C. Ehaliotis - Academia.edu (original) (raw)

Papers by C. Ehaliotis

Science of The Total Environment, 2015

Wastewaters from the fruit-packaging industry constitute a serious point source contamination wit... more Wastewaters from the fruit-packaging industry constitute a serious point source contamination with pesticides. In the absence of effective depuration methods, they are discharged in municipal wastewater treatment plants or spread to land. Modified biobeds could be an applicable solution for their treatment. We studied the dissipation of thiabendazole (TBZ), imazalil (IMZ), ortho-phenylphenol (OPP), diphenylamine (DPA) and ethoxyquin (EQ), used by the fruit-packaging industry, in anaerobically digested sewage sludge, liquid aerobic sewage sludge and in various organic substrates (biobeds packing materials) composed of soil, straw and spend mushroom substrate (SMS) in various volumetric ratios. Pesticide sorption was also determined. TBZ and IMZ showed higher persistence especially in the anaerobically digested sewage sludge (DT 50 = 32.3-257.6 d), in contrast to OPP and DPA which were rapidly dissipated especially in liquid aerobic sewage sludge (DT 50 = 1.3-9.3 d). EQ was rapidly oxidized mainly to quinone imine (QI) which did not persist and dimethyl ethoxyquinoline (EQNL, minor metabolite) which persisted for longer. Sterilization of liquid aerobic sewage sludge inhibited pesticide decay verifying the microbial nature of pesticide dissipation. Organic substrates rich in SMS showed the highest dissipation capacity with TBZ and IMZ DT 50s of ca. 28 d compared to DT 50s of N50 d in the other substrates. TBZ and IMZ showed

Annals of botany, 2006

Recent studies have shown that certain composts may trigger indirect defence mechanisms by sensit... more Recent studies have shown that certain composts may trigger indirect defence mechanisms by sensitizing the plant to create an increased state of resistance, similar to systemic acquired resistance. In this study, the capacity of a disease-suppressive compost to alter the expression pattern of certain pathogenesis-related (PR) genes in the root system of tomato plants (Solanum lycopersicum) provided the opportunity to study their cellular expression pattern and to investigate putative roles of these genes in the mechanisms of plant defence. Employing the reverse transcription-polymerase chain reaction (RT-PCR) and in situ RNA:RNA hybridization techniques, the accumulation and distribution of the transcripts of the differentially expressed PR genes were examined in plants grown on compost and compared with those of control plants grown on peat. Elevated levels of expression of the pathogenesis-related genes PR-1, PR-5 and P69/PR-7 were detected in the roots of tomato plants grown on t...

The Journal of Microbiology, 2010

Microbial assessment of grape marc wastes, the residual solid by-product of the wine-industry, wa... more Microbial assessment of grape marc wastes, the residual solid by-product of the wine-industry, was performed by identifying phylogenetically the fungal culturable diversity in order to evaluate environmental and disposal safety issues and to discuss ecological considerations of applications on agricultural land. Fungal spores in grape marc were estimated to 4.7 x 10(6) per g dry weight. Fifty six fungal isolates were classified into eight operational taxonomic units (OTUs) following amplified ribosomal DNA restriction analysis (ARDRA) and colony morphology. Based on 18S rRNA gene and 5.8S rRNA gene-ITS sequencing, the isolates representing OTUs #1, #2, #3, and #4, which comprised 44.6%, 26.8%, 12.5%, and 5.3%, respectively, of the number of the total isolates, were identified as Aspergillus fumigatus, Bionectria ochroleuca, Haematonectria haematococca, and Trichosporon mycotoxinivorans. The isolates of OTU#5 demonstrated high phylogenetic affinity with Penicillium spp., while members of OTUs #6 and #7 were closer linked with Geotrichum candidum var. citri-aurantii and Mycocladus corymbifer, respectively (95.4 and 97.9% similarities in respect to their 5.8S rRNA gene-ITS sequences). The OTU#8 with a single isolate was related with Aspergillus strains. It appears that most of the fungal isolates are associated with the initial raw material. Despite the fact that some of the species identified may potentially act as pathogens, measures such as the avoidance of maintaining large and unprocessed quantities of grape marc wastes in premises without adequate aeration, together with its suitable biological treatment (e.g., composting) prior to any agriculture-related application, could eliminate any pertinent health risks.

