Amplification Of Polymorphic DNA Research Articles

Forensic Application of Genetic and Toxicological Analyses for the Identification and Characterization of the Opium Poppy (Papaver somniferum L.).

Simple SummaryThe identification and characterization of illicit plant species such as Papaver somniferum L. (opium poppy) are essential in order for law enforcement agencies to obtain information about the origin of seized drugs, and to improve the monitoring of illegal drug trafficking routes. This study focuses on the genetic and toxicological analyses of some poppy capsules seized by the Italian Police Forces in 2017 and 2018. The detection of specific morphological traits, the chemical study of the alkaloid profile by gas chromatography coupled with mass spectrometry (GC/MS), and the genetic analysis performed by the DNA barcode approach showed that the seized poppy capsules belonged to P. somniferum. The data collected also suggested that the opium capsules originated from Afghanistan.Background: A reliable and science-based taxonomic determination of Papaver somniferum L. (opium poppy), the illegal species of the genus Papaver, may have practical and legal implications for law enforcement. P. somniferum is a controlled plant because of its narcotic substances, such as morphine and codeine. As poppy plants have rather similar morphological features, both chemical and genetic analysis are required in order to achieve an accurate characterization of such species. The chemical structures of alkaloids are extremely variable even within the same species, which is why the genetic approach may lead to a more scientific Papaver sp. differentiation. The aim of our study was the taxonomic identification of poppy capsules seized by the Italian Police Forces being considered as potential P. somniferum derivatives. Methods: The alkaloids detected using gas chromatography/mass-spectrometry (GC/MS) were morphine, codeine, thebaine, noscapine, meconin, hydrocotarnine, and traces of papaverine. Further genetic analysis was carried out simultaneously using three plastid DNA barcoding regions (matK, trnH-psbA, and rbcL) for the samples’ identification. Results: The Random Amplification of Polymorphic DNA (RAPD) method showed that the analysed samples were genetically identical. Conclusions: The morphological, toxicological, and genetic profile of the samples revealed that they belonged to P. somniferum species. Furthermore, the alkaloid content of dried poppy capsules might be used to investigate and track their origin.

Assessment of Genetic Variation of the Genus Gymnema in Vietnam, Using RAPD and ITS-rDNA Markers

ABSTRACT Gymnema is a genus of the Apocynaceae with more than 50 species. Some of its species such as G. sylvestre and G. latifolium have been reported for their medicinal value. In this study, the genetic diversity of 20 samples of four species of Gymnema in Vietnam was evaluated using the Random Amplification of Polymorphic DNA (RAPD) and the internal transcribed spacer of nuclear ribosomal DNA (ITS-rDNA). Amplified bands obtained with primers UBC701, UBC709, and OPC4 were the highest polymorphic in RAPD analysis. The phylogenetic trees were built grouping the 20 samples into four clusters corresponding to the four Gymnema species according to morphological classification. A number of characteristic SNPs were identified for each species which can be used for authentication and differentiation. The results showed the consensus and usefulness of the two barcoding techniques in the molecular identification and characterization of the Gymnema genus.

Molecular Typing, Antibiotic Resistance and Enterotoxin Gene Profiles of Staphylococcus aureus Isolated from Humans in South Korea.

The emergence of antimicrobial-resistant Staphylococcus aureus has become a grave concern worldwide. In this study, 95 strains of S. aureus isolated from stool samples were collected from Busan, South Korea to characterize their antimicrobial susceptibility, enterotoxin genes, and molecular typing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and random amplification of polymorphic DNA (RAPD) assay. Only two strains showed no drug resistance, whereas resistance to three or more antibiotics was observed in 87.4% of strains. Ampicillin resistance was the most common at 90% and all strains were susceptible to vancomycin. The distribution of enterotoxin genes encoded in isolates was sea (32.6%), sec (11.6%), seg (19%), sea & sec (2.1%), and sec & seg (34.7%). Molecular typing using both MALDI-TOF MS and RAPD indicated that S. aureus exhibited diverse clonal lineages and no correlations were observed among the profiling of enterotoxin, MALDI-TOF MS, and RAPD. This investigation provides useful information on foodborne pathogenic S. aureus that has a significant public health impact in South Korea.

