Identification and Complete Genome Sequence of an Alternavirus From Airborne Spores of the Phytopathogenic Fungus Fusarium Bullatum

A double-stranded RNA (dsRNA) mycovirus was isolated from airborne spores of Fusarium bullatum and was named Fusarium bullatum alternavirus 1 (FbAV1). Sequencing analysis and the rapid amplification of cDNA ends (RACE) of 5’ and 3’-end confirmed three segments: dsRNA1 (3546 nt), dsRNA2 (2511 nt) and dsRNA3 (2484 nt). BLASTN search of sequences showed that FbAV1 has 92-96% identity with Fusarium incarnatum Alternavirus 1 (FiAV1). Phylogenetic analysis of the RdRp amino acid sequences suggested that the dsRNA mycovirus in this study clustered with the newly proposed family “Alternaviridae”. This is the first report of FbAV1 mycovirus from airborne spores of a fungus F. bullatum.

Towards improved detection and identification of rust fungal pathogens in environmental samples using a metabarcoding approach

The dispersion of fungal inocula such as the airborne spores of rust fungi (Pucciniales) can be monitored by metabarcoding the internal transcribed spacer 2 (ITS2) of the rRNA gene in environmental DNAs. This is largely dependent upon a high-quality reference database (refDB) and primers with proper taxonomic coverage and specificity. For this study, a curated ITS2 reference database (named CR-ITS2-refDB) comprising representatives of the major cereal rust fungi and phylogenetically related species was compiled. Inter- and intra-specific variation analyses suggested that the ITS2 region had reasonable discriminating power for the majority of the Puccinia species or species complexes in the database. In silico evaluation of nine forward and seven reverse ITS2 primers, including three newly designed, revealed marked variation in DNA amplification efficiency for the rusts. The theoretical assessment of rust-enhanced (Rust2inv/ITS4var_H) and universal fungal (ITS9F/ITS4) ITS2 primer pairs was validated by profiling the airborne rust fungal communities from environmental samples using a metabarcoding approach. Species or subspecific level identification of the rusts was improved by using CR-ITS2-refDB, and the Automated Oligonucleotide Design Pipeline (AODP), which identified all mutations distinguishing highly conserved DNA markers amongst close relatives. A generic bioinformatics pipeline was developed, including all steps employed in this study from in silico evaluation of primers to accurate identification of short metabarcodes at the level of interest for defining phytopathogens. The results highlighted the importance of primer selection, refDBs that are resolved to reflect phylogenetic relationships, and the use of AODP for improving the reliability of metabarcoding in phytopathogen biosurveillance.

Mucormycosis: the black fungus maiming COVID-19 patients in India

The COVID-19 infection caused by the novel SARS-CoV-2 may be associated with a wide range of disease patterns, ranging from mild to life-threatening pneumonia. Mucormycosis is an emerging angioinvasive fungal infection caused by the ubiquitous filamentous fungi of the Mucorales order of the class of Zygomycetes. The prevalence of mucormycosis in India is about 80 times the prevalence in developed countries. Mucorales invade deep tissues via inhalation of airborne spores, percutaneous inoculation or ingestion. Rhino-orbito-cerebral form of mucormycosis is a relatively fatal infection and mortality rate rises to 50-85%. Extensive use of corticosteroids/monoclonal antibodies/broad-spectrum antibiotics may lead to the development/exacerbation of a preexisting fungal disease. Only amphotericin B and its lipid formulations and recently isavuconazole have been studied as first-line therapy for mucormycosis. On the contrary, posaconazole has been mainly studied as salvage therapy.

An Overview of the Epidemiology of Phakopsora pachyrhizi in the State of Mato Grosso, Brazil

This review seeks to expand the knowledge about the epidemiology of Asian sybean rust in the state of Mato Grosso and contribute to ensuring the economic sustainability of soybean crop. It is discussed the Phakopsora pachyrhizi potential of dispersal from Asia to South America and finally to Mato Grosso state. The origin of the Asian soybean rust inoculum within Mato Grosso is addressed by the survival in volunteer and soybean weed plants (Pitelli, 2015) in other crops such as cotton. Data on the adverse environmental effect on the soybean plants survival are shown mainly the water deficit from June to August. Reports on the effect air temperature and mainly solar radiation on the mortality of airborne spores during their anemophilous spread on sunny days are also discussed. This increase of knowledge aims to make the soybean-free period more efficient by the knowledge on the soybean plants survival and on the fungus viability in the month of August. Due to the proximity of soybean farms, during the soybean-free period, in other states (Tocantins, Goiás, Rondônia, etc.) and in other neighbor countries we discuss the likelihood that inoculum in the state may also originate in out-of-state crops during the Mato Grosso soybean-free period.

