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The Mediterranean countries face common challenges in adapting their agro-systems to climate change and demographic threats. It is on this basis that ARIMNet (Agricultural Research in the Mediterranean Network) programme was implemented by 15 Euro-Mediterranean partners to foster agricultural research and innovation with the support of two successive grants from the European Commission. Our work aims to evaluate the impact of this collaborative work of 10 years over the period (2008–2017) on the implementation of a EURO-MED Research and Innovation Area. Considering ARIMNet as the first regional experience of joint programming and co-funding, it has allowed the funding of 46 research projects in the Mediterranean region with a budget of €25 M. The carried survey with coordinators shows that ARIMNet activities have a positive effect on regional networking, mobility, scientific production, innovation and the construction of a regional common vision regarding societal challenges regarding food security and sustainable agriculture. This transnational programme has consolidated collaboration between EU-MED policymakers and impacted as well national research governance in South Mediterranean countries, as stated by the questionnaire sent to partners from these countries. The ARIMNet experience inspired the current PRIMA initiative (Partnership for Research and Innovation in the Mediterranean Area) which represents a step ahead for the reinforcement of the scientific Euro-Mediterranean collaboration in agriculture. The lessons learned from ARIMNet can benefit the Mediterranean and other regions in developing future common science and technology-based approaches to achieve Sustainable Development Goals. [ABSTRACT FROM AUTHOR]

This paper aims to analyze the scientific evolution and research trends concerning the water–energy–food (WEF) nexus, as well as its development within scientific databases. To achieve this, a bibliometric analysis has been conducted using publications sourced from Scopus and Web of science databases. This study examined key aspects such as primary journals, prominent authors, affiliated institutions, countries of origin, subject areas, and notable keywords. Furthermore, there is a dedicated section that delves into research and innovation gaps within publications related to the WEF nexus. Results reveal that research on the WEF nexus has experienced exponential growth over the past decade, with the majority of publications emerging between 2017 and 2023. The United States leads in this field, with engineering and environmental science being the predominant research categories, with Spain and Italy being the prominent countries in Europe. The WEF nexus concept in the agriculture sector is notably underdeveloped, particularly in its ties with the Sustainable Development Goals and the science–policy–society interface. The study stresses the importance of integrating health considerations into the WEF Nexus to understand the interconnections and their implications on public health, thereby enriching the Nexus approach with a critical dimension of human well-being. This situation underscores the urgent need to create a nexus community that bridges science and practice, and to incorporate this specialized discipline into university curricula. [ABSTRACT FROM AUTHOR]

The article evaluates the performance of the partnership between European and non-European participating states after 2 years of implementation of the Partnership for Research and Innovation in the Mediterranean Area (PRIMA) programme. A total of 742 participating entities were involved in 83 funded projects based on two funding calls of 2018 and 2019. The results show that while extensive partnerships were established between southern and northern Mediterranean countries, there was lower project coordination by non-European states. As a result, the grant distribution was in favour of European countries which received the majority of funds. A networking analysis was performed, and it demonstrates low cooperation between Northern African countries and Eastern Mediterranean countries. Italy, France and Spain are clustered with Northern African countries; however, Germany and Portugal are more affiliated with Eastern Mediterranean countries. The private sector analysis shows an excellent participation of SMEs in Sect. 1 (funded by PRIMA) for both calls in 2018 and 2019. SMEs received 22% of EU funds — well in line with Horizon 2020 target — demonstrating the vital role that PRIMA plays for the development of SMEs. However, for Sect. 2 (funded by participating states), the participation of SMEs was low and received only 6.4% of participating state funds. The participation of SMEs from non-European countries was low and represented 30% in Sect. 1 of the total number of SMEs and only 15% in Sect. 2. [ABSTRACT FROM AUTHOR]

This article reports on the profiles of the National Agricultural Research Systems (NARS) in the three Maghreb countries: Algeria, Morocco and Tunisia, through their research policies, human resources, governance, funding and scientific production. A bibliometric study was carried out for the three selected countries based on the Scopus database covering the period between 2005 and 2019. The research shows the distinctive case of Tunisian growth of scientific production compared to the other two countries; it also stresses the universities' emergence as a major research actor, thus challenging the predominance of the public mission-oriented institutions dedicated to agriculture and veterinary sciences. Finally, it indicates significant differences between the three countries concerning governance and funding, and human resources. Overall, the NARS in the three countries are still very fragile, and a need for significant changes in the research policy making is certainly required to overcome these shortcomings. [ABSTRACT FROM AUTHOR]

