Fungal Biology Reviews最新文献

Over three decades ago, the plant-derived anticancer agent taxol (brand name: paclitaxel) was reported from a fungal endophyte colonizing the producing plant. The hope that this finding could ever result in a sustainable production process has thus far been disappointed. Modern evidence on the evolution of secondary metabolites in plants vs. fungi suggests that this hypothesis (that fungi could produce such complex plant metabolites) is invalid. Still, numerous inconclusive original studies -and in particular, review papers by non-experts in the field-are continuously being published that claim the opposite. The current commentary tries to deal with the topic, taking the findings of –OMICS studies and current state-of-the art mycology into account. This can hopefully help to stop the scientific papermills from further spreading the fake news that fungi were capable of sustainable production of taxol.

The demand to develop protein production systems that are both economically and scientifically viable is reflected in the global scenario, where filamentous fungi, due to their interesting characteristics such as the high capacity to secrete proteins into the culture medium, growth in relatively simple substrates and robust post-translational machinery, among others, are presented as promising alternatives for the creation and establishment of these systems. Currently, these organisms produce a wide range of proteins, such as glycosidases, lipases, and proteases, for example. Scientific and technological development has increasingly allowed the evolution of molecular biology techniques that facilitate the genetic modification of organisms, thus, stimulating the establishment of new protein production systems. Amongst these techniques, it is possible to highlight the CRISPR/Cas system, a relatively simple, low-cost, and high-efficient tool for genetic modifications. Filamentous fungi, organisms widely used for protein production, have been used in a relatively low number of studies related to the production of (hemi-)cellulases using the CRISPR/Cas system as a genomic editing tool. (Hemi-)cellulases, enzymes that catalyze the breakdown of saccharides, are a class of enzymes that are highly researched and applied in several biotechnological areas in order to obtain a wide range of value-added bioproducts, such as bioethanol, for example. In this context, this review aims to illustrate the scenario of the application of the CRISPR/Cas technique for the production of (hemi-)cellulases, highlighting the main studies to date and the perspectives of a market that tends to grow exponentially in the coming years.

Many unnamed fungi have been revealed from DNA sequences but cannot be formally named due to a lack of physical materials required for the description of a taxon by the International Code of Nomenclature for algae, fungi, and plants. While the mycological community generally discusses the necessity to amend the code to permit DNA sequence data as the nomenclatural type of these fungal ‘dark taxa’ (FDT), the standard of DNA sequences is mainly in debate. Here, I suggest to set an approximate fifteen years transition period. During that time, it is recommended to sequence the whole genomes of all known species and newly published species with available physical materials; meanwhile, the FDT can be provisionally named with priority using whole genome data as the type. After the transition period, these provisionally named FDT will become valid, provided no known species from physical materials with a priority can be proved to be conspecific. Moreover, in this new era of fungal taxonomy when the whole genome data will be commonly used as the crucial evidence to delimit fungal species, new taxa should be named along with the deposition of whole genome sequences in public databases, and the whole genome data may be the type of the FDT.

In many eukaryotes, small RNAs (sRNAs) can mediate gene expression regulation through a mechanism known as RNA silencing. In fungi, RNA silencing plays a crucial role in numerous biological processes, including parasitic and mutualistic fungus-plant interactions. This review summarizes recent findings on the role of RNA silencing in parasitic fungus-fungus and fungus-insect interactions in relation to their use for the biological control (biocontrol) of fungal plant diseases and insect damage. Genes belonging to the RNA silencing machinery are identified in the genomes of almost all known fungal and oomycete biocontrol organisms. However, recent functional genetic studies in Ascomycota species of the Hypocreales order, such as Trichoderma atroviride and Clonostachys rosea, show how RNA silencing can have family-specific effects, as conidiation is affected differently in the two organisms when the same elements of the RNA silencing machinery are deleted. The size of sRNAs regulated by RNA silencing can also vary between organisms. Cross-species RNA silencing represents a new field in the study of antagonistic interactions. For example, a microRNA (miRNA) of another hypocrealean fungus, Beauveria bassiana, was proven to target genes involved in the immune response of mosquitoes, and there are indications that miRNAs from the mycoparasitic C. rosea may target factors of virulence in its plant-pathogenic host fungi. Accumulating evidence from many species shows that the number of endogenous genes affected by the disruption of the RNA silencing mechanism is always much higher than the number of predicted direct target genes. As several putative targets of fungal sRNAs are transcription factors, it is possible that specific sRNAs have a role as master regulators of gene expression, affecting the transcription of a high number of genes through cascading regulating effects. The challenges faced when studying cross-species RNA silencing, including sRNA trafficking during mycoparasitism, are also discussed. This includes the difficulties in separating the extracellular vesicles of mycoparasitic fungi from those of their hosts, the high amount of sequencing reads lost in bioinformatics filtering steps, imprecise target prediction and the lack of a streamlined accepted way of reporting results.

