Recep Kotan

Evaluation of antimicrobial activities of Satureja hortensis L.

The present study was designated to evaluate the antimicrobial activities of methonol and hexane extracts of Satureja hortensis L. which is an annual herb used as traditional folk medicine in Eastern Anatolia region of Turkey for the treatment of different infectious diseases and disorders. The antimicrobial activities of the extracts against 147 laboratory strains belong to 55 bacterial species, and 31 isolates of 1 yeast and 4 fungi species were tested by using disc diffusion assay. The results showed that hexane extract of Satureja hortensis had no antifungal, but antibacterial activity against four strains of three Bacillus species whereas methanol extract of Satureja hortensis had both anticandidal and antibacterial effects. It inhibited the growth of 23 strains of 11 bacterial species and 6 isolates of Candida albicans, at the concentration of 300microg/ml. Satureja hortensis did not show antimicrobial activity against the remaining microorganisms (83%) tested including most and all of the clinic and plant pathogenic microorganisms, respectively. Methanol extract showed stronger and broader spectrum of antimicrobial activity as compared to hexane extract.

Screening of Antibacterial Activities of Twenty-One Oxygenated Monoterpenes

Plant essential oils are widely used as fragrances and flavours in the cosmetic, perfume, drug and food industries. Oxygenated monoterpenes are widespread components of the essential oils, usually occurring in high amount. In this paper, the antibacterial activities of twenty-one oxygenated monoterpenes (borneol, borneol acetate, camphor, carvone, 1,8-cineole, citronellal, β-citronellol, dihydrocarvone, fenchol, fenchone, geraniol acetate, isomenthol, limonene oxide, linalool, linalool acetate, nerol, nerol acetate, terpinen-4-ol, α-terpineol, menthol and menthone) and penicillin (standard antibiotic) were determined using a disc diffusion method (in vitro) against 63 bacterial strains, belonging to 37 different genera and 54 species (plant, food and clinic origins). The results showed that the oxygenated monoterpenes exhibited a variable degree of antibacterial activities. These compounds also inhibited the growth of bacterial strains by producing a weak zone of inhibition from 7 to 11 mm in diameter, depending on the susceptibility of the tested bacteria. Among the tested compounds, nerol, linalool α-terpineol, fenchol and terpinen-4-ol showed antibacterial activity at a broad spectrum. However, their antibacterial activities were lower than those of penicillin. In contrast to these compounds, camphor and 1,8-cineole exhibited no inhibition effects on the growth of all tested bacteria

Control of Aspergillus flavus with essential oil and methanol extract of Satureja hortensis.

The essential oil and methanol extract of Satureja hortensis were tested for antifungal activity against Aspergillus flavus in vitro on Petri plates and liquid culture, and under storage conditions. The oil showed strong antifungal activity based on the inhibition zone and minimal inhibitory concentration values against the pathogen on Petri plates assays. The very low concentrations of them also reduced wet and dry mycelium weight of pathogen fungus in liquid culture. When the oils at 25, 12.5 and 6.25 microl/mL concentrations were applied to lemon fruits before seven days of pathogen inoculation on storage conditions, the decay on fruits caused by the pathogen could be prevented completely. The results in this study showed that the essential oil of S. hortensis had strong antifungal activity against pathogen fungi tested. So, the essential oil of S. hortensis could be used for management of this pathogen as a potential source of sustainable eco-friendly botanical fungicides.

Antibacterial activities of essential oils and extracts of Turkish Achillea, Satureja and Thymus species against plant pathogenic bacteria

BACKGROUND The aims of this study were to examine the chemical composition of the essential oils and hexane extracts of the aerial parts of Satureja spicigera (C. Koch) Boiss., Thymus fallax Fisch. & CA Mey, Achillea biebersteinii Afan, and Achillea millefolium L. by GC and GC-MS, and to test antibacterial efficacy of essential oils and n-hexane, chloroform, acetone and methanol extracts as an antibacterial and seed disinfectant against 25 agricultural plant pathogens. RESULTS Thymol, carvacrol, p-cymene, thymol methyl ether and gamma-terpinene were the main constituents of S. spicigera and T. fallax oils and hexane extracts. The main components of the oil of Achillea millefolium were 1,8-cineole, delta-cadinol and caryophyllene oxide, whereas the hexane extract of this species contained mainly n-hexacosane, n-tricosane and n-heneicosane. The oils and hexane extracts of S. spicigera and T. fallax exhibited potent antibacterial activity over a broad spectrum against 25 phytopathogenic bacterial strains. Carvacrol and thymol, the major constituents of S. spicigera and T. fallax oils, also showed potent antibacterial effect against the bacteria tested. The oils of Achillea species showed weak antibacterial activity. Our results also revealed that the essential oil of S. spicigera, thymol and carvacrol could be used as potential disinfection agents against seed-borne bacteria. CONCLUSION Our results demonstrate that S. spicigera, T. fallax oils, carvacrol and thymol could become potentials for controlling certain important agricultural plant pathogenic bacteria and seed disinfectant.

