Fusarium: more than a node or a foot-shaped basal cell

Abstract

Recent publications have argued that there are potentially serious consequences for researchers in recognising distinct genera in the terminal fusarioid clade of the family Nectriaceae . Thus, an alternate hypothesis, namely a very broad concept of the genus Fusarium was proposed. In doing so, however, a significant body of data that supports distinct genera in Nectriaceae based on morphology, biology, and phylogeny is disregarded. A DNA phylogeny based on 19 orthologous protein-coding genes was presented to support a very broad concept of Fusarium at the F1 node in Nectriaceae . Here, we demonstrate that re-analyses of this dataset show that all 19 genes support the F3 node that represents Fusarium sensu stricto as defined by F. sambucinum (sexual morph synonym Gibberella pulicaris ). The backbone of the phylogeny is resolved by the concatenated alignment, but only six of the 19 genes fully support the F1 node, representing the broad circumscription of Fusarium. Furthermore, a re-analysis of the concatenated dataset revealed alternate topologies in different phylogenetic algorithms, highlighting the deep divergence and unresolved placement of various Nectriaceae lineages proposed as members of Fusarium . Species of Fusarium s. str. are characterised by Gibberella sexual morphs, asexual morphs with thin- or thick-walled macroconidia that have variously shaped apical and basal cells, and trichothecene mycotoxin production, which separates them from other fusarioid genera. Here we show that the Wollenweber concept of Fusarium presently accounts for 20 segregate genera with clear-cut synapomorphic traits, and that fusarioid macroconidia represent a character that has been gained or lost multiple times throughout Nectriaceae . Thus, the very broad circumscription of Fusarium is blurry and without apparent synapomorphies, and does not include all genera with fusarium-like macroconidia, which are spread throughout Nectriaceae ( e.g. , Cosmosporella , Macroconia , Microcera ). In this study four new genera are introduced, along with 18 new species and 16 new combinations. These names convey information about relationships, morphology, and ecological preference that would otherwise be lost in a broader definition of Fusarium . To assist users to correctly identify fusarioid genera and species, we introduce a new online identification database, Fusarioid-ID, accessible at www.fusarium.org . The database comprises partial sequences from multiple genes commonly used to identify fusarioid taxa ( ...

Fusarium nirenbergiae (Fusarium oxysporum Species Complex) Causing the Wilting of Passion Fruit in Italy

“…To the best of our knowledge, this paper represents the first report of F. nirembergiae, belonging to the FOSC complex, as a causal agent of Fusarium wilt of passion fruit. In this regard, both the morphological characterization and the analysis of the ITS, EF1-α and RBP2 sequences allowed us to correctly allocate a representative number of detected strains within the F. nirenbergiae group, being distinctly separated by the other taxa, as recently shown by Lombard et al [20] and Crous et al [21]. Based on the present findings, F. nirenbergiae was strongly grouped in a separated subclade of FOSC, phylogenetically close to F. curvatum.…”

“…Comprehensively, the increasing trend of tropical plantations in Italy leads us to focus more on fungal diseases that could represent limiting factors for future production. According to presented data combined with recent findings [20,21], it cannot be excluded that some past reports of F. oxysporum f. sp. passiflorae could confirm that F. nirembergiae is a causal agent of Fusarium wilt.…”

Antifungal Activity and Biocontrol Mechanism of Fusicolla violacea J-1 against Soft Rot in Kiwifruit Caused by Alternaria alternata

“…The Fusicolla violacea (Ascomycota, Hypocreales, Nectriaceae) is synonymous with Fusarium merismoides var. Violaceum [23]. In general, most Fusarium sp.…”

Draft Genome Sequence of a New Fusarium Isolate Belonging to Fusarium tricinctum Species Complex Collected From Hazelnut in Central Italy

“…In fact, polyphasic taxonomic approach, instead, gives a more robust classification of the species under examination, from the bacterial level to the more complicated Fusarium family ( Das et al, 2014 ; Crous et al, 2021 ). In contrast, the still limited availability of WGSs in the databases may restrict the comparison range.…”

“…A second ML phylogenetic tree was built using raxmlHPC on the core genome SNPs identified during a pan genome analysis performed using Panseq, with the run mode set to pan, the fragment size at 500 nucleotides, the percentage of identity at 90%, and the core genome threshold to 28 genomes, in order to find out the sequences in common among all the strains ( Laing et al, 2010 ). To better discriminate between isolates belonging to the F. tricinctum species complex (FTSC), a phylogenetic ML tree was built on the alignment of the concatenated sequence of the DNA-directed RNA polymerase II largest (RPB1) and second largest subunit (RPB2) nucleotide sequence, as previously applied by O’Donnell et al (2013); Ponts et al (2020) , and Crous et al (2021) . MUSCLE and RAxML were used as previously described, and the 63 Fusarium isolates used in this analysis are reported in Supplementary Table 1 .…”