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ELife Oct 2022Priority effects, where arrival order and initial relative abundance modulate local species interactions, can exert taxonomic, functional, and evolutionary influences on...
Priority effects, where arrival order and initial relative abundance modulate local species interactions, can exert taxonomic, functional, and evolutionary influences on ecological communities by driving them to alternative states. It remains unclear if these wide-ranging consequences of priority effects can be explained systematically by a common underlying factor. Here, we identify such a factor in an empirical system. In a series of field and laboratory studies, we focus on how pH affects nectar-colonizing microbes and their interactions with plants and pollinators. In a field survey, we found that nectar microbial communities in a hummingbird-pollinated shrub, (formerly ) , exhibited abundance patterns indicative of alternative stable states that emerge through domination by either bacteria or yeasts within individual flowers. In addition, nectar pH varied among flowers in a manner that is consistent with the existence of these alternative stable states. In laboratory experiments, , the bacterium most commonly found in nectar, exerted a strongly negative priority effect against , the most common nectar-specialist yeast, by reducing nectar pH. This priority effect likely explains the mutually exclusive pattern of dominance found in the field survey. Furthermore, experimental evolution simulating hummingbird-assisted dispersal between flowers revealed that could evolve rapidly to improve resistance against the priority effect if constantly exposed to -induced pH reduction. Finally, in a field experiment, we found that low nectar pH could reduce nectar consumption by hummingbirds, suggesting functional consequences of the pH-driven priority effect for plant reproduction. Taken together, these results show that it is possible to identify an overarching factor that governs the eco-evolutionary dynamics of priority effects across multiple levels of biological organization.
Topics: Animals; Plant Nectar; Pollination; Flowers; Birds; Plants; Yeasts; Bacteria
PubMed: 36300797
DOI: 10.7554/eLife.79647 -
Persoonia Jun 2021Novel species of fungi described in this study include those from various countries as follows: , from , from soil. , as endophyte from healthy leaves of , in fruit...
Novel species of fungi described in this study include those from various countries as follows: , from , from soil. , as endophyte from healthy leaves of , in fruit of , from stem of , on stems of , from rhizosphere soil of , on living leaves of , , and on living leaves of sp. , from soil. , from soil under , from an unidentified fern. , on deteriorated hardwood. , from tea bag with fruit tea, as endophyte from , on surface of biscuits with chocolate glaze and filled with jam. , on basic to calcareous soil, from , from buds of , as endophyte from roots , on leaves of , on soil under sp., from soil. , from compost. , on leaves of unidentified succulent, on leaves of sp., on leaves of sp., from hypolith under a rock, on leaves of unidentified tree, and from hypolith under a rock, on leaves of sp., (incl. gen. nov.) on persistent inflorescence remains of , on twigs of , on dung of sp., on zebra dung, on stems of . , on sandy soil, on nutrient poor (acid) soil, on plant debris, amongst grasses. , from leaf spots of sp., and from stem discolouration and leaf spots of sp., from leaf spots of sp., (incl. gen. nov.) and from leaf spots of , from leaf spots of , from leaf spots of , on soil in semi-natural grassland, on soil in calcareous and forests, on soil semi-natural grasslands, on gravelly soil. , on soil in association with , on debris beneath fallen bark of Norway spruce , on à moss covered rotting trunk of , on debris of , on soil on calcareous grasslands, on soil in subalpine grasslands, on rotted wood of , on fallen dead branches of , from fruits of , on soil, as endophyte from , on mowed grassland, from corticated branches of sp. , on leaves of unidentified , on dead pods of , on leaves of sp., on leaves of sp., on bark of , on leaves of , as epiphyte on brown stem of , and on leaves of , on on bark of , (incl. gen. nov.) on leaves of , (incl. gen. nov.) on leaves of , (incl. gen. nov.) on leaf litter of , on leaves of , on leaf litter of , (incl. gen. nov.) on leaves of , on twigs of , on leaves of sp., from larval feed of an Afrotropical bee , on leaf litter of , on leaves of sp., on pods of , with in calcareus soils, under subsp in calcareous soil, (incl. gen. nov.) from root-associated soil in a wet heathland, on acidic soils, on volcanic lapilii material, in calcareus soil. , on soil under and , on inflorescence of , on on underside of unidentified dicotyledonous leaf. , on leaves of , from surface sterilised roots of , from outside wall of alcohol distillery. , on soil. Morphological and culture characteristics are supported by DNA barcodes. : Crous PW, Cowan DA, Maggs-Kölling, et al. 2021. Fungal Planet description sheets: 1182-1283. Persoonia 46: 313-528. https://doi.org/10.3767/persoonia.2021.46.11.