Plant growth-promoting rhizobacteria improved growth, nutrient, and hormone content of cabbage (Brassica oleracea) seedlings

Metin TURAN, Melek EKİNCİ, Ertan YILDIRIM*, Adem GÜNEŞ, Kenan KARAGÖZ, Recep KOTAN, Atilla DURSUN Department of Genetics and Bioengineering, Faculty of Engineering and Architecture, Yeditepe University, Kayışdağı, İstanbul, Turkey Department of Horticulture, Faculty of Agriculture, Atatürk University, Erzurum, Turkey Department of Soil Science, Faculty of Agriculture, Erciyes University, Kayseri, Turkey Department of Plant Protection, Faculty of Agriculture, Atatürk University, Erzurum, Turkey

Pandoraea oxalativorans sp. nov., Pandoraea faecigallinarum sp. nov. and Pandoraea vervacti sp. nov., isolated from oxalate-enriched culture.

Five isolates, designated TA2, TA4, TA25(T), KOx(T) and NS15(T) were isolated in previous studies by enrichment in mineral medium with potassium oxalate as the sole carbon source and were characterized using a polyphasic approach. The isolates were Gram-reaction-negative, aerobic, non-spore-forming rods. Phylogenetic analyses based on 16S rRNA and DNA gyrase B subunit (gyrB) gene sequences confirmed that the isolates belonged to the genus Pandoraea and were most closely related to Pandoraea sputorum and Pandoraea pnomenusa (97.2-99.7 % 16S rRNA gene sequence similarity). The isolates could be differentiated from their closest relatives on the basis of several phenotypic characteristics. The major cellular fatty acid profiles of the isolates comprised C₁₆:₀, C₁₈:₁ω7c, C₁₇:₀ cyclo and summed feature 3 (C₁₆:₁ω7c and/or iso-C₁₅:₀ 2-OH). On the basis of DNA-DNA hybridization studies and phylogenetic analyses, the isolates represent three novel species within the genus Pandoraea, for which the names Pandoraea oxalativorans sp. nov. (TA25(T)  = NBRC 106091(T)  = CCM 7677(T)  = DSM 23570(T)), Pandoraea faecigallinarum sp. nov. (KOx(T)  = NBRC 106092(T)  = CCM 2766(T)  = DSM 23572(T)) and Pandoraea vervacti sp. nov. (NS15(T)  = NBRC 106088(T)  = CCM 7667(T)  = DSM 23571(T)) are proposed.

Phenotypic and genotypic characterization of Xanthomonas campestris pv. zinniae strains

During 1997 and 1998, serious outbreaks of bacterial leaf spot disease were observed on zinnia plants grown in home and commercial gardens in Ohio, USA. Twenty-two strains of Xanthomonas campestris pv. zinniae, isolated from diseased zinnia plants and contaminated seeds, were identified based on morphological, physiological and biochemical tests, fatty acid methyl ester analyses and pathogenicity tests on zinnia cv. Scarlet. Host range studies indicated that all of the X. campestris pv. zinniae strains were pathogenic on zinnia and tomato, but not on cabbage, lettuce, pepper and radish. The phenotypic and genotypic relationships among the strains determined based on serological reaction pattern, fatty acid profiles, repetitive extragenic palindromic-polymerase chain reaction (rep-PCR) fingerprints and sequence analysis of the 16S–23S rDNA spacer region suggested that X. campestris pv. zinniae strains were closely related to each other, but clearly distinct from other Xanthomonas species including X. campestris pv. campestris, X. axonopodis pv. vesicatoria, X. vesicatoria and X. hortorum pv. vitians tested in this study. The results also demonstrated that rep-PCR fingerprinting is rapid, reliable and the most practical method for routine detection and identification of X. campestris pv. zinniae strains.

