-
World Journal of Microbiology &... Oct 2019Yeasts occur in all environments and have been described as potent antagonists of various plant pathogens. Due to their antagonistic ability, undemanding cultivation... (Review)
Review
Yeasts occur in all environments and have been described as potent antagonists of various plant pathogens. Due to their antagonistic ability, undemanding cultivation requirements, and limited biosafety concerns, many of these unicellular fungi have been considered for biocontrol applications. Here, we review the fundamental research on the mechanisms (e.g., competition, enzyme secretion, toxin production, volatiles, mycoparasitism, induction of resistance) by which biocontrol yeasts exert their activity as plant protection agents. In a second part, we focus on five yeast species (Candida oleophila, Aureobasidium pullulans, Metschnikowia fructicola, Cryptococcus albidus, Saccharomyces cerevisiae) that are or have been registered for the application as biocontrol products. These examples demonstrate the potential of yeasts for commercial biocontrol usage, but this review also highlights the scarcity of fundamental studies on yeast biocontrol mechanisms and of registered yeast-based biocontrol products. Yeast biocontrol mechanisms thus represent a largely unexplored field of research and plentiful opportunities for the development of commercial, yeast-based applications for plant protection exist.
Topics: Biological Control Agents; Plant Diseases; Yeasts
PubMed: 31576429
DOI: 10.1007/s11274-019-2728-4 -
Applied Microbiology and Biotechnology Feb 2024Aureobasidium is omnipresent and can be isolated from air, water bodies, soil, wood, and other plant materials, as well as inorganic materials such as rocks and marble.... (Review)
Review
Aureobasidium is omnipresent and can be isolated from air, water bodies, soil, wood, and other plant materials, as well as inorganic materials such as rocks and marble. A total of 32 species of this fungal genus have been identified at the level of DNA, of which Aureobasidium pullulans is best known. Aureobasidium is of interest for a sustainable economy because it can be used to produce a wide variety of compounds, including enzymes, polysaccharides, and biosurfactants. Moreover, it can be used to promote plant growth and protect wood and crops. To this end, Aureobasidium cells adhere to wood or plants by producing extracellular polysaccharides, thereby forming a biofilm. This biofilm provides a sustainable alternative to petrol-based coatings and toxic chemicals. This and the fact that Aureobasidium biofilms have the potential of self-repair make them a potential engineered living material avant la lettre. KEY POINTS: •Aureobasidium produces products of interest to the industry •Aureobasidium can stimulate plant growth and protect crops •Biofinish of A. pullulans is a sustainable alternative to petrol-based coatings •Aureobasidium biofilms have the potential to function as engineered living materials.
Topics: Aureobasidium; Biofilms; Calcium Carbonate; Crops, Agricultural; Gasoline
PubMed: 38349550
DOI: 10.1007/s00253-024-13025-5 -
Fungal Biology and Biotechnology Nov 2022Extracellular vesicles (EVs) are increasingly recognized as an important mechanism for cell-cell interactions. Their role in fungi is still poorly understood and they...
Extracellular vesicles (EVs) are increasingly recognized as an important mechanism for cell-cell interactions. Their role in fungi is still poorly understood and they have been isolated from only a handful of species. Here, we isolated and characterized EVs from Aureobasidium pullulans, a biotechnologically important black yeast-like fungus that is increasingly used for biocontrol of phytopathogenic fungi and bacteria. After optimization of the isolation protocol, characterization of EVs from A. pullulans by transmission electron microscopy (TEM) revealed a typical cup-shaped morphology and different subpopulations of EVs. These results were confirmed by nanoparticle tracking analysis (NTA), which revealed that A. pullulans produced 6.1 × 10 nanoparticles per milliliter of culture medium. Proteomic analysis of EVs detected 642 proteins. A small fraction of them had signal peptides for secretion and transmembrane domains. Proteins characteristic of different synthesis pathways were found, suggesting that EVs are synthesized by multiple pathways in A. pullulans. Enrichment analysis using Gene Ontology showed that most of the proteins found in the EVs were associated with primary metabolism. When sequencing the small RNA fraction of A. pullulans EVs, we found two hypothetical novel mil-RNAs. Finally, we tested the biocontrol potential of EVs from A. pullulans. The EVs did not inhibit the germination of spores of three important phytopathogenic fungi-Botrytis cinerea, Colletotrichum acutatum, and Penicillium expansum. However, exposure of grown cultures of C. acutatum and P. expansum to A. pullulans EVs resulted in visible changes in morphology of colonies. These preliminary results suggest that EVs may be part of the antagonistic activity of A. pullulans, which is so far only partially understood. Thus, the first isolation and characterization of EVs from A. pullulans provides a starting point for further studies of EVs in the biotechnologically important traits of the biocontrol black fungus A. pullulans in particular and in the biological role of fungal EVs in general.
