Fusarium (family Nectriaceae) is a species-rich fungal
genus that poses a dual threat to agriculture because many species
cause destructive crop diseases and/or contaminate infected crops
with toxic secondary metabolites (mycotoxins) that are health
hazards to humans and other animals. Some Fusarium
mycotoxins are frequent contaminants of dried distillers’
grains, a coproduct of grain-based ethanol production used as a
protein-rich livestock feed. In addition, some species of
Fusarium are pathogens of energy crops such as corn and
sugar cane. Some species can also exist as endophytes in plants,
including some bioenergy crops.
DNA-based phylogenetic analyses have resolved Fusarium
into 23 multi-species lineages, or species complexes. Fusarium
sulawesiense is a member of the Fusarium
incarnatum-equiseti species complex, which is comprised of at
least 36 phylogenetically distinct species that resolve into two
distinct clades, the Incarnatum clade and the Equiseti clade.
Fusarium sulawesiense groups within the
Incarnatum clade. During its evolutionary diversification,
Fusarium has undergone multiple chromosomal fusions. As a
result, members of early diverging species complexes tend to have
more chromosomes (15 – 20) than later diverging complexes (4
– 7). Although chromosome number in F. sulawesiense
has not been determined, other members of the F.
incarnatum-equiseti species complex that have been examined
have 9 chromosomes. Collectively, members of the complex occur in
soil and on diverse crops, are geographically wide-spread, and
produce trichothecenes, one of the mycotoxin groups of most concern
to agriculture. However, members of the complex typically cause
less severe crop disease and trichothecene contamination than
members of the closely related F. sambucinum species
complex. Analysis of the trichothecene biosynthetic gene cluster in
F. sulawesiense revealed how the cluster has grown by
translocation of genes into the cluster from other loci.
Fusarium sulawesiense NRRL 66472 was isolated from the
grass (Konza sp.) growing in a native tallgrass prairie at
the Konza Prairie Biological Station in the U.S. state of
Kansas.
References:
Geiser DM, Al-Hatmi A, Aoki et al. 2021. Phylogenomic analysis of a 55.1 kb 19-gene dataset resolves a monophyletic Fusarium that includes the Fusarium solani Species Complex. Phytopathology 111: 1064-1079.
Xia JW, Sandoval-Denis M, Crous PW, et al. 2019. Numbers to names - restyling the Fusarium incarnatum-equiseti species complex. Persoonia 43:186-221.