Soil Biology and Biochemistry, 2009

ABSTRACT Recycling of olive mill wastewaters (OMW) into agricultural soils is a controversial iss... more ABSTRACT Recycling of olive mill wastewaters (OMW) into agricultural soils is a controversial issue since benefits to soil fertility should counterbalance potential short-term toxicity effects. We investigated the short-term effects of OMW on the soil–plant system, regarding the diversity, structure and root colonization capacity of arbuscular mycorrhizal (AM) fungi and the respective growth response of Vicia faba L, commonly used as green manure in olive-tree plantations. A compartmentalized pot system was used that allowed the establishment of an AM fungal community in one compartment (feeder) and the application of three OMW dose levels in an adjacent second compartment (receiver). At 0, 10, and 30 days after OMW treatment (DAT), V. faba pre-germinated seeds were seeded in the receiver compartment. At harvest, shoot and root dry weights, AM fungal root colonization, soil hyphal length and P availability were recorded in the receiver compartment. In addition, OMW effects on AM fungal diversity in plant roots were studied by DGGE. A transient effect of OMW application was observed; plant growth and AM fungal colonization were initially inhibited, whereas soil hyphal length was stimulated, but in most cases differences were absent when seeding was performed 30 DAT. Similarly, changes induced in the structure of the root AM fungal community were of transient nature. Cloning and sequencing of all the major DGGE bands showed that roots were colonized by Glomus spp. The transient effects of OMW on the structure and function of AM fungi could be attributed to OMW-derived phytoxicity to V. faba plants or to an indirect effect via alteration of soil nutritional status. The high OMW dose significantly increased soil P availability in the presence of AM fungi, suggesting efficient involvement of AM fungi in organic-P minerilization. Overall our results indicate that soil application of OMW would cause transient changes in the AM fungal colonization of V. faba plants, which, would not impair their long-term plant growth promoting ability.

Plant and Soil, 2011

Background and Aims Rocket salad (Eruca sativa Mills) is one of the major leafy vegetables produc... more Background and Aims Rocket salad (Eruca sativa Mills) is one of the major leafy vegetables produced worldwide and has been characterized as a rich source of chemoprotective glucosinolates (GSL). The relationship between N fertilization and the resulting plant biomass and N status with GSL quantity and quality in rocket leaves was examined. Methods A pot experiment was conducted, applying ten different N-rates and destructive sampling was carried out 15, 30 and 45 days after transplanting (DAT). The Mitscherlich equation was used to establish NO 3-N critical levels at each growth stage and as an indicator of N demand for relative maximum dry matter accumulation and glucosinolate content and composition was determined. Results Glucosinolate content was significantly influenced by N rate, growth stage and their interaction. Different GSL types showed dissimilar responses to N fertilization: aliphatic GSLs were significantly reduced under increased N rates whereas indole GSL showed the reverse. Under excess N fertilization (>1.04 g/plant), dry matter accumulation remained constant, NO 3-N was significantly increased and total

Phytochemical Analysis, 2009

IntroductionGlucosinolates (GSLs) are secondary plant metabolites that are abundant in brassicas ... more IntroductionGlucosinolates (GSLs) are secondary plant metabolites that are abundant in brassicas and their hydrolysis products, isothiocyanates, are toxic to soil pathogens. Efficiency and extraction time are critical for routine analysis of GSLs in plant tissues. Robust analytical procedures are required for the extraction of GSL from soil.ObjectiveDevelopment and optimisation of a microwave‐assisted extraction (MAE) method for the recovery of GSL from plant tissues and soil and comparison of its efficiency with other established extraction methods.MethodologySolvents, temperature, microwave power and extraction time were examined as parameters controlling MAE efficiency. In rocket seeds the efficiency of MAE was determined through recovery of GSLs from seeds and of sinigrin (1) that was used as internal standard. MAE was then compared with the certified ISO‐9167 method and an ultrasonic‐assisted extraction (UAE). MAE was also applied for the extraction of GSLs from soils fortified...

