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Climate change and global warming have contributed to increase terrestrial drought, causing negative impacts on agricultural production. Drought stress may be addressed using novel agronomic practices and beneficial soil microorganisms, such as arbuscular mycorrhizal fungi (AMF), able to enhance plant use efficiency of soil resources and water and increase plant antioxidant defence systems. Specific traits functional to plant resilience improvement in dry conditions could have developed in AMF growing in association with xerophytic plants in maritime sand dunes, a drought-stressed and low-fertility environment. The most studied of such plants are European beachgrass (Ammophila arenaria Link), native to Europe and the Mediterranean basin, and American beachgrass (Ammophila breviligulata Fern.), found in North America. Given the critical role of AMF for the survival of these beachgrasses, knowledge of the composition of AMF communities colonizing their roots and rhizospheres and their distribution worldwide is fundamental for the location and isolation of native AMF as potential candidates to be tested for promoting crop growth and resilience under climate change. This review provides quantitative and qualitative data on the occurrence of AMF communities of A. arenaria and A. breviligulata growing in European, Mediterranean basin and North American maritime sand dunes, as detected by morphological studies, trap culture isolation and molecular methods, and reports on their symbiotic performance. Moreover, the review indicates the dominant AMF species associated with the two Ammophila species and the common species to be further studied to assess possible specific traits increasing their host plants resilience toward drought stress under climate change. [ABSTRACT FROM AUTHOR]

Maize cropping systems need to be re-designed, within a sustainable intensification context, by focusing on the application of high-use efficiency crop practices, such as those that are able to enhance an early plant vigor in the first critical growth stages; such practices could lead to significant agronomic and yield benefits. The aim of this study has been to evaluate the effects of the cultivation of hybrids with superior early vigor, of the distribution of starter fertilizers at sowing, and of the seed application of biostimulants on promoting plant growth and grain yield in full factorial experiments carried out in both a growth chamber and in open fields. The greatest benefits, in terms of plant growth enhancement (plant height, biomass, leaf area) and cold stress mitigation, were detected for the starter fertilization, followed by the use of an early vigor hybrid and a biostimulant seed treatment. The starter fertilization and the early vigor hybrid led to earlier flowering dates, that is, of 2.1 and 2.8 days, respectively, and significantly reduced grain moisture at harvest. Moreover, the early vigor hybrid, the starter NP fertilization, and the biostimulant treatment increased grain yield by 8.5%, 6.0%, and 5.1%, respectively, compared to the standard hybrid and the untreated controls. The combination of all the considered factors resulted in the maximum benefits, compared to the control cropping system, with an increase in the plant growth of 124%, a reduction of the sowing-flowering period of 5 days, and a gain in grain yield of 14%. When choosing the most suitable crop practice, the diversity of each cropping system should be considered, according to the pedo-climatic conditions, the agronomic background, the yield potential, and the supply chain requirements. [ABSTRACT FROM AUTHOR]

The sustainable intensification of maize-based systems may reduce greenhouse-gas emissions and the excessive use of non-renewable inputs. Considering the key role that the microbiological fertility has on crop growth and resilience, it is worth of interest studying the role of cropping system on the rhizosphere bacterial communities, that affect soil health and biological soil fertility. In this work we monitored and characterized the diversity and composition of native rhizosphere bacterial communities during the early growth phases of two maize genotypes of different early vigor, using a nitrogen (N)-phosphorus (P) starter fertilization and a biostimulant seed treatment, in a growth chamber experiment, by polymerase chain reaction-denaturing gradient gel electrophoresis of partial 16S rRNA gene and amplicon sequencing. Cluster analyses showed that the biostimulant treatment affected the rhizosphere bacterial microbiota of the ordinary hybrid more than that of the early vigor, both at plant emergence and at the 5-leaf stage. Moreover, the diversity indices calculated from the community profiles, revealed significant effects of NP fertilization on richness and the estimated effective number of species (H2) in both maize genotypes, while the biostimulant had a positive effect on plant growth promoting community of the ordinary hybrid, both at the plant emergence and at the fifth leaf stage. Our data showed that maize genotype was the major factor shaping rhizosphere bacterial community composition suggesting that the root system of the two maize hybrids recruited a different microbiota. Moreover, for the first time, we identified at the species and genus level the predominant native bacteria associated with two maize hybrids differing for vigor. These results pave the way for further studies to be performed on the effects of cropping system and specific crop practices, considering also the application of biostimulants, on beneficial rhizosphere microorganisms. [ABSTRACT FROM AUTHOR]

