Pseudomonas viridiflava, a Multi Host Plant Pathogen with Significant Genetic Variation at the Molecular Level

The pectinolytic species Pseudomonas viridiflava has a wide host range among plants, causing foliar and stem necrotic lesions and basal stem and root rots. However, little is known about the molecular evolution of this species. In this study we investigated the intraspecies genetic variation of P. viridiflava amongst local (Cretan), as well as international isolates of the pathogen. The genetic and phenotypic variability were investigated by molecular fingerprinting (rep-PCR) and partial sequencing of three housekeeping genes (gyrB, rpoD and rpoB), and by biochemical and pathogenicity profiling. The biochemical tests and pathogenicity profiling did not reveal any variability among the isolates studied. However, the molecular fingerprinting patterns and housekeeping gene sequences clearly differentiated them. In a broader phylogenetic comparison of housekeeping gene sequences deposited in GenBank, significant genetic variability at the molecular level was found between isolates of P. viridiflava originated from different host species as well as among isolates from the same host. Our results provide a basis for more comprehensive understanding of the biology, sources and shifts in genetic diversity and evolution of P. viridiflava populations and should support the development of molecular identification tools and epidemiological studies in diseases caused by this species

Preconditioning-induced ischemic tolerance: a window into endogenous gearing for cerebroprotection

Ischemic tolerance defines transient resistance to lethal ischemia gained by a prior sublethal noxious stimulus (i.e., preconditioning). This adaptive response is thought to be an evolutionarily conserved defense mechanism, observed in a wide variety of species. Preconditioning confers ischemic tolerance if not in all, in most organ systems, including the heart, kidney, liver, and small intestine. Since the first landmark experimental demonstration of ischemic tolerance in the gerbil brain in early 1990's, basic scientific knowledge on the mechanisms of cerebral ischemic tolerance increased substantially. Various noxious stimuli can precondition the brain, presumably through a common mechanism, genomic reprogramming. Ischemic tolerance occurs in two temporally distinct windows. Early tolerance can be achieved within minutes, but wanes also rapidly, within hours. Delayed tolerance develops in hours and lasts for days. The main mechanism involved in early tolerance is adaptation of membrane receptors, whereas gene activation with subsequent de novo protein synthesis dominates delayed tolerance. Ischemic preconditioning is associated with robust cerebroprotection in animals. In humans, transient ischemic attacks may be the clinical correlate of preconditioning leading to ischemic tolerance. Mimicking the mechanisms of this unique endogenous protection process is therefore a potential strategy for stroke prevention. Perhaps new remedies for stroke are very close, right in our cells

First report of bacterial blight of anthurium caused by Xanthomonas axonopodis pv. dieffenbachiae in Turkey

[No abstract available

An outbreak of crown gall disease on rose caused by Agrobacterium tumefaciens in Turkey

[No abstract available

Aqueous plant extracts as seed treatments on tomato bacterial speck disease

Bacterial speck disease caused by Pseudomonas syringae pv. tomato (Pst) is one of the most important seed-borne bacterial diseases of tomato. The use of disease-free seeds is a significantly effective method to manage the disease. In this study, the antibacterial activity of aqueous extracts from 25 medical and aromatic plants was investigated by using the paper disc method. In-vitro inhibition of bacterial growth was recorded with extracts from six different plants (eucalyptus, coriander, garlic, ginger, Istanbul thyme and Izmir thyme). Based on their antibacterial activity, these extracts were selected for seed experiments. Disease severity was evaluated in cotyledons 3 weeks after germination, using a 0-3 scale, taking as a reference the necrotic symptoms developed by positive control seedlings. The effect of seed treatment on disease incidence, disease severity and seed germination was recorded. Under these experimental conditions, five of the six aqueous plant extracts assayed reduced disease incidence and severity, by approximately 63-100 and 57-100%, respectively. Additionally, seed treatment did not reduce seed germination. The results of this study indicate that aqueous plant extracts of the Turkish endemic plants Kastamonu garlic (Allium sativum ‘Kastamonu’), Izmir thyme (Origanum onites) and Istanbul thyme (Origanum vulgare subsp. hirtum) and a Eucalyptus sp. reduce seed-borne bacterial speck disease of tomato, and are promising biological seed treatments that could be used in organic farming for disease control. © 2018 International Society for Horticultural Science. All rights reserved.FDK-2015-4071This study was financed by Cukurova University with project number FDK-2015-4071

Occurrence of bacterial spot disease, caused by Xanthomonas axonopodis pv. vesicatoria, on pepper in the eastern Mediterranean region of Turkey

[No abstract available

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

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