PubMed: 36320088
DOI: 10.1186/s40694-022-00146-7 -
Molecules (Basel, Switzerland) Apr 2021Although the anti-tumor and anti-infective properties of β-glucans have been well-discussed, their role in bone metabolism has not been reviewed so far. This review... (Review)
Review
Although the anti-tumor and anti-infective properties of β-glucans have been well-discussed, their role in bone metabolism has not been reviewed so far. This review discusses the biological effects of β-glucans on bone metabolisms, especially on bone-resorbing osteoclasts, which are differentiated from hematopoietic precursors. Multiple immunoreceptors that can recognize β-glucans were reported to be expressed in osteoclast precursors. Coordinated co-stimulatory signals mediated by these immunoreceptors are important for the regulation of osteoclastogenesis and bone remodeling. Curdlan from the bacterium negatively regulates osteoclast differentiation in vitro by affecting both the osteoclast precursors and osteoclast-supporting cells. We also showed that laminarin, lichenan, and glucan from baker's yeast, as well as β-1,3-glucan from inhibit the osteoclast formation in bone marrow cells. Consistent with these findings, systemic and local administration of β-glucan derived from and suppressed bone resorption in vivo. However, zymosan derived from stimulated the bone resorption activity and is widely used to induce arthritis in animal models. Additional research concerning the relationship between the molecular structure of β-glucan and its effect on osteoclastic bone resorption will be beneficial for the development of novel treatment strategies for bone-related diseases.
Topics: Animals; Bone Regeneration; Bone Resorption; Bone and Bones; Cartilage; Cell Differentiation; Glucans; Humans; Immunomodulation; Osteoclasts; Osteogenesis; Receptors, Immunologic
PubMed: 33915775
DOI: 10.3390/molecules26071982 -
The Journal of General and Applied... Feb 2021Aureobasidium pullulans YTP6-14 was demonstrated to be an excellent multiple biosurfactant producer utilizing cheap carbon sources available in Thailand, including...
Aureobasidium pullulans YTP6-14 was demonstrated to be an excellent multiple biosurfactant producer utilizing cheap carbon sources available in Thailand, including glycerol and cassava flour hydrolysate. A. pullulans YTP6-14 maximally produced 1.81 g/l biosurfactant in an aqueous layer (BS-AQ) in a medium containing glycerol, and 7.37 or 6.37 g/l biosurfactant in a heavy oil layer (BS-HO) in cassava flour hydrolysate or a glucose containing medium, respectively. Each BS-AQ and BS-HO had critical micelle concentration values of 41.32 mg/l and 13.51 mg/l, and both biosurfactants formed a stable food oil emulsion and reduced the amount of biofilms formed by Streptococcus sobrinus and Streptococcus mutans. BS-AQ and BS-HO were mainly composed of liamocins or exophilins and massoia lactone, respectively.
Topics: Anti-Bacterial Agents; Aureobasidium; Biofilms; Oils; Streptococcus mutans; Streptococcus sobrinus; Surface-Active Agents
PubMed: 33012773
DOI: 10.2323/jgam.2020.01.011 -
Molecules (Basel, Switzerland) Feb 2021Intrinsic hydrophobicity is the reason for efficient bacterial settlement and biofilm growth on silicone materials. Those unwelcomed phenomena may play an important role...