Prevalence and Genetic Diversity of Escherichia coli Isolated from Sewage Samples of Hospitals in Different Regions of Bangladesh

Escherichia coli are a large and diverse group of bacteria found in the environment, foods and intestines of humans and animals. This study was carried out to observe the genotypic variations in E. coli found at different regions in Bangladesh using Amplified Ribosomal DNA Restriction Analysis (ARDRA) of the 16S rDNA and RAPD (Random Amplified Polymorphic DNA). Sewage samples were collected from different medical college hospitals and a total of 118 samples were observed in this study of which 26 were identified as E. coli based on their cultural, biochemical and molecular characteristics. Antibiotic susceptibility test was carried out where most isolates were resistant to Amoxicillin, Rifampicin and Erythromycin; and some were resistant to kanamycin, ceftriaxone, Chloramphenicol and Azithromycin; besides 73% (N=19 out of 26) of the test isolates were multi-drug resistant. Results of Polymerase chain reaction (PCR) showed that none of the isolates carried Stx1, Stx2 and LT gene. Two genotypic groups were found from Amplified Ribosomal DNA Restriction Analysis (ARDRA) by Alu1 restriction enzyme and seven different Random Amplification of Polymorphic DNA (RAPD) patterns were found. After analyzing, it was found that 24 out of 26 isolates showed similarity with Escherichia coli strain NBRC 102203 and the remaining two isolates showed similarity with Escherichia coli strain Mui T5 based on the restriction patterns of ARDRA and sequences of 16S rDNA. From the study, it was concluded that Escherichia coli strain NBRC 102203 was more prevalent than Escherichia coli strain Mui T5 isolated from sewage sample of hospitals from different regions of Bangladesh.
 Bangladesh J Microbiol, Volume 38, Number 2, December 2021, pp 39-44

High-Frequency Plant Regeneration, Genetic Uniformity, and Flow Cytometric Analysis of Regenerants in Rutachalepensis L.

Ruta chalepensis L., an evergreen shrub in the citrus family, is well-known around the world for its essential oils and variety of bioactivities, indicating its potential medicinal applications. In this study, we investigated the effect of different culture conditions, including plant growth regulators, media types, pH of the medium, and carbon sources, on in vitro regeneration from nodal explants of R. chalepensis. Following 8 weeks of culture, the highest percentage of regeneration (96.3%) and maximum number of shoots (40.3 shoot/explant) with a length of 4.8 cm were obtained with Murashige and Skoog (MS) medium at pH 5.8, supplemented with 3.0% sucrose and 5.0 µM 6-Benzyladenine (BA) in combination with 1.0 µM 1-naphthaleneacetic acid (NAA). For rooting, individually harvested shootlets were transferred on ½ MS (half-strength) supplemented with IAA (indole-3-acetic acid), IBA (indole 3-butyric acid), or NAA, and the best response in terms of root induction (91.6%), number of roots (5.3), and root mean length (4.9 cm) was achieved with 0.5 µM IBA after 6 weeks. An average of 95.2 percent of healthy, in vitro regenerated plantlets survived after being transplanted into potting soil, indicating that they were effectively hardened. DNA assays (PCR-based markers) such as random amplification of polymorphic DNA (RAPD) and directed amplification of minisatellite-region (DAMD) were employed to assess in vitro cultivated R. chalepensis plantlets that produced a monomorphic banding pattern confirming the genetic stability. Additionally, no changes in the flow cytometric profile of ploidy between regenerated plantlets and donor plants were detected. Regeneration of this valuable medicinal plant in vitro will open up new avenues in pharmaceutical biotechnology by providing an unconventional steadfast system for mass multiplication and might be effectively used in genetic manipulation for enhanced bioactive constituents.

