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Many species in the Fusarium fujikuroi Species Complex (FFSC) have an affinity for grass species, with whom they live in an endophytic association or cause disease. We recovered isolates of Fusarium from agriculturally important grasses in Africa and Brazil, and characterized them with morphological markers, mating type, and Amplified Fragment Length Polymorphisms (AFLPs). We also conducted multi-locus phylogenetic analyses based on partial DNA sequences of translation elongation factor-1α (TEF1), β-tubulin (TUB), and the second largest subunit of RNA polymerase (RPB2) gene regions. Sexual cross fertility was used to test the biological species concept and the sexual stage of F. madaense is described. A novel species within the FFSC, Fusarium mirum, that is different from the other known species in the complex, was formally described. Fusarium mirum, F. madaense, and Fusarium andiyazi are a tightly intertwined species trio that are morphologically identical, but phylogenetically distinguishable, and amongst whom interspecific genetic exchange may still occur. These three species are so close that they cannot be reliably distinguished if only sequences of the TEF1 gene are used. In pathogenicity tests, all tested isolates of F. madaense from sugarcane, sorghum, maize, millet and Brachiaria could induce stalk rot in sorghum, maize and millet, and pokkah boeng in sugarcane. This study increases our understanding of the diversity of species within the FFSC that cause disease in tropical grasses or act as endophytes, and their geographic distributions. The genetically close relationship between F. mirum, F. madaense, and F. andiyazi provides an opportunity to study and identify factors underlying their limited inter-specific cross-fertility and sympatric speciation., Competing Interests: Declaration of competing interest None., (Copyright © 2021 British Mycological Society. All rights reserved.)

Background: The fungal pathogen Fusarium oxysporum f.sp. pisi (Fop) causes Fusarium wilt in peas. There are four races globally: 1, 2, 5 and 6 and all of these races are present in Australia. Molecular infection mechanisms have been studied in a few other F. oxysporum formae speciales; however, there has been no transcriptomic Fop-pea pathosystem study., Results: A transcriptomic study was carried out to understand the molecular pathogenicity differences between the races. Transcriptome analysis at 20 days post-inoculation revealed differences in the differentially expressed genes (DEGs) in the Fop races potentially involved in fungal pathogenicity variations. Most of the DEGs in all the races were engaged in transportation, metabolism, oxidation-reduction, translation, biosynthetic processes, signal transduction, proteolysis, among others. Race 5 expressed the most virulence-associated genes. Most genes encoding for plant cell wall degrading enzymes, CAZymes and effector-like proteins were expressed in race 2. Race 6 expressed the least number of genes at this time point., Conclusion: Fop races deploy various factors and complex strategies to mitigate host defences to facilitate colonisation. This investigation provides an overview of the putative pathogenicity genes in different Fop races during the necrotrophic stage of infection. These genes need to be functionally characterised to confirm their pathogenicity/virulence roles and the race-specific genes can be further explored for molecular characterisation., (© 2021. The Author(s).)

The genetic diversity of pathogenic members of the Fusarium oxysporum species complex (FOSC) has been intensively studied worldwide, yet strains occurring in native soils with low anthropogenic disturbance remain poorly understood. This study focused on 355 F. oxysporum isolates from soils with low anthropogenic activity obtained from the grassland biome of South Africa. Analysis of the translation elongation factor 1-alpha ( tef-1α ) gene revealed high levels of sequence type diversity within the soil population in comparison with the global dataset. Phylogenetic relationships of the South African isolates revealed that four nested within FOSC clade 1. This is the first report of members of the basal clade recovered from ecosystems with low anthropogenic disturbance from Sub-Saharan Africa. The remaining strains nested within clades 2 to 5. This study contributes significantly to our understanding of the distribution of the FOSC in natural systems as we show that FOSC populations in the South African grassland biome are genetically diverse. This fills in our knowledge gap because previous studies reported only on the occurrence and diversity of the FOSC isolated from plant debris in South Africa. This is the first comprehensive survey of fusaria from grassland soils with low anthropogenic disturbance in South Africa.

Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora , with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium , and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium , as it remains the best scientific, nomenclatural, and practical taxonomic option available.

This article is to alert medical mycologists and infectious disease specialists of recent name changes of medically important species of the filamentous mold Fusarium Fusarium species can cause localized and life-threating infections in humans. Of the 70 Fusarium species that have been reported to cause infections, close to one-third are members of the Fusarium solani species complex (FSSC), and they collectively account for approximately two-thirds of all reported Fusarium infections. Many of these species were recently given scientific names for the first time by a research group in the Netherlands, but they were misplaced in the genus Neocosmospora In this paper, we present genetic arguments that strongly support inclusion of the FSSC in Fusarium There are potentially serious consequences associated with using the name Neocosmospora for Fusarium species because clinicians need to be aware that fusaria are broadly resistant to the spectrum of antifungals that are currently available.

