmelt gradients in northern Japan. We found significant differences in morphological traits between fellfield and snowbed habitats in a northern distribution region. These differences were maintained when plants were grown under uniform conditions in a greenhouse. Allozyme variations among 15 populations from geographically separated regions with different historical backgrounds showed that the populations are more genetically differentiated between the fellfield and snowbed habitats within a region than between populations occupying the same habitat type in different regions. These results suggest that variation in snowmelt regimes could be a driving force creating local adaptation and genetic differentiation of alpine plant populations.     

Comparative studies of diurnal variations of nitrate reductase activity in wheat, oat and barley

Diurnal variations of in vitro and in vivo (intact tissue assay) nitrate reductase (EC 1.6.6.1) activity and stability were examined in leaves of wheat ( Triticum aestivum L. cv. Runar), oat ( Avcna saliva L. cv. Mustang) and barley ( Hordeum vulgure L. cv. Agneta and cv. Gunillu). Nitrate reductase activity was generally higher for wheat than for oat and barley. However, the diurnal variations of nitrate reductase activity and stability were principally the same for all species, e.g. the high activity during the photoperiod was associated with low stability. All species showed a rapid (30-60 min) increase in the in vitro and in vivo activity when the light was switched on. When light was switched off the in vitro activity decreased rapidly whereas decrease in in vivo activity was slower. These experiments support the hypothesis that an activation/ deactivation mechanism is involved in the regulation of diurnal variations in nitrate reductase activity. Red light enhanced nitrate reductase activity in etiolated wheat and barley leaves. In green leaves, however, the daily increase in nitrate reductase activity was not induced by a brief red light treatment. Indications of different regulation mechanisms for the diurnal variations of nitrate reductase activity among the cereals were not found.     

Paurodontella parapitica n. sp. (Nematoda: Hexatylina,Sphaerularioidea) from Kermanshah Province,Western Iran

Paurodontella parapitica n. sp., collected from the rhizosphere of an apple tree in Kermanshah province, western Iran, is described. The new species is characterized by a body length of 505 to 723 µm (females) and 480 to 600 µm (males), lip region continuous by depression; 7 to 8 μm broad, 3 to 4 µm high, stylet length 7 to 9 µm or 1 to 1.3 times the lip region diameter, short postuterine sac of 4 to 6 μm long, lateral fields with five to six incisures; outer incisures crenated and inner incisures weakly crenated, excretory pore situated 90 to 100 µm from anterior end; functional males common in the population, with spicules 24 to 26 μm long. Tail of both sexes similar, almost straight and elongate-conoid. The new species resembles in morphology and morphometrics to four known species of the genus, namely P. apitica, P. minuta, P. myceliophaga, and P. sohailai. The results of phylogenetic analyses based on sequences of D2/D3 expansion region of 28S rRNA gene revealed this genus is polyphyletic in four different clades in Tylenchid.     

A genetic model and molecular markers for wild oat (Avena fatua L.) seed dormancy

Seed dormancy allows weed seeds to persist in agricultural soils. Wild oat (Avena fatua L.) is a major weed of cereal grains and expresses a range of seed dormancy phenotypes. Genetic analysis of wild oat dormancy has been complicated by the difficulty of phenotypic classification in segregating populations. Therefore, little is known about the nature of the genes that regulate dormancy in wild oat. The objectives of our studies were to develop methods to classify the germination responses of segregating wild oat populations and to find molecular markers linked to quantitative trait loci (QTL) that regulate seed dormancy in wild oat. RAPD markers OPX-06 and OPT-04 explained 12.6% and 6.8% respectively, of the F₂ phenotypic variance. OPF-17 was not significant in a simple regression model, but it was linked in repulsion to OPT-04. A three-locus model of seed dormancy in wild oat is presented based on the 41-day germination profiles of F₁, F₂, F₃, BC₁P₁F₁, BC₁P₁F₂, and BC₁P₂F₁ generations, and the 113 day germination profile of 126 F₇ recombinant inbred lines. Loci G ₁ and G ₂ promote early germination, and the D locus promotes late germination. If at least one copy of the dominant G ₁ or G ₂ alleles are present regardless of the genotype at D locus, then the individual will be nondormant. If the genotype is g ₁ g ₁ g ₂ g ₂ D_, then the phenotype will be dormant. Received: 1 December 1998 / Accepted: 1 February 1999     

Morphological and molecular characterization of Laimaphelenchus deconincki (Nematoda: Aphelenchoididae) based on specimens from Iran

During a survey for nematodes associated with conifers in northern Iran, a known species of Laimaphelenchus was found in the bark samples of Taxus baccata L. trees and is described and illustrated here as L. deconincki Elmiligy & Geraert, 1972. It is characterized by lacking a distinct labial disc on the cephalic region; having six amalgamated labial sectors of equal width, separated by pairs of well-developed ribs; three lines in lateral field; the presence of a vulva flap; vagina surrounded by a cuticularised tube in which the walls vary in thickness; the post-uterine sac 25–62 μm long; tail with a single stalk-like terminus and four pedunculate tubercles; and absence of males. L. deconincki is morphologically very similar to L. cocuccii, but differs in the shape of the vaginal musculature (more angular vs round). Additional information on morphological characters and also the phylogenetic relationships of this known species using sequences of the D2/D3 region of the 28S ribosomal RNA gene is provided and added herein.