Effect of Bacteria Inoculation on Colonization of Roots by Tuber melanosporum and Growth of Quercus ilex Seedlings.

Tuber melanosporum is an ascomycete that forms ectomycorrhizal (ECM) symbioses with a wide range of host plants, producing edible fruiting bodies with high economic value. The quality of seedlings in the early symbiotic stage is important for successful truffle cultivation. Numerous bacterial species have been reported to take part in the truffle biological cycle and influence the establishment of roots symbiosis in plant hosts and the development of the carpophore. In this work, three different bacteria formulations were co-inoculated in Quercus ilex L. seedlings two months after T. melanosporum inoculation. At four months of bacterial application, the T. melanosporum ECM root tip rate of colonization and bacterial presence were assessed using both morphological and molecular techniques. A 2.5-fold increase in ECM colonization rate was found in the presence of Pseudomonas sp. compared to the seedlings inoculated only with T. melanosporum. The same treatment caused reduced plant growth either for the aerial and root part. Meanwhile, the ECM colonization combined with Bradyrhizobium sp. and Pseudomonas sp. + Bradyrhizobium sp. reduced the relative density of fibrous roots (nutrient absorption). Our work suggests that the role of bacteria in the early symbiotic stages of ECM colonization involves both the mycorrhizal symbiosis rate and plant root development processes, both essential for improve the quality of truffle-inoculated seedlings produced in commercial nurseries.

Knot formation and spread along the shoot stem in 13 olive cultivars inoculated with an indigenous pathobiome of 7 species of Pseudomonas including Pseudomonas savastanoi.

Olive knot is a widely spread disease among olive (Olea europaea L.) trees. Pseudomonas savastanoi pv. savastanoi is recognized as the primary causative agent of the disease however, recent evidence indicated that consortia of bacteria (pathobiome), may favor its development. Several factors are involved in the host-plant relationship and affect the intensity of the symptoms. Among these the presence of wounds, or damages to the plants' tissues may affect the intensity and propagation of the disease. It remains unknown whether or not bacteria move from an infected wound to another not infected one via shoot tissues. The present investigation focused on the susceptibility to olive knot of several cultivars after inoculating artificial wounds with selected Pseudomonas species, while spreading the disease from these to wounds on the same stem, that had not been purposefully inoculated. The pathobiome for the inoculum was prepared with 7 species of Pseudomonas (including Pseudomonas savastanoi pv. savastanoi), isolated from knot samples collected from two different, heavily infected olive orchards. The inoculation was done after the manual execution of 10 horizontal wounds on the stem of potted plants of 13 olive cultivars grown in the greenhouse. Only the lowest 5 wounds were inoculated. The inoculated wounds showed a maximum percentage of knots after 187 days. All 13 cultivars showed knots yet, the cultivar with the most severe disease level to Pseudomonas savastanoi pv. savastanoi was 'Rosciola colli Esini'. The metataxonomic analysis performed on the olive knots removed after 225 days confirmed the dominance of the inoculated species Pseudomonas savastanoi in all the assayed cultivars. The not inoculated wounds did not show the knot disease likely because the bacterium's inability to transmigrate from the inoculated wounds to the non-inoculated ones.

Arginase 1+ IL-10+ polymorphonuclear myeloid-derived suppressor cells are elevated in patients with active pemphigus and correlate with an increased Th2/Th1 response.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells, which are characterized by their capability to suppress T-cell responses. While MDSCs have been traditionally associated with cancer diseases, their role as regulators of autoimmune diseases is emerging. Pemphigus is a chronic autoimmune blistering skin disease characterized by dysregulated T-cell responses and autoantibody production. The role of MDSCs in pemphigus disease has not been defined yet. The aim of this study was to characterize MDSCs in pemphigus patients and to dissect their relationship with CD4+ T-cell subsets and clinical disease assessments. For this purpose, we performed a cross-sectional analysis of 20 patients with pemphigus. Our results indicate that a population of CD66b+ CD11b+ polymorphonuclear-like MDSCs (PMN-MDSCs) is expanded in the peripheral blood mononuclear cell fraction of pemphigus patients compared to age-matched healthy donors. These PMN-MDSCs have the capability of suppressing allogeneic T-cell proliferation in vitro and show increased expression of characteristic effector molecules such as arginase I and interleukin-10. We further demonstrate that PMN-MDSCs are especially expanded in patients with active pemphigus, but not in patients in remission. Moreover, MDSC frequencies correlate with an increased Th2/Th1 cell ratio. In conclusion, the identification of a functional PMN-MDSC population suggests a possible role of these cells as regulators of Th cell responses in pemphigus.