PubMed: 35935893
DOI: 10.3767/persoonia.2021.46.11 -
Foods (Basel, Switzerland) Oct 2023Three strains marketed as bioprotection yeasts were studied to compare their antimicrobial effect on a mixture of two yeast strains in synthetic must at 12 °C,...
Three strains marketed as bioprotection yeasts were studied to compare their antimicrobial effect on a mixture of two yeast strains in synthetic must at 12 °C, mimicking pre-fermentative maceration by combining different approaches. The growth of the different strains was monitored, their nitrogen and oxygen requirements were characterised, and their metabolomic footprint in single and co-cultures studied. Only the strain and one strains colonised the must and induced the rapid decline of . The efficiency of these two strains followed different inhibition kinetics. Furthermore, the initial ratio between and was an important factor to ensure optimal bioprotection. Nutrient consumption kinetics showed that apiculate yeasts competed with strains for nutrient accessibility. However, this competition did not explain the observed bioprotective effect, because of the considerable nitrogen content remaining on the single and co-cultures. The antagonistic effect of on probably implied another form of amensalism. For the first time, metabolomic analyses of the interaction in a bioprotection context were performed after the pre-fermentative maceration step. A specific footprint of the interaction was observed, showing the strong impact of the interaction on the metabolic modulation of the yeasts, especially on the nitrogen and vitamin pathways.
PubMed: 37959046
DOI: 10.3390/foods12213927 -
Scientific Reports Jan 2021Drosophila suzukii flies cause economic losses to fruit crops globally. Previous work shows various Drosophila species are attracted to volatile metabolites produced by...
Drosophila suzukii flies cause economic losses to fruit crops globally. Previous work shows various Drosophila species are attracted to volatile metabolites produced by individual fruit associated yeast isolates, but fruits naturally harbour a rich diversity of yeast species. Here, we report the relative attractiveness of D. suzukii to yeasts presented individually or in combinations using laboratory preference tests and field trapping data. Laboratory trials revealed four of 12 single yeast isolates were attractive to D. suzukii, of which Metschnikowia pulcherrima and Hanseniaspora uvarum were also attractive in field trials. Four out of 10 yeast combinations involving Candida zemplinina, Pichia pijperi, M. pulcherrima and H. uvarum were attractive in the laboratory. Whilst a combination of M. pulcherrima + H. uvarum trapped the greatest number of D. suzukii in the field, the efficacy of the M. pulcherrima + H. uvarum combination to trap D. suzukii was not significantly greater than traps primed with volatiles from only H. uvarum. While volatiles from isolates of M. pulcherrima and H. uvarum show promise as baits for D. suzukii, further research is needed to ascertain how and why flies are attracted to certain baits to optimise control efficacy.
Topics: Animals; Drosophila; Fruit; Hanseniaspora; Insect Control; Laboratories; Metschnikowia
PubMed: 33441642
DOI: 10.1038/s41598-020-79691-3 -
Frontiers in Plant Science 2023The use of biocontrol agents (BCAs) represents a promising alternative to conventional methods for the management of gray mold in vineyards during the berry ripening...
The use of biocontrol agents (BCAs) represents a promising alternative to conventional methods for the management of gray mold in vineyards during the berry ripening stage. The main advantages of BCAs are the short preharvest interval and lack of chemical fungicide residues in wine. In this study, eight commercial BCAs (based on different or species and strains, , , and ) and a reference fungicide (boscalid) were applied to a vineyard during berry ripening over three seasons to evaluate the dynamics over time in terms of their relative efficacies in gray mold control. At 1-13 days after application of BCAs to the berry surfaces in field conditions, the berries were collected and artificially inoculated with conidia of under controlled laboratory conditions, and gray mold severity was observed after 7 days of incubation. Significant differences were observed in gray mold severity among years, according to the number of days the BCAs grew on the berry surface before inoculation, and the season by day interaction (altogether accounting for >80% of the experimental variance). The variability in BCA efficacy was closely related to the environmental conditions at the time of application and in the following days. Overall, the BCA efficacy increased with the degree days accumulated between BCA application in the vineyard and inoculation in the dry (no rain) periods (r = 0.914, P = 0.001). Rainfall and the associated drop in temperature caused a relevant reduction of BCA efficacy. These results demonstrate that BCAs are an effective alternative to conventional chemicals for the preharvest control of gray mold in vineyards. However, environmental conditions can considerably affect the BCA efficacy.
