-
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 -
World Journal of Microbiology &... Mar 2024Probiotic microorganisms are used to improve the health and wellness of people and the research on this topic is of current relevance and interest. Fifty-five yeasts,...
Probiotic microorganisms are used to improve the health and wellness of people and the research on this topic is of current relevance and interest. Fifty-five yeasts, coming from honeybee's ecosystem and belonging to Candida, Debaryomyces, Hanseniaspora, Lachancea, Metschnikowia, Meyerozyma, Starmerella and Zygosacchromyces genera and related different species, were evaluated for the probiotic traits. The resistance to gastrointestinal conditions, auto-aggregation, cell surface hydrophobicity or biofilm formation abilities as well as antimicrobial activity against common human pathogenic bacteria were evaluated. The safety analysis of strains was also carried out to exclude any possible negative effect on the consumer's health. The influence of proteinase treatment of living yeasts and their adhesion to Caco-2 cells were also evaluated. The greatest selection occurred in the first step of survival at the acidic pH and in the presence of bile salts, where more than 50% of the strains were unable to survive. Equally discriminating was the protease test which allowed the survival of only 27 strains belonging to the species Hanseniaspora guilliermondii, Hanseniaspora uvarum, Metschnikowia pulcherrima, Metschnikowia ziziphicola, Meyerozyma caribbica, Meyerozyma guilliermondii, Pichia kluyveri, Pichia kudriavzevii and Pichia terricola. An integrated analysis of the results obtained allowed the detection of seven yeast strains with probiotic aptitudes, all belonging to the Meyerozyma genus, of which three belonging to M. guillermondii and four belonging to M. caribbica species.
Topics: Bees; Animals; Humans; Ecosystem; Caco-2 Cells; Yeasts; Candida; Probiotics
PubMed: 38538981
DOI: 10.1007/s11274-024-03941-z -
Genes Jan 2019Yeasts belonging to the genus are particularly interesting for the unusual formation of only two needle-shaped ascospores during their mating cycle. Presently, the...
Yeasts belonging to the genus are particularly interesting for the unusual formation of only two needle-shaped ascospores during their mating cycle. Presently, the meiotic process that can lead to only two spores from a diploid zygote is poorly understood. The expression of fluorescent nuclear proteins should allow the meiotic process to be visualized in vivo; however, no large-spored species of has ever been transformed. Accordingly, we aimed to develop a transformation method for , a particularly large-spored species of , with the goal of enabling the genetic manipulations required to study biological processes in detail. Genetic analyses confirmed that , and many other species, are CUG-Ser yeasts. Codon-optimized selectable markers lacking CUG codons were used to successfully transform by electroporation and lithium acetate, and transformants appeared to be the result of random integration. Mating experiments confirmed that transformed-strains were capable of generating large asci and undergoing recombination. Finally, random integration was used to transform an additional 21 yeast strains, and all attempts successfully generated transformants. The results provide a simple method to transform many yeasts from an array of different clades and can be used to study or develop many species for various applications.
Topics: Codon; Electroporation; Fungal Proteins; Gene Transfer Techniques; Transformation, Genetic; Yeasts
PubMed: 30678093
DOI: 10.3390/genes10020078 -
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 -
Frontiers in Microbiology 2018The yeast was reported as an efficient biological control agent of postharvest diseases of fruits and vegetables, and it is the bases of the commercial formulated...
The yeast was reported as an efficient biological control agent of postharvest diseases of fruits and vegetables, and it is the bases of the commercial formulated product "Shemer." Several mechanisms of action by which inhibits postharvest pathogens were suggested including iron-binding compounds, induction of defense signaling genes, production of fungal cell wall degrading enzymes and relatively high amounts of superoxide anions. We assembled the whole genome sequence of two strains of using PacBio and Illumina shotgun sequencing technologies. Using the PacBio, a high-quality draft genome consisting of 93 contigs, with an estimated genome size of approximately 26 Mb, was obtained. Comparative analysis of proteins with the other three available closely related genomes revealed a shared core of homologous proteins coded by 5,776 genes. Comparing the genomes of the two strains using a SNP calling approach resulted in the identification of 564,302 homologous SNPs with 2,004 predicted high impact mutations. The size of the genome is exceptionally high when compared with those of available closely related organisms, and the high rate of homology among genes points toward a recent whole-genome duplication event as the cause of this large genome. Based on the assembled genome, sequences were annotated with a gene description and gene ontology (GO term) and clustered in functional groups. Analysis of CAZymes family genes revealed 1,145 putative genes, and transcriptomic analysis of CAZyme expression levels in during its interaction with either grapefruit peel tissue or revealed a high level of CAZyme gene expression when the yeast was placed in wounded fruit tissue.