GENETIC DIVERSITY EEL Anguilla marmorata BY RAPD IN THUA THIEN HUE PROVINCE, VIETNAM

Anguilla marmorata is a species with high economic value and increasingly interested by organizations and scientists. So far, many of the eel's biological characteristics remain mysterious, and they are often classified according to morphological features such as pigmentation patches, number of vertebrae, ... It is even difficult to distinguish one individual from another in some species, especially in the larval stage. In this study, the Random amplification of polymorphic DNA (RAPD) molecular marker was used to evaluate the genetic diversity of 48 eels collected in Thua Thien Hue province. Results showed that the genetic diversity of individuals in the Eel population studied is quite high. With 8 random primers via PCR, 77 DNA tapes with 76 polymorphic tapes were obtained, the tape size ranged from 170-2,500 bp, in which primer S10 showed the highest diversity with an average Ho value of 0.563, followed by primer S8 (Ho = 0.558). The lowest diversity was in the OPD5 primer (Ho = 0.300). The OPG17 primer is the primer that produces the most polymorphic tapes (13/13 tapes) and the S3 primer for the least amplified tapes polymorphism (9/10 DNA tapes). The diversity coefficient in each random primer ranged from about 0.300 to 0.563, with an average of 0.433. The genetic variation in the Eel population is random. Genetic variation can be attributed mainly to different eel breeding conditions and origins. Genetic similarity coefficients among the Eels varied from 0.660 to 0.910 and were divided into two main groups in genetic similarity coefficient 0.660.

Antibiotic resistance and phylogenetic comparison of human, pet animals and raw milk Staphylococcus aureus isolates

The present study was conducted to compare the S. aureus isolates from different sources in the basis of resistance phenotypic and genotypic features and phylogenetic differences. Total of 70 S. aureus isolates (including 25 human, 25 raw milk and 20 pet animal isolates) were subjected to the antimicrobial susceptibility testing, polymerase chain reaction (PCR) detection of the resistance genes and DNA fingerprinting using random amplification of polymorphic DNA–PCR (RAPD-PCR) to survey the variability of the isolates. Among 70 S. aureus, 55 (78.5%) isolates were MRSA. The isolates showed the highest antibiotic resistance to methicillin, ampicillin and penicillin (78.5%) and showed the lowest resistance to ciprofloxacin (12.8%). ErmB and tetM resistance genes were present in all isolates and the vanA gene was not detected in any of the isolates. Thirteen distinct clusters were identified in RAPD-PCR fingerprinting. Statistical analysis showed that the isolates without resistance to antibiotics were significantly in associated with raw milk origin (P < 0.05). According to the results of the study, S. aureus strains with pets and raw milk origin are significant sources of antibiotic-resistant isolates such as MRSA. They are also carriers of resistance genes that can be transmit to human isolates and cause drug resistance in human infections. Identifying the source of these infections is possible with a reliable genotyping method such as RAPD-PCR.

Prevalence of \u03b2-lactamase-encoding genes and molecular typing of Acinetobacter baumannii isolates carrying carbapenemase OXA-24 in children

Backgroundβ-Lactam antibiotics have been broadly used for the treatment of Acinetobacter baumannii infections, resulting in development of β-lactam inactivating β-lactamases. Here, we described antibiotic resistance rate, prevalence of β-lactamase-encoding genes, and clonal relationships of A. baumannii strains isolated from children referred to Children’s Medical Center in Tehran, Iran, during 2019–2020.MethodsA total of 60 non-replicate A. baumannii isolates were recovered from clinical specimens of pediatric patients. Antibiotic susceptibility testing was done by the disc diffusion method. Colistin susceptibility of isolates was performed by the broth microdilution method. β-lactamase-encoding genes were characterized by PCR. The presence of ISAba1 element upstream of the several oxacillinase genes was also checked. Genetic relatedness of isolates was determined by using random amplification of polymorphic DNA (RAPD) typing.ResultsThe antimicrobial susceptibility tests showed that 83.3% of A. baumannii isolates were MDR, and 40% XDR. Both MDR and XDR A. baumannii isolates were susceptible to colistin. The frequency of blaOXA-51-like, blaOXA-23-like, blaTEM, blaOXA-24-like, blaPER, blaSHV, blaCTX-M, blaOXA-58-like, and blaIMP was 100, 93.33, 60, 36.67, 28.33, 8.33, 5, 3.33, and 1.67%, respectively. Coexistence of ISAba1/blaOXA-23-like and ISAba1/blaOXA-51-like was observed in 65% and 85% of isolates, respectively. RAPD analysis revealed 4 common types and 2 single types of A. baumannii isolates.ConclusionsThe multiple clones harboring blaOXA-23-like, ISAba1-blaOXA-51-like, and ISAba1-blaOXA-23-like were responsible for the spread of A. baumannii isolates in our clinical wards. Dissemination of the well-established clones is worrisome and would become therapeutic challenges due to the possible transferring genetic elements associated with resistance.