PubMed: 36993848
DOI: 10.3389/fpls.2023.1154370 -
Microorganisms Dec 2021Pathogenic fungi belonging to the genera , , , and are responsible for vines diseases that affect the growth, grapevine yield and organoleptic quality. Among...
Pathogenic fungi belonging to the genera , , , and are responsible for vines diseases that affect the growth, grapevine yield and organoleptic quality. Among innovative strategies for in-field plant disease control, one of the most promising is represented by biocontrol agents, including wild epiphytic yeast strains of grapevine berries. Twenty wild yeast, isolated and molecularly identified from three different Malaysian regions (Perlis, Perak and Pahang), were evaluated in a preliminary screening test on agar to select isolates with inhibition against On the basis of the results, nine yeasts belonging to genera , , , were selected and then tested against five grape berry pathogens: , , , and FE08.05 and GP8 and GM19 showed the highest effect on inhibiting mycelial growth, which ranged between 15.1 and 4.3 mm for the inhibition ring. The quantitative analysis of the volatile organic compound profiles highlighted the presence of isoamyl and phenylethyl alcohols and an overall higher presence of low-chain fatty acids and volatile ethyl esters. The results of this study suggest that antagonist yeasts, potentially effective for the biological control of pathogenic moulds, can be found among the epiphytic microbiota associated with grape berries.
PubMed: 34946182
DOI: 10.3390/microorganisms9122582 -
Microorganisms Feb 2021Postharvest spoilage fungi, such as , are considered the main cause of losses of fresh fruit quality and vegetables during storage, distribution, and consumption. The...
Postharvest spoilage fungi, such as , are considered the main cause of losses of fresh fruit quality and vegetables during storage, distribution, and consumption. The current control strategy is the use of SO generator pads whose application is now largely under observation. A high quantity of SO can be deleterious for fresh fruits and vegetables and it is not allowed in organic agriculture. For this reason, great attention has been recently focused on identifying Biological Control Agents (BCA) to implement biological approaches devoid of chemicals. In this direction, we carried out our study in isolating five different non- yeast strains from local vineyards in the South of Italy as possible BCA. We performed both in vitro and in vivo assays in semi-commercial conditions on detached grape berries stored at 0 °C, simulating the temperature normally used during cold storage, and obtained relevant results. We isolated three strains and one strain able to largely antagonize the development of the , at both in vitro and in vivo conditions. In particular, we detected the ability of the three isolates of strains Ale4, N20/006, and Pr7 and the strain N10 to completely inhibit (100% in reduction) the mycelial growth of by producing fungistatic compounds. We found, using an extracellular lytic enzymes activity assay, that such activity could be related to lipid hydrolyzation, β-1,3-glucanase and pectinase activity, and pectinase and protease activity, depending on the yeasts used. Results from our in vitro assays allowed us to hypothesize for strains Ale4 and N20/006 a possible combination of both the production of soluble metabolites and volatile organic compounds to antagonize against growth. Moreover, in semi-commercial conditions, the strain N20/006 and strain N10 showed relevant antagonistic effect also at low concentrations (with a significantly reduction of 'slip skin' incidence of 86.4% and 72.7%, respectively), thus highlighting a peculiar property to use in commercial development for organic agriculture and the handling process.
PubMed: 33671825
DOI: 10.3390/microorganisms9020457 -
Frontiers in Microbiology 2021Biosurfactants are potential biomolecules that have extensive utilization in cosmetics, medicines, bioremediation and processed foods. Yeast produced biosurfactants...
