Search

The present study was conducted to differentiate pathotypes of Xanthomonas citri subsp. citri (Xcc) the causal agent of citrus canker in Iran. A collection of 29 strains were isolated from infected plant parts. In order to investigate the genetic diversity of bacterial isolates, RAPD and ISSR markers were used and discrimination power of these markers for the pathotype detection was assessed. Based on the amplified fragments of the RAPD, the dendrogram divided the strains into three main groups. In the first group, there were eight strains of both pathotypes A and A*, and all strains of A* pathotype were categorized in this group. Strains of pathotype A formed the second and third groups. Based on the results of the ISSR amplified fragments, the dendrogram classified the strains into three main groups. The resultant grouping was indicative of placement of A strains in one group, and in all groups, both A and A* pathotypes were grouped together. The electrophoresis patterns of amplified fragments with RAPD primers revealed high specificity of this marker in pathotype differentiation.

In this study, a simple, rapid, and efficient plant-mediated green approach was presented for the synthesis of stable and ultra-small zinc telluride quantum dots (ZnTe QDs) using the aqueous extract of the Ficus johannis plant. Two modern techniques, namely ultrasonic and microwave techniques, were applied to prepare the plant extracts, which were then used as stabilizing precursors in the synthesis of ZnTe QDs. The synthesized samples were characterized via different techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible absorption, photoluminescence and Fourier transform infrared spectroscopy. The TEM images confirmed the formation of ultra-small nanoparticles with an average size of 8 nm. According to the optical characterization, a wide absorption band around 390 nm and an intense emission peak at 463 nm clarified the successful synthesis of ZnTe QDs. After synthesis and characterization, the antioxidant, antimicrobial, and antifungal potentials of the as-prepared QDs as well as the plant extracts were examined by different tests, comparatively. In addition, the determination of the total phenolic and flavonoid contents of the as-prepared samples was carried out. Moreover, the toxicity of the samples was investigated by Artemia uramiana from their brine shrimp lethality potentials. In the cytotoxicity tests, the inhibition of root growth was considered as an indicator to evaluate the cytotoxicities of the samples.

Lead (Pb) is one of the most dangerous pollutants in the environment. In this research, the effects of Pb on growth, Pb accumulation in root and shoot and the levels of physiological/biochemical stress markers in leaves were investigated in two types of faba bean (Vicia faba L.). Plants were grown in sand, watered with half-strength Hoagland’s nutrient solution with 0, 5, 25, 100 or 125 μM of lead nitrate. Pb did not significantly affect the root and shoot dry weights. After two weeks of Pb treatment, the plants were harvested and stored for analyses. In leaves Pb significantly decreased the relative water content and the total chlorophyll concentration and significantly increased the proline concentration, but did not significantly affect the peroxidase activity and soluble sugar concentration. Overall, the large-seeded and the small-seeded type responded similarly to Pb, although there were barely significant type *Pb interactions for total chlorophyll and proline. The large-seeded type had significantly higher root and shoot dry weights and a higher foliar soluble sugar concentration, compared to the small-seeded one. Pb accumulation in roots was not significantly different between the types. However, the small-seeded type accumulated much more Pb in the shoot, resulting in a significantly higher root to shoot translocation factor.

The genetic diversity of 18 Iranian populations of Nigella sativa L. was tested using RAPD (10 primers) and ISSR (12 primers) molecular markers. RAPD primers produced 103 acceptable bands and out of them, 42 bands were polymorphic and the total percentage of polymorphism was estimated 40.5%. Out of the 12 ISSR primers, only 5 of them produced acceptable bands. Five ISSR primers generated 39 amplified products and out of them, 19 bands were polymorphic and the total percentage of polymorphism was estimated 57.4%. As a result, the level of polymorphism obtained from the ISSR markers was higher than of the RAPD markers. Mean of marker index (MI) (0.822 for RAPD and 0.74 for ISSR) and Polymorphic information content (PIC) (0.402 for RAPD and 0.35 for ISSR) for each of the marker systems indicated that both markers were effective for evaluating genetic diversity. Cluster analysis classified the populations into 5 groups for both DNA markers. By integration and analyzing of the two marker systems, the populations were classified into 4 groups. The results of this research showed that RAPD and ISSR molecular markers can be useful for identifying and classifying the Iranian Nigella sativa L. populations.

Contamination of soil with heavy metals is one of the important concerns of public health and food production. Nickel is a heavy metal whose toxic properties have been confirmed. In some plants, nickel has also been known as a useful metal for their growth. In this research, the response of two chamomile species to different levels of nickel was investigated in two stages of germination and callogenesis in vitro conditions in factorial experiment based on completely randomized design. In the first experiment, the effect of different concentrations of nickel sulfate (0, 60, 120, and 180 µM) was examined on germination of German (Matricaria chamomilla) and Aurea (M. aurea) chamomile seeds in the MS culture medium. The results indicated that at high levels of nickel sulfate, the speed and percentage of germination increased in both types of chamomile. In M. chamomilla, with the increase in the concentration of nickel sulfate, the length of the seedling decreased, but the seed weight vigor, length of the radicle, and dry weight of the seedling increased. M. aurea showed elevation in most indices. The results of the second experiment indicated that the M. chamomilla leaf explants had callogenesis and its callogenesis indices showed a significant decrease at high levels of nickel, when compared with the control In M. aurea, the calluses did not grow sufficiently, suggesting the sensitivity of M. aurea’s callogenesis to the presence of different levels of nickel. In conclusion, chamomile appears to be tolerant to nickel stress.

