Polyphasic approach used for distinguishing Fusarium temperatum from Fusarium subglutinans

Morphological, biological, and phylogenetic approaches were undertaken for the identification of pathogenic species F. temperatum in the Serbian population of F. subglutinans collected in the 1999-2010 period from Zea mays (3 root, 15 stalk, and 6 seed samples), Sorghum bicolor (two seed samples), Hordeum vulgare (one seed sample) and Taraxacum officinale (one seed sample). Based on interspecies mating compatibility analyses and the maximum parsimony analysis of EF-1α sequences, only two strains, originating from S. bicolor seed (MRIZP 0418 and MRIZP 0552), were identified as F. temperatum, while the remaining 26 single-spore strains were identified as F. subglutinans Group 2. In situ detached barley leaf assay and artificially stalk and ear inoculation of two maize hybrids demonstrated that both F. temperatum and F. subglutinans strains were medium and strong pathogens under laboratory and field conditions, respectively. These are the first data on the F. temperatum as seed-borne pathogens of sorghum, as well as pathogenicity of F. temperatum strains on maize

Genetic divergence and chemotype diversity in the fusarium head blight pathogen Fusarium poae

Fusarium head blight is a disease caused by a complex of Fusarium species. F. poae is omnipresent throughout Europe in spite of its low virulence. In this study, we assessed a geographically diverse collection of F. poae isolates for its genetic diversity using AFLP (Amplified Fragment Length Polymorphism). Furthermore, studying the mating type locus and chromosomal insertions, we identified hallmarks of both sexual recombination and clonal spread of successful genotypes in the population. Despite the large genetic variation found, all F. poae isolates possess the nivalenol chemotype based on Tri7 sequence analysis. Nevertheless, Tri gene clusters showed two layers of genetic variability. Firstly, the Tri1 locus was highly variable with mostly synonymous mutations and mutations in introns pointing to a strong purifying selection pressure. Secondly, in a subset of isolates, the main trichothecene gene cluster was invaded by a transposable element between Tri5 and Tri6. To investigate the impact of these variations on the phenotypic chemotype, mycotoxin production was assessed on artificial medium. Complex blends of type A and type B trichothecenes were produced but neither genetic variability in the Tri genes nor variability in the genome or geography accounted for the divergence in trichothecene production. In view of its complex chemotype, it will be of utmost interest to uncover the role of trichothecenes in virulence, spread and survival of F. poae

Phylogenomic analysis of a 55.1 kb 19-gene dataset resolves a monophyletic Fusarium that includes the Fusarium solani Species Complex

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 availabl

A European Database of Fusarium graminearum and F. culmorum Trichothecene Genotypes

. Fusarium species, particularly Fusarium graminearum and F culmorum, are the main cause of trichothecene type B contamination in cereals. Data on the distribution of Fusarium trichothecene genotypes in cereals in Europe are scattered in time and space. Furthermore, a common core set of related variables (sampling method, host cultivar, previous crop, etc.) that would allow more effective analysis of factors influencing the spatial and temporal population distribution, is lacking. Consequently, based on the available data, it is difficult to identify factors influencing chemotype distribution and spread at the European level. Here we describe the results of a collaborative integrated work which aims (1) to characterize the trichothecene genotypes of strains from three Fusarium species, collected over the period 2000-2013 and (2) to enhance the standardization of epidemiological data collection. Information on host plant, country of origin, sampling location, year of sampling and previous crop of 1147 F graminearurn, 479 F culmorum, and 3 F cortaderiae strains obtained from 17 European countries was compiled and a map of trichothecene type B genotype distribution was plotted for each species. All information on the strains was collected in a freely accessible and updatable database (www.catalogueeu.luxmcc.lu), which will serve as a starting point for epidemiological analysis of potential spatial and temporal trichothecene genotype shifts in Europe. The analysis of the currently available European dataset showed that in F. grarninearum, the predominant genotype was 15-acetyldeoxynivalenol (15-ADON) (82.9%), followed by 3-acetyldeoxynivalenol (3-ADON) (13.6%), and nivalenol (NIV) (3.5%). In F culmorum, the prevalent genotype was 3-ADON (59.9%), while the NIV genotype accounted for the remaining 40.1%. Both, geographical and temporal patterns of trichothecene genotypes distribution were identified.</p

A European Database of Fusarium graminearum and F-culmorum Trichothecene Genotypes

Fusarium species, particularly Fusarium graminearum and F culmorum, are the main cause of trichothecene type B contamination in cereals. Data on the distribution of Fusarium trichothecene genotypes in cereals in Europe are scattered in time and space. Furthermore, a common core set of related variables (sampling method, host cultivar, previous crop, etc.) that would allow more effective analysis of factors influencing the spatial and temporal population distribution, is lacking. Consequently, based on the available data, it is difficult to identify factors influencing chemotype distribution and spread at the European level. Here we describe the results of a collaborative integrated work which aims (1) to characterize the trichothecene genotypes of strains from three Fusarium species, collected over the period 2000-2013 and (2) to enhance the standardization of epidemiological data collection. Information on host plant, country of origin, sampling location, year of sampling and previous crop of 1147 F graminearurn, 479 F culmorum, and 3 F cortaderiae strains obtained from 17 European countries was compiled and a map of trichothecene type B genotype distribution was plotted for each species. All information on the strains was collected in a freely accessible and updatable database (www.catalogueeu.luxmcc.lu), which will serve as a starting point for epidemiological analysis of potential spatial and temporal trichothecene genotype shifts in Europe. The analysis of the currently available European dataset showed that in F. grarninearum, the predominant genotype was 15-acetyldeoxynivalenol (15-ADON) (82.9%), followed by 3-acetyldeoxynivalenol (3-ADON) (13.6%), and nivalenol (NIV) (3.5%). In F culmorum, the prevalent genotype was 3-ADON (59.9%), while the NIV genotype accounted for the remaining 40.1%. Both, geographical and temporal patterns of trichothecene genotypes distribution were identified

From taxonomy to field monitoring, a polyphasic approach applied to Fusarium temperatum sp. nov.

Numerous Fusarium species are important mycotoxin-producing pathogens affecting maize worldwide. Crop quality is often reduced by ear and stalk rot diseases, and mycotoxin contaminations can pose a serious problem for both human and animal health. As several Fusarium species are integrated into legislation, commercial trade agreements, or quarantine regulations, field monitoring and accurate identification of the Fusarium species involved in diseases have been and remain important tasks, allowing relevant preventive or curative measures. In the present work, we contributed to an example of integrated description, study and management of a new Fusarium species, from its taxonomical status to its potential field impacts. We used a robust polyphasic approach based on amplified fragment length polymorphism, on phylogenetic studies using maximum parsimony and Bayesian inference, on biological characterization using diagnostic sexual crosses, and on morphological recognition to formally describe F. temperatum sp. nov. According to a three-year epidemiological survey, to pathogenicity tests in greenhouse conditions and to in vitro toxin production studies, F. temperatum clearly contributes to the risk of disease development and mycotoxin accumulation in maize fields. Therefore, a rapid, specific and sensitive real-time PCR protocol was developed for detection and quantification of four mycotoxigenic Fusarium species including F. temperatum, in monoplex and multiplex conditions. Such an integrated description study might contribute to taxonomical clarification between other potential distinct species that are included in individual morphospecies or species complexes, resulting in better focused and species-targeted efforts for field monitoring and mycotoxin management.(AGRO 3) -- UCL, 201