The Fusarium incarnatum-equiseti species complex (FIESC) includes mycotoxigenic species associated with several diseases of cereals and other crops. Although these species are considered as moderately aggressive, they are able to produce multiple mycotoxins, including beauvericin, zearalenone, equisetin, fusarochromanone, butenolide as well as the trichothecenes DAS, MAS, FUS-X, DON, NIV, and scirpentriol. Thus, members of FIESC are potential contributors to mycotoxin contamination of cereals. FIESC includes high levels of cryptic speciation as most species within the complex cannot be distinguished from one another by morphological traits. However, a previous DNA-based analysis of human isolates from the US resolved FIESC into 28 phylogenetically distinct lineages, or multilocus sequence types (MLSTs). Here, we investigated the phylogenetic diversity of 69 FIESC isolates recovered from cereals grown in Europe and North America by comparison to the previously described MLSTs. In phylogenetic analyses of the four housekeeping genes EF-1a, RPB2, CaM and TUB2, 4 isolates were resolved within the F. incarnatum clade of FIESC, and all other isolates were resolved within the F. equiseti clade. However, 8 isolates were resolved into a lineage that is distinct from all previously described MLSTs, suggesting that they constitute novel MLST within FIESC. Phylogenomic analysis of 12 isolates, representing one novel and 11 previously described and MLSTs, inferred a phylogeny that was consistent with but more highly resolved than the phylogeny inferred from fourgenes. Comparative analysis of the genome sequences revealed variation in distribution of mycotoxin biosynthetic gene clusters. For example, the trichothecene cluster is present in all nine genomes, whereas the fusarin and zearalenone clusters are present in only three and four genomes respectively. These data indicate that different FIESC MLSTs vary in their genetic potential to produce and contaminate cereal crops with different mycotoxins.
GENETIC VARIATION IN ISOLATES OF THE FUSARIUM INCARNATUMEQUISETI SPECIES COMPLEX RECOVERED FROM CEREALS
Villani A;Logrieco A;Moretti A;Susca A
2015
Abstract
The Fusarium incarnatum-equiseti species complex (FIESC) includes mycotoxigenic species associated with several diseases of cereals and other crops. Although these species are considered as moderately aggressive, they are able to produce multiple mycotoxins, including beauvericin, zearalenone, equisetin, fusarochromanone, butenolide as well as the trichothecenes DAS, MAS, FUS-X, DON, NIV, and scirpentriol. Thus, members of FIESC are potential contributors to mycotoxin contamination of cereals. FIESC includes high levels of cryptic speciation as most species within the complex cannot be distinguished from one another by morphological traits. However, a previous DNA-based analysis of human isolates from the US resolved FIESC into 28 phylogenetically distinct lineages, or multilocus sequence types (MLSTs). Here, we investigated the phylogenetic diversity of 69 FIESC isolates recovered from cereals grown in Europe and North America by comparison to the previously described MLSTs. In phylogenetic analyses of the four housekeeping genes EF-1a, RPB2, CaM and TUB2, 4 isolates were resolved within the F. incarnatum clade of FIESC, and all other isolates were resolved within the F. equiseti clade. However, 8 isolates were resolved into a lineage that is distinct from all previously described MLSTs, suggesting that they constitute novel MLST within FIESC. Phylogenomic analysis of 12 isolates, representing one novel and 11 previously described and MLSTs, inferred a phylogeny that was consistent with but more highly resolved than the phylogeny inferred from fourgenes. Comparative analysis of the genome sequences revealed variation in distribution of mycotoxin biosynthetic gene clusters. For example, the trichothecene cluster is present in all nine genomes, whereas the fusarin and zearalenone clusters are present in only three and four genomes respectively. These data indicate that different FIESC MLSTs vary in their genetic potential to produce and contaminate cereal crops with different mycotoxins.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