PubMed: 29666611
DOI: 10.3389/fmicb.2018.00593 -
Scientific Reports May 2024In molecular systematics, the delimitation of yeast species is based on the notion that the barcode differences are smaller within species than between them. The most...
In molecular systematics, the delimitation of yeast species is based on the notion that the barcode differences are smaller within species than between them. The most widely used barcodes are segments of the chromosomal repeats coding for ribosomal RNAs that are homogenised in yeasts. The analysis of these segments of the type strains of ten species recently merged in Metschnikowia pulcherrima and 37 new isolates demonstrated that this is not the case in this species. The intragenomic diversity significantly exceeded the threshold gaps used to differentiate related yeast species. Large segments of the D1/D2 domains were not diverse within the genomes and could therefore be used to determine the taxonomic affiliation of the isolates. The genome structures of the isolates were compared by RAPD and the RFLP of the mitochondrial DNA. Both patterns were highly heterogeneous. The sequence analysis of the PUL4 gene (a member of the PUL gene cluster involved in pulcherrimin production) revealed very high intragenomic differences, suggesting that the genomes may be chimerised. Three phenotypic traits related to the antimicrobial antagonism characteristic of the species were also highly diverse and prone to reversible segregation resembling epigenetic processes (silencing and reactivation of regulators) rather than mutations and back-mutations. These features make M. pulcherrima unique among yeasts and indicate that it evolves in a non-standard way.
Topics: Metschnikowia; Genome, Fungal; Evolution, Molecular; Phylogeny; Genetic Variation; Phenotype; DNA, Mitochondrial
PubMed: 38714828
DOI: 10.1038/s41598-024-61335-5 -
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 -
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 -
American Journal of Botany Mar 2022Yeasts are often present in floral nectar and can influence plant fitness directly (independently of pollinators) or indirectly by influencing pollinator visitation and...
PREMISE
Yeasts are often present in floral nectar and can influence plant fitness directly (independently of pollinators) or indirectly by influencing pollinator visitation and behavior. However, few studies have assessed the effect of nectar yeasts on plant reproductive success or compared effects across different plant species, limiting our understanding of the relative impact of direct vs. indirect effects.
METHODS
We inoculated the nectar of six plant species in the field with the cosmopolitan yeast Metschnikowia reukaufii to analyze the direct and indirect effects on female reproductive success over 2 years. The pollinator assemblage for each species was recorded during both flowering years.
RESULTS
Direct yeast effects on female fecundity were statistically nonsignificant for all plant species. There were significant indirect, pollinator-mediated effects on fruit production and seed mass for the two species pollinated almost exclusively by bumblebees or hawkmoths, with the direction of the effects differing for the quantity- and quality-related fitness components. There were no consistent effects of the yeast on maternal fecundity for any of the species with diverse pollinator assemblages.
CONCLUSIONS
Effects of M. reukaufii on plant reproduction ranged from negative to neutral or positive depending on the plant species. The among-species variation in the indirect effects of nectar yeasts on plant pollination could reflect variation in the pollinator community, the specific microbes colonizing the nectar, and the order of microbial infection (priority effects), determining potential species interactions. Elucidating the nature of these multitrophic plant-pollinator-microbe interactions is important to understand complex processes underlying plant pollination.
Topics: Flowers; Plant Nectar; Plants; Pollination; Reproduction; Yeasts
PubMed: 35315515
DOI: 10.1002/ajb2.1834