Recent occurrence in Tunisia of Citrus blast and black pit disease, caused by Pseudomonas syringae pv. syringae (Pss), the few available antibacterial chemicals, and the increasing resistance of Pss to copper sulfate highlighted the need for new antibacterial agents. In vitro analysis of the antagonistic activity of fifty-four native epiphytic bacterial isolates from the Citrus phyllosphere towards pathogenic Pss resulted in the selection of eight potential biocontrol strains according to their various antagonistic activities. Based on analysis of the (partial) 16S rRNA gene sequence and the rpoD housekeeping gene, five isolates were presumptively identified as Pseudomonas atacamensis (strains Y28, Y58 and Y128), P. cremoris (strain Y40), and P. lactis (strain Y21). In vivo test of these antagonistic strains showed no pathogenicity towards plant tissues. Three strains (Y28, Y128 and Y21) exhibited considerable inhibitory activities and significantly reduced disease severity in five Citrus cultivars (Cassar, Eurêka, Maltaise, Washington Navel and Pomelo) on shoots, leaves and fruits. Determination of genes coding for antibiotic production showed the presence of gacA gene in the five strains mentioned above. However, the genes prnD, pltC, pltB, phlD and phzC as well as phzD (and their homologs phzF and phzA), described earlier for Pf-5, were not detected among the tested Tunisian antagonistic Pseudomonas strains. This study presents the first description of P. atacamensis, P. cremoris, and P. lactis as potential biocontrol agents. The characterized bacterial strains may be considered as potential sources of novel bioactive metabolites as well as promising candidates to develop new biocontrol agents for sustainable control of Citrus. blast and black pit disease. [ABSTRACT FROM AUTHOR]

SuccFerr (N-[4-ferrocenyl,5-5-bis (4-hydroxyphenyl)-pent-4-enyl]-succinimide) has remarkable antiproliferative effects in vitro, attributed to the formation of a stabilized quinone methide. The present article reports in vivo results for a possible preclinical study. SuccFerr is lipophilic and insoluble in water, so the development of a formulation to obviate this inconvenience was necessary. This was achieved by complexation with randomly methylated cyclodextrins (RAMEßCDs). This supramolecular water-soluble system allowed the in vivo experiments below to proceed. Application of SuccFerr on the glioblastoma cancer cell line U87 indicates that it affects the cellular cycle by inducing a blockade at G0/G1 phase, linked to apoptosis, and another one at the S phase, associated with senescence. Using healthy Fischer rats, we show that both intravenous and subcutaneous SuccFerr: RAMEßCD administration at 5 mg/kg lacks toxic effects on several organs. To reach lethality, doses higher than 200 mg/kg need to be administered. These results prompted us to perform an ectopic in vivo study at 1 mg/kg i.v. ferrocidiphenol SuccFerr using F98 cells xenografted in rats. Halting of cancer progression was observed after six days of injection, associated with an immunological defense response linked to the active principle. These results demonstrate that the properties of the selected ferrocidiphenol SuccFerr transfer successfully to in vivo conditions, leading to interesting therapeutic perspectives based on this chemistry. [ABSTRACT FROM AUTHOR]

Pistachio (Pistacia vera L.) cultivation under rainfed conditions of the South Mediterranean has not been studied in depth. Under changing climate conditions, knowledge of cultivar and rootstock performances allows for the optimal use of genetic resources to improve yield and nut quality. This study aimed to evaluate growth, yield, and fruit characteristics of 'Mateur' and 'Achouri' pistachio cultivars grafted on P. vera and P. atlantica rootstocks grown in northeastern Tunisia. The research was based on three years worth of monitoring of growth, yield and fruit quality. Results showed that annual bio-climatic features had significant effects on all studied parameters. The 'Mateur' cultivar showed higher vigor and fruit yield than 'Achouri'. Fruit production was higher in P. atlantica rootstock for 'Mateur' but similar in both studied rootstocks for 'Achouri'. Kernel fat contents (40.7–46.8%) and fatty acid profiles were low or not affected by cultivar, rootstock and their combination. Oleic acid (C18:1) was the major fatty acid (68.94–69.22%) in kernel oil. The unsaturated/saturated fatty acid and oleic/linoleic acid ratios indicated that nuts obtained had high quality. The lower performances of 'Achouri' cultivar in the studied conditions may be related to low acclimation ability of this cultivar. These conditions, however, seem to be suitable for both studied rootstocks. [ABSTRACT FROM AUTHOR]