Staphylococcal Enterotoxins Dose-Dependently Modulate the Generation of Myeloid-Derived Suppressor Cells.

Staphylococcus aureus is one of the major human bacterial pathogens causing a broad spectrum of serious infections. Myeloid-derived suppressor cells (MDSC) represent an innate immune cell subset capable of regulating host-pathogen interactions, yet their role in the pathogenesis of S. aureus infections remains incompletely defined. The aim of this study was to determine the influence of different S. aureus strains and associated virulence factors on human MDSC generation. Using an in vitro MDSC generation assay we demonstrate that low concentrations of supernatants of different S. aureus strains led to an induction of functional MDSC, whereas increased concentrations, conversely, reduced MDSC numbers. The concentration-dependent reduction of MDSC correlated with T cell proliferation and cytotoxicity. Several findings supported a role for staphylococcal enterotoxins in modulating MDSC generation. Staphylococcal enterotoxins recapitulated concentration-dependent MDSC induction and inhibition, T cell proliferation and cytotoxicity, while an enterotoxin-deficient S. aureus strain largely failed to alter MDSC. Taken together, we identified staphylococcal enterotoxins as main modulators of MDSC generation. The inhibition of MDSC generation by staphylococcal enterotoxins might represent a novel therapeutic target in S. aureus infections and beyond in non-infectious conditions, such as cancer.

Human T cells modulate myeloid-derived suppressor cells through a TNF-α-mediated mechanism.

Myeloid-derived suppressor cells (MDSC) represent an innate immune cell subset capable of suppressing T-cell responses in cancer and chronic inflammation. While the effect of MDSC on T cells has been defined thoroughly, the reciprocal impact of T cells on MDSC homeostasis remains poorly understood. Therefore, we comprehensively analyzed the effect of different T-cell subsets on the generation and survival of human MDSC. Using an in vitro MDSC generation assay, we demonstrate that unstimulated CD4+, but not CD8+ T cells, induce polymorphonuclear MDSC (PMN-MDSC) from CD33+ myeloid cells. This effect was dependent on direct cell-cell contact and required TNF-α signaling. Soluble TNF-α was dispensable for PMN-MDSC generation, suggesting that transmembrane TNF-α is involved in that trans-cellular process. Stimulated human CD3+ T cells delayed the apoptosis of PMN-MDSC, which was independent of TNF-α signaling or direct cell-cell contact, but was recapitulated by IL-2. Taken together, our study shows that human T cells modulate MDSC generation and survival through two distinct mechanisms and thereby fine-tune the homeostasis of human MDSC in a regulated manner.

Oil Characteristics of Four Palestinian Olive Varieties.

Olive oil represents an important source of income for Palestinian farmers in local, national and international markets. Sometimes, olive oil produced in local climatic conditions, does not achieve the International Olive Council (IOC) trade standards so that international markets are precluded. The oil chemical composition and sensory profile of four Palestinian olive varieties (Nabali Baladi, Nabali Mohassan, Souri and K18) were characterized in 2010 throughout an in situ evaluation. Most of the physicchemical characteristics and the fatty acid composition of the varieties met the International Olive Council trade standards (IOC-TS) for extra virgin olive oils. Values of K270 for Nabali Baladi and linolenic acid for Souri slightly exceeded the limit. Eicosanoic acid exceeded the IOC-TS limits in the oils of all considered varieties. Among the sterols, the Δ-7-stigmastenol resulted too high for Nabali Baladi and Souri. Sensory profile for the tested varieties showed a reminiscence of tomato or artichoke and light to medium bitter and pungent sensations. Results represent an important baseline reference for further studies about oil composition and quality of the main Palestinian olive germplasm and provide indication of potential critical points to be controlled in order to ensure the full achievement of IOC-TS and access international markets.