Three killer toxins that were previously investigated, one excreted by Kluyveromyces wickerhamii and two by different strains of Wickerhamomyces anomalus, were produced at the pilot scale, lyophilized and characterized, and the formulates were assessed for their zymocidial effect against Brettanomyces bruxellensis spoilage yeast. A comparative analysis allowed the evaluation of the minimum inhibitory concentration (MIC) against a sensitive strain. Fungicidal and fungistatic concentrations were used to evaluate the cytocidal effect using a cytofluorimetric approach that confirmed the lethal effect of all lyophilized formulates against B. bruxellensis spoilage yeasts. Moreover, the potential killer toxins' cytotoxicity against human intestinal cells (Caco-2) were evaluated to exclude any possible negative effect on the consumers. Finally, the effective lethal effect of all three lyophilized killer toxins toward B. bruxellensis sensitive strain were tested. The results indicated that all of them acted without dangerous effects on the human epithelial cells, opening the way for their possible commercial application. In particular, D15 showed the lowest MIC and the highest activity, was evaluated also in wine, revealing a strong reduction of Brettamonyces yeast growth and, at the same time, a control of ethyl phenols production. [ABSTRACT FROM AUTHOR]

Simple Summary: Arbuscular mycorrhizal fungi (AMF), as well as ultraviolet-B radiation (UV-B), could act as key factors affecting plant–insect interactions. The stress related to one of these two factors could be balanced by the positive effects of the other. In the present work, the feeding preferences of Myzus persicae aphids for lettuce plants exposed to two abiotic factors, i.e., AMF and UV-B, singly or in combination, was evaluated. Results showed that lettuce plants treated with UV-B increased in callose and oxidative stress indicators, signalling an alteration in the volatile organic compounds (VOCs) emitted. On the other hand, the negative effects of UV-B were partially mitigated in lettuces inoculated with AMF. Differently treated lettuces did not affect the feeding preferences of the M. persicae aphid population. Overall, this study shed light on how UV-B and AMF impact lettuce VOCs emission and defence mechanisms, but not the feeding behaviour of a polyphagous aphid species. Arbuscular mycorrhizal fungi (AMF) and ultraviolet-B radiation (UV-B) play important roles in plant–insect interactions by altering plant physiology and histology. We hypothesized that UV-B-induced oxidative stress was mitigated by AMF symbiosis. In this study, we conducted a multifactorial experiment to explore lettuce plant response to AMF inoculation and UV-B exposure (0.4 W m−2; 16 h d−1; 2 weeks), either together or individually, as well as the interaction with the polyphagous insect pest Myzus persicae (Sulzer). Lettuce plants subjected to UV-B radiation showed an increase in callose and oxidative stress indicators, as well as a decrease in stomatal density. Mycorrhizal colonization cancelled out the effect of UV-B on stomatal density, while the symbiosis was not affected by UV-B treatment. The plant volatile emission was significantly altered by UV-B treatment. Specifically, the non-terpene 1-undecene abundance (+M/+UVB: 48.0 ± 7.78%; −M/+UVB: 56.6 ± 14.90%) was increased, whereas the content of the non-terpene aldehydes decanal (+M/+UVB: 8.50 ± 3.90%; −M/+UVB: 8.0 ± 4.87%) and undecanal (+M/+UVB: 2.1 ± 0.65%; −M/+UVB: 1.20 ± 1.18%) and the sesquiterpene hydrocarbons (+M/+UVB: 18.0 ± 9.62 %; −M/+UVB: 19.2 ± 5.90%) was decreased. Mycorrhization, on the other hand, had no significant effect on the plant volatilome, regardless of UV-B treatment. Aphid population was unaffected by any of the treatments, implying a neutral plant response. Overall, this study provides new insights about the interactions among plants, UV-B, and AMF, outlining their limited impact on a polyphagous insect pest. [ABSTRACT FROM AUTHOR]