Influence of Summer Savory Essential Oil (Satureja hortensis) on Decay of Strawberry and Grape

Abstract The essential oil isolated from the aerial parts of wild Turkish Satureja hortensis L. (summer savory) was analyzed by GC-MS, and carvacrol (54.7 %), y-terpinene (20.9 %), p-cymene (12.3 %), a-terpinene (2.0 %), and thymol (2.0 %) were found to be major components of the oil. Post-harvest decay of fruits caused by some fungi is still a most important problem and causes major crop losses during storage and shipment. High relative humidity during storage and marketing conditions accelerate development of fungal disease and decay of the grapes. The six different concentrations of the oil (0.01, 0.02, 0.04, 0.11, 0.22 and 0.45 µL/cm3) were tested for their effectiveness in reducing decay of strawberry and grape fruits at three storage temperature (5, 10 and 20°C). The oil tested reduced decay of strawberry and grape fruits compared to controls, in particularly at low temperatures (5 and 10°C). Decay reducing effect of the oil on strawberry and grape fruits increased with increase in doses of the oil. However, microbial development in the fruits increased with increase in temperature. Nevertheless, the present results showed that S. hortensis essential oil has a significant reducing effect on the decay of strawberry and grape fruits during storage at low temperatures. Therefore, the essential oil of summer savory may be a potential source of alternative fungicides to protect strawberry and grape fruits as well as other stored products from pathogens and saprophytes.

First Report of Bacterial Blight of Mulberries Caused by Pseudomonas syringae pv. mori in the Eastern Anatolia Region of Turkey

During spring 1999, a severe bacterial blight disease was observed on white mulberry (Morus alba L.) trees grown in the Erzincan, Erzurum, and Artvin provinces in the eastern Anatolia region of Turkey. Initial symptoms appeared as small, water-soaked spots on leaves and shoots. The spots eventually expanded and resulted in dark brown to black, elongated, stripe-like lesions on shoots. Diseased leaves wilted at the twig tips and later died. Disease incidence was close to 100% in the regions surveyed. Fluorescent bacteria were isolated consistently from lesions on diseased leaves and shoots on Kings medium B. Morphological and biochemical characteristics of 16 presumptive strains tested were rod-shaped, aerobic, gram negative, oxidase negative, and catalase and levan positive. None of the strains reduced nitrate or hydrolyzed gelatin. All strains were confirmed as Pseudomonas syringae by gas-chromatography fatty acid methyl ester (GC-FAME) analysis, with a similarity index ranging from 0.82 to 0.94. The pathogen was identified as P. syringae pv. mori based on pathogenicity tests performed by spray-inoculating healthy leaves (M. alba cv. Beyaz Dut) on 1-year-old host twigs with suspensions of 108 CFU/ml each strain (2). Inoculated plants and sterile water-sprayed controls were maintained in a greenhouse at 18 to 28°C. Plants were covered with polyethylene bags for 48 h after inoculation. Within 7 to 10 days, necrotic spots typical of those found in the nursery were observed on inoculated leaves. No symptoms were seen on control plants. The pathogen was reisolated from lesions on inoculated leaves. Recovered strains were identical to initial strains, based on morphological and biochemical tests and GC-FAME analysis. To our knowledge, the occurrence and incidence of this disease in different geographic regions of Turkey, except the central Anatolia and Aegean regions, have not been studied (1). This is the first report of bacterial blight of mulberries at high incidence in the eastern Anatolia region of Turkey. References: (1) K. Türkolu and Y. E. Öktem. Plant Prot. Bull 13:19, 1973. (2) J. M. Young et al. N. Z.J. Agric. Res. 21:159, 1978.

INOCULATION EFFECTS OF PANTOEA AGGLOMERANS STRAINS ON GROWTH AND CHEMICAL COMPOSITION OF PLUM

In this study, five non-pathogenic Pantoea agglomerans strains were utilized. The objective of this study was to test for biochemical characteristics of these strains, and to evaluate their inoculation effects on fruit set rate, fruit pomological traits, fruit chemical compositions and some vegetative parameters of plum cultivar ‘Stanley’. The results showed that some of the tested strains had beneficial effects on the fruit set rate, fruit pomological traits, fruit chemical composition and/or some vegetative growth parameters of plum in comparison to the control. In conclusion, tested Pantoea agglomerans strains (especially RK-85) are the suitable inoculants for plum cultivation in cold areas such as Erzurum, and these strains may be considered as biofertilizer and protector sensitive plants against frost damage by applying in suitable timing and dose.