Microbial Ecology, 2010

Biofumigation (BIOF) is carried out mainly by the incorporation of brassica plant parts into the ... more Biofumigation (BIOF) is carried out mainly by the incorporation of brassica plant parts into the soil, and this fumigation activity has been linked to their high glucosinolate (GSL) content. GSLs are hydrolyzed by the endogenous enzyme myrosinase to release isothiocyanates (ITCs). A microcosm study was conducted to investigate the effects induced on the soil microbial community by the incorporation of broccoli residues into soil either with (BM) or without (B) added myrosinase and of chemical fumigation, either as soil application of 2-phenylethyl ITC (PITC) or metham sodium (MS). Soil microbial activity was evaluated by measuring fluorescein diacetate hydrolysis and soil respiration. Effects on the structure of the total microbial community were assessed by phospholipid fatty acid analysis, while the impact on important fungal (ascomycetes (ASC)) and bacterial (ammonia-oxidizing bacteria (AOB)) guilds was evaluated by denaturating gradient gel electrophoresis (DGGE). Overall, B, and to a lesser extent BM, stimulated microbial activity and biomass. The diminished effect of BM compared to B was particularly evident in fungi and Gram-negative bacteria and was attributed to rapid ITC release following the myrosinase treatment. PITC did not have a significant effect, whereas an inhibitory effect was observed in the MS-treated soil. DGGE analysis showed that the ASC community was temporarily altered by BIOF treatments and more persistently by the MS treatment, while the structure of the AOB community was not affected by the treatments. Cloning of the ASC community showed that MS application had a deleterious effect on potential plant pathogens like Fusarium, Nectria, and Cladosporium compared to BIOF treatments which did not appear to inhibit them. Our findings indicate that BIOF induces changes on the structure and function of the soil microbial community that are mostly related to microbial substrate availability changes derived from the soil amendment with fresh organic materials. Abbreviations BIOF Biofumigation GSLs Glucosinolates B Broccoli BM Broccoli+myrosinase ITC Isothiocyanate PITC 2-phenylethyl isothiocyanate MS Metham sodium PLFA Phospholipid fatty acids FAME Fatty acid methyl esters Electronic supplementary material The online version of this article

Journal of Agricultural and Food Chemistry, 2009

Brassica vegetables are commercially recognized for their nutritive values and levels of benefici... more Brassica vegetables are commercially recognized for their nutritive values and levels of beneficial phytochemicals that aid in health maintenance and disease prevention. Watercress (Nasturtium officinal R. Br.) is a leafy vegetable of the Brassicacea family that provides a significant source of carotenoids and glucosinolates (GSs). Lutein, the main carotenoid in watercress, is a lipid-soluble pigment recognized as active in the prevention of cancers and cardiovascular and eye diseases. Gluconasturtiin, an aromatic GS found in high concentrations in watercress, exhibits both antioxidant and anticarcinogenic activity upon hydrolysis to phenethyl isothiocynate (PEITC). Our research objective was to determine the influence of nitrogen and sulfur fertilization on carotenoid and glucosinolate metabolism in hydroponically grown watercress. Plants were grown in a factorial arrangement with three nitrogen (N) treatments (6, 56, and 106 mg•L-1) and three sulfur (S) treatments (8, 16, and 32 mg•L-1). Total concentrations of carotenoids and glucosinolates were measured by HPLC analysis. Nitrogen was positively correlated to lutein concentration which ranged from 2.4 to 9.5 mg•100 g-1 fresh weight (FW); however, S availability did not influence lutein concentrations. Both (N) and (S) treatments were positively correlated with gluconasturtiin concentrations which ranged from 1.5 to 19.6 µmol•g-1 of dry weight (DW). The impact of (N) and (S) concentration on biomass, chlorophylls, and other individual carotenoids and glucosinolates was determined.

Journal of Agricultural and Food Chemistry, 2010

Biobeds have been used in northern Europe for minimizing point source contamination of water reso... more Biobeds have been used in northern Europe for minimizing point source contamination of water resources by pesticides. However, little is known regarding their use in southern Europe where edaphoclimatic conditions and agriculture practices significantly differ. A first step toward their adaptation in southern Europe is the use of low-cost and easily available substrates as biomixture components. This study investigated the possibility of replacing peat with agricultural composts in the biomixture. Five composts from local substrates including olive leaves, cotton crop residues, cotton seeds, spent mushroom substrate, and commercial sea wrack were mixed with topsoil and straw (1:1:2). Degradation of a mixture of pesticides (dimethoate, indoxacarb, buprofezin, terbuthylazine, metribuzin, metalaxyl-M, iprodione, azoxystrobin) at two dose rates was tested in the compost biomixtures (BX), in corresponding peat biomixtures (OBX), and in soil. Adsorption-desorption of selected pesticides were also studied. Pesticide residues were determined by gas chromatography with nitrogen-phosphorus detector, except indoxacarb, which was determined with a microelectron capture detector. Overall, BX degraded the studied pesticides at rates markedly higher than those observed in soil and OBX, in which the slowest degradation rates were evident. Overall, the olive leaf compost biomixture showed the highest degradation capacity. Adsorption studies showed that OBX and BX had higher adsorption affinity compared to soil. Desorption experiments revealed that pesticide adsorption in biomixtures was not entirely reversible. The results suggest that substitution of peat with local composts will lead to optimization of the biobed system for use in Mediterranean countries.