Citrus bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc), is a widespread disease in citrus-producing areas of the tropics and subtropics. It is a serious threat to most commercial citrus cultivars and species. In this study, aggressiveness of different isolates of Xcc was determined on leaves of Citrus aurantiifolia, Citrus limon ‘Eureka’ and Citrus sinensis, and the population dynamics of isolates of two Xcc pathotypes (A and A*) was evaluated on eight plant species considered weeds of citrus, including Amaranthus caudatus, Medicago sativa, Sorghum halepense, Xanthium strumarium, Portulaca oleracea, Avena ludoviciana, Plantago lanceolata and Chenopodium album under greenhouse conditions. Isolates varied from aggressive to weakly aggressive on the basis of the intensity and persistence of water soaking and the development of necrosis 12 days post-inoculation. Both Xcc pathotypes multiplied on all plant species tested except Portulaca oleracea up to 20 days post-inoculation under greenhouse conditions. A high bacterial growth rate was observed on Medicago sativa and Plantago lanceolata. Strains of the A* pathotype successfully proliferated on all weeds except Portulaca oleracea, attaining a population density even higher than that of the A pathotype. The results clearly suggest that weed management is an important strategy in controlling canker disease in citrus-growing areas.

In this work, a quick, facile and efficient approach was presented for green synthesis of cadmium telluride quantum dots (CdTe QDs) based on an aqueous extract of the Ficus johannis plant. Two extraction methods involving microwave assisted extraction (MWAE; 90 and 270 w; 15 min) and ultrasonic assisted extraction (USAE; 15 min; 45 °C) were performed as eco-friendly, effective, green and fast techniques for the extract preparation of the fruit's plant. The as-prepared plant extracts were used as natural stabilizing precursors in the synthesis of CdTe QDs. The synthesized QDs were characterized using various techniques. The average particle size of the QDs from the X-ray diffraction patterns was calculated to be 1.2 nm. UV–Vis absorption and fluorescence spectroscopic studies show a wide absorption band from 400 to 425 nm and a maximum emission peak around 470 nm, which confirmed the successful synthesis of CdTe QDs via the applied synthetic method. After synthesis and characterization of the samples, the antimicrobial properties, genotoxicity, toxicity and antifungal activities of the as-prepared CdTe QDs were investigated. In addition, antioxidant properties of the samples (QDs and extracts), were evaluated by different antioxidant assays. The results indicate the significant antimicrobial activity of the extract and CdTe QDs samples, with negligible toxicity and genotoxicity impacts.

Myrtus communis L. is one member of the Myrtaceae family. It is one of the important medicinal plants in the Zagros region of Iran. The Essential oils include a large percentage of compounds called terpenes. In this study, the chemical composition of essential oils of Myrtus (Myrtus communis L.) was identified by the GC-MS method. Results showed that essential oils of populations from different regions have a series of similar compounds, but different in quality and quantity. In fact, they have several organic compounds such as hydrocarbons, alcohols, ketones, aldehydes, ethers, esters, oxides and other volatile oil and so on. Percentage of essential oils in different populations were variable. Essential oil of “Basht” population has 35 compounds such as 1,8-cineole, linalool, α- pinene and lynalyl acetate. Essential oils of “Dehno-Rostam” population has 30 compounds include 1, 8 cineole, linalool, α terpineol, α-pinene. Essential oils of “Sarab-Bahram” population has 19 compounds include α-pinene, 1,8- cineole, linalool, and α terpineol. Essential oils of “Keveshk” population has 29 compounds such as 1,8-cineole, α- pinene, linalool, and α-terpineol and Essential oils of “Tang-Tamoradi” population has 25 compounds include Eugenol, δ-3-carene, 1,8-cineole, and α-terpineol. Aqueous extracts of those populations were evaluated, and the results showed that they have antibacterial properties against Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa, but have not any antifungal activity (Aspergillus oryzae).

Tissue plasminogen activator (tPA) as a serine protease with 72 kD molecular mass and 527 amino acids plays an important role in the fibrinolytic system and the dissolution of fibrin clots in human body. The collective production of this drug in plants such as cucumber, one of the most important vegetables in the world, could reduce its production costs. In this study, after scrutiny of the appropriate regeneration of cucumber plant (Isfahan variety) on MS medium with naphthalene acetic acid hormone (NAA; 0/1 mg L⁻¹) and benzyl amino purine hormone (BAP; 3 mg L⁻¹) hormones, the cloned human tPA gene under the CaMV 35S promoter and NOS terminator into pBI121 plasmid was transferred into cotyledon explants by Agrobacterium tumefaciens strain LBA4404. Subsequent to the regeneration of inoculated explants on the selective medium, the persistence of tPA gene in recombinant plants was confirmed by polymerase chain reaction (PCR) with specific primers. To evaluate the tPA gene expression in transgenic plants, RNA was extracted and the tPA gene transcription was confirmed by reverse-transcription (RT) PCR. Followed the extraction of protein from the leaves of transgenic plants, the presence of tPA protein was confirmed by dot blot and sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) analysis in order to survey the production of recombinant tPA protein. The enzyme-linked immunosorbent assay (ELISA) test was used for recombinant tPA protein level in transgenic cucumber plants. It was counted between 0.8 and 1%, and based on this, it was concluded that the presence of three expressions of regulatory factors (CaMV 35S, Kozak, NOS) and KDEL signal in the construct caused the increase of the tPA gene expression in cucumber plants.