Pub Date : 2024-12-01DOI: 10.1016/j.funbio.2024.03.003
Sonia Marín, Laila Aldars-García, Francisco Molino, Antonio J. Ramos, Vicente Sanchis
Aspergillus flavus occurs as a contaminant of various foods and animal feeds and can produce the mycotoxin aflatoxin B1 that is a danger to human and animal health. Here, we develop models to predict the behaviour of A. flavus in maize extract agar and maize grains. Growth and aflatoxin B1 production were recorded on maize extract agar at 20–35 °C and water activities from 0.84 to 0.90. We then obtained probability models—using temperature, water activity, and time as explanatory variables—based on data of growth and aflatoxin B1 production. Additional data were generated under two dynamically changing temperature regimes. Initial water activity, and relative humidity during incubation, were recorded. Predicted probability of growth under dynamic conditions based on models built under static conditions depended on the temperature regime and substrate, concordance ranging from 66 to 100%, with lower concordances obtained for aflatoxin B1 production prediction. Interestingly, aflatoxin B1 production was higher on maize grains than on maize extract agar. Moreover, this work suggests that the safe water activity for a cereal may depend on the previous water activity and temperatures which may have allowed fungal growth and so trigger later toxin production under water stress.
玉米中的黄曲霉毒素是各种食品和动物饲料的污染物，可产生危害人类和动物健康的霉菌毒素黄曲霉毒素 B。在这里，我们建立了一些模型来预测玉米提取物琼脂和玉米粒中黄曲霉毒素的行为。我们记录了玉米提取物琼脂在 20-35 °C 和 0.84-0.90 水活度条件下的生长情况和黄曲霉毒素 B 产量。然后，我们根据生长和黄曲霉毒素 B 产量的数据，利用温度、水活度和时间作为解释变量，建立了概率模型。我们还在两种动态变化的温度条件下生成了其他数据。最初的水活性和培养过程中的相对湿度都被记录下来。根据静态条件下建立的模型预测的动态条件下的生长概率取决于温度制度和基质，吻合度从 66% 到 100% 不等，黄曲霉毒素 B 产量预测的吻合度较低。有趣的是，玉米粒上的黄曲霉毒素 B 产量高于玉米提取物琼脂。此外，这项研究还表明，谷物的安全水活性可能取决于以前的水活性和温度，因为以前的水活性和温度可能允许真菌生长，从而引发后来在水胁迫下产生毒素。
{"title":"Aflatoxin B1 production: A time–water activity–temperature model","authors":"Sonia Marín, Laila Aldars-García, Francisco Molino, Antonio J. Ramos, Vicente Sanchis","doi":"10.1016/j.funbio.2024.03.003","DOIUrl":"10.1016/j.funbio.2024.03.003","url":null,"abstract":"<div><div><em>Aspergillus flavus</em> occurs as a contaminant of various foods and animal feeds and can produce the mycotoxin aflatoxin B<sub>1</sub> that is a danger to human and animal health. Here, we develop models to predict the behaviour of <em>A. flavus</em> in maize extract agar and maize grains. Growth and aflatoxin B<sub>1</sub> production were recorded on maize extract agar at 20–35 °C and water activities from 0.84 to 0.90. We then obtained probability models—using temperature, water activity, and time as explanatory variables—based on data of growth and aflatoxin B<sub>1</sub> production. Additional data were generated under two dynamically changing temperature regimes. Initial water activity, and relative humidity during incubation, were recorded. Predicted probability of growth under dynamic conditions based on models built under static conditions depended on the temperature regime and substrate, concordance ranging from 66 to 100%, with lower concordances obtained for aflatoxin B<sub>1</sub> production prediction. Interestingly, aflatoxin B<sub>1</sub> production was higher on maize grains than on maize extract agar. Moreover, this work suggests that the safe water activity for a cereal may depend on the previous water activity and temperatures which may have allowed fungal growth and so trigger later toxin production under water stress.</div></div>","PeriodicalId":12683,"journal":{"name":"Fungal biology","volume":"128 8","pages":"Pages 2399-2407"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140151728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.funbio.2023.12.003
Kevin K. Newsham
The surface temperatures of Antarctic soils and bryophyte colonies can fluctuate from close to freezing point to approximately 20 °C under clear skies around solar noon during midsummer. However, whether diurnally fluctuating temperatures influence the growth and metabolic activities of fungi inhabiting these substrates remains unknown. Here, 10 isolates of Pseudogymnoascus roseus, an ascomycete that is widespread in Antarctica, were exposed in vitro to temperatures fluctuating daily from 2 °C to 15–24 °C. Relative to controls incubated at the constant mean temperature of each treatment, temperatures fluctuating from 2 °C to ≥18 °C inhibited the growth of all isolates by 10–51% at 24 h and 48 h, and by up to 79% for individual isolates. Over a period of 21 days, all fluctuating temperature treatments reduced mean growth rates by between 3% and 48%, but had few effects on specific β-glucosidase activity, a proxy measure for metabolic activity. It is concluded that temperatures fluctuating diurnally to ≥18 °C during summer in mesic Antarctic soils and bryophyte colonies, exacerbated by the occurrence of climate-change associated heatwaves, are likely to inhibit the growth of P. roseus and perhaps also other ecologically important fungi.