The genetic relationships among the arbuscular mycorrhiza Glomus mosseae from Europe and the United States examined by vegetative compatibility tests, protein profiles, and internal transcribed spacer-restriction fragment length polymorphism profiles Results suggest that the two European isolates, IMA1 and BEG25 exhibit a higher level of molecular diversity than between IMA1 and the two American isolates.

Arbuscular mycorrhizal fungi (AMF) represent an important group of root symbionts, given the key role they play in the enhancement of plant nutrition, health, and product quality. The services provided by AMF often are facilitated by large and diverse beneficial bacterial communities, closely associated with spores, sporocarps, and extraradical mycelium, showing different functional activities, such as N2 fixation, nutrient mobilization, and plant hormone, antibiotic, and siderophore production and also mycorrhizal establishment promotion, leading to the enhancement of host plant performance. The potential functional complementarity of AMF and associated microbiota poses a key question as to whether members of AMF-associated bacterial communities can colonize the root system after establishment of mycorrhizas, thereby becoming endophytic. Root endophytic bacterial communities are currently studied for the benefits provided to host plants in the form of growth promotion, stress reduction, inhibition of plant pathogens, and plant hormone release. Their quantitative and qualitative composition is influenced by many factors, such as geographical location, soil type, host genotype, and cultivation practices. Recent data suggest that an additional factor affecting bacterial endophyte recruitment could be AMF and their associated bacteria, even though the mechanisms allowing members of AMF-associated bacterial communities to actually establish in the root system, becoming endophytic, remain to be determined. Given the diverse plant growth–promoting properties shown by AMF-associated bacteria, further studies are needed to understand whether AMF may represent suitable tools to introduce beneficial root endophytes in sustainable and organic agriculture where the functioning of such multipartite association may be crucial for crop production. [ABSTRACT FROM AUTHOR]