The primary cause of blindness and visual impairment worldwide is fungal keratitis, an infection of the cornea. The predominant etiology of these fungal infections is influenced by several variables, including socioeconomic level, geographic origin, and climatic circumstances. Aspergillus spp. and Fusarium spp. are typically responsible for the infection in tropical and subtropical regions, whereas Candida spp. predominate in temperate zones. Anatomical barriers are a crucial first line of protection because most infectious agents are exogenous. By releasing antimicrobial chemicals like lysozyme, lactoferrin, lipocalin, and defensins that are found in tears or secreted over the cornea, corneal cells operate as the body's second line of defense. Additionally, immunity against fungal infections is provided by the cellular immune response that is triggered by the presence of fungi or their products at the corneal surface. T lymphocytes and neutrophils are drawn to the infection site as a result of activated signaling pathways in corneal cells. A comprehensive defense against fungal keratitis is provided by the antifungal mechanism acting as the host defense at the corneal surface. Furthermore, developing treatment plans for fungal keratitis may be influenced by knowledge of the molecular underpinnings of host protection against fungal infections. In the current work, we outlined the most recent developments in our understanding of the host-pathogen interaction and host-immune response in fungal keratitis of mouse and human corneal tissue.

Skin, hair, and nail fungal infections affect almost a billion people globally and their incidence is rising. Candida spp. and Malassezia spp., two yeasts that are part of the skin microbiota, normally do not cause disease. But, when dysbiosis occurs and the skin microbiome is disturbed, they can become pathogenic. There are conventional antifungals that treat candidiasis and Malassezia infections, such as azoles and allylamines, among others. However, the limitations of these treatments (resistance, side effects) lead to the search for new, alternative, and natural drugs, such as plant extracts (PEs) and essential oils (EOs). But these substances present some limitations (poor bioavailability and poor target capacity), which limits their efficiency. Their incorporation in formulations such as films and hydrogels (HGs) can help overcome these issues and may be a potential alternative to the current treatments. The main objective of this work is to provide a state-of-the-art review on Candida spp., Malassezia spp., mucocutaneous candidiasis and Malassezia infections, the conventional existing treatments and the incorporation of PEs and EOs in films and hydrogels as possible new alternative treatments for these diseases.

Cancer is a multifaceted disease that closes the curtains of life of infected individuals globally. By 2030, it is predicted that there will be a rise in new cancer cases and cancer deaths of up to 26 million and 17 million per year, respectively. Growing demand for chemotherapy over the past few years and a constrained supply of different anti-cancer drugs have ultimately driven up the price of various anticancerous drugs available in the clinical market. In order to address the widespread concerns about increasing cancer cases and the current costs of chemotherapy, researchers have explored extreme fungal diversity, which has significant source for the sustainable alternative production of anti-cancerous agents with higher yields, lower production costs, and less time consumption. In addition to extremophilic bacteria, which have been most extensively studied, extremophilic fungi are also ubiquitous but have received less attention in the past as a source of novel bioactive compounds. Along with the diversity of extremophilic fungi, endophytic fungi also hold out a new, hope for the eventual finding of cancer treatments. The major components of novel fungi exhibiting anti-cancerous effects are alkaloids, terpenoids, glycosides, saponin, peptides, steroids, phenols, quinones, and flavonoids. Therefore, the focus of the current review is on the reported anti-cancerous compounds produced by novel extremophilic and endophytic fungi, which offers a promising prospect for their bench-scale commercial production. The prospects and constraints for further clinical development along with the cost analysis of available commercial drugs in comparison to those derived from fungi also discussed.