Copyright of Arab Gulf Journal of Scientific Research is the property of Arabian Gulf University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Olive anthracnose caused by Colletotrichum species causes dramatic losses of fruit yield and oil quality worldwide. A total of 185 Colletotrichum isolates obtained from olives and other hosts showing anthracnose symptoms in Spain and other olive-growing countries over the world were characterized. Colony and conidial morphology, benomyl-sensitive, and casein-hydrolysis activity were recorded. Multilocus alignments of ITS, TUB2, ACT, CHS-1, HIS3, and/or GAPDH were conducted for their molecular identification. The pathogenicity of the most representative Colletotrichum species was tested to olive fruits and to other hosts, such as almonds, apples, oleander, sweet oranges, and strawberries. In general, the phenotypic characters recorded were not useful to identify all species, although they allowed the separation of some species or species complexes. ITS and TUB2 were enough to infer Colletotrichum species within C. acutatum and C. boninense complexes, whereas ITS, TUB2, ACT, CHS-1, HIS-3, and GADPH regions were necessary to discriminate within the C. gloesporioides complex. Twelve Colletotrichum species belonging to C. acutatum, C. boninense, and C. gloeosporioides complexes were identified, with C. godetiae being dominant in Spain, Italy, Greece, and Tunisia, C. nymphaeae in Portugal, and C. fioriniae in California. The highest diversity with eight Colletotrichum spp. was found in Australia. Significant differences in virulence to olives were observed between isolates depending on the Colletotrichum species and host origin. When other hosts were inoculated, most of the Colletotrichum isolates tested were pathogenic in all the hosts evaluated, except for C. siamense to apple and sweet orange fruits, and C. godetiae to oleander leaves. [ABSTRACT FROM AUTHOR]

The reduction of the use chemical pesticides in agriculture is gaining importance as an objective of decision-makers in both politics and economics. Consequently, the development of technically efficient and economically affordable alternatives as, e.g., biological control agents or practices is highly solicited. Crown gall disease of dicotyledonous plants is caused by ubiquitous soil borne pathogenic bacteria of the Agrobacterium tumefaciens species complex, that comprises the species Agrobacterium fabrum and represents a globally relevant plant protection problem. Within the framework of a screening program for bacterial Agrobacterium antagonists a total of 14 strains were isolated from Tunisian soil samples and assayed for antagonistic activity against pathogenic agrobacteria. One particularly promising isolate, termed strain MBY2, was studied more in depth. Using a Multilocus Sequence Analysis (MLSA) approach, the isolate was assigned to the taxonomic species Bacillus velezensis. Strain MBY2 was shown to display antagonistic effects against the pathogenic A. fabrum strain C58 in vitro and to significantly decrease pathogen populations under sterile and non-sterile soil conditions as well as in the rhizosphere of maize and, to a lower extent, tomato plants. Moreover, the ability of B. velezensis MBY2 to reduce C58-induced gall development has been demonstrated in vivo on stems of tomato and almond plants. The present study describes B. velezensis MBY2 as a newly discovered strain holding potential as a biological agent for crown gall disease management. [ABSTRACT FROM AUTHOR]

Citrus blast and black pit caused by Pseudomonas syringae pv. syringae (Pss) is the only bacterial disease reported in Tunisian Citrus orchards. The phylogenetic relationship between Pss strains was studied based on multilocus sequence analysis (MLSA), using partial sequences of housekeeping genes rpoD, rpoB, gyrB, cts, and pfk for 14 representative Pss Citrus strains, including the reference strain LMG5496. The MLSA revealed that the studied Tunisian Citrus strains are closely related to LMG5496 and cluster in phylogroup 02. Based on the cts gene, the majority of Citrus strains clustered in clades "a" and "b". However, five strains were placed in a newly defined clade "g". We describe the presence of six different type III secreted effectors (T3SEs). These were found with frequencies of 100% for the effector hopAN1 and the helper hrpK1, 65% for hopT1‐2, and 14% for hopN1, hopR1, and hopQ1‐2. Investigation of copper resistance showed that 67% of our Pss Citrus strains from Tunisia are resistant to copper sulphate in vitro, and the copper resistance genes copABCDR were detected in 23% of the strains. Our results present new data concerning the genetic diversity and phylogeny, presence of T3SEs, and copper resistance within the Pss populations that affect Citrus in Tunisia. [ABSTRACT FROM AUTHOR]

Since 1927, outbreaks of the leafy gall disease caused by Rhodococcus fascians on annual and perennial herbaceous plants have put the ornamental plant industry at risk. More recently, Pistachio Bushy top syndrome (PBTS), a serious disease emerging in the Western United States, has been declared as a natural disaster by the U.S. Department of Agriculture. Recent developments indicate that the taxonomic position of R. fascians should be re‐evaluated and circumscribed from other members of the genus. Due to the broad host range of this bacterium, economically important crops are in a vulnerable position especially with new members within the genus becoming able to interact synergistically with R. fascians to cause symptom development. The virulence strategies employed by R. fascians and the involvement of cytokinins (CKs) in its pathogenicity have been the subject of much controversy in the last years. Additionally, the detection of virulent strains of R. fascians from symptomatic tissues has been problematic for many researchers. This review focuses on plant–pathogen interaction in context with more recent findings on the association of CKs in virulence of R. fascians. Current knowledge on the worldwide distribution of the pathogen, a historical recap of its discovery and the economic impact of the disease caused by R. fascians are also described here. [ABSTRACT FROM AUTHOR]

The article offers information on the plant disease caused by the phytopathogenic isolates of Rhodococcus fascians, a Gram-positive bacterium. It discusses that the bacteria cause disease on numerous plants by inducing fasciation and leafy galls. It mentions that the bacteria altered plant morphology resulting from these infections cause serious economic losses to ornamental industries.