Genetic diversity of Betula nana in Sweden and conservation implications for protection of relict Polish populations

Abstract The natural range of the dwarf birch (Betula nana L.) includes the boreal, subarctic and arctic regions of Europe, Asia and North America, where it is relatively common. In Poland, it is a relict species occurring in fragmented populations. Using the random amplification of polymorphic DNA (RAPD) technique, we investigated the genetic diversity of the four Swedish populations representing a part of the continuous range of dwarf birch. With the knowledge of the level of genetic diversity of a population from a continuous distribution, we can assess the genetic status of polish populations and answer the question if habitat fragmentation and a decrease in population size lead to a loss in genetic diversity. Knowledge of genetic diversity is important for species conservation, especially to predict their ability to respond to environmental pressures. We found that the populations Abisko, Malbo, Gällivare and Storlien, which are located at the edge of the natural range of B. nana and occupy different habitats, are genetically diverse to varying degrees. The northern populations from Abisko and Gällivare showed a lower level of genetic polymorphism than the population from Malbo, the southernmost site of dwarf birch in Sweden. The data presented indicate higher genetic diversity existed within populations, whereas genetic differentiation between populations was lower. The high level of genetic differentiation within B. nana populations that were analysed in the present study may be explained by a limited capacity for dispersal among populations via both pollen and seeds. We found that the level of genetic diversity in one of the Polish populations of B. nana is comparable to that in areas in Scandinavia where populations are large and continuous. Based on these studies, we conclude that the “Linje” population has sufficient genetic resources.

Genetic variability of spiralling whitefly Aleurodicus disperses Russell on Citrus aurantifolia Christm and Ocimum gratissimum L.

The spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae), has a wide range of anatomy, physiology, behaviour, and ecology depending on the host plant. This research looked at the genetic variations between A. dispersus populations on two separate host plants (Citrus aurantifolia and Ocimum gratissimum). The existence of host-related genetic variation in A. dispersus populations was determined using Rapid Amplification of Polymorphic DNA (RAPD) markers. Our findings revealed that the A. dispersus populations on the two host plants had a considerable amount of genetic divergence. The spiralling whiteflies on the adaxial part of Citrus aurantifolia were genetically distinct from those on the abaxial part of the same plants. Various population genetic parameters such as heterozygosity, Nei's genetic gap, and fixation indices (FST) revealed that spiralling whitefly populations vary genetically, which may be attributable to spiralling whitefly populations originating from multiple sources. These findings also have consequences for the invasive pest's quarantine safety strategy.

Investigation of Phages Infecting Escherichia coli Strains B and C, and Enterobacter cloacae in Sewage and Ebrié Lagoon, Côte d'Ivoire.

Background: Bacteriophages are a promising biotechnological against bacterial pathogens. Currently, phage research is garnering interest in sub-Saharan countries as bacterial resistance to antibiotics becomes widespread. They are sought in all environments as they offer the possibility of a sustainable alternative to antibiotics. Materials and Methods: Altogether 30 water samples from urban sewage and environmental water were screened for the presence of bacteriophages able to infect Escherichia coli and Enterobacter cloacae. Their genomic diversity was determined by random amplification of polymorphic DNA (RAPD)-PCR fingerprinting. Results: We isolated 35 phages including 9 polyvalent phages that infect simultaneously E. coli and E. cloacae. This study allowed first isolation of E. cloacae-specific phages in Côte d'Ivoire. All phages were distinct based on their RAPD band patterns. Conclusions: Sewage systems of Yopougon and the environmental water of Ebrié lagoon were a rich source of phages. The phage collection could be useful for phage application in Côte d'Ivoire.

First report from Bangladesh on genetic diversity of multidrug-resistant Pasteurella multocida type B:2 in fowl cholera.

