Wild rice (O. latifolia) from natural ecosystems in the Pantanal region of Brazil: host to Fusarium incarnatum-equiseti species complex and highly contaminated by zearalenone

We assessed the mycobiota diversity and mycotoxin levels present in wild rice (Oryza latifolia) from the Pantanal region of Brazil; fundamental aspects of which are severely understudied as an edible plant from a natural ecosystem. We found a variety of fungal species contaminating the rice samples;...

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Published inbioRxiv
Main Authors Tralamazza, Sabina M, Piacentini, Karim, Savi, Geovana D, Lorena Carnielli- Queiroz, Fontes, Livia C, Martins, Camila S, Correa, Benedito, Rocha, Liliana O
Format Paper
LanguageEnglish
Published Cold Spring Harbor Cold Spring Harbor Laboratory Press 07.07.2020
Subjects
Contamination
Deoxynivalenol
Fusarium
Fusarium incarnatum
Oryza latifolia
Phylogeny
Rice
Species
Zearalenone
Brazil
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Summary:We assessed the mycobiota diversity and mycotoxin levels present in wild rice (Oryza latifolia) from the Pantanal region of Brazil; fundamental aspects of which are severely understudied as an edible plant from a natural ecosystem. We found a variety of fungal species contaminating the rice samples; the most frequent genera being Fusarium, Nigrospora and Cladosporium (35.9%, 26.1% and 15%, respectively). Within the Fusarium genus, the wild rice samples were mostly contaminated by the Fusarium incarnatum-equiseti species complex (FIESC) (80%) along with Fusarium fujikuroi species complex (20%). Phylogenetic analysis supported multiple FIESC species and gave strong support to the presence of two previously uncharacterized lineages within the complex (LN1 and LN2). Deoxynivalenol (DON) and zearalenone (ZEA) chemical analysis showed that most of the isolates were DON/ZEA producers and some were defined as high ZEA producers, displaying abundant ZEA levels over DON (over 19 times more). Suggesting that ZEA likely has a key adaptive role for FIESC in wild rice (O. latifolia). Mycotoxin determination in the rice samples revealed high frequency of ZEA, and 85% of rice samples had levels >100 ppb; the recommended limit set by regulatory agencies. DON was only detected in 5.2% of the samples. Our data shows that FIESC species are the main source of ZEA contamination in wild rice and the excessive levels of ZEA found in the rice samples raises considerable safety concerns regarding wild rice consumption by humans and animals. Competing Interest Statement The authors have declared no competing interest.
DOI:10.1101/2020.07.06.190306