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SESSION 5: DISEASE CONTROL AND FORECASTING MODELS
Biological strategy applied to maize