{"title":"Diurnal temperature fluctuation inhibits the growth of an Antarctic fungus","authors":"Kevin K. Newsham","doi":"10.1016/j.funbio.2023.12.003","DOIUrl":"10.1016/j.funbio.2023.12.003","url":null,"abstract":"<div><div>The surface temperatures of Antarctic soils and bryophyte colonies can fluctuate from close to freezing point to approximately 20 °C under clear skies around solar noon during midsummer. However, whether diurnally fluctuating temperatures influence the growth and metabolic activities of fungi inhabiting these substrates remains unknown. Here, 10 isolates of <em>Pseudogymnoascus roseus</em>, an ascomycete that is widespread in Antarctica, were exposed <em>in vitro</em> to temperatures fluctuating daily from 2 °C to 15–24 °C. Relative to controls incubated at the constant mean temperature of each treatment, temperatures fluctuating from 2 °C to ≥18 °C inhibited the growth of all isolates by 10–51% at 24 h and 48 h, and by up to 79% for individual isolates. Over a period of 21 days, all fluctuating temperature treatments reduced mean growth rates by between 3% and 48%, but had few effects on specific β-glucosidase activity, a proxy measure for metabolic activity. It is concluded that temperatures fluctuating diurnally to ≥18 °C during summer in mesic Antarctic soils and bryophyte colonies, exacerbated by the occurrence of climate-change associated heatwaves, are likely to inhibit the growth of <em>P. roseus</em> and perhaps also other ecologically important fungi.</div></div>","PeriodicalId":12683,"journal":{"name":"Fungal biology","volume":"128 8","pages":"Pages 2365-2371"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139036988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.funbio.2024.02.001
Andrieli Stefanello , Alessandra Marcon Gasperini , Juliana Copetti Fracari , Carlos Augusto Mallmann , Marina Venturini Copetti
Aspergillus westerdijkiae can grow as ‘golden mould’ on the surface of dry-cured meat products, causing deterioration, and can produce the mycotoxin known as ochratoxin A that is a risk to human health. The aim of this study was to evaluate the growth and ochratoxin production by A. westerdijkiae at different temperatures (15, 20, and 25 °C), in salami-based culture media supplemented with glycerol and NaCl to adjust the water activity (0.85, 0.90, 0.93, 0.97 and 0.99). The growth of the two strains of A. westerdijkiae (S1 and S2) was evaluated for 28 days and, after this period, ochratoxin A was extracted from the culture media and analysed by high-performance liquid chromatography. For both strains, the optimal growth (>10 mm day−1) occurred at 0.97 and 0.99 water activity at 20–25 °C. The lowest water activity (0.85) and temperature (15 °C) resulted in the slowest growth rates (<2.0 mm day−1). However, ochratoxin A production by strain S1 was highest (21 μg g−1) at 20 °C on glycerol-supplemented media at 0.97 water activity; the strain S2 produced its higher level of ochratoxin A (7.0 μg g−1) at water activity 0.99 and 20 °C on NaCl-supplemented media. Whereas some microorganisms produce toxic secondary metabolites under stress/boundary conditions, we noted that mycotoxin production by A. westerdijkiae occurred at optimal growth conditions (high water activities). These conditions also show a more intense interspecies competition of microbial communities. Insights into the ecophysiology of fungi can be used to make knowledge-based decisions to reduce contamination of dry-cured meat products.
