Fusarium incarnatum-equiseti species complex associated with Brazilian rice: Phylogeny, morphology and toxigenic potential

• Published in: International journal of food microbiology Vol. 306; p. 108267
• Main Authors: Avila, Caroline F., Moreira, Gláucia M., Nicolli, Camila P., Gomes, Larissa B., Abreu, Lucas M., Pfenning, Ludwig H., Haidukowski, Miriam, Moretti, Antonio, Logrieco, Antonio, Del Ponte, Emerson M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 02-10-2019; Elsevier BV
• Subjects: Dominant species; Fusarium; Fusarium incarnatum; Fusarium semitectum; Gene sequencing; Morphology; Mycotoxins; Oryza; Oryza sativa; Phylogenetics; Phylogeny; Rice; Southern Hemisphere; Trichothecenes; Zearalenone; Brazil; Oryza sativa; Zearalenone; Trichothecenes; Fusarium semitectum
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2019.108267

Fusarium incarnatum-equiseti species complex (FIESC) is commonly detected in Brazilian rice, but knowledge of the species limits and their toxigenic potential is lacking. Seventy strains morphologically identified as FIESC-like, isolated from the major rice-growing regions of Brazil, were subjected to sequencing of EF-1α gene. Among them, 18 strains were selected and analyzed for their RPB2 gene sequences. Nine phylogenetic species were identified, among which eight matched the previously reported FIESC 4 (F. lacertarum), 6, 16, 17 (F. pernambucanum), 20 (F. caatingaense), 24, 26 and 29. One new phylogenetic species was identified, and named FIESC 38. Five strains formed new singleton lineages. The most dominant species were FIESC 26 (22/70 strains) and FIESC 38 (21/70), the newly identified species. The incarnatum morphotype was dominant (10 phylogenetic species) over the equiseti (4 species). Among 46 strains selected to represent all species, only 16 strains produced detectable levels of mycotoxins in vitro. FIESC 26 produced ZEA and FIESC 38 produced both ZEA and DON. ZEA was produced by nine isolates of three other species, among which few isolates produced trichothecenes: DON (5/46), NIV (3/46), 4-ANIV (2/46), 15-ADON (1/46) and 3-ADON (1/46). The T-2 and HT-2 mycotoxins were not detected. Our results contribute novel information on species limits and mycotoxin production within cereal-infecting FIESC in the southern hemisphere and provide baseline data for further exploring morphological differences among the species.
•Nine species within the Fusarium incarnatum-equiseti species complex were found in Brazilian rice.•A new species, FIESC 38 was found to be second in prevalence, following FIESC 26.•Sixteen out of 46 strains produced mycotoxins in vitro.•FIESC 26 produced zearalenone (ZEA) and FIESC 38 produced deoxynivalenol (DON) and ZEA.•The incarnatum morphotype was dominant compared to equiseti morphotype.