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United States Department of Agriculture

Agricultural Research Service

Research Project: COMPARATIVE GENOMIC SYSTEMS FOR MOLECULAR DETECTION AND CONTROL OF TOXIGENIC FUSARIUM

Location: Bacterial Foodborne Pathogens & Mycology Research Unit

Title: Species diversity, pathogenicity and toxigenicity of Fusarium associated with rice seeds in Brazil

Authors
item Gomes, L -
item Buttner, V C -
item Furlong, E -
item Ward, Todd
item Del Ponte, E -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 25, 2013
Publication Date: October 25, 2013
Citation: Gomes, L.B., Buttner, V.Z., Furlong, E.B., Ward, T.J., Del Ponte, E.M. 2013. Species diversity, pathogenicity and toxigenicity of Fusarium associated with rice seeds in Brazil [abstract]. Brazilian Phytopathological Meeting.

Technical Abstract: Fusarium is commonly reported in association with rice seeds in Brazil, but knowledge on the species diversity and toxigenic potential is lacking. Such information is critical because maximum limits for Fusarium mycotoxins were set for Brazilian rice in 2011. Ninety-eight rice seed samples from the production regions of Rio Grande do Sul and 12 samples from Goiás state, collected during the 2012 harvest, were analyzed using a standard blotter test. For each sample, isolations were made from all colonies resembling the Fusarium graminearum species complex (FGSC), together with a maximum of five isolates resembling other Fusarium. Species and trichothecene genotypes of putative FGSC isolates were determined using a multilocus genotype (MLGT) assay and species identifications for other Fusarium were determined by sequencing the TEF1-alpha gene. Trichothecene production was determined for 15 FGSC isolates grown on rice. Fusarium spp. were found in all samples but FGSC isolates were found in 44% of the samples with a 5% mean incidence. Based on morphology, 101 FGSC-like and 44 other Fusarium were selected for further molecular identification. Based on MLGT analyses, the nine FGSC isolates analyzed to date were identified as F. asiaticum (Fasi) with a nivalenol genotype. In a greenhouse pathogenicity study, Fasi isolates from rice were highly pathogenic on rice and weakly pathogenic on wheat, whereas Fasi isolates from wheat were highly pathogenic on wheat and weakly pathogenic on rice. This result is suggestive of differences in host preference among Fasi isolates. Further results will be presented and discussed.

Last Modified: 10/23/2014
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