Featured Application: The molecular methods here identified as the best performing tools to type K. humilis, S. cerevisiae and L. sanfranciscensis isolates could be further utilized for the selection of sourdough yeasts and LAB to be used as starters for the production of functional baked goods. The diverse metabolites, positively affecting the nutritional, organoleptic and technological traits of leavened baked goods, are produced by different sourdough lactic acid bacteria (LAB) and yeast strains, as the result of their genetic intraspecific diversity. Therefore, the molecular and functional strain-level characterization of sourdough microbiota is crucial to valorize traditional or origin protected baked end-products, develop innovative starter cultures and design functional cereal-based foods. To this aim, the genetic intraspecific diversity of 96 Lactobacillus sanfranciscensis, 65 Kazachstania humilis and three Saccharomyces cerevisiae characterizing Protected Designation of Origin (PDO) Tuscan bread sourdough, was investigated, using P4, P7 and M13 random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), (GTG)5 repetitive element sequence-based (rep)-PCR and inter-delta region analyses, respectively. Regarding LAB, the combination of P4, P7 and M13 RAPD-PCR analyses revealed a huge degree of intraspecific variability, discriminating 43 biotypes out of 96 isolates of L. sanfranciscensis. (GTG)5 rep-PCR showed a discriminatory index of 0.95, grouping the 65 K. humilis isolated from PDO Tuscan bread sourdough in 9 biotypes. The high polymorphism among both LAB and yeast isolates of PDO Tuscan bread sourdough outlines a highly complex microbial community structure, whose relative composition and specific physiological characteristics could be responsible for the peculiar organoleptic, rheological, nutritional and potentially nutraceutical features of PDO Tuscan bread. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungi and plant growth-promoting rhizobacteria (PGPR) are beneficial microorganisms that may associate with grapevine roots, improving stress tolerance, growth, and nutrition. AM fungi and PGPR enhance the production of plant secondary metabolites, including volatile organic compounds (VOCs) that play a key role in the interaction of plants with the environment and are involved in defence mechanisms. The aim of this study was to analyse the effects of an AM fungus and a rhizobacterium on plant growth and VOCs in Vitis vinifera cv. Cabernet Sauvignon roots to gain insight into the potential role of plant-rhizosphere microorganisms in vine growth and defence. Grapevines were inoculated or not with the AM fungus Funneliformis mosseae IN101 and/or the plant growth-promoting rhizobacterium Ensifer meliloti TSA41. Both microbial strains enhanced plant growth. Fifty-eight VOCs extracted from ground roots were identified using headspace solid-phase microextraction coupled to gas chromatography/mass spectrometry. VOCs were induced by F. mosseae IN101, increasing up to 87% compared with control plants. Monoterpenes were strongly enhanced by F. mosseae IN101, increasing up to 113% compared with control plants. Interestingly, monoterpene alcohols related to plant defence, such as myrtenol, p-cymen-7-ol, and p-mentha-1.8-dien-7-ol were increased. By contrast, E. meliloti TSA41 did not significantly affect VOCs. The knowledge of the effects of AM fungi and PGPR on grapevine VOCs may contribute to an integrated and sustainable management of vineyards. [ABSTRACT FROM AUTHOR]

This study aimed at characterising the endophytic bacterial communities living in durum wheat roots, as affected by wheat cultivar and inoculation of the Arbuscular mycorrhizal fungus Funneliformis mosseae IMA1 and the wheat root endophytic bacterium Lactobacillus plantarum B.MD.R.A2. These microorganisms were inoculated, alone or in combination, in durum wheat (cultivars Odisseo and Saragolla). Non-inoculated plants of each cultivar represented the controls. Forty-three days after sowing, roots were deprived of the epiphytic microbiota and subjected to DNA extraction. The DNA was used as template in PCR-DGGE analysis of the 16S rRNA gene (variable region V3–V5) and 16S (region V1–V3) metagenetics. Odisseo and Saragolla root endophytic bacterial biotas differed for number of OTUs and composition. In detail, Pseudomonas was higher in Odisseo than in Saragolla. The inoculation of F. mosseae and L. plantarum increased the abundance of Pseudomonas , some Actinobacteria (e.g., Streptomyces , Microbacterium , two genera including several plant growth promoting (PGP) strains) and Bacteroidetes in both cultivars. However, the endophytic bacterial biota of Saragolla roots inoculated just with lactobacilli did not differ from that of the control. The inoculation of Saragolla with F. mosseae , alone or in combination with lactobacilli, led to higher abundance of Rhodococcus , belonging to Actinobacteria and encompassing PGP strains. First, this work showed that F. mosseae and L. plantarum shape the endophytic bacterial biota of durum wheat roots. Abundance of some OTUs was affected by the microbial inoculation, depending on the cultivar. This result represents a starting point for exploitation of beneficial endophytes of wheat roots. [ABSTRACT FROM AUTHOR]