{"title":"Aspergillus westerdijkiae growth and ochratoxin A on salami-based media","authors":"Andrieli Stefanello , Alessandra Marcon Gasperini , Juliana Copetti Fracari , Carlos Augusto Mallmann , Marina Venturini Copetti","doi":"10.1016/j.funbio.2024.02.001","DOIUrl":"10.1016/j.funbio.2024.02.001","url":null,"abstract":"<div><div><span><span>Aspergillus</span><em> westerdijkiae</em></span><span><span> can grow as ‘golden mould’ on the surface of dry-cured meat products, causing deterioration, and can produce the mycotoxin known as </span>ochratoxin A<span> that is a risk to human health. The aim of this study was to evaluate the growth and ochratoxin production by </span></span><em>A. westerdijkiae</em> at different temperatures (15, 20, and 25 °C), in salami-based culture media supplemented with glycerol and NaCl to adjust the water activity (0.85, 0.90, 0.93, 0.97 and 0.99). The growth of the two strains of <em>A. westerdijkiae</em><span> (S1 and S2) was evaluated for 28 days and, after this period, ochratoxin A was extracted from the culture media and analysed by high-performance liquid chromatography. For both strains, the optimal growth (>10 mm day</span><sup>−1</sup>) occurred at 0.97 and 0.99 water activity at 20–25 °C. The lowest water activity (0.85) and temperature (15 °C) resulted in the slowest growth rates (<2.0 mm day<sup>−1</sup>). However, ochratoxin A production by strain S1 was highest (21 μg g<sup>−1</sup>) at 20 °C on glycerol-supplemented media at 0.97 water activity; the strain S2 produced its higher level of ochratoxin A (7.0 μg g<sup>−1</sup><span>) at water activity 0.99 and 20 °C on NaCl-supplemented media. Whereas some microorganisms produce toxic secondary metabolites<span> under stress/boundary conditions, we noted that mycotoxin production by </span></span><em>A. westerdijkiae</em><span> occurred at optimal growth conditions (high water activities). These conditions also show a more intense interspecies competition of microbial communities<span>. Insights into the ecophysiology of fungi can be used to make knowledge-based decisions to reduce contamination of dry-cured meat products.</span></span></div></div>","PeriodicalId":12683,"journal":{"name":"Fungal biology","volume":"128 8","pages":"Pages 2390-2398"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139670027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.funbio.2024.07.004
Victoria J. Armer , Erika Kroll , Martin Darino , Daniel P. Smith , Martin Urban , Kim E. Hammond-Kosack
The Ascomycete genus Fusarium, first introduced by Link in 1809, currently consists of 431 species and 3558 unclassified isolates and hybrids (according to NCBI Taxonomy lists). Collectively, these fungi have diverse lifestyles and infection cycles exploiting a wide range of environments, hosts, ecological niches, and nutrient sources. Here, we carried out a pan-Fusarium species review to describe and explore the glamorous, and the less attractive niches, exploited by pathogenic and endophytic species. We survey species that infect plant, human, animal and/or invertebrate hosts, free-living non-pathogenic species dwelling in land, air or water-based natural ecosystems, through to those species that exploit human-modified environments or are cultivated in industrial production systems. Fully sequenced, assembled and annotated reference genomes are already available for 189 Fusarium species, many at chromosome scale. In addition, for some of the world's most important species extensive single species pangenomes or closely related formae speciales genome clusters are readily available. Previous comparative genomics studies have focussed on taxonomically restricted clusters of Fusarium species. We now investigate potential new relationships between these vastly contrasting Fusarium biologies, niches and environmental occupancies and the evolution of their respective genomes.
