A polyphasic approach for characterization of a collection of cereal isolates of the Fusarium incarnatum-equiseti species complex

Abstract

DNA-based phylogenetic analyses have resolved the fungal genus Fusarium into multiple species complexes. The F. incarnatum-equiseti species complex (FIESC) includes fusaria associated with several diseases of agriculturally important crops, including cereals. Although members of FIESC are considered to be only moderately aggressive, they are able to produce a diversity of mycotoxins, including trichothecenes, which can accumulate to harmful levels in cereals. High levels of cryptic speciation have been detected within the FIESC. As a result, it is often necessary to use approaches other than morphological characterization to distinguish species. In the current study, we used a polyphasic approach to characterize a collection of 69 FIESC isolates recovered from cereals in Europe, Turkey, and North America. In a species phylogeny inferred from nucleotide sequences from four housekeeping genes, 65 of the isolates were resolved within the Equiseti clade of the FIESC, and four isolates were resolved within the Incarnatum clade. Seven isolates were resolved as a genealogically exclusive lineage, designated here as FIESC 31. Phylogenies based on nucleotide sequences of trichothecene biosynthetic genes and MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry) were largely concordant with phylogeny inferred from the housekeeping gene. Finally, Liquid Chromatography (Time-Of-Flight) Mass Spectrometry [LC-(TOF-)MS(/MS)] revealed variability in mycotoxin production profiles among the different phylogenetic species investigated in this study.

Fusarium incarnatum-equiseti complex from China

“…Members of the FIESC group are ubiquitous, mainly saprobes, pathogens or secondary invaders of environmental habitats, plants, humans and animals (Desjardins 2006, O'Donnell et al 2009, Sandoval-Denis et al 2018a. Furthermore, some of them pose threats to public health that can cause superficial infections such as keratitis on skin and nails, and deeply invasive and hematogenously disseminated infections with high mortality (e.g., FIESC phylogenetic species 15, 25;O'Donnell et al 2009O'Donnell et al , 2012 and some produce mycotoxins (e.g., trichothecenes) on cereals (e.g., FIESC phylogenetic species 5, 31; Villani et al 2016).…”

Invisible but consequential: root endophytic fungi have variable effects on belowground plant–insect interactions

“…, Villani et al. ), we were unable to measure any effects of these two endophytes on root feeding of R. majalis larvae, further highlighting the context dependency of plant–endophyte–insect interactions.…”

New endemic Fusarium species hitch-hiking with pathogenic Fusarium strains causing Panama disease in small-holder banana plots in Indonesia

“…The highest diversity of isolates obtained in this study belonged to the FIESC. This species complex displays a remarkable abundance of phylogenetic species diversity which include both animal and plant associated pathogens, plant endophytes and soil inhabitants (Leslie & Summerell 2006, O'Donnell et al 2009, Villani et al 2016. Many of the FIESC have been isolated from various plants displaying disease symptoms, but their pathogenicity was never established (Leslie & Summerell 2006).…”