Fungi are ubiquitous in all kinds of ecosystems with key ecological roles, while less than 10% of them have been described, of which, only about 1.2% are from marine habitats. Although the advance of next-generation sequencing has unquestionably improved our understanding of marine fungi, living cultures of marine fungi are important for studying the cell biology, ecological roles and evolution of microorganisms. In recent years, a number of efficient cultivation strategies, technologies, and devices have been newly developed, most of which were designed for prokaryotes and have been poorly applied to marine fungi. In this review, we give a brief discussion on the factors that may affect the isolation and cultivation of novel microorganisms, and review the omics-based innovative methods for the culturomics or targeted isolation. At last, we discuss the limitations of these approaches and their application potential on isolation and cultivation of marine fungi.

Fungal pathogens are responsible for 30% of emerging infectious diseases (EIDs) in plants. The risk of a pathogen emerging on a new host is strongly tied to its host breadth; however, the determinants of host range are still poorly understood. Here, we explore the factors that shape host breadth of plant pathogens within Botryosphaeriaceae, a fungal family associated with several devastating diseases in economically important crops. While most host plants are associated with just one or a few fungal species, some hosts appear to be susceptible to infection by multiple fungi. However, the variation in the number of fungal taxa recorded across hosts is not easily explained by heritable plant traits. Nevertheless, we reveal strong evolutionary conservatism in host breadth, with most fungi infecting closely related host plants, but with some notable exceptions that seem to have escaped phylogenetic constraints on host range. Recent anthropogenic movement of plants, including widespread planting of crops, has provided new opportunities for pathogen spillover. We suggest that constraints to pathogen distributions will likely be further disrupted by climate change, and we may see future emergence events in regions where hosts are present but current climate is unfavorable.

Rhizoctonia solani Kuhn (Basidiomycota, Cantharellales) is the main causal agent of rice sheath blight (RSB), which causes serious yield losses worldwide. The lack of rice varieties with resistance against RSB, which has a high sclerotia (dense masses of hyphal cells that function as compact survival structures in the fungal life cycle, enabling the fungus to endure adverse conditions and serve as reservoirs for subsequent growth and reproduction) survival rate, and the wide host range of R. solani, create basic challenges in the control of RSB. Overwinter sclerotium is the primary source of infection during the tillering stage of rice growth. In R. solani, a loose type of sclerotia is present. The sclerotia are primarily formed of compact masses of monilioid cells, but they may also be composed of undifferentiated hyphae. Three stages of sclerotial metamorphosis process are based on phenotypic changes, including the mycelium stage, the initial sclerotia stage (formation of monilioid cells), and sclerotia maturation. The metamorphosis of sclerotia involves the energy metabolism pathways and signal transduction pathways in the cell. In addition, there is evidence that the expression of genes encoding cell cycle activities may be important for sclerotia formation. During sclerotia metamorphosis, R. solani significantly expresses genes that encode antioxidants and respond to stimuli. The oxidative bursts begin in the initial sclerotia metamorphosis stage; at this time, reactive oxygen species (ROS) are mostly produced at the hyphal branches. In this sense, two classes of proteins related to glycosyltransferases B and the RNA recognition motif superfamily play a critical role in the sclerotial metamorphosis process in R. solani as scavengers of free radicals. The analysis of metabolic differences during sclerotia metamorphosis indicates that the NO metabolism may play an important role in sclerotia metamorphosis. Moreover, an increase in glycerophosphoethanolamines (PE) and glycerophosphoserines (PS) levels may indicate an advanced state of differentiation in mature R. solani sclerotia. Understanding the mechanisms involved in the sclerotial metamorphosis of R. solani can introduce new strategies for the management of RSB. In this review, we discuss the putative signaling and regulation mechanisms (such as quorum sensing) involved in the metamorphosis of sclerotia.