{"title":"Navigating the Fusarium species complex: Host-range plasticity and genome variations","authors":"Victoria J. Armer , Erika Kroll , Martin Darino , Daniel P. Smith , Martin Urban , Kim E. Hammond-Kosack","doi":"10.1016/j.funbio.2024.07.004","DOIUrl":"10.1016/j.funbio.2024.07.004","url":null,"abstract":"<div><div>The Ascomycete genus <em>Fusarium</em><em>,</em> first introduced by Link in 1809, currently consists of 431 species and 3558 unclassified isolates and hybrids (according to NCBI Taxonomy lists). Collectively, these fungi have diverse lifestyles and infection cycles exploiting a wide range of environments, hosts, ecological niches, and nutrient sources. Here, we carried out a pan-<em>Fusarium</em> species review to describe and explore the glamorous, and the less attractive niches, exploited by pathogenic and endophytic species. We survey species that infect plant, human, animal and/or invertebrate hosts, free-living non-pathogenic species dwelling in land, air or water-based natural ecosystems, through to those species that exploit human-modified environments or are cultivated in industrial production systems. Fully sequenced, assembled and annotated reference genomes are already available for 189 <em>Fusarium</em> species, many at chromosome scale. In addition, for some of the world's most important species extensive single species pangenomes or closely related <em>formae speciales</em> genome clusters are readily available. Previous comparative genomics studies have focussed on taxonomically restricted clusters of <em>Fusarium</em> species. We now investigate potential new relationships between these vastly contrasting <em>Fusarium</em> biologies, niches and environmental occupancies and the evolution of their respective genomes.</div></div>","PeriodicalId":12683,"journal":{"name":"Fungal biology","volume":"128 8","pages":"Pages 2439-2459"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141694948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Şalgam is a traditional drink produced via the lactic-acid fermentation of vegetables (black carrot and turnip), sourdough, and bulgur flour; with rock salt also added. During storage, an additional yeast-mediated fermentation can occur, causing changes in organoleptic properties, as evidenced by the microbe-mediated release of gases. Here, we characterise şalgam as a microbial habitat, identify the yeasts that cause spoilage, and characterise yeast-induced changes of the şalgam. The total acidity of the spoiled şalgam, in terms of lactic acid, ranged from 5.33 to 8.36 g/L with pH values from 3.86 to 4.10. Nine different spoilage fungi were isolated and then identified using molecular techniques (combination of PCR-RFLP of the 5.8 S-rRNA region and sequencing of the D1/D2 domain of the 26 S-rRNA gene). The highest frequencies of species were for the (apparently dominant) Saccharomyces cerevisiae, Galactomyces candidum, and Pichia kudriavzevii. Notably, two of these yeasts—P. kudriavzevii and Saccharomyces cerevisiae—are known to be acid-tolerant, have a robust stress biology, and can dominate various microbial habitats including those of fermented foods and drinks. Şalgam is a nutrient-rich, high-water-activity habitat that can favour the growth of various microbes and becomes less acidic (so more ecologically open) after the proliferation of yeasts.
{"title":"Black-carrot drink şalgam as a habitat for spoilage yeasts","authors":"Dilek Safkan , Bilal Agirman , Bekir Safkan , Yesim Soyer , Huseyin Erten","doi":"10.1016/j.funbio.2024.01.002","DOIUrl":"10.1016/j.funbio.2024.01.002","url":null,"abstract":"<div><div><em>Şalgam</em><span> is a traditional drink produced via the lactic-acid fermentation of vegetables (black carrot and turnip), sourdough, and bulgur<span> flour; with rock salt also added. During storage, an additional yeast-mediated fermentation can occur, causing changes in organoleptic properties, as evidenced by the microbe-mediated release of gases. Here, we characterise </span></span><em>şalgam</em> as a microbial habitat, identify the yeasts that cause spoilage, and characterise yeast-induced changes of the <em>şalgam</em>. The total acidity of the spoiled <em>şalgam</em>, in terms of lactic acid, ranged from 5.33 to 8.36 g/L with pH values from 3.86 to 4.10. Nine different spoilage fungi were isolated and then identified using molecular techniques (combination of PCR-RFLP of the 5.8 S-rRNA region and sequencing of the D1/D2 domain of the 26 S-rRNA gene). The highest frequencies of species were for the (apparently dominant) <span><em>Saccharomyces cerevisiae</em></span>, <span><em>Galactomyces</em><em> candidum</em></span>, and <span><span>Pichia kudriavzevii</span></span>. Notably, two of these yeasts—<em>P. kudriavzevii</em> and <em>Saccharomyces cerevisiae</em><span>—are known to be acid-tolerant, have a robust stress biology, and can dominate various microbial habitats including those of fermented foods and drinks. </span><em>Şalgam</em> is a nutrient-rich, high-water-activity habitat that can favour the growth of various microbes and becomes less acidic (so more ecologically open) after the proliferation of yeasts.</div></div>","PeriodicalId":12683,"journal":{"name":"Fungal biology","volume":"128 8","pages":"Pages 2471-2478"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139656837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.funbio.2024.05.014