Verticillium dahliae is one of the most important soil pathogens, causing verticillium wilt. It is well known that the use of chemical products against this pathogen is not without side effects on the environment. In this regard, the present study was aimed to search for antagonistic rhizobacteria as an alternative of biological control against this causal agent. A total of 162 isolates were screened for their antagonistic activity according to the "double layer" and the "well diffusion" methods. Three of them (RS11, SF82 and ZO4), were subsequently selected as biological control agent (BCAs) according to their efficiency and were identified by 16S rRNA sequencing and Biolog microplate GEN III as Bacillus spp. Using 10 different lipopeptide gene primers, PCR reactions only revealed the involvement of genes responsible for iturins (ituA, ituD, ituC), bacillomycin (bmyA) and Bacilysin (bacA / B-F, bacA / B-R) biosynthesis. The Plant Growth Promoting Rhizobacteria traits [enzymatic activities, phytohormones production] of the three BCAs were also studied in vitro then on pepper plant (Capsicum annuum L.), indicating that Bacillus subtilis ZO4 was the most effective, enhancing leaf, stem and root growth comparing to the control. [ABSTRACT FROM AUTHOR]

Objective: We synthesized new tamoxifen derivatives as anticancer drug candidates and elaborated on convection‐enhanced delivery (CED) as a strategy for delivery. Methods: To overcome the issue of their poor solubility, these ferrocenyl‐tamoxifen derivatives were esterified and encapsulated into different nanocarriers, that is lipid (LNC) and polymeric nanocapsules (PNL‐NC). We describe the chemistry, the encapsulation and the physicochemical characterization of these formulations. Key findings: Starting compounds [phthalimido‐ferrocidiphenol and succinimido‐ferrocidiphenol], esterified prodrugs and their nanocapsules formulations were characterized. These drug candidates displayed a strong in vitro activity against breast and glioblastoma cancer cells. The ester prodrugs were toxic for glioblastoma cells (IC50 = 9.2 × 10−2 μm and 6.7 × 10−2 μm, respectively). The IC50 values for breast cancer cells were higher for these compounds. The encapsulation of the esterified compounds in LNCs (≈50 nm) or PCL‐NCs (≈300 nm) did not prevent their efficacy on glioblastoma cells. These anticancer effects were due to both blockade in the S‐phase of the cell cycle and apoptosis. Moreover, the tamoxifen derivatives‐loaded nanocapsules induced no toxicity for healthy astrocytes and showed no haemolytic properties. Loaded Lipid Nanocapsules (LNCs) presented interesting profiles for the optimal delivery of active compounds. Conclusions: Phthalimido‐ and Succinimido‐esters represent an innovative approach to treat cancers with cerebral localizations such as glioblastoma or brain metastases from breast cancers. [ABSTRACT FROM AUTHOR]

Agrobacterium biovar 1 is responsible for crown gall disease of many plant species. However, according to the current species definition, this taxon displays too large a genomic divergence to be a single species. This is why it is considered as a complex of distinct genomic species. Members of this taxon are common inhabitants of soils and rhizospheres, with several species and strains commonly found in the same samples. Understanding factors that shape their populations is very important for ecological and epidemiological issues. In this regard, this study was aimed at assessing whether plant genotypes differentially select agrobacteria genomospecies in their root systems. To test this hypothesis, we followed the evolution of tagged Agrobacterium fabrum C58 strains co-inoculated with members of different genomospecies (G1, G4, G7 and G8), in the soil and the rhizosphere of tomato and maize seedling plants under controlled conditions. The total number of the agrobacterial population was always statistically higher in rhizospheres than in bulk soils, confirming that agrobacteria are rhizospheric bacteria. The plasmid, pTi, was found not to be necessary for either rhizosphere colonization or the multiplication of the C58 strain. The difference between proportions of co-introduced bacteria from different genomic species shows the presence of a competition between them, which can vary with the plant species. While there were no significant differences between the proportion of co-inoculated strains of G8 (J07 and C58Gmr) in either plant species, they were more abundant in tomato than maize rhizosphere. [ABSTRACT FROM AUTHOR]

