Biocontrol of phytophthora capsici on pepper plants by Bacillus megaterium strains

Phytophthora blight or crown blight of peppers, caused by Phytophthora capsici Leonian, is one of the most important diseases of pepper in the eastern Mediterranean region of Turkey. The possibility to reducedisease severity using phosphate-solubilizing bacteria was investigated in growth room and field experiments. The pepper plants, inoculated with the pathogen after pre-inoculation with three phosphate-solubilizing strains of Bacillus megaterium employed alone or in combination, were monitored for growth parameters and disease severity. Inoculation with the selected strains significantly reduced disease severity in field experiments and two strains increased the yield by 36.2 and 47.7% compared to untreated controls. Bacteria were identified by fatty acid methyl ester (FAME) profiling

Detection of xanthomonas axonopodis pv. vesicatoria in naturally infected pepper seeds in turkey

Bacterial spot, caused by Xanthomonas axonopodis pv. vesicatoria, is one of the most important diseases of pepper in Turkey, where the disease has been epidemic in the last six years in the eastern Mediterranean region. The incidence and importance of natural infection in pepper seeds produced in the region was investigated in the present study. A total of 29 seed samples were tested by immunofluorescence assay using a commercial specific antibody, semi-selective isolation on medium Tween B, and a seedling screening tests, where plantlets were examined for typical spot symptoms on cotyledons 7-14 days after emergence. Pathogen populations were found to be in the range of 5×101-5×104 cells/g seed when using semi-selective medium Tween B. The diseased seeds as determined in the seedling screening ranged from 7 to 36%; these figures agreed with numbers found in the Tween B medium test. The strains isolated on Tween B were identified by PCR using primer designed on the hrp gene specific for Xanthomonas spp., and pathogenicity on pepper plants. Twenty-one out of 29 seed samples were found to be contaminated by Xanthomonas axonopodis pv. vesicatoria. On the basis of these findings, infested seeds must be seen as a major source of inoculum for this disease in the region

Phenotypic and genotypic characterization of pseudomonas savastanoi pv. savastanoi isolates and disease prevalence of olive knot disease in Marmara region of Turkey [Marmara bölgesinde zeytin dal kanseri hastalıgının yaygınlıgı ve pseudomonas savastanoi pv. savastanoi izolatlarının fenotipik ve Genotipik Karakterizasyonu]

Olive growing areas in Tekirdag, Çanakkale, Bali{dotless}kesir, Bursa, and Yalova cities of Marmara region were visited and prevalence and incidence of olive knot disease were noted. Disease prevalence was recorded as 100, 81, 66, 4 and 0% in Çanakkale, Bali{dotless}kesir, Tekirdag, Bursa and Yalova, respectively. Disease incidence was 73, 56, 30 and 0.6% in Çanakkale, Bali{dotless}kesir, Tekirdag and Bursa, respectively. Totaly 208 bacterial strains which showed positive hypersensitive reaction on tobacco leaves were isolated from 104 diseased plants on King's medium B and PVF1 medium from Marmara region. Pathogenicity tests were performed with selected 38 strains and a reference strain (CFPB 1672). All strains were pathogenic on olive plants cv Edremit. Eighty eight strains were re-isolated and used in identification tests. All strains were gram negative, oxidase negative, pectolytic activity negative, levan negative, and arginin dehydrolase negative, but hypersensitive reaction on tobacco leaves was positive. The identification of the strains was confirmed by BIOLOG, spesific-PCR and microbial identification system (MIS) based on whole cell fatty acids. Pseudomonas savastanoi pv. savastanoi strains showed phenotypic similarity as a ratio of 96.7% by whole cell fatty acid compositions. The strains were genotypically similar as a ratio of 97.4% by polymorphism in BOX-PCR. © Ankara Üniversitesi Ziraat Fakültesi

Investigation of Mechanical Properties of Carbon Nanotubes / High Density Polyethylene Composites Produced by Extrusion Method "Investigation of Mechanical Properties of Carbon Nanotubes / High Density Polyethylene Composites Investigation of Mechanical P

Abstract In this study, mechanical properties of multiwalled carbon nanotubes / high density polyethylene (MWCNT/HDPE) nanocomposite materials produced by method of injection molding have been investigated experimentally. Multi-walled carbon nanotubes (MWCNTs) have been incorporated into a high-density polyethylene (HDPE) matrix using twin screw extrusion and injection technique. High density polyethylene, which was reinforced with different percentages (1%, 3% and 5%) of carbon nanotubes, was produced in the form of tensile test bars and then tested. The tensile tests were performed according to ASTM D 638 test standards. The increase in tensile strength as a result of the added carbon nanotube was studied. After the experiments, changes of mechanism at fracture surfaces were examined. Experiments were repeated three times. As a result, it could be inferred that minimum percentage of carbon nanotubes reinforcement should be between 1% -3%