Hyang Burm Lee , Thuong T.T. Nguyen , So Jeong Noh , Dong Hee Kim , Ki Hyun Kang , Su Jin Kim , Paul M. Kirk , Simon V. Avery , Angel Medina , John E. Hallsworth
Eurotiales fungi are thought to be distributed worldwide but there is a paucity of information about their occurrence on diverse substrates or hosts and at specific localities. Some of the Eurotiales, including Aspergillus and Penicillium species, produce an array of secondary metabolites of use for agricultural, medicinal, and pharmaceutical applications. Here, we carried out a survey of the Eurotiales in South Korea, focusing on soil, freshwater, and plants (dried persimmon fruits and seeds of Perilla frutescens, known commonly as shiso). We obtained 11 species that—based on morphology, physiology, and multi-locus (ITS, BenA, CaM, and RPB2) phylogenetic analyses—include two new species, Aspergillus ullungdoensis sp. nov. and Penicillium jeongsukae sp. nov., and nine species that were known, but previously not described in South Korea, Aspergillus aculeatinus, Aspergillus aurantiacoflavus, Aspergillus croceiaffinis, Aspergillus pseudoviridinutans, Aspergillus uvarum, Penicillium ferraniaense, Penicillium glaucoroseum, Penicillium sajarovii, and one, Penicillium charlesii, that was isolated from previously unknown host, woodlouse (Porcellio scaber). We believe that biodiversity survey and identifying new species can contribute to set a baseline for future changes in the context of humanitarian crises such as climate change.
{"title":"Aspergillus ullungdoensis sp. nov., Penicillium jeongsukae sp. nov., and other fungi from Korea","authors":"Hyang Burm Lee , Thuong T.T. Nguyen , So Jeong Noh , Dong Hee Kim , Ki Hyun Kang , Su Jin Kim , Paul M. Kirk , Simon V. Avery , Angel Medina , John E. Hallsworth","doi":"10.1016/j.funbio.2024.05.014","DOIUrl":"10.1016/j.funbio.2024.05.014","url":null,"abstract":"<div><div><span><em>Eurotiales</em></span> fungi are thought to be distributed worldwide but there is a paucity of information about their occurrence on diverse substrates or hosts and at specific localities. Some of the <em>Eurotiales</em>, including <span><span>Aspergillus</span></span> and <em>Penicillium</em><span> species, produce an array of secondary metabolites of use for agricultural, medicinal, and pharmaceutical applications. Here, we carried out a survey of the </span><em>Eurotiales</em><span><span> in South Korea, focusing on soil, freshwater, and plants (dried </span>persimmon fruits and seeds of </span><span><span>Perilla frutescens</span></span>, known commonly as <em>shiso</em>). We obtained 11 species that—based on morphology, physiology, and multi-locus (ITS, <em>BenA</em>, <em>CaM</em>, and <em>RPB2</em>) phylogenetic analyses—include two new species, <em>Aspergillus ullungdoensis</em> sp. nov. and <em>Penicillium jeongsukae</em> sp. nov., and nine species that were known, but previously not described in South Korea, <em>Aspergillus aculeatinus</em>, <em>Aspergillus aurantiacoflavus</em>, <em>Aspergillus croceiaffinis</em>, <em>Aspergillus pseudoviridinutans</em>, <em>Aspergillus uvarum</em>, <em>Penicillium ferraniaense</em>, <em>Penicillium glaucoroseum</em>, <em>Penicillium sajarovii</em>, and one, <em>Penicillium charlesii</em><span>, that was isolated from previously unknown host, woodlouse (</span><span><em>Porcellio scaber</em></span><span>). We believe that biodiversity survey and identifying new species can contribute to set a baseline for future changes in the context of humanitarian crises such as climate change.</span></div></div>","PeriodicalId":12683,"journal":{"name":"Fungal biology","volume":"128 8","pages":"Pages 2479-2492"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141402914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.funbio.2024.08.002
F. Pinzari , J. Cuadros , A. Saiardi , E. Humphreys-Williams , A.D. Jungblut
Phyllosilicates provide a primary source of minerals used by microorganisms and plants, particularly clay minerals, i.e., phyllosilicates of very small particle size. Fungi can actively break down (or “weather”) minerals to extract nutrients, but whether they use identical mechanisms when accessing different clay minerals is unclear. In addition, it is yet to be understood whether starvation stresses due to the limited availability of a mineral-nutrient would result in different weathering behaviours of microbes.