The low diversification of rootstocks can be a problem in reducing the adaptation of pistachio to the Tunisian climatic and soil conditions. Nowadays, the most used rootstock is Pistacia vera; however, the autochthonous Pistacia atlantica could be a good alternative. The aim of this work was to study the effect of two different rootstocks Pistacia vera and Pistacia atlantica on the quality and functionality of two pistachio cultivars (the local variety "Mateur" and the Syrian one "Achoury"). The different parameters studied were: morphological (size, weight), chemical (minerals and fatty acids) and functional (total phenolic content, and antioxidant activity: ABTS+, DPPH•, and FRAP). The pistachios are a good source of minerals (especially Ca and K 19.9 and 9.8 g kg-1, respectively, and Fe 54.5 mg kg-1), polyunsaturated fatty acids (oleic and linoleic acids), and phenolic compounds (16.0 g GAE kg-1). The combination P. atlantica and variety "Mateur" led to proper values of tree yield, nut dehiscence, morphology (length and width), and oleic acid content. Thus, it can be concluded that the use of the local rootstock P. atlantica led to promising results and can be a good option due to its higher adaptation to the local climatic and soil conditions. [ABSTRACT FROM AUTHOR]

Purpose: The quantity of Olive by-products does not stop increasing and a water shortage that threatens the olive tree culture; require a serious valuation of these by-products. A comparative and valorization study of two kinds of OMW; Fresh OMW (FOMW), directly issue from three-phase continuous extraction factory and Disposal Evaporation Ponds OMW (DOMW) were done.Methods: Physico-chemical and biological parameters of OMWs and soil irrigated with OMWs, respectively, were determined. An antibacterial activity test of FOMW against Clinic Standard Bacteria was determined. A statistical analysis was performed for all defined parameters.Results: A significant increase of pH value of 6 and a lower failure of the EC in 8.94 (mS/cm−1) were registered after OMW disposal in evaporation ponds. We registered a fall of BOD5 and COD from 61.05-116.37 (g/L) to 55.67-103.82 (g/L), respectively. A significant increment of phenol compound removal was observed after OMW disposal. However, a switch of fatty acids distribution and content was observed, which several fermentation pathways could explain took place. This result suggested by a clear shift in biomass composition. An important soil fertility after DOMW soil irrigated was traduced by an important value of the germination index (170.55%) and efficient organic matter increment of 2.3%. A CMI rate of 32.76 (μg mL−1) was determined by FOMW against different clinic standard bacteria.Conclusion: A spectacular soil fertility effect was obtained from DOMW soil spreading, that efficiently evaluate the OMW biological treatment. In addition, the FOMW was valorized as its powerful antibacterial. [ABSTRACT FROM AUTHOR]

Agrobacterium fabrum is one of the eleven Agrobacterium spp. complex species that has been observed to carry a Ti plasmid and induce crown gall, a disease causing significant damage to economically important perennial agricultural crops. Members of this species complex, including A. fabrum, are morphologically indistinguishable from one another on culture media and are known to grow together in soil and within host galls. Consequently, the tracking of this species in its natural environment requires a cautious approach to tagging strains without altering any of their ecologically important traits. A gentamicin resistant cassette (aacCl) was inserted, by homologous recombination, into a non-coding region of the A. fabrum C58 chromosome between the genes atull82 and atull83. The resultant strain did not show any significant in vitro growth differences compared to the wild-type strain, and the marker was stable in rich medium, both with and without selective pressure. The mutant/marked strain was indistinguishable from the parental strain for ability to induce galls, grow in bulk soil and colonize the rhizosphere of tomato plants. Easy, precise, safe and stable tagging of the A. fabrum C58 genome facilitates environmental population surveys by either simple selection or direct detection by PCR. This methodology provides understanding of the ecology of this species complex as an integral part of managing the soil microbiota for improved crown gall management. [ABSTRACT FROM AUTHOR]

Olive mill wastewater (OMW) contains large amounts of organic substances, including phenols, that can have negative environmental consequences when applied to soil. Because of the high concentrations of organic matter and mineral nutrients, OMW holds promise as a fertilizer source for cropping systems. The effects of the addition of 0.5, 1, or 2% OMW to a soil on carbon (C) and nitrogen (N) dynamics and microbiological characteristics of the soil were investigated. Mineral N presented a significant negative correlation with the amount of OMW. The total number of soil bacteria and fungi increased. However, the nitrifying population was sensitive to 2% OMW during the first month. The increase in microbiological activity accelerated the loss of soil organic carbon (SOC). However, the treated soil recovered the SOC, and the total C gains were 2.1, 1.9, and 2.4 g kg−1for the three doses, whereas the SOC loss was 1.1 g kg−1for the control. [ABSTRACT FROM AUTHOR]