Characterization of Pseudomonas savastanoi pv. savastanoi strains isolated from several host plants in Turkey and report of fontanesia as a new host

Several strains of Pseudomonas savastanoi pv. savastanoi, causal agent of galls or knots on leaves, twigs, and stems of various plant species, were isolated from infected olive (Olea sp.), oleander (Nerium oleander), jasmine (Jasminium officinale), fontanesia (Fontanesia phillyreoides) and myrtle (Myrtus communis) plants growing in Adana, Antalya, Bursa, Canakkale, Hatay, Izmir, Mersin, Mugla, Samsun and Tekirdag provinces of Turkey. Among the strains initially tested, 33 of them from different hosts were selected for further analyses. The strains were Gram-, oxidase-, pectolytic activity-, levan-, and arginine dihydrolase negative, showed fluorescence on King's B and PVF-1 media and induced hypersensitive reaction on tobacco leaves. Three products 464 bp, 684 bp and 1064 bp in size were amplified by PCR. Fatty acid methyl ester profiles confirmed the identity of tested strains as P. savastanoi pv. savastanoi. Based on cluster analysis of fatty acids, the strains were divided into two different groups. No correlation was found, however, between host plant and geographical origin of the strains under study. Olive, oleander, jasmine, fontanesia and myrtle plants were used to determine pathogenicity of the strains, which were generally most virulent when inoculated to the original host. This is the first detailed study showing that P. savastanoi pv. savastanoi can cause knot disease on the new oleaceous host Fontanesia phillyreoides

Occurrence of bacterial fruit blotch of watermelon caused by Acidovorax avenae subsp citrulli in the eastern Mediterranean Region of Turkey.

WOS: 000237693500033PubMed ID: 30781258

Characterization of Pseudomonas cichorii isolated from different hosts in Turkey

Stem and pith necrosis symptoms on tomato, varnish spot symptoms on lettuce and leaf spot symptoms on dwarf umbrella trees were observed in late winter and spring of 2002 and 2008 in the Eastern Mediterranean region of Turkey. Fluorescent bacteria were isolated from typical diseased plants on King's medium B as nearly pure cultures. All of the bacterial strains isolated in the study were identified as Pseudomonas cichorii compared with reference strains GSPB 2097, CFPB 2102 and NCPPB 3802, based on conventional methods, ELISA and fatty acid methyl ester analysis. The strains were divided into five different groups according to cluster analysis of fatty acid compositions in phenotypic characterization of the strains. In sensitive assays, tomato, lettuce and dwarf umbrella trees strains are sensitive to cupric sulfate and streptomycin. The study also demonstrated that P. cichorii strains isolated from tomato, lettuce and dwarf umbrella trees can be distinguished based on BOX-PCR experiments in genotypic characterization of the strains. In pathogenicity tests, tomato and lettuce strains were more aggressive on tomato, lettuce and dwarf umbrella trees, while dwarf umbrella trees strains were pathogenic only on their host. When strains were inoculated to their original host, they were more aggressive on their host than on other species. This is the first detail study of P. cichorii causing stem and pith necrosis on tomato, bacterial rot and varnish spot on lettuce and leaf spot on dwarf umbrella trees in Turkey. © 2011 Friends Science Publishers

Copper-resistant strains of Xanthomonas axonopodis pv. vesicatoria (doidge) dye in the eastern mediterranean region of Turkey

Bacterial spot, caused by Xanthomonas axonopodis (syn: campestris) pv. vesicatoria is a widespread disease of processing pepper in Adana and Osmaniye (eastern Mediterranean Turkey). According to our and pepper growers' observations, chemical control by copper compounds has not been effective on the disease in commercial pepper fields for the last three years. Therefore, sensitivities to copper and streptomycin among strains were tested under in vitro conditions. In the summers of 2002-2004, sixty-seven bacterial strains were isolated from diseased pepper plants in the region. The strains were identified as Xanthomonas axonopodis pv. vesicatoria by morphological, physiological and biochemical tests, hypersensitive reaction on tobacco (Nicotiana tabacum cv. Samsun N), pathogenicity tests on pepper plants (a local cultivar, Bursa Yaglik), das-ELISA and amplification of the 355 bp hrp genes by PCR. Of the 67 strains, all were found to be tolerant to 100 µg ml -1 of cupper sulfate and 7% were resistant to streptomycin (20 µg ml-1)