The implementation of sustainable agriculture encompasses practices enhancing the activity of beneficial soil microorganisms, able to modulate biogeochemical soil cycles and to affect soil fertility. Among them, arbuscular mycorrhizal fungi (AMF) establish symbioses with the roots of most food crops and play a key role in nutrient uptake and plant protection from biotic and abiotic stresses. Such beneficial services, encompassing improved crop performances, and soil resources availability, are the outcome of the synergistic action of AMF and the vast communities of mycorrhizospheric bacteria living strictly associated with their mycelium and spores, most of which showing plant growth promoting (PGP) activities, such as the ability to solubilize phosphate and produce siderophores and indole acetic acid (IAA). One of the strategies devised to exploit AMF benefits is represented by the inoculation of selected isolates, either as single species or in a mixture. Here, for the first time, the microbiota associated with a commercial AMF inoculum was identified and characterized, using a polyphasic approach, i.e., a combination of culture-dependent analyses and metagenomic sequencing. Overall, 276 bacterial genera were identified by Illumina high-throughput sequencing, belonging to 165 families, 107 orders, and 23 phyla, mostly represented by Proteobacteria and Bacteroidetes. The commercial inoculum harbored a rich culturable heterotrophic bacterial community, whose populations ranged from 2.5 to 6.1 × 106 CFU/mL. The isolation of functional groups allowed the selection of 36 bacterial strains showing PGP activities. Among them, 14 strains showed strong IAA and/or siderophores production and were affiliated with Actinomycetales (Microbacterium trichotecenolyticum, Streptomyces deccanensis/scabiei), Bacillales (Bacillus litoralis, Bacillus megaterium), Enterobacteriales (Enterobacter), Rhizobiales (Rhizobium radiobacter). This work demonstrates for the first time that an AMF inoculum, obtained following industrial production processes, is home of a large and diverse community of bacteria with important functional PGP traits, possibly acting in synergy with AMF and providing additional services and benefits. Such bacteria, available in pure culture, could be utilized, individually and/or in multispecies consortia with AMF, as biofertilizers and bioenhancers in sustainable agroecosystems, aimed at minimizing the use of chemical fertilizers and pesticides, promoting primary production, and maintaining soil health and fertility. [ABSTRACT FROM AUTHOR]

Most beneficial services provided by arbuscular mycorrhizal fungi (AMF), encompassing improved crop performance and soil resource availability, are mediated by AMF-associated bacteria, showing key-plant growth-promoting (PGP) traits, i.e., the production of indole acetic acid, siderophores and antibiotics, and activities increasing the availability of plant nutrients by nitrogen fixation and phosphate mobilization. Such functions may be affected by the ability of AMF-associated bacteria to communicate through the production and secretion of extracellular small diffusible chemical signals, N-acyl homoserine lactone signal molecules (AHLs), that regulate bacterial behavior at the community level (quorum sensing, QS). This work investigated the occurrence and extent of QS among rhizobia isolated from AMF spores, using two different QS reporter strains, Agrobacterium tumefaciens NTL4 pZRL4 and Chromobacterium violaceum CV026. We also assessed the quorum quenching (QQ) activity among Bacillus isolated from the same AMF spores. Most rhizobia were found to be quorum-signaling positive, including six isolates producing very high levels of AHLs. The results were confirmed by microtiter plate assay, which detected 65% of the tested bacteria as medium/high AHL producers. A 16S rDNA sequence analysis grouped the rhizobia into two clusters, consistent with the QS phenotype. None of the tested bacteria showed QQ activity able to disrupt the QS signaling, suggesting the absence of antagonism among bacteria living in AMF sporosphere. Our results provide the first evidence of the ability of AMF-associated rhizobia to communicate through QS, suggesting further studies on the potential importance of such a behavior in association with key-plant growth-promoting functions. [ABSTRACT FROM AUTHOR]