Intrinsic hydrophobicity is the reason for efficient bacterial settlement and biofilm growth on silicone materials. Those unwelcomed phenomena may play an important role in pathogen transmission. We have proposed an approach towards the development of new anti-biofilm strategies that resulted in novel antimicrobial hydrophobic silicones. Those functionalized polysiloxanes grafted with side 2-(carboxymethylthioethyl)-, 2-(-propylamidomethylthioethyl)- and 2-(mercaptoethylamidomethylthioethyl)- groups showed a wide range of antimicrobial properties towards selected strains of bacteria (reference strains , and water-borne isolates , ), fungi () and algae (), which makes them valuable antibacterial and antibiofilm agents. Tested microorganisms showed various levels of biofilm formation, but particularly effective antibiofilm activity was demonstrated for bacterial isolate with high adhesion abilities. In the case of modified surfaces, the relative coefficient of adhesion for this strain was 18 times lower in comparison to the control glass sample.
Topics: Anti-Infective Agents; Cell Adhesion; Hydrophobic and Hydrophilic Interactions; Siloxanes
PubMed: 33557279
DOI: 10.3390/molecules26040814 -
Medical Mycology Case Reports Sep 2022is a yeast-like dematiaceous fungus ubiquitous in nature. It is a rare cause of skin and soft tissue infection, peritonitis, and catheter-related fungemia in certain...
is a yeast-like dematiaceous fungus ubiquitous in nature. It is a rare cause of skin and soft tissue infection, peritonitis, and catheter-related fungemia in certain human hosts. We report a case of recurrent catheter-related fungemia that was successfully treated with caspofungin, posaconazole, and catheter removal.
PubMed: 35855930
DOI: 10.1016/j.mmcr.2022.06.004 -
Bioresources and Bioprocessing Aug 2023Aureobasidium pullulans (A. pullulans) has a wide range of applications. Ultraviolet (UV) rays from the sun can cause skin photoaging. In order to explore the protective...
BACKGROUND
Aureobasidium pullulans (A. pullulans) has a wide range of applications. Ultraviolet (UV) rays from the sun can cause skin photoaging. In order to explore the protective effect and application potential of A. pullulans lysate on UV-damaged human skin fibroblasts (HSF) and HaCaT Cells, this study investigates the anti-aging and anti-inflammatory effects of A. pullulans lysate as well as the mechanism of anti-oxidative stress at the cellular and molecular levels through cytotoxicity experiments, enzyme-linked immunosorbent assays (ELISA), and real-time quantitative PCR (RT-qPCR).
RESULTS
The experimental results have shown that the A. pullulans lysate can effectively reduce the loss of extracellular matrix components (EMC), such as collagen and hyaluronic acid (HA). It is also capable of scavenging excess reactive oxygen species (ROS) from the body, thereby increasing the activity of catalase, decreasing the overexpression of intracellular matrix metalloproteinases (MMPs), enhancing the gene expression of metalloproteinase inhibitors (TIMPs), and decreasing the level of inflammatory factors, reducing UV-induced apoptosis of HaCaT cells. Meanwhile, oxidative stress homeostasis is also regulated through the Nrf2/Keap1 and MAPK signaling pathways.
CONCLUSIONS
This study shows that the A. pullulans lysate has the potential to resist photoaging.
PubMed: 38647892
DOI: 10.1186/s40643-023-00678-9 -
Frontiers in Bioengineering and... 2023Pullulan has many potential applications in the food, pharmaceutical, cosmetic and environmental industries. However, the yield and molecular properties of pullulan...
Pullulan has many potential applications in the food, pharmaceutical, cosmetic and environmental industries. However, the yield and molecular properties of pullulan produced by various strains still need to be promoted to fit the application needs. A novel yeast-like strain BL06 producing high molecular weight (Mw) pullulan (3.3 × 10 Da) was isolated and identified in this study. The remarkable Mw of pullulan produced by BL06 was the highest level ever reported thus far. To further regulate the biosynthesis of pullulan in BL06, three gene knockout strains BL06 ΔPMAs, BL06 Δmel, and BL06 ΔPMAsΔmel, were constructed. The results showed that BL06 ΔPMAs could produce 140.2 g/L of moderate Mw (1.3 × 10 Da) pullulan after 120 h of fermentation. The highest yield level of pullulan to date could vastly reduce its production cost and expand its application scope and potential. The application experiments in food preservation showed that the moderate-Mw pullulan obtained in this work could reduce the weight loss of celery cabbages and mangos by 12.5% and 22%, respectively. Thus, the novel strains BL06 and BL06 ΔPMAs possessed unlimited development prospects in pullulan production at various Mw ranges and pullulan applications in multiple fields.
