EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
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SESSION 2: SECONDARY METABOLITES – BIOCHEMISTRY,<br />
BIOSYNTHESIS, FEED AND FOOD SAFETY<br />
P18 - Effect <strong>of</strong> cry 1Ab toxins on FUM gene cluster<br />
expression and on fumonisin production by Fusarium<br />
verticillioides<br />
L. O. Rocha 1 , G. M. Reis 1 , V. M. Barroso 1 , L. J. Andrade 1 , B. Corrêa 1<br />
1 University <strong>of</strong> São Paulo, Biomedical Sciences Institute, Avenue Pr<strong>of</strong>essor Lineu Prestes, 1374, São<br />
Paulo-Brazil<br />
E-mail: lilianarocha@usp.br<br />
F. verticillioides is most commonly associated with maize worldwide and produces<br />
high levels <strong>of</strong> fumonisins, one <strong>of</strong> the most important mycotoxins. Previous studies<br />
have demonstrated that cry 1Ab protein from Bacillus thuringiensis sbsp. kurstaki<br />
could be suitable for Fusarium toxins management due to the control <strong>of</strong> crop<br />
insect injuries. The aim <strong>of</strong> this study was to assess the impact <strong>of</strong> cry 1Ab protein<br />
expressed in the 30F35YG (YieldGard) corn hybrid on FUM gene expression and<br />
on fumonisin production by F. verticillioides ICB 13BA (GU 989110/NCBI<br />
accession number). We also evaluated the influence <strong>of</strong> B. thuringiensis sbsp.<br />
kurstaki spores and cry 1Ab crystals on the F. verticillioides growth. In order to<br />
eliminate the original microbiota, Bt corn samples and its respective non-Bt<br />
isogenic were previously irradiated with 20 kGy. Plates were inoculated with 5 x<br />
10 8 F. verticillioides spores/mL and incubated at 25 o C and relative humidity <strong>of</strong><br />
97.5%. After 10, 20 and 30 days, samples were analysed regarding FB1<br />
contamination and expression <strong>of</strong> 14 FUM genes. The statistical analyses were<br />
performed using the s<strong>of</strong>twares R 2.9, Gamlss package and SAS 9.1. An initial<br />
fungal inoculum <strong>of</strong> 5 x 10 8 spores/mL was cultured with 10 μg/mL <strong>of</strong> bacterial<br />
spores and crystals. F. verticillioides biomass was estimated by dry weight <strong>of</strong><br />
mycelia during 1, 3 and 5 days . The results showed reduced fumonisin B1<br />
contamination on 30F35 YG in comparison to its isogenic non-Bt corn during the<br />
periods <strong>of</strong> the analyses (p= 0.0095, Weibull distribution). There was no correlation<br />
between FUM gene cluster and fumonisin production according to Pearson’s<br />
correlation test (except for FUM19, p