Nationwide survey reveals high diversity of Fusarium species and related mycotoxins in Brazilian rice: 2014 and 2015 harvests

Abstract

Ninety three samples of rice were obtained from both research and commercial plots at eight rice-growing regions of Brazil. These were assessed for the presence of Fusarium species complex and 14 mycotoxins. A total of 352 Fusarium-like isolates were obtained from 85% of the samples and assigned to four species complexes (SC) based on morphological identification. F. incarnatum-equiseti was the most frequent (FIESC, 32.4%) followed by F. fujikuroi (FFSC, 26.1%), F. graminearum (FGSC, 24.7%) and F. chlamydosporum (FCSC, 16.8%). FGSC was limited geographically and dominant in the southern subtropical Brazil while the others occurred in all regions, particularly FIESC. The samples were individually contaminated with at least three and a maximum of eight mycotoxins. The most common were zearalenone (ZEA), beauvericin, and acetylated forms of deoxynivalenol (AcDON). In addition, enniatins, T-2, HT-2, DON, neosolaniol and moniliformin at lower frequency. The concentration levels were all below the Brazilian limits currently promugalted for DON (<750 ppb), and ZEA (<100 ppb). There was on sample with ZEA above the limit. Most mycotoxins toxins were found in both the husk and flour fractions, but AcDON tended to show higher concentration in the husk. Results of this survey extends the knowledge of the Fusarium complexes infecting rice and provides an update on the status of rice mycotoxin contamination at the country level, which can be considered generally safe. However, attention should be paid to the widespread contamination of beauvericin.