Here, we performed a microcosm experiment to address these questions. We used the ectomycorrhizal basidiomycete Paxillus involutus and the phyllosilicates K-vermiculite, muscovite and phlogopite. These silicates have different degrees of recalcitrance to the removal of K cations from the mineral, and each was provided in the microscosm experiment as the sole potassium (K) source. The type of potassium “extraction-assimilation” was tested against a potassium-availability gradient, with a situation of maximum starvation stress (no potassium availability) and one of maximum availability (potassium provided as a solute in the culture medium). Our study revealed that different phyllosilicate minerals stimulated different patterns of fungal gene expression, which indicated bespoke weathering mechanisms for different phyllosilicates. The potassium uptake capacity of the fungus was highest with K-vermiculite compared to phlogopite and muscovite. Interestingly, the assimilation of phosphorus by the fungus was reduced in K-depleted conditions.
Moreover, the potassium deprivation condition prompted the fungus to assimilate sodium instead. Also, in the presence of the minerals, the fungus showed significant differences in gene expression compared with the negative and positive control conditions, suggesting that the mineral environment modulates the starvation stress levels. The nutrients assimilated by the mycelium from both the minerals and the culture medium also varied according to the type of silicate added and the K starvation level to which the fungus was subjected. Based on what has been observed here, many geochemical processes could depend on fungi's genetic and functional plasticity, which would have considerable environmental consequences with a direct link between the evolution of fungi and that of the Earth's crust.
{"title":"Bespoke strategies of Paxillus involutus to extract potassium from diverse phyllosilicates","authors":"F. Pinzari , J. Cuadros , A. Saiardi , E. Humphreys-Williams , A.D. Jungblut","doi":"10.1016/j.funbio.2024.08.002","DOIUrl":"10.1016/j.funbio.2024.08.002","url":null,"abstract":"<div><div>Phyllosilicates provide a primary source of minerals used by microorganisms and plants, particularly clay minerals, i.e., phyllosilicates of very small particle size. Fungi can actively break down (or “weather”) minerals to extract nutrients, but whether they use identical mechanisms when accessing different clay minerals is unclear. In addition, it is yet to be understood whether starvation stresses due to the limited availability of a mineral-nutrient would result in different weathering behaviours of microbes.</div><div>Here, we performed a microcosm experiment to address these questions. We used the ectomycorrhizal basidiomycete <em>Paxillus involutus</em> and the phyllosilicates K-vermiculite, muscovite and phlogopite. These silicates have different degrees of recalcitrance to the removal of K cations from the mineral, and each was provided in the microscosm experiment as the sole potassium (K) source. The type of potassium “extraction-assimilation” was tested against a potassium-availability gradient, with a situation of maximum starvation stress (no potassium availability) and one of maximum availability (potassium provided as a solute in the culture medium). Our study revealed that different phyllosilicate minerals stimulated different patterns of fungal gene expression, which indicated bespoke weathering mechanisms for different phyllosilicates. The potassium uptake capacity of the fungus was highest with K-vermiculite compared to phlogopite and muscovite. Interestingly, the assimilation of phosphorus by the fungus was reduced in K-depleted conditions.</div><div>Moreover, the potassium deprivation condition prompted the fungus to assimilate sodium instead. Also, in the presence of the minerals, the fungus showed significant differences in gene expression compared with the negative and positive control conditions, suggesting that the mineral environment modulates the starvation stress levels. The nutrients assimilated by the mycelium from both the minerals and the culture medium also varied according to the type of silicate added and the K starvation level to which the fungus was subjected. Based on what has been observed here, many geochemical processes could depend on fungi's genetic and functional plasticity, which would have considerable environmental consequences with a direct link between the evolution of fungi and that of the Earth's crust.</div></div>","PeriodicalId":12683,"journal":{"name":"Fungal biology","volume":"128 8","pages":"Pages 2341-2354"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.funbio.2023.12.008
Raphael Bchini , Sylvain Darnet , Arthur de Butler , Annick Doan , Lydie Oliveira-Correia , David Navarro , Eric Record , Mélanie Morel-Rouhier
Plant metabolites have a great potential for limiting the spread of harmful fungi. However, a better understanding of the mode-of-action of these molecules and the defense systems developed by fungi to resist them, is needed to assess the benefits/risks of using them as antifungal treatment. White-rot fungi are excellent models in this respect, as they have adapted to the hostile habitat that is wood. In fact, wood is a source of putative antifungal compounds that can be derived using extraction techniques. In this study, we demonstrated that esculin and esculetin, which are coumarins found in plants and wood, reduce the growth of the wood-rotting fungi Fomitiporia mediterranea, Phanerochaete chrysosporium, Pycnoporus cinnabarinus and Trametes versicolor. We have shown that extracellular strategies are developed by the fungi to deal with esculin, through the involvement of laccases, peroxidases and glycoside hydrolases, and intracellular strategies, mainly via upregulated protein translation. Comparative proteomic and metabolomic approaches revealed that, despite the fact that the species analysed are closely related (they all belong to the Agaricomycetes, and have the same trophic mode), their defense responses to esculin differ.