Induction of Myeloid-Derived Suppressor Cells in Cryopyrin-Associated Periodic Syndromes.

Cryopyrin-associated periodic syndromes (CAPS) are caused by mutations in the NLRP3 gene leading to overproduction of IL-1ß and other NLRP3 inflammasome products. Myeloid-derived suppressor cells (MDSCs) represent a novel innate immune cell subset capable of suppressing T-cell responses. As inflammasome products were previously found to induce MDSCs, we hypothesized that NLRP3 inflammasome-dependent factors induce the generation of MDSCs in CAPS. We studied neutrophilic MDSCs, their clinical relevance, and MDSC-inducing factors in a unique cohort of CAPS patients under anti-IL-1 therapy. Despite anti-IL-1 therapy and low clinical disease activity, CAPS patients showed significantly elevated MDSCs compared to healthy controls. MDSCs were functionally competent, as they suppressed polyclonal T-cell proliferation, as well as Th1 and Th17 responses. In addition, MDSCs decreased monocytic IL-1ß secretion. Multiplex assays revealed a distinct pattern of MDSC-inducing cytokines, chemokines, and growth factors. Experimental analyses demonstrated that IL-1 cytokine family members and autoinflammation-associated alarmins differentially induced human MDSCs. Increased MDSCs might represent a novel autologous anti-inflammatory mechanism in autoinflammatory conditions and may serve as a future therapeutic target.

Impact of Alternative Fungicides on Grape Downy Mildew Control and Vine Growth and Development.

Grapevine downy mildew (GDM) is one of the most serious diseases of grapevines. With limitations in the use of copper-based products imposed for organic agriculture by the European Union, research for alternatives is encouraged. The aim of this research was to follow a 2-year trial to evaluate the control of GDM using some alternative compounds, and to determine their effects on shoot growth, plant photosynthesis, and grape quality and quantity. Under low disease pressure, Bordeaux mixture, copper hydroxide, laminarin combined with low copper, and 0.5 and 0.8% chitosan had the lowest GDM incidence, reduced on leaves by 96, 95, 75, 56, and 81%, respectively, compared with the untreated control in the last survey. With high disease pressure, Bordeaux mixture, laminarin combined with Saccharomyces extracts, and 0.5 and 0.8% chitosan had the lowest GDM incidence, reduced on grape by 86, 37, 66, and 75%, respectively, compared with the untreated control in the survey of mid-July. Chitosan at 0.8% lowered net photosynthesis, due to reduced stomatal conductance, leaf area, and dry weight, with no negative effects observed on the quantity of the grape berries and the quality parameters of their juice. Among the alternatives to copper, chitosan provided the best GDM protection and reduced the vigor of the vegetation, inducing physiological changes without negative effects on grape production.

Flagellin induces myeloid-derived suppressor cells: implications for Pseudomonas aeruginosa infection in cystic fibrosis lung disease.

Pseudomonas aeruginosa persists in patients with cystic fibrosis (CF) and drives CF lung disease progression. P. aeruginosa potently activates the innate immune system, mainly mediated through pathogen-associated molecular patterns, such as flagellin. However, the host is unable to eradicate this flagellated bacterium efficiently. The underlying immunological mechanisms are incompletely understood. Myeloid-derived suppressor cells (MDSCs) are innate immune cells generated in cancer and proinflammatory microenvironments and are capable of suppressing T cell responses. We hypothesized that P. aeruginosa induces MDSCs to escape T cell immunity. In this article, we demonstrate that granulocytic MDSCs accumulate in CF patients chronically infected with P. aeruginosa and correlate with CF lung disease activity. Flagellated P. aeruginosa culture supernatants induced the generation of MDSCs, an effect that was 1) dose-dependently mimicked by purified flagellin protein, 2) significantly reduced using flagellin-deficient P. aeruginosa bacteria, and 3) corresponded to TLR5 expression on MDSCs in vitro and in vivo. Both purified flagellin and flagellated P. aeruginosa induced an MDSC phenotype distinct from that of the previously described MDSC-inducing cytokine GM-CSF, characterized by an upregulation of the chemokine receptor CXCR4 on the surface of MDSCs. Functionally, P. aeruginosa-infected CF patient ex vivo-isolated as well as flagellin or P. aeruginosa in vitro-generated MDSCs efficiently suppressed polyclonal T cell proliferation in a dose-dependent manner and modulated Th17 responses. These studies demonstrate that flagellin induces the generation of MDSCs and suggest that P. aeruginosa uses this mechanism to undermine T cell-mediated host defense in CF and other P. aeruginosa-associated chronic lung diseases.