PubMed: 36777253
DOI: 10.3389/fbioe.2023.1131875 -
Plant Disease Jan 2022Asian pear (Pyrus pyrifolia Nakai cv. cuiguan), is widely grown in Zhejiang province of China. In April 2019, symptoms consisting of small black, round leaf spots and...
Asian pear (Pyrus pyrifolia Nakai cv. cuiguan), is widely grown in Zhejiang province of China. In April 2019, symptoms consisting of small black, round leaf spots and blight flower petals were observed on over 30 % of 'Cuiguan' pear trees in an orchard (ca. 0.8 ha) near Cixi city, Zhejiang province, China. Initially, leaf spots were observed on leaf petioles, which, with time, enlarged and coalesced into necrotic streaks (1-2 cm) along the length of the petioles. Irregularly, reddish brown spots developed on flower petals, which hastened their senescence. Additional symptoms included round, black spots on leaves (2-3 mm in diameter) and necrosis of shoot tips. Symptomatic tissues from petals, petioles and leaves were plated onto potato dextrose agar (PDA). After five days of incubation at 26 °C, slimy fungal colonies (48×48 mm) with pinkish to orange-colored mycelia and with regular annulations were isolated from all tissues. After 10 days, cultured were shiny and dark brown in the center. The color of conidia ranged from hyaline to dark brown. Hyaline conidia were blastic, unicellular, ellipsoidal, smooth, with lengths that ranged from 11.03 to 27.14 (avg. 18.38) μm, and widths that ranged from 3.45 to 8.86 (avg. 6.04) μm (n = 50). Dark brown conidia were 1 to 2 celled, 10.89 to 26.03 (avg. 17.41) μm in length and 4.26 to 12.15 (avg. 6.94) μm in width (n = 50), and a slight septal constriction. Conidiogenous cells were clavate, hyaline, eseptate and top smoothly with 3-11 spores. Indistinct scars remained when the conidia dislodge from the conidiogenous cells. Single spore isolation was used to obtain pure cultures. Mycelia and conidia were scraped from cultures and DNA was extracted using Ezup Column Fungi Genomic DNA Purification Kit (Sangon Biotech). Amplified PCR products from the internal transcribed spacer (ITS) region ITS1F/ITS4 (White et al. 1990), the partial 28S rDNA (LSU) NL1/NL4 (Boekhout et al. 1995), the β-tubulin (TUB) gene Bt2a/Bt2b (Glass & Donaldson 1995) and the partial elongase gene (ELO) ELO2-F/ELO2-R (Zalar et al. 2008) were sequenced (Tsingke Biotechnology Co., Hangzhou, Zhejiang). A blast search (GenBank Accession No. MT107050, OK485685, OK631951, OK631950) showed 99% Aureobasidium pullulans reference isolate CBS584.75 and EXF-150, which was consistent with the morphological data (Cene et al. 2014). Three-yr-old seedlings from 'Cuiguan' pears were spray with conidial suspension (106 conidia/ml) on the both sides of leaves without wounding. In a greenhouse (26 °C, natural light), six inoculated plants and three noninoculated plants (sprayed with sterile distilled water) enclosed in plastic bags to maintain humidity for 72 h. At 5 days after inoculation, shoot tips blackened and began to wilt. At 15 days after inoculation, symptoms similar to those on the original sample developed on inoculated petioles and leaves, whereas the control plants remained healthy. No symptoms were observed on leaves that were mature at the time of inoculation. Aureobasidium pullulans var. pullulans was reisolated from all inoculated plant. Overall, this disease shortened the life of pear flowers and reduced fruit set. To our knowledge, A. pullulans var. pullulans has not previously been reported as a pathogen of P. pyrifolia.
PubMed: 35100838
DOI: 10.1094/PDIS-10-21-2367-PDN