{"title":"Responses to and detoxification of esculin in white-rot fungi","authors":"Raphael Bchini , Sylvain Darnet , Arthur de Butler , Annick Doan , Lydie Oliveira-Correia , David Navarro , Eric Record , Mélanie Morel-Rouhier","doi":"10.1016/j.funbio.2023.12.008","DOIUrl":"10.1016/j.funbio.2023.12.008","url":null,"abstract":"<div><div>Plant metabolites have a great potential for limiting the spread of harmful fungi. However, a better understanding of the mode-of-action of these molecules and the defense systems developed by fungi to resist them, is needed to assess the benefits/risks of using them as antifungal treatment. White-rot fungi are excellent models in this respect, as they have adapted to the hostile habitat that is wood. In fact, wood is a source of putative antifungal compounds that can be derived using extraction techniques. In this study, we demonstrated that esculin and esculetin, which are coumarins found in plants and wood, reduce the growth of the wood-rotting fungi <em>Fomitiporia mediterranea, Phanerochaete chrysosporium</em>, <em>Pycnoporus cinnabarinus</em> and <em>Trametes versicolor</em>. We have shown that extracellular strategies are developed by the fungi to deal with esculin, through the involvement of laccases, peroxidases and glycoside hydrolases, and intracellular strategies, mainly via upregulated protein translation. Comparative proteomic and metabolomic approaches revealed that, despite the fact that the species analysed are closely related (they all belong to the Agaricomycetes, and have the same trophic mode), their defense responses to esculin differ.</div></div>","PeriodicalId":12683,"journal":{"name":"Fungal biology","volume":"128 8","pages":"Pages 2372-2380"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139094607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The occurrence of mycothalli, symbioses between liverworts and fungi, is poorly documented in sub-Antarctica, and biogeographical patterns in Serendipita, the main fungal genus forming the symbiosis, remain understudied. Here, 83 specimens of 16 leafy liverwort species were sampled from sub-Antarctic South Georgia and were examined for mycothalli. Microscopy was used to enumerate fungal structures in liverwort tissues, and sequencing of fungal ribosomal DNA was used to determine the taxonomic and biogeographical affinities of the fungi. Stained hyphal coils, a defining feature of the symbiosis, were found to be frequent (>40% of stem length colonised) in Barbilophozia hatcheri, Cephaloziella varians and Lophoziopsis excisa. A single species of Serendipita, based on a 3% cut-off for ITS2 region sequence divergence, was a frequent colonist of these liverworts. A further 18 basidiomycete and ascomycete taxa colonised other liverwort species. The presence of the Serendipita species was positively associated with the occurrence of stained hyphal coils in stem epidermal cells. Phylogenetic analyses, incorporating worldwide accessions from leafy liverwort-associated Serendipita, showed that the same species, which also occurs in Chile, mainland Europe and on Svalbard, is apparently the sole symbiont of sub- and maritime Antarctic leafy liverworts, and indicated much higher species richness of the genus outside Antarctica.