In order to examine whether olive pomace (OP), the mean by-product of olive oil extraction, can be included in the animal diet, its effect on the raw mixture and sausages made from meat from OP-fed Cinta Senese swine is tested by comparing it with a diet supplemented with high oleic sunflower oil (SO) and a control diet (C). Proximate composition, pH, color, total culturable bacteria, lactic acid bacteria (LAB), and lipid oxidation are evaluated in both the raw mixture and sausages. The aroma profile is also evaluated in sausages. Olive pomace affected the fatty acid composition of the raw mixture and strongly limited the lipid peroxidation of sausages, probably due to the synergistic action of 3,4-DHPEA and α-tocopherol. Olive pomace selectively promotes LAB growth, and protected the raw mixture and sausages from discoloration. The diet also affected the content of volatile organic compounds thus enabling OP sausages to be distinguished from other sausages. Practical Applications: The protection of foods against lipid peroxidation is a very important aspect in terms of their quality. Achieving this naturally is a high priority for consumers, as there is an increasing demand for 'low impact' and 'environment-safe' production processes. The approach proposed in the present study is aimed at meeting both these objectives. Our findings demonstrate that the inclusion of olive pomace in the swine diet effectively slowed down the lipid oxidation in the sausages. The strategy we propose also meets both economic and ecological goals. Olive pomace is the main by-product of olive oil spinneret, and its re-use in another spinneret is a cost-effective way of improving the sustainability of the production process. Three different kinds of sausages are made. The experiment is aimed at studying the effect of olive pomace (OP) in controling the progression of lipid oxidation. OP have protected sausages against cholesterol oxidation, thus limiting the production of COPs (α-hydroxycholesterol, α-epoxycholesterol, and 7-ketocholesterol). The most probable mechanism is attributable to electron or H+ donor properties of polyphenols contained in olive pomace. [ABSTRACT FROM AUTHOR]

Abstract: The effect of different sulphur dioxide concentrations on culturability and viability of seven strains of Brettanomyces bruxellensis was tested in a synthetic wine medium (SWM) and a different response to molecular SO2 among strains was detected. Sulphur dioxide induced a viable but non culturable (VBNC) state in all the strains. The greater percentage of VBNC cells were identified for five strains at molecular SO2 concentrations of 0.2mg/L and for two strains at the concentration of 0.4mg/L. Vinyl phenols were detected in media containing VBNC or not viable B. bruxellensis, suggesting that its spoilage metabolism could be maintained during wine storage. Overall, this study indicates that SO2 is a chemical stressor inducing VBNC state in B. bruxellensis grown in synthetic wine medium. Further studies are needed to evaluate the effects of SO2 on the metabolism of this yeast in wine spoilage. [ABSTRACT FROM AUTHOR]

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Isolation and physiological and molecular characterisation of culturable bacterial strains belonging to actinomycetes, pseudomonads and aerobic spore-forming bacteria were carried out on mycorrhizal root tips of Quercus robur var. peduncolata infected by Tuber borchii. Cellular density of the three bacterial groups in ectomycorrhizal root tips was estimated to be 1.3±0.11×106 cfu g−1 dry weight for total heterotrophic bacteria and 1.08±0.6×105 (mean±S.E.), 1.3±0.3×105 and 1.4±0.2×105 cfu g−1 dry weight for pseudomonads, actinomycetes and spore-forming bacteria respectively. Identification of pseudomonads by the Biolog® system indicated, besides the most represented species Pseudomonas fluorescens (biotypes B, F and G), the occurrence of strains belonging to Pseudomonas corrugata. Amplified ribosomal DNA restriction analysis of actinomycetes and spore formers revealed at least three and six different groups of patterns, respectively. Many bacterial isolates were able to induce variations in growth rates of T. borchii mycelium; among these, 101 strains showed antifungal activity, whereas 17 isolates, belonging to spore formers, were able to increase mycelial growth up to 78% when compared to uninoculated mycelial growth. The potential role of these populations in the development and establishment of mycorrhizas is discussed. [Copyright &y& Elsevier]