Background and Aim:Fowl cholera (FC) caused by Pasteurella multocida is a highly contagious bacterial disease of global importance for poultry production. The severity and incidence of FC caused by P. multocida may vary considerably depending on several factors associated with the host (including species and age of infected birds), the environment, and the bacterial strain. This study aimed to investigate the genetic diversity of multidrug-resistant P. multocida strains isolated from FC outbreaks in laying hens from commercial farms of Bangladesh.Materials and Methods:We collected 57 samples of suspected FC, including 36 live and 21 dead laying hens. P. multocida isolates were characterized by biochemical and molecular-biological methods.Results:Twenty-two strains of P. multocida were isolated from these samples through phenotypic and genotypic characterization. The strains were grouped into two distinct random amplification of polymorphic DNA (RAPD) biotypes harboring a range of pathogenic genes; exbB, ompH, ptfA, nanB, sodC, and hgbA. In this study, 90.90% and 81.82% P. multocida strains were multidrug-resistant and biofilm formers, respectively. Whole-genome sequencing of the two representative RAPD phylotypes confirmed as P. multocida type B: L2:ST122, harboring a number of virulence factors-associated genes (VFGs), and antimicrobial resistance (AMR) genes (ARGs). In addition, pan-genome analysis revealed 90 unique genes in the genomes of P. multocida predicted to be associated with versatile metabolic functions, pathogenicity, virulence, and AMR.Conclusion:This is first-ever report on the association of P. multocida genotype B: L2:ST122 and related VFGs and ARGs in the pathogenesis of FC in laying hens. This study also provides a genetic context for future researches on the evolutionary diversity of P. multocida strains and their host adaptation.

Using Primers of Random Amplification Polymorphism DNA (RAPD) in Molecular Identification of Peach Cultivars Prunus persica (L.) Batsch Rosaceae

The present study includes identification of (9) cultivars of the species Prunus persica (L.) Batsch. Which were Early Grand , Babcock , Giant Babcock , Mammoth , Elberta , Cardinal , Blanko , Novadona ,and Transvalia cultivated in Ninevah Iraq by using random genetic primers in amplification polymorphic DNA (RAPD). (9) random primers were used and amplifications were deported within the agrose . The results showed that the amount of the nucleic acid ranged between (20-25) µg/ml of the leaves extract and reactions of the randomly amplification were carried out with (9) primers, all of them migrated within agarose gel, and generated an amplified bands of DNA. The results have admitted to the Computer and analyzed using private statistical program PAST. The results have showed that the genetic discrepancy value reached (0.7264) in Transvalia cultivar whereas the minimum value of the genetic variant reached to (0.108) in the cultivar Cardinal. The dendrogram was also showed that the cultivar Babcock, Giant Bacock, Transvalia and Novadona were the most similar to each other, whereas cultivars Cardinal was the most variant from the other cultivar studies.

DNA Damage in Human Amniotic Cells: Antigenotoxic Potential of Curcumin and α-Lipoic Acid.

Oxidative imbalances in the gestational phase are responsible for certain complications during pregnancy and for foetal and neonatal genetic disorders. In this work, using human amniocytes, we aimed to evaluate the protection provided to foetal DNA by two concentrations of antioxidant molecules, α-lipoic acid (LA) and curcumin (Cur), against hydrogen peroxide (H2O2)-induced damage. Genotoxicity tests, performed by the random amplification of polymorphic DNA (RAPD-PCR) technique and TUNEL tests, showed that the lowest concentration of LA-protected cells and DNA from H2O2 insults. However, a greater ability to protect the amniocytes’ DNA against H2O2 was observed following co-treatment with the highest concentration of Cur with H2O2. In fact, a genomic template stability (GTS%) similar to that of the negative control and a statistically significant reduction in the DNA fragmentation index (DFI) were revealed. Moreover, following a combined treatment with both antioxidants and H2O2, no statistical difference from controls was observed, in terms of both induced mutations and DNA breaks. Furthermore, no effect on morphology or cell viability was observed. The results demonstrate the ability of LA and Cur to protect the genetic material of amniocytes against genotoxic insults, suggesting their beneficial effects in pathologies related to oxidative stress.

Strain Typing of Trichosporon asahii Clinical Isolates by Random Amplification of Polymorphic DNA (RAPD) Analysis.