FEMS Microbiology Ecology, 1999

Olive-mill wastewater (OMW) has a high organic and polyphenol content and is resistant to biodegr... more Olive-mill wastewater (OMW) has a high organic and polyphenol content and is resistant to biodegradation. Its disposal leads to a major environmental pollution problem in the Mediterranean basin. The detoxification of OMW following inoculation with Azotobacter vinelandii (strain A) was performed for two successive 5-day-period cycles in an aerobic, biowheel-type reactor, under non-sterile conditions. The phytotoxicity of the processed product was reduced by over 90% at the end of both cycles. To exclusively monitor the A. vinelandii population in the reactor a most probable number-PCR approach was employed and applied daily to serial dilutions of total DNA extracted from reactor samples. PCR sensitivity was independent of the presence of OMW or non-target DNA. The A. vinelandii population dynamics were successfully monitored, showing an initial adaptation period, followed by a sharp population maximum on the fourth day of both cycles (1.6U10 8 and 9.6U10 7 cells ml 31 respectively), after a major phytotoxicity decline. N 2 fixation rates were estimated using the acetylene reduction assay and reached a peak during the first 1^2 days of each cycle (36 and 29 nmol C 2 H 2 ml 31 h 31 respectively). The data are consistent with an initial physiological adaptation phase, where the presence of phenolic compounds limits A. vinelandii growth but stimulates N 2 fixation, followed by a rapid growth phase as phytotoxicity declines.

European Journal of Soil Biology, 2011

Fusarium solani strain FsK (FsK), isolated from a plant pathogen-suppressive compost, grows endop... more Fusarium solani strain FsK (FsK), isolated from a plant pathogen-suppressive compost, grows endophytically in tomato roots and controls infestations by Fusarium oxysporum f.sp. radicis-lycopersici (FORL). The effect of root colonization by the two fungi on the diversity of rhizosphere microbial community was studied. Tomato plants were inoculated with FsK and/or FORL and rhizosphere soil was collected 8, 15 and 30 days post inoculation (dpi) and analyzed by denaturating gradient gel electrophoresis (DGGE) of PCR-amplified internal transcribed spacer (ITS) sequences of fungi and 16S rRNA gene sequences of common rhizosphere bacterial guilds like alpha-proteobacteria and pseudomonads. Cluster analysis of DGGE fingerprints showed that FsK had a transient impact on the fungal and alpha-proteobacterial community only during its endophytic stage (15 dpi), while FORL had a readily distinguished and persistent effect on the fungal community. The changes observed in the rhizosphere fungal and bacterial communities may depict the interactions of the two fungal inocula with the plant. Cloning of selected DGGE bands stimulated by FsK showed that the responsive bacteria were closely related to species known to include biological control agents (BCA). Overall, the inoculation of FsK in tomato rhizosphere did not appear to have a significant impact on the diversity of non-target microbial groups inhabiting plant rhizosphere.

Environmental Pollution, 2012

The high wastewater volumes produced during citrus production at pre-and post-harvest level prese... more The high wastewater volumes produced during citrus production at pre-and post-harvest level presents serious pesticide point-source pollution for groundwater bodies. Biobeds are used for preventing such point-source pollution occurring at farm level. We explored the potential of biobeds for the depuration of wastewaters produced through the citrus production chain following a lab-to-field experimentation. The dissipation of pesticides used pre-or post-harvest was studied in compost-based biomixtures, soil, and a straw-soil mixture. A biomixture of composted grape seeds and skins (GSS-1) showed the highest dissipation capacity. In subsequent column studies, GSS-1 restricted pesticides leaching even at the highest water load (462 L m À3). Ortho-phenylphenol was the most mobile compound. Studies in an on-farm biobed filled with GSS-1 showed that pesticides were fully retained and partially or fully dissipated. Overall biobeds could be a valuable solution for the depuration of wastewaters produced at pre-and post-harvest level by citrus fruit industries.