Biosurfactants are potential biomolecules that have extensive utilization in cosmetics, medicines, bioremediation and processed foods. Yeast produced biosurfactants offer thermal resistance, antioxidant activity, and no risk of pathogenicity, illustrating their promising use in food formulations. The present study is aimed to assess potential of biosurfactant screened from a novel yeast and their inhibition against food spoilage fungi. A novel asexual ascomycetes yeast strain CIG-6A producing biosurfactant, was isolated from the gut of stingless bee from Churdhar, HP, India. The phylogenetic analysis revealed that the strain CIG-6A was closely related to , showing 94.38% sequence similarity in the D1D2 region for which the name f.a., sp. nov., is proposed. The strain CIG-6A was able to produce sophorolipid biosurfactant under optimum conditions. Sophorolipid biosurfactant from strain CIG-6A effectively reduced the surface tension from 72.8 to 35 mN/m. Sophorolipid biosurfactant was characterized using TLC, FTIR, GC-MS and LC-MS techniques and was a mixture of both acidic and lactonic forms. Sophorolipid assessed promising activity against pathogenic fungi viz. (MTCC 9913), (MTCC 350), and (MTCC 2190). The inhibitory effect of biosurfactant CIG-6A against was studied and MIC was 49 μgm/ml, further confirmed through confocal laser scanning microscopy. We illustrated the antifungal activity of sophorolipid biosurfactant from genus for the first time and suggested a novel antifungal compound against food spoilage and human fungal pathogen.
PubMed: 34149670
DOI: 10.3389/fmicb.2021.678668 -
Foods (Basel, Switzerland) Sep 2021The pre and postharvest disease named 'aqueous spot' is an emerging risk for sweet cherries growing in Jerte Valley (Cáceres, Spain). Early stages of the disease appear...
The pre and postharvest disease named 'aqueous spot' is an emerging risk for sweet cherries growing in Jerte Valley (Cáceres, Spain). Early stages of the disease appear in the tree, but it is usually detected after harvesting, during the postharvest period. Symptoms include the appearance of skin discolouration and translucency in the shoulder areas. At the most advanced stages, a mycelium of white colour partially or completely covers the fruit. This manuscript provides a detailed description of the microbes involved in this disease, such as bacteria, yeasts, and moulds. Microbes of different cherry cultivars were studied during two consecutive seasons (2019 and 2020). The counts of bacteria and yeast in damaged tissues were higher (7.05 and 6.38 log10 CFU/g for total aerobic mesophilic microbes and yeasts, respectively) than sound tissues (6.08 and 5.19 log10 CFU/g, respectively). The Enterobacterales order dominated the bacteria population. Among yeasts, , in 2019, and and , in 2020, were consistently isolated from all samples. The presence of moulds was inconsistently detected at the early stage of this disease by plate counts. However, microscopic observations revealed the presence of hyphae in cherry flesh. Different pathogenic moulds were identified, although white mycelium, identified as by molecular methods, was consistently isolated at later stages. Inoculation tests confirmed the involvement of white-mycelium in the development of this new postharvest disease in the Jerte Valley. Its combination with Enterobacterales enhanced the evolution of rotting, whereas the combination with yeasts decreased and delayed the symptoms. This work presents the first report of a consortia of microorganisms implicated in the development of 'aqueous spot', an emerging disease in sweet cherry cultivars in the Jerte Valley.
PubMed: 34681330
DOI: 10.3390/foods10102281 -
Frontiers in Microbiology 2022Lipids are essential energy storage compounds and are the core structural elements of all biological membranes. During wine alcoholic fermentation, the ability of yeasts...
Lipids are essential energy storage compounds and are the core structural elements of all biological membranes. During wine alcoholic fermentation, the ability of yeasts to adjust the lipid composition of the plasma membrane partly determines their ability to cope with various fermentation-related stresses, including elevated levels of ethanol and the presence of weak acids. In addition, the lipid composition of grape juice also impacts the production of many wine-relevant aromatic compounds. Several studies have evaluated the impact of lipids and of their metabolism on fermentation performance and aroma production in the dominant wine yeast , but limited information is available on other yeast species. Thus, the aim of this study was to evaluate the influence of specific fatty acid and sterol mixtures on various non- yeast fermentation rates and the production of primary fermentation metabolites. The data show that the response to different lipid mixtures is species-dependent. For , a slight increase in carbon dioxide production was observed in media enriched with unsaturated fatty acids whereas fermented significantly better in synthetic media containing a higher concentration of polyunsaturated fatty acids than monounsaturated fatty acids. fermentation rate increased in media supplemented with lipids present at an equimolar concentration. The data indicate that these different responses may be linked to variations in the lipid profile of these yeasts and divergent metabolic activities, in particular the regulation of acetyl-CoA metabolism. Finally, the results suggest that the yeast metabolic footprint and ultimately the wine organoleptic properties could be optimized species-specific lipid adjustments.
PubMed: 35677913
DOI: 10.3389/fmicb.2022.823581