Threats of desertification have been projected for the Mediterranean basin under relatively minor warming and drying scenarios. This situation raises the need for mitigation strategies and adaptation of crop production. Crop vulnerability assessment is therefore needed. In Tunisia, olive culture is a major activity. In some cases, olive is the only crop able to grow in local conditions. However, olive production may be among the more vulnerable systems to climate change since perennial crops adapt slowly. No studies have been dedicated to vulnerability evaluation of olive production. Here, the vulnerability of Tunisian olive trees to drought was assessed under extremely low precipitation levels, of 50% of normal precipitation, from 1999 to 2002. The impact of drought was quantified using a severity scale with three levels. A map of the impact of drought on olive trees was constructed for all Tunisian olive groves. We found that the number of wilting olive trees in 2002 was 7.8 millions of about 60 millions trees. A correlation was observed between olive tree affection by drought and olive orchard age. Thus, under the same drought conditions, senescent orchards were less resistant to drought than young ones. Locally, data showed that compact soils and soils containing more than 1% gypsum were not suitable for olive growth under drought. [ABSTRACT FROM AUTHOR]

We evaluated the biocontrol efficacy of a Bacillus subtilis strain isolated from symptomless olive leaves against the olive knot disease pathogen Pseudomonas savastanoi pv. savastanoi. Bacillus subtilis F and F-4 displayed antibacterial activity against the pathogen. In planta, only B. subtilis F significantly reduced the weight of knots caused by P. savastanoi pv. savastanoi IVIA 1628 and Aw, whereas copper treatment was effective only when using strain Aw, thus a reduction of 50% was obtained. Preliminary characterisation of the active compound produced by B. subtilis F showed that it was proteinaceous in nature. These results suggest that B. subtilis strain F could be used to control, and prevent infection by, the causal agent of olive knot disease. [ABSTRACT FROM AUTHOR]

Bacillus subtilis strain 14B was used to produce a novel antimicrobial peptide (bacteriocin) called Bac 14B. Pure bacteriocin was obtained after heat and acidic treatments (80°C and pH 4), precipitation by ammonium sulfate, and chromatography on Sephadex G-50 and Mono Q Sepharose columns. Based on MALDI-TOF mass spectrometry analysis, purified Bac 14B is a monomer protein with a molecular mass of 20110.13 Da. N-terminal sequencing allowed for the straightforward identification of its first 12 residues, which were of a pure bacteriocin. It also revealed that this bacteriocin contained a unique sequence, namely M-L-K-A-N-L-Q-N-P-L-N-A, suggesting the identification of a novel compound. Bac 14B was stable for 1 h at temperatures up to 80°C and pH of 4 ∼ 8. It also proved sensitive to various proteases, which demonstrated its protein nature. Bac 14B displayed a bacteriolytical mode of action and a broad range of inhibitory spectra toward Gram-positive and -negative pathogens. Interestingly, based on conventional agronomic seed vigor parameters, the application of Bac 14B (500 activity units/mL) to various crops revealed that this bacteriocin was a potent exogenous enhancer of growth that stimulated the seedling vigor of tomatoes and muskmelons. Compared to those of the control, the germination percentage, shoot weight, shoot height, and root length were all significantly enhanced in Bac 14B-treated plant seeds. Bac 14B also exhibited effective disinfectant properties against a wide range of seedborne diseases and significant effects on the control of damping off diseases, particularly at the pregermination stage. It also proved to be effective against root rot diseases caused by Alternaria solani and other bacterial seedborne pathogens such as wilt diseases. The findings indicate that Bac 14B is the first B. subtilis-produced bacteriocin ever reported to exhibit such promising biological properties. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Pathology is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Olive trees (cv. Chemlali) showing typical symptoms of wilt and dieback were collected from several areas in Tunisia. Visual diagnostic, isolation and microscopic observations identified the causal pathogen as Verticillium dahliae. The pathotype was determined using specific primers pairs for D (defoliating) and ND (non-defolitating) . Artificial inoculation of olive plants resulted in typical wilting with defoliation, proving that the isolate tested was pathogenic on olive, and this isolate belongs to the D pathotype. This is the first report of the defoliating pathotype causing wilting disease on olive in Tunisia. [ABSTRACT FROM AUTHOR]