Traditional fermented foods are obtained by a complex consortium of autochthonous microorganisms producing a wide variety of bioactive compounds, thus representing a reservoir of strains with new functional properties. Here, doughs obtained using five different wholegrain flours were singly fermented with selected yeast strains, which were evaluated for their functional traits. Lactate, volatile fatty acids and conjugated linoleic acid isomers produced by fermented doughs were detected by HPLC, while dough anti-inflammatory capacity was measured on human peripheral blood mononuclear cells by flow cytometry. Yeast potential probiotic activity was assessed by evaluating their resistance to simulated gastric and intestinal fluids. For the first time we report evidence of yeast strains producing high levels of the conjugated linoleic acid (CLA) isomer CLA 10-12tc and propionic acid, which are known for their specific health benefits. Moreover, such yeast strains showed an anti-inflammatory capacity, as revealed by a significantly decreased production of the strongly pro-inflammatory cytokine IL-1β. All our Saccharomyces cerevisiae strains were remarkably resistant to simulated gastric and intestinal fluids, as compared to the commercial probiotic strain. The two strains S. cerevisiae IMA D18Y and L10Y showed the best survival percentage. Our novel yeast strains may be exploited as valuable functional starters for the industrial production of cereal-based innovative and health-promoting fermented foods. [ABSTRACT FROM AUTHOR]

The fungal microbiota usually growing on the cheese surface during ripening processes promote rind formation and the development of organoleptic characteristics, imparting positive sensory attributes to cheeses. As cheese contamination may also occur by undesirable molds, specific actions for preventing their growth are usually realized in dairy industries by using the antibiotic natamycin, which may represent a risk factor for human health and environmental sustainability. Here, agroindustrial by-products with natural antimicrobial properties, i.e. tannins and chitosan, were tested in a cheese-making trial producing PDO Tuscan pecorino cheese. Morphological and molecular methods revealed that the main components of rind fungal communities of PDO Tuscan pecorino cheese were represented by P. solitum , P. discolour and P. verrucosum. The use of chitosan on cheese rinds did not significantly affect the composition of rind fungal communities developing during the whole ripening process compared with controls treated with natamycin, whose numbers ranged from 3.4 ± 1.3 × 103 to 3.2 ± 1.8 × 104 and from 6.3 ± 3.5 × 102 to 4.0 ± 1.5 × 104, respectively. Overall, grape marc tannins and chitosan did not significantly affect the number and composition of fungal communities developing during PDO Pecorino Toscano cheese ripening, as well as its physical, chemical and nutritional profiles, showing that they may represent effective alternatives to the antibiotic natamycin. • The mycobiota of PDO Pecorino Toscano cheese was studied using a polyphasic approach. • Rind fungal community was mainly represented by P. solitum , P. discolour and P. verrucosum. • Fungal composition was not affected by grape marc tannins and chitosan rind treatments. • Rind treatments did not affect cheese physical, chemical and nutritional profiles. • Grape marc tannins and chitosan represent potential alternatives to natamycin. [ABSTRACT FROM AUTHOR]