Objective The aim of this study was to identify and isolate Trichosporon asahii ( T. asahii ) from clinical samples and to assess the genetic relatedness of the most frequently isolated strains of T. asahii using random amplification of polymorphic DNA (RAPD) primers GAC-1 and M13. Methods All the clinical samples that grew Trichosporon species, identified and confirmed by polymerase chain reaction (PCR) using Trichosporon genus-specific primers, were considered for the study. Confirmation of the species T. asahii was carried out by T. asahii- specific PCR. Fingerprinting of the most frequently isolated T. asahii isolates was carried out by RAPD using random primers GAC-1 and M13. Results Among the 72 clinical isolates of Trichosporon sp. confirmed by Trichosporon -specific PCR, 65 were found to be T. asahii as identified by T. asahii- specific PCR. Fingerprinting of the 65 isolates confirmed as T. asahii using GAC-1 RAPD primer yielded 11 different patterns, whereas that of M13 primer produced only 5 patterns. The pattern I was found to be the most predominant type (29.2%) followed by pattern III (16.9%) by GAC-1 primer. Conclusions This study being the first of its kind in India on strain typing of T. asahii isolates by adopting RAPD analysis throws light on genetic diversity among the T. asahii isolates from clinical samples. Fingerprinting by RAPD primer GAC-1 identified more heterogeneity among the T. asahii isolates than M13.

Genetic Resources and Diversity among Sheep Breeds of Asia and Europe

Sheep has been domesticated southwestern Asia for about 8000-9000 years ago and represented one of earliest livestock species. Ancestor relationship can be investigated through mtDNA data. There are many genetic markers to determine the relationship between and among the sheep breeds. Restriction fragment length polymorphisms are basic technique and have less variability and many restrictions as compared to Random amplification of polymorphic DNA. Due to specific amplification of Amplified fragment length polymorphisms it is more suitable than Restriction fragment length polymorphisms and Random amplification of polymorphic DNA. Microsatellites are widely used technique for the determination of genetic diversity. This technique provides information about the classification and characterization of sheep breeds. However this technique cannot provides information on breed functional traits. On the basis of mtDNA analysis haplotypes groups differ in sequences by any extent of Ovis species. Haplotype A and B are two of most important haplotype groups. Haplotype A carries Asiatic mouflon (Ovis orientalis) while Haplotype B carries European mouflon (Ovis musimon). Actually Haplotype A and B are both found in Asia while Haplotype B only dominates in Europe so sheep descent from one or more Asiatic mouflon. Haplotype C also found in Turkey, Portugal, Caucasus and China while Haplotype D present in Karachai sheep from Caucasian. Haplotype E which is very rare and found only in Turkey.

Molecular Systematic Investigations of Three Fin Fish Cichlid Species of Oreochromis niloticus (Nile Tilapia), Genetically Improved Farmed Tilapia (GIFT) and Astronotus ocellatus (Oscar Cichlid)

Fisheries in India contribute significantly to the total GDP of agriculture and earn significant foreign exchange. Aquaculture is playing an important role in India and is bestowed with a huge biodiversity of aquatic organisms. India ranks second in total fish production in the world. Nile tilapia has become the world’s second most popular farmed fish, after carps. Oscars is a popular aquarium fish around the world. In the present study, efforts were made to analyze the extent of divergence or similarity among three cichlid finfishes (Nile Tilapia, GIFT Tilapia, and Oscar Cichlid) using molecular biology techniques such as Random Amplification of Polymorphic DNA (RAPD) and Restriction Fragment Length Polymorphism (RFLP). The Phylogenetic tree was constructed using PhyElph software to study the evolutionary relationship between the three cichlid finfish species. The Phylogenetic or evolutionary relationship was established for the three fishes, Nile tilapia, GIFT, and Oscar cichlid, with the Phylogenetic tree. It was found that Nile tilapia and GIFT share a recent common ancestor, while Oscar cichlid does not share any evolutionary relationship with Nile tilapia and GIFT.