Olive mill wastewater (OMW) is a rich source of antifungal agents and has a merit as alternative to synthetic fungicides. To develop disease control agents against Botrytis cinerea, a hydroxytyrosol-rich (29.27% weight:dry weight) olive mill wastewater (HROMW) and a hydroxytyrosol-rich (52.67% weight:dry weight) extract (HRE) were prepared from fresh OMW using hydrolysis and post-hydrolysis purification processes. The HROMW and HRE showed strong fungicidal activity against B. cinerea with minimal fungicidal concentrations (MFCs) of 14.36-28.72 and 28.72-57.44 mg l (dry weight), respectively. According to EN 1275: 1997 standard method, HROMW and HRE at 1.25% (dry weight:volume) showed powerful disinfectant properties resulting in a reduction in the viability of B. cinerea spores by >4 log units after 30 min of contact time. The HROMW or HRE foliar spray treatments, of the B. cinerea inoculated tomato plants, resulted in disease control percentage of 95 and 91%, respectively, whereas 70% was conferred by benomyl treatment. Although, HRE possessed a similar disease severity reduction than HROMW, it showed great advantage by fortifying plants and by improving their growth and healthy aspect. Indeed, HRE-treated plants showed significantly better: (i) plant height (146.2 and 130.5%), (ii) average stem diameter (135% and 110%), (iii) leaf number (163.6 and 128.5%), and (iv) leaf colour (chlorophyll a content) (144.4 and 103%) than benomyl-treated and non-treated plants, respectively. This study revealed that HRE offers a natural and effective extract to control grey mould. [ABSTRACT FROM AUTHOR]

The analysis of housekeeping recA gene sequences from 138 strains from 13 species or genomic species of Agrobacterium, nine being biovar 1 genomospecies, and the others Agrobacterium larrymoorei, Agrobacterium rubi, Agrobacterium sp. NCPPB 1650, and Agrobacterium vitis and one 'former' Agrobacterium species, Rhizobium rhizogenes, led to the identification of 50 different recA alleles and to a clear delineation of the 14 species or genomospecies entirely consistent with that obtained by amplified fragment length polymorphism (AFLP) analysis. The relevance of a recA sequencing approach for epidemiological analyses was next assessed on agrobacterial Tunisian isolates. All Tunisian isolates were found to belong to the Agrobacterium tumefaciens/biovar 1 species complex by both biochemical tests and rrs sequencing. recA sequence analysis further permitted their unambiguous assignment to A. tumefaciens genomospecies G4, G6, G7, and G8 in total agreement with the results of an AFLP-based analysis. At subspecific level, several Tunisian recA alleles were novel, indicating the power and accuracy of recA-based typing for studies of Agrobacterium spp. [ABSTRACT FROM AUTHOR]

Aflatoxins (AFs) are potent sources of health risks to both humans and animals. Among them, AFB1 is the most hazardously toxic and the most frequent in various food commodities, including pistachio nuts. In this survey, the effect of the storage period on AFB1 accumulation on pistachio nuts was investigated. A total of 49 samples collected during the crop year of 2005 from the most cultivated pistachio cultivars in Tunisia were rapidly screened by enzyme-linked immunosorbent assay (ELISA) combined with an immunoaffinity step. The obtained results showed that the contamination of pistachio nuts has occurred clearly after two years of storage for all the tested cultivars except the case of Mateur variety and Thyna ecotypes. In this study, the cultivar Mateur was found to be the most susceptible cultivar to contamination by AFB1. After 4 years of storage, the average contamination levels in nut samples ranged from 2.7 ± 0.3 to 12.7 ± 2.2 µg/kg for AFB1, according to the cultivar. These levels exceeded the maximum permitted limit of 2 µg/kg set by the European Commission in nuts. [ABSTRACT FROM AUTHOR]

Ripe and overripe olive fruits (cv. Meski, Manzanilla and Picholine) showing circular spots 1 to 10 mm in diameter, slightly depressed and reddish-brown in color, were collected from local markets and orchards located in the regions of Takelsa, Zarzis and Rgueb in Tunisia. Colletotrichum gloeosporioides was isolated from symptomatic fruits and Koch's postulates were fulfilled. This is the first report of Colletotrichum gloeosporioides causing anthracnose of olives in Tunisia. [ABSTRACT FROM AUTHOR]

Rheological and thermal properties of xanthan produced by Xanthomonas campestris from date by-products (DBP-xanthan) and commercial xanthan were determined. DBP-xanthan gave solutions with lower apparent viscosity than commercial xanthan. However, DBP-xanthan solutions were more stable to temperature changes and ionic strength than commercial xanthan. Gradual increase of storage modulus (G′ ) as function of frequency was observed for the two polysaccharides. On the other hand, loss modulus (G″ ) remained constant for DBP-xanthan and an increase was observed for commercial xanthan. Granulometric profile indicates that DPB-xanthan particle size was lower than commercial xanthan. Differential scanning calorimetry showed that the melting temperatures (T m) and enthalpy (ΔH m) of DBP-xanthan were higher than those of commercial xanthan. These properties of DBP-xanthan are quite rare among xanthan described in the literature and give this new gum great potential for use in the field of bioindustries as thickening and stabilizing agents. PRACTICAL APPLICATIONS Xanthan gum from date by-products (DBP-xanthan) was recently produced in our laboratory. No work has been undertaken to study the rheological properties of this polysaccharide to date. Rheological and some physicals properties were compared to those of commercial xanthan. This could promote industrial use of DBPs as low-cost natural source for xanthan gum production. [ABSTRACT FROM AUTHOR]