Disseminated coccidioidomycosis in a patient who is immunocompromised in the setting of immune reconstitution inflammatory syndrome

Coccidioidomycosis is a systemic fungal infection first described in 1892. More than 95% of annual cases occur in Arizona and California. It is an opportunistic infection (OI) transmitted via inhalation of airborne spores (arthroconidia) and rarely via percutaneous inoculation into a tissue or solid organ transplantation in patients who are immunocompromised and with HIV. With the advent of antiretroviral therapy (ART), the incidence of OIs has markedly reduced; however, OIs continue to occur, particularly in patients who present late for medical care or delay ART initiation. In rare cases, immunodeficient individuals may experience a paradoxical worsening or unmasking of OI symptoms, known as the immune reconstitution inflammatory syndrome (IRIS). We present a case of a 31-year-old man with disseminated coccidioidomycosis affecting the spleen, lymph nodes, lungs, bone marrow, and adrenals who developed IRIS after the initiation of ART.

Crumenulopsis sororia.

C. sororia is an apothecia-forming ascomycete (cup fungus) that causes cankers in the bark and wood of Pinus species in Europe. Its presence in North America is unlikely (Groves, 1969), but it is known to infect native and introduced species of Pinus. Once introduced, its small size, resemblance to related canker-causing species, and spread by airborne spores, would make control difficult.

Random Mutagenesis of Filamentous Fungi Strains for High-Yield Production of Secondary Metabolites: The Role of Polyamines

A filamentous fungus (also called molds or moldy fungus) is a taxonomically diverse organism from phylum Zygomycota and Ascomycota with filamentous hyphae and has the ability to produce airborne spores or conidia. Currently, more than 70,000 molds are known, and some of them contain unique and unusual biochemical pathways. A number of products from such pathways, especially, the secondary metabolite (SM) pathways are used as important pharmaceuticals, including antibiotics, statins, and immunodepresants. Under different conditions, the individual species can produce more than 100 SM. The strain improvement programs lead to high yielding in target SM and significant reduction of spin-off products. The main tool for the strain improvement of filamentous fungi is random mutagenesis and screening. The majority of industrial overproducing SM strains were developed with the help of such technique over the past 50–70 years; the yield of the target SM increased by 100- to 1000-fold or more. Moreover, most of the strains have reached their technological limit of improvement. A new round of mutagenesis has not increased overproduction. Recently, it was shown that that the addition of exogenous polyamines may increase the production of such improved strains of filamentous fungi. The possible molecular mechanism of this phenomenon and its biotechnological applications are discussed.

Stimulation of surfactant exocytosis in primary alveolar type II cells by A. fumigatus

Aspergillus fumigatus is an opportunistic fungal pathogen with small airborne spores (conidia) that may escape clearance by upper airways and directly impact the alveolar epithelium. Consequently, innate alveolar defense mechanisms are being activated, including professional phagocytosis by alveolar macrophages, recruitment of circulating neutrophils and probably enhanced secretion of pulmonary surfactant by the alveolar type II (AT II) cells. However, no data are available in support of the latter hypothesis. We therefore used a coculture model of GFP-Aspergillus conidia with primary rat AT II cells and studied fungal growth, cellular Ca2+ homeostasis, and pulmonary surfactant exocytosis by live cell video microscopy. We observed all stages of fungal development, including reversible attachment, binding and internalization of conidia as well as conidial swelling, formation of germ tubes and outgrowth of hyphae. In contrast to resting conidia, which did not provoke immediate cellular effects, metabolically active conidia, fungal cellular extracts (CE) and fungal culture filtrates (CF) prepared from swollen conidia caused a Ca2+-independent exocytosis. Ca2+ signals of greatly varying delays, durations and amplitudes were observed by applying CE or CF obtained from hyphae of A. fumigatus, suggesting compounds secreted by filamentous A. fumigatus that severely interfere with AT II cell Ca2+ homeostasis. The mechanisms underlying the stimulatory effects, with respect to exocytosis and Ca2+ signaling, are unclear and need to be identified.