Molecular Characterization and Allelopathic Potential of Radish Species on Wheat and Weed Species

This study was conducted at Salahaddin University/ College of Agricultural Engineering Science, to inspect the allelopathic effects of radish (Raphanus sativus L.) on two wheat species and two endemic weed species. The study included two experiments, first one was bioassay experiment to estimate the aqueous extracts effect of three radish species (red, black and white) at five concentration levels (0, 10, 20, 30, and 40%) on germination and seedling growth of bread wheat (Triticum aesitivum Var. Adana), hard wheat (Triticum durum Def. Var. Smito) and two endemic weed species wild oat (Avena fatua) and wild barely (Hordeum spontaneum). Results indicated that aqueous extracts of black radish possess more allelopathic potential compare to red and white radish, also, aqueous extracts significantly affected on all studied plant species at dissimilar ratio, while most effective concentration was (40%). Whereas the germination of all plant species totally inhibited at this concentration. The second experiment aimed to indicate the genetic relatedness (genetic diversity) among radish species by using Random amplification of polymorphic DNA (RAPD-PCR) technique. The results indicate that the genetic distance among the three studied radish species ranged from 17.33 to 37.6. The lowest genetic distance was recorded between black and red that was 17.33 and the highest genetic distance recorded between black, red with white was 37.6 and white radish with each of black and red radish were 65.067. the results suggested that radish species have different allelopathic potential and genetic variance exist among them.

GENETIC DIVERSITY OF Digitaria horizontalis Willd. IN BUILT ENVIRONMENTS IN BENIN CITY, NIGERIA

The influence of humans on biodiversity at the genetic, species, community, and ecosystem levels is enormous. This is even more impactful on plant populations, which, being immobile, are at the mercy of their immediate environment. Digitaria horizontalis is a very common grass species in Benin City. Its ruderal nature accounts mostly for its widespread. The current study investigated the existence of possible genetic diversity of the grass in built environment in Benin City. Plant samples were randomly collected from 21 built environment locations within 6 Local Government Council Areas that make up Benin City. Test plants were allowed to acclimatize in experimental bowls and then allowed to grow for 4 weeks after which morphological characteristics were determined. Genetic diversity was determined by Random Amplification of Polymorphic DNA. Significant differences in plant height (33.0 – 59.0 cm) occurred when plants were compared based on location of collection. Changes in patterns of the association with weeds within the vicinity of the test plant was observed. The most prevalent plant species associated with the test plant was Pennisetum purpureum with a 12.18% prevalence. RAPD analysis using primer OPA 04 revealed a locus (about 600bp) that was absent in one or more of the locations with minimum disturbance. This 600pb fragment was however observed in most samples from highly built up and trampled environments. Primer OPA 03 showed monomorphic bands in 2 test samples with a band size of 400bp. It is therefore reported that there is an existence of the genetic diversity in a landscape of grass species (Digitaria horizontalis) found in different built environment in Benin City, Edo State, Nigeria.

RAPD, ISSR, and SCoT markers based genetic stability assessment of micropropagated Dendrobium fimbriatum Lindl. var. oculatum Hk. f.- an important endangered orchid

Dendrobium fimbriatum is an ornamental and medicinal orchid listed in the Red data book of IUCN. Phytohormones' effect on the in vitro regeneration of the orchid was studied using Mitra medium supplemented with different growth regulators. KN produced effective shoot formation when present alone or in combination with IBA or NAA. The shooting was gradually increased when KN concentration was increased from 0.8 to 4.8 mg L-1, but the opposite response was observed with BAP at higher concentration (4.8 mg L-1). IBA either in combination with BAP or KN promoted effective root development and multiplication. Micropropagated orchids grown in the basal medium devoid of any phytohormone showed 100% monomorphism, while low genetic polymorphism of 1.52% (RAPD-Random Amplification of Polymorphic DNA), 1.19% (ISSR-Inter Simple Sequence Repeat) and 3.97% (SCoT-Start Codon Targeted) was exhibited among the regenerants propagated in the hormone enriched medium. UPGMA (Unweighted pair group method using arithmetic averages) dendrograms showed the grouping of mother plant (MP) with the in vitro regenerants. The principal coordinate analysis (PCoA) further confirmed the clustering patterns as determined by the cluster analysis. The study reported for the first time the successful in vitro propagation of Dendrobium fimbriatum and their genetic stability assessment using molecular markers.