Biodegradation, 2010

Wastewaters from the fruit packaging industry contain a high pesticide load and require treatment... more Wastewaters from the fruit packaging industry contain a high pesticide load and require treatment before their environmental discharge. We provide first evidence for the potential bioremediation of these wastewaters. Three white rot fungi (WRF) (Phanerochaete chrysosporium, Trametes versicolor, Pleurotus ostreatus) and an Aspergillus niger strain were tested in straw extract medium (StEM) and soil extract medium (SEM) for degrading the pesticides thiabendazole (TBZ), imazalil (IMZ), thiophanate methyl (TM), ortho-phenylphenol (OPP), diphenylamine (DPA) and chlorpyrifos (CHL). Peroxidase (LiP, MnP) and laccase (Lac) activity was also determined to investigate their involvement in pesticide degradation. T. versicolor and P. ostreatus were the most efficient degraders and degraded all pesticides (10 mg l⁻¹) except TBZ, with maximum efficiency in StEM. The phenolic pesticides OPP and DPA were rapidly degraded by these two fungi with a concurrent increase in MnP and Lac activity. In contrast, these enzymes were not associated with the degradation of CHL, IMZ and TM implying the involvement of other enzymes. T. versicolor degraded spillage-level pesticide concentrations (50 mg l⁻¹) either fully (DPA, OPP) or partially (TBZ, IMZ). The fungus was also able to rapidly degrade a mixture of TM/DPA (50 mg l⁻¹), whereas it failed to degrade IMZ and TBZ when supplied in a mixture with OPP. Overall, T. versicolor and P. ostreatus showed great potential for the bioremediation of wastewaters from the fruit packaging industry. However, degradation of TBZ should be also achieved before further scaling up.

European Journal of Soil Biology, 2013

ABSTRACT Glucosinolates (GSLs) are secondary metabolites found in Brassica species. Upon tissue d... more ABSTRACT Glucosinolates (GSLs) are secondary metabolites found in Brassica species. Upon tissue disruption GSLs are hydrolyzed by myrosinase enzymes to isothiocyanates (ITCs) which are highly toxic to microbes. Therefore the incorporation of fresh Brassicaceae tissues into soil for the control of soil-born plant pathogens is viewed as a biofumigation process. Its efficacy relies on the rate of GSL conversion to ITCs, but also on environmental factors controlling GSL availability in the soil matrix. We studied the dissipation of GSLs, applied either by broccoli leaves or as pure compounds, in a clay loam soil at two soil moisture content levels. Regardless of their mode of application, GSLs were rapidly dissipated in soil with half-life values ranging from 3.2 to 15.5 h. Increasing moisture from 20 to 90% of the soil water holding capacity significantly accelerated their dissipation. Indolyl broccoli-derived GSLs dissipated faster than aliphatic GSLs at high moisture levels, while at low moisture levels a three-fold reduction in their dissipation rates was observed. The dissipation of aliphatic GSLs was less affected by soil moisture levels. Application of pure GSLs resulted in increased soil metabolic quotients (qCO2), suggesting a decline is microbial metabolic efficiency. Their dissipation was related to myrosinase activity apparently derived from soil microbes.

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN017700 / BLDSC - British Librar... more SIGLEAvailable from British Library Document Supply Centre-DSC:DXN017700 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

The majority of innovations pioneered within/for the organic olive oil production (OOOP) chain ma... more The majority of innovations pioneered within/for the organic olive oil production (OOOP) chain may, and are, increasingly becoming, adopted by the conventional olive oil production chain, especially regarding cultivation, inputs related to plant/ecosystem protection and trade/promotion of specialized high quality products. Therefore the OOOP-chain may become a pioneering paradigm, for the implementation and convergence of agricultural production, marketing, sustainable rural development and environmental/biodiversity protection EU policies in the Mediterranean. Moreover, it appears that OOOP systems are increasingly becoming model systems for developing, applying and evaluating innovations that may have far more general applicability for Mediterranean agriculture. There is little divergence between conventional and organic production regarding water consumption and waste production, but the OOOP-chain has a lower impact as regards to soil erosion, desertification, pollution due chem...

FEMS microbiology ecology, 2021

Sand dunes of the Mediterranean region constitute drought-stressed, low-fertility ecosystems. Arb... more Sand dunes of the Mediterranean region constitute drought-stressed, low-fertility ecosystems. Arbuscular mycorrhizal fungi (AMF) are regarded as key components of their biota, that contribute to plant host adaptation and fitness. However, AMF community assembly rules in the roots of the psammophilous plants of coastal sand dunes have not been investigated. We studied the root colonizing AMF communities of four characteristic native plants of eastern Mediterranean coastal foredunes, in nine locations in Greece. Host specificity (plant identity) was the major driver of AMF community assembly in the plant roots, while geographical distance between locations was not related to differences in the AMF communities. Additionally, colonizer AMF communities were characterized by overdominance of a single OTU which was remarkably host-specific among locations. Wider dissimilarity in AMF communities was observed in small and disturbed (SD) sites compared to large and undisturbed (LU) sites, a t...