Fusarium solani f. sp. cucurbitae (syn. Neocosmosporum cucurbitae ) is one of the most devastating soilborne pathogens affecting the production of cucurbits worldwide. Since its first detection in Almería Province in Spain in the spring of 2007, it has become one of the main soilborne pathogens affecting zucchini production. It has also been reported on melon, watermelon, and squash rootstocks in Spain, representing a high risk of dissemination in the area. The objectives of this study were to investigate the incidence and distribution of this disease in southeastern Spain and characterize isolates collected over 5 years. These strains were characterized on the basis of greenhouse aggressiveness assays on a range of cucurbit hosts, morphological characteristics, and elongation factor 1-α and RNA polymerase II second largest subunit phylogenies. All pathogenic isolates were highly aggressive on zucchini plants, causing a high mortality rate a few weeks after inoculation. The rest of the cucurbit hosts showed differential susceptibility to the pathogen, with cucumber being the least susceptible. Plants belonging to other families remained asymptomatic. Morphological characterization revealed the formation of verticilate monophialides and chlamydospores forming long chains, characteristics not described for this forma specialis. Phylogenetic studies of both the individual loci and combined datasets revealed that all pathogenic isolates clustered together with strong monophyletic support, nested within clade 3 in the F. solani species complex.

Background: The Fusarium oxysporum species complex (FOSC) is a ubiquitous group of fungal species readily isolated from agroecosystem and natural ecosystem soils which includes important plant and human pathogens. Genetic relatedness within the complex has been studied by sequencing either the genes or the barcoding gene regions within those genes. Phylogenetic analyses have demonstrated a great deal of diversity which is reflected in the differing number of clades identified: three, five and eight. Genetic limitation within the species in the complex has been studied through Genealogical Concordance Phylogenetic Species Recognition (GCPSR) analyses with varying number of phylogenetic 'species' identified ranging from two to 21. Such differing views have continued to confuse users of these taxonomies., Results: The phylogenetic relationships between Australian F. oxysporum isolates from both natural and agricultural ecosystems were determined using three datasets: whole genome, nuclear genes, and mitochondrial genome sequences. The phylogenies were concordant except for three isolates. There were three concordant clades from all the phylogenies suggesting similar evolutionary history for mitochondrial genome and nuclear genes for the isolates in these three clades. Applying a multispecies coalescent (MSC) model on the eight single copy nuclear protein coding genes from the nuclear gene dataset concluded that the three concordant clades correspond to three phylogenetic species within the FOSC. There was 100% posterior probability support for the formation of three species within the FOSC. This is the first report of using the MSC model to estimate species within the F. oxysporum species complex. The findings from this study were compared with previously published phylogenetics and species delimitation studies., Conclusion: Phylogenetic analyses using three different gene datasets from Australian F. oxysporum isolates have all supported the formation of three major clades which delineated into three species. Species 2 (Clade 3) may be called F. oxysporum as it contains the neotype for F. oxysporum.

The fungal genus Fusarium is one of the most important groups of plant-pathogenic fungi and affects a huge diversity of crops in all climatic zones across the globe. In addition, it is also a human pathogen and produces several extremely important mycotoxins in food products that have deleterious effects on livestock and humans. These fungi have been plagued over the past century by different perspectives of what constitutes the genus Fusarium and how many species occur within the genus. Currently, there are conflicting views on the generic boundaries and what defines a species that impact disease diagnosis, management, and biosecurity legislation. An approach to defining and identifying Fusarium that places the needs of the community of users (especially, in this case, phytopathologists) to the forefront is presented in this review.

Fusarium goolgardi, isolated from the grass tree Xanthorrhoea glauca in natural ecosystems of Australia, is closely related to fusaria that produce a subgroup of trichothecene (type A) mycotoxins that lack a carbonyl group at carbon atom 8 (C-8). Mass spectrometric analysis revealed that F. goolgardi isolates produce type A trichothecenes, but exhibited one of two chemotypes. Some isolates (50%) produced multiple type A trichothecenes, including 4,15-diacetoxyscirpenol (DAS), neosolaniol (NEO), 8-acetylneosolaniol (Ac-NEO) and T-2 toxin (DAS-NEO-T2 chemotype). Other isolates (50%) produced only DAS (DAS chemotype). In the phylogenies inferred from DNA sequences of genes encoding the RNA polymerase II largest (RPB1) and second largest (RPB2) subunits as well as the trichothecene biosynthetic genes (TRI), F. goolgardi isolates were resolved as a monophyletic clade, distinct from other type A trichothecene-producing species. However, the relationships of F. goolgardi to the other species varied depending on whether phylogenies were inferred from RPB1 and RPB2, the 12-gene TRI cluster, the two-gene TRI1-TRI16 locus, or the single-gene TRI101 locus. Phylogenies based on different TRI loci resolved isolates with different chemotypes into distinct clades, even though only the TRI1-TRI16 locus is responsible for structural variation at C-8. Sequence analysis indicated that TRI1 and TRI16 are functional in F. goolgardi isolates with the DAS-NEO-T2 chemotype, but non-functional in isolates with DAS chemotype due to the presence of premature stop codons caused by a point mutation.

