Describing novel Fusarium species
- Matthew Laurence
- Survey natural ecosystems for novel Fusarium species.
- Describe novel species through morphology and phylogenetic analyses.
- Use resulting sequence data to infer patterns of biogeography in Fusarium.
- Use resulting phylogenies to make predictions on toxin production and the origin of pathogenicity in the genus Fusarium.
Fusarium is one of the most agriculturally significant genera of fungi, because it includes many species that cause disease and mycotoxin contamination in crop plants. But where do Fusarium pathogens and mycotoxin producers come from? This ongoing research program explores natural ecosystems to answer questions relating to origin, diversity, mycotoxin production and biogeography in Fusarium.
A series of continental scale surveys of Fusarium in natural ecosystems of Australia have been conducted over the past 40 years, encompassing a wide range of bioclimatic regions, including tropical, arid, temperate and alpine bioregions. These surveys have resulted in the discovery of novel species including F. nygamai (Burgess and Trimboli, 1986), F. beomiforme (Nelson et al., 1987), F. lyarnte, F. werrikimbe (Walsh et al., 2010), F. gaditjirri (Phan et al., 2004), F. babinda (Summerell et al., 1995), F. aywerte, F. nurragi (Benyon et al., 2000), F. burgessii (Laurence et al., 2011), F. coicis, F. goolgardi, F. mundagurra, F. newnesense, F. tjaetaba and F. tjaynera (Laurence et al., 2015).
This work has provided insights into the biogeography of Fusarium with the novel Australian species having close relatives in Africa and supports the post Gondwanaland radiation of Fusarium in the late Miocene. Furthermore, the discovery that one of the novel species, F. goolgardi, is closely related to a group of species responsible for the contamination of cereal crops with the trichothecene mycotoxin has led to a collaboration with the USDA to investigate the evolution of mycotoxins in this group. In addition, the pathogenicity genes Secreted In Xylem (SIX) have been detected in many of the novel species. The presence of pathogenicity genes in natural ecosystems is providing valuable insights into the origin of pathogenicity in Fusarium. We are currently describing another seven Fusarium species due for publication in 2016.
These studies highlight the importance of mycogeographic surveys in natural ecosystems of minimal anthropogenic disturbance for providing base line information for rigorous studies on the phylogeny, taxonomy, phylogeography, pathology and ecology of Fusarium.