The aim of this work was to study the effect of the irrigation with treated wastewater (TWW) on the quality parameters of “Chemlali” olive oil through two crop seasons (2004/2005 and 2006/2007). The results showed that irrigation with TWW did not affect the examined oil quality indices (free acidity, specific ultraviolet absorbance K232 and K270). During the two crop seasons, the mean values of these parameters are lower than the upper limits established for the best commercial olive oil quality designated as “Extra Virgin.” However, a significant increase of palmitic, palmitoleic, linoleic, linolenic and stearic acid contents was found in the 2006/2007 crop season in the plot irrigated with TWW as compared to the one treated with well water. In addition, a decrease of oleic acid and polyphenol content was observed at the end of experimental period. PRACTICAL APPLICATIONS The availability of fresh water is very scarce in the Middle East and North Africa. Yet consequently, good quality water is used to irrigate crops more sensitive to water shortage than olive trees. Brackish water or recycled wastewater can be used for irrigation, minimizing the exploitation of natural water resources. In Tunisia, treated wastewater (TWW) is commonly used to irrigate olive trees. The aim of the present study was to assess changes in quality characteristics (free acidity, specific ultraviolet absorbance K232 and K270, fatty acid composition and total phenolic compounds) of “Chemlali” olive oil obtained from trees irrigated with TWW. [ABSTRACT FROM AUTHOR]

Olive trees (Olea europaea) cv. Meski having leaves with yellow spots on the upper surface and grey blotches on the lower surface were found in three orchards located in the regions of Takelsa, Testour and Enfidha, central and northern Tunisia. The shoots of the olive trees had also become defoliated indicating a severe attack of a pathogen. Pseudocercospora cladosporioides was isolated from symptomatic leaves and Koch's postulates were fulfilled. This is the first Tunisian report of P. cladosporioides causing Cercospora leaf spot of olive trees. [ABSTRACT FROM AUTHOR]

The purpose of this study was to isolate and identify Rhodococcus spp. strains from almond and pistachio rootstocks and trees in Tunisia. Twenty-eight strains were identified through 16S rDNA and vicA genes amplification and sequencing. Pea bioassay was performed to determine the pathogenicity of the strains. Representative 16S rDNA and vicA sequences of eight strains from pistachio and seven strains from almond were closely related (>98% similarity) to Rhodococcus spp. accessions in GenBank. Phylogenetic analysis based on 16S rDNA sequences revealed that the yellow-colored strains clustered with phytopathogenic Rhodococcusfascians. The red and orange-colored strains were separated into a different group with R. kroppenstedtii and R. corynebacteiroides isolates. Eleven strains affected the pea seedlings' growth and exhibited different levels of virulence. The number of shoots was significantly higher in seedlings inoculated with four Rhodococcus strains, whereas the other three strains caused up to 80% of plant height reduction and reduced root secondary growth compared to non-inoculated pea seedlings. These strains, most of which are epiphytes from asymptomatic hosts, showed strong pathogenicity during pea bioassay and were established endophytically in pea tissues. Ten att and five fas genes were detected in four strains and may represent a novel model of plant pathogenic Rhodococcus virulence. The results of our survey showed that Rhodococcus is present but not prevalent in all visited orchards of almond and pistachio rootstocks and trees. Our surveys complemented the investments being made on ornamental species in Tunisia and unveiled the presence of undocumented plant-associated Rhodococcus spp. on economically important crops. [ABSTRACT FROM AUTHOR]

Durum wheat ( Triticum turgidum) is one of the most important cereal crops in the world and the staple food for the Tunisian population. The main growing areas of durum wheat are located in the Northern part of the country, which is characterised by a sub humid climate favourable for fungal spoilage of grain such as Alternaria species. These species are able to produce plant pathogenic as well as toxic metabolites. For mycological analysis, the agar test was used. After mycelial growth, the Alternaria species were inoculated on potato carrot agar media. A PCR-based assay followed by a sequencing step allowed the identification of Alternaria alternata; Alternaria tenuissima and Alternaria japonica from grains. [ABSTRACT FROM AUTHOR]

Newly discovered Erwinia amylovora phages PEar1, PEar2, PEar4 and PEar6 were isolated from three different orchards in North Tunisia to study their potential as biocontrol agents. Illumina sequencing revealed that the PEar viruses carry a single-strand DNA genome between 6608 and 6801 nucleotides and belong to the Inoviridae, making them the first described filamentous phages of E. amylovora. Interestingly, phage-infected cells show a decreased swimming and swarming motility and a cocktail of the four phages can significantly reduce infection of E. amylovora in a pear bioassay, potentially making them suitable candidates for phage biocontrol. [ABSTRACT FROM AUTHOR]