Effects of Bois noir on carbon assimilation, transpiration, stomatal conductance of leaves and yield of grapevine (Vitis vinifera) cv. Chardonnay.

Bois noir (BN) is one of the main phytoplasma diseases of grapevine (Vitis vinifera). It is widespread, and can cause severe losses in European vineyards. The infective agent colonizes phloem elements and induces visible symptoms of leaf yellowing or reddening after a relatively long incubation period. As the most sensitive cultivars to BN, Chardonnay plants were grouped as healthy or symptomatic in spring, based on the records from the previous year. Leaf gas exchange and chlorophyll a fluorescence were measured weekly from July to September in healthy plants, and in symptomatic and asymptomatic leaves from symptomatic plants. The midday relative water content (mRWC) was measured once per month. The detection of phytoplasma DNA by nested-polymerase chain reaction revealed BN infection in symptomatic leaf samples at the end of September. A significant decrease in pigment content and maximum quantum efficiency of photosystem II (Fv/Fm) of these symptomatic leaves was detected from July to September, although in the asymptomatic leaves of the symptomatic plants the net photosynthesis (Pn) decrease was not significant. In the leaves from the healthy plants, Pn and transpiration were relatively stable. Of note, in July, an initially healthy plant showed a strong Pn reduction that was followed by visible leaf yellowing symptoms only in August. The phytoplasma infection also stimulated significant reductions in mRWC of the symptomatic leaves, with a final large decrease in yield.

Cherry antioxidants: from farm to table.

The dietary consumption of fruits and vegetables is associated with a lower incidence of degenerative diseases such as cardiovascular disease and certain types of cancers. Most recent interest has focused on the bioactive phenolic compounds found in vegetable products. Sweet and sour cherries contain several antioxidants and polyphenols that possess many biological activities, such as antioxidant, anticancer and anti-inflammation properties. The review describes the effect of environment and other factors (such as production, handling and storage) on the nutritional properties of cherries, with particular attention to polyphenol compounds. Moreover the health benefits of cherries and their polyphenols against human diseases such as heart disease, cancers, diabetes are reviewed.

Strawberry plant relationship through the stolon.

Stolon is an elongated, two-node, vegetative, axillary shoot, which supports the ramet (rooted rosette) until it is completely independent on its own roots. The reciprocal capacity of the ramets, in a single runner chain, to sustain the growth and share locally abundant resources or to tolerate a local stress, is still in debate. This capacity may play an important role for improving nursery plant production and for better understanding the natural clonal multiplication. To describe strawberry stolon action, in plant-to-plant relationship, bare-rooted Camarosa ramets, joint in couples by their own stolons (generally, second and third ramet in a runner chain) were transplanted in two pots. The couples of ramets were treated in a factorial experiment with decortication (peeling a 2-mm ring of bark from the stolon), removal of root system or glyphosate application to one of the two ramets. In the studied system, the older ramet was referred as mother and the other as daughter. The two ramets were very similar in age and seem to act with a very limited hierarchic prevalence of the mother. When the root system of one ramet was eliminated, leaf number and chlorophyll content had a very slight decrease, independently in the mother ramet or in the daughter. The decortication did not reduce water integration, in any group of plants, but limited assimilate allocation towards the daughter ramet when the mother ramet had a severe root cut (not vice versa). The glyphosate action resulted localized in the sprayed ramet, which reduced chlorophyll content within 2 days and expired after 4 days.