Fusarium oxysporum is an important plant and human pathogenic ascomycetous group, with near ubiquity in agricultural and non-cultivated ecosystems. Phylogenetic evidence suggests that F. oxysporum is a complex of multiple morphologically cryptic species. Species boundaries and limits of genetic exchange within this complex are poorly defined, largely due to the absence of a sexual state and the paucity of morphological characters. This study determined species boundaries within the F. oxysporum species complex using Genealogical Concordance Phylogenetic Species Recognition (GCPSR) with eight protein coding loci. GCPSR criteria were used firstly to identify independent evolutionary lineages (IEL), which were subsequently collapsed into phylogenetic species. Seventeen IELs were initially identified resulting in the recognition of two phylogenetic species. Further evidence supporting this delineation is discussed., (Copyright © 2014 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

The Fusarium oxysporum species complex (FOSC) is a ubiquitous ascomycetous group that includes both pathogenic and non-pathogenic strains, the former being responsible for disease in over 100 cultivated plant species. Previous phylogenetic studies have uncovered at least four major clades within the FOSC, with Clade 1 hypothesised as being ancestral. However, the origin of these clades and pathogenic strains is poorly understood. Due to an emphasis on agricultural isolates in previous studies, the underlying diversity of this species complex in non-cultivated soils is largely unknown. To address this imbalance an extensive survey of isolates associated with native vegetation geographically isolated from cultivation throughout the Australian continent was conducted. A multi-gene phylogenetic analysis of the translation elongation factor (EF-1α) and the mitochondrial small subunit (mtSSU) rDNA loci did not recover any novel clades. However, the Australian isolates had high levels of intra-Clade diversity based on EF-1α sequence type (ST) comparison with a global dataset. The ST diversity was not equally distributed across the four clades, with the majority of novel STs recovered from Clade 1. Implications on the origin of the FOSC are discussed., (Copyright © 2011 British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

Numerous pathogenic Fusarium species have well-characterized sexual cycles, whereas others, including the crown rot fungus F. pseudograminearum, do not. We conducted studies to elucidate the potential frequency and nature of sexual reproduction in field populations of F. pseudograminearum and developed tester strains for controlled crossings under laboratory conditions. Studies on the role of sexual recombination in the life cycle of F. pseudograminearum revealed apparently low levels of female fertility under controlled laboratory conditions, despite the observation of naturally occurring perithecia of the teleomorph Gibberella coronicola at two field sites. Female fertility levels were experimentally increased to produce female fertile tester strains using four generations of single and multi-stage crossings between sibling progeny derived from fertile laboratory crosses between field isolates collected in northeastern Australia. The production of reliable female fertile tester strains has potential applications for the construction of biological species boundaries, elucidation of the physical characters of reproductive structures, and the generation of genetic diversity via sexual recombination in F. pseudograminearum. As such, the current study is a significant advancement in the understanding of G. coronicola, allowing for future characterisation of various biological, epidemiological, and genetic parameters.

Crown rot, caused by the fungus Fusarium pseudograminearum (teleomorph Gibberella coronicola) is a major disease of wheat in the Australian grain belt. However, there is little information available on the population structure of this pathogen. We measured genetic diversity as assessed with amplified fragment length polymorphism (AFLP) analysis within and between populations of F. pseudograminearum from northeastern, south central, and southwestern regions of the Australian grain belt. Amongst the 217 isolates, 176 haplotypes were identified and grouped into two main clusters. One cluster contained isolates from populations in northeastern Australia, and the other cluster contained isolates from populations in south central and southwestern Australia. The southern populations were distinguished from the northeastern populations by higher levels of population differentiation (Gst) between them and genetic identity amongst the regional populations. We hypothesize that the F. pseudograminearum populations from northeastern and southern Australia are independent, which could result from different founding events or from geographic isolation and the accumulation of genetic differences due to genetic drift and/or selection.

We described the teleomorph of Fusarium sacchari as Gibberella sacchari, sp. nov. This species can be separated from other species of Gibberella on the basis of the longer, narrower ascospores found in G. sacchari and by sexual cross fertility. Female-fertile mating type tester strains were developed that can be used for making sexual crosses with this heterothallic fungus under laboratory conditions. The anamorph, Fusarium sacchari, was neotypified.