{"title":"A cosmopolitan Serendipita forms mycothalli with sub-Antarctic leafy liverworts","authors":"K.K. Newsham , G.W. Foot , C.J. Sands , W.P. Goodall-Copestake","doi":"10.1016/j.funbio.2023.11.006","DOIUrl":"10.1016/j.funbio.2023.11.006","url":null,"abstract":"<div><div>The occurrence of mycothalli, symbioses between liverworts and fungi, is poorly documented in sub-Antarctica, and biogeographical patterns in <em>Serendipita</em>, the main fungal genus forming the symbiosis, remain understudied. Here, 83 specimens of 16 leafy liverwort species were sampled from sub-Antarctic South Georgia and were examined for mycothalli. Microscopy was used to enumerate fungal structures in liverwort tissues, and sequencing of fungal ribosomal DNA was used to determine the taxonomic and biogeographical affinities of the fungi. Stained hyphal coils, a defining feature of the symbiosis, were found to be frequent (>40% of stem length colonised) in <em>Barbilophozia hatcheri</em>, <em>Cephaloziella varians</em> and <em>Lophoziopsis excisa</em>. A single species of <em>Serendipita</em>, based on a 3% cut-off for ITS2 region sequence divergence, was a frequent colonist of these liverworts. A further 18 basidiomycete and ascomycete taxa colonised other liverwort species. The presence of the <em>Serendipita</em> species was positively associated with the occurrence of stained hyphal coils in stem epidermal cells. Phylogenetic analyses, incorporating worldwide accessions from leafy liverwort-associated <em>Serendipita</em>, showed that the same species, which also occurs in Chile, mainland Europe and on Svalbard, is apparently the sole symbiont of sub- and maritime Antarctic leafy liverworts, and indicated much higher species richness of the genus outside Antarctica.</div></div>","PeriodicalId":12683,"journal":{"name":"Fungal biology","volume":"128 8","pages":"Pages 2355-2364"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139292203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The disaccharide trehalose plays a crucial role in multiple facets of the stress biology of yeasts and fungi. Here, we evaluate the properties, cellular and ecophysiological roles, metabolism, and stress-protection mechanisms of trehalose. We integrate disparate sources of knowledge across these topics, and bring new information about the mechanisms by which trehalose stabilises biomacromolecules and how trehalose metabolism is regulated thus giving rise to its diverse roles in fungi including stress protector, carbohydrate reserve, and regulatory/signaling molecule. We also present new findings about the effect of trehalose on microbial adaptation, complexity and spatio-temporal heterogeneity of microbial populations, and implications for industrial processes that apply fungi. Based on the elucidation of the structures of enzymes involved in trehalose synthesis, their catalytic mechanisms, and the regulation of trehalose synthesis, we discuss prospects for the development of more-efficient fungicides. Current humanitarian crises, such as overpopulation, global warming, malnutrition, immunocompromised conditions, and usage of immunosuppressant drugs, are making the incidence of human pathogens increases. Furthermore, fungal infections can be difficult to treat due to the conserved biochemistry between human and fungi cells. Serendipitously, however, trehalose is not synthesised by mammals, which makes trehalose synthesis an interesting target for the development of new therapies.
{"title":"Trehalose promotes biological fitness of fungi","authors":"Gabriela Delaqua Ribeiro, Luan de Holanda Paranhos, Elis Cristina Araujo Eleutherio","doi":"10.1016/j.funbio.2024.03.004","DOIUrl":"10.1016/j.funbio.2024.03.004","url":null,"abstract":"<div><div><span>The disaccharide </span>trehalose<span><span><span><span> plays a crucial role in multiple facets of the stress biology of yeasts and fungi. Here, we evaluate the properties, cellular and ecophysiological roles, metabolism, and stress-protection mechanisms of trehalose<span>. We integrate disparate sources of knowledge across these topics, and bring new information about the mechanisms by which trehalose stabilises biomacromolecules and how trehalose metabolism is regulated thus giving rise to its diverse roles in fungi including stress protector, carbohydrate reserve, and regulatory/signaling molecule. We also present new findings about the effect of trehalose on microbial adaptation, complexity and spatio-temporal heterogeneity of microbial populations, and implications for industrial processes that apply fungi. Based on the elucidation of the structures of </span></span>enzymes involved in trehalose synthesis, their </span>catalytic mechanisms<span>, and the regulation of trehalose synthesis, we discuss prospects for the development of more-efficient fungicides. Current humanitarian crises, such as overpopulation, global warming, malnutrition, immunocompromised conditions, and usage of </span></span>immunosuppressant drugs<span><span><span>, are making the incidence of human pathogens increases. Furthermore, </span>fungal infections can be difficult to treat due to the conserved </span>biochemistry between human and fungi cells. Serendipitously, however, trehalose is not synthesised by mammals, which makes trehalose synthesis an interesting target for the development of new therapies.</span></span></div></div>","PeriodicalId":12683,"journal":{"name":"Fungal biology","volume":"128 8","pages":"Pages 2381-2389"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140151733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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