The concept of food quality, traditionally based on nutritional and sensory properties, has recently acquired an additional meaning, referring to the health-promoting properties of plant products, that are ascribed to plant secondary metabolites called phytochemicals, primarily represented by polyphenolic compounds and glucosinolates. The diversity and content of phytochemicals in plant products are affected by different variables, such as plant genotype, agronomic factors, and arbuscular mycorrhizal fungi (AMF), which establish mycorrhizal symbioses with most crops, including cereals, legumes, vegetables, fruit trees, sunflower, cotton, and sugarcane. AMF and associated bacteria enhance plant growth and health, and affect the production of polyphenols and carotenoids, and the activity of antioxidant enzymes. The production of health-promoting phytochemicals was shown to be differentially modulated by different AMF isolates and bacterial strains, in several food plants, i.e., tomato, lettuce, strawberry, artichoke, maize, grapevine, sunflower. Here, we provide an overview of recent studies concerning the multiple roles played by AMF and associated bacteria in the modulation of the biosynthesis of plant secondary metabolites with health-promoting activity, and discuss the development of designed multifunctional consortia to be used in sustainable agriculture. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) are beneficial soil microorganisms establishing mutualistic symbioses with the roots of the most important food crops and playing key roles in the maintenance of long-term soil fertility and health. The great inter- and intra-specific AMF diversity can be fully exploited by selecting AMF inocula on the basis of their colonization ability and efficiency, which are affected by fungal and plant genotypes and diverse environmental variables. The multiple services provided by AMF are the result of the synergistic activities of the bacterial communities living in the mycorrhizosphere, encompassing nitrogen fixation, P solubilization, and the production of phytohormones, siderophores, and antibiotics. The tripartite association among host plants, mycorrhizal symbionts, and associated bacteria show beneficial emerging properties which could be efficiently exploited in sustainable agriculture. Further in-depth studies, both in microcosms and in the field, performed on different AMF species and isolates, should evaluate their colonization ability, efficiency, and resilience. Transcriptomic studies can reveal the expression levels of nutrient transporter genes in fungal absorbing hyphae in the presence of selected bacterial strains. Eventually, newly designed multifunctional microbial consortia can be utilized as biofertilizers and biostimulants in sustainable and innovative production systems. [ABSTRACT FROM AUTHOR]

Hákarl is produced by curing of the Greenland shark (Somniosus microcephalus) flesh, which before fermentation is toxic due to the high content of trimethylamine (TMA) or trimethylamine N-oxide (TMAO). Despite its long history of consumption, little knowledge is available on the microbial consortia involved in the fermentation of this fish. In the present study, a polyphasic approach based on both culturing and DNA-based techniques was adopted to gain insight into the microbial species present in ready-to-eat hákarl. To this aim, samples of ready-to-eat hákarl were subjected to viable counting on different selective growth media. The DNA directly extracted from the samples was further subjected to Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) and 16S amplicon-based sequencing. Moreover, the presence of Shiga toxin-producing Escherichia coli (STEC) and Pseudomonas aeruginosa was assessed via qualitative real-time PCR assays. pH values measured in the analyzed samples ranged from between 8.07 ± 0.06 and 8.76 ± 0.00. Viable counts revealed the presence of total mesophilic aerobes, lactic acid bacteria and Pseudomonadaceae. Regarding bacteria, PCR-DGGE analysis highlighted the dominance of close relatives of Tissierella creatinophila. For amplicon sequencing, the main operational taxonomic units (OTUs) shared among the data set were Tissierella , Pseudomonas , Oceanobacillus , Abyssivirga and Lactococcus. The presence of Pseudomonas in the analyzed samples supports the hypothesis of a possible role of this microorganism on the detoxification of shark meat from TMAO or TMA during fermentation. Several minor OTUs (<1%) were also detected, including Alkalibacterium , Staphylococcus , Proteiniclasticum , Acinetobacter , Erysipelothrix , Anaerobacillus , Ochrobactrum , Listeria and Photobacterium. Analysis of the yeast and filamentous fungi community composition by PCR-DGGE revealed the presence of close relatives of Candida tropicalis, Candida glabrata, Candida parapsilosis, Candida zeylanoides, Saccharomyces cerevisiae, Debaryomyces, Torulaspora, Yamadazyma, Sporobolomyces, Alternaria, Cladosporium tenuissimum, Moristroma quercinum and Phoma/Epicoccum , and some of these species probably play key roles in the development of the sensory qualities of the end product. Finally, qualitative real-time PCR assays revealed the absence of STEC and Pseudomonas aeruginosa in all of the analyzed samples. • The microbiota of hákarl was studied using a polyphasic approach. • Both metagenomic sequencing and PCR-DGGE highlighted the dominance of Tissierella sp. • The contribution of Pseudomonas in the detoxification of shark meat was hypothesized. • The fungal community was mainly represented by Debaryomyces and Candida species. • Real-time PCR showed the absence STEC and Pseudomonas aeruginosa in all the samples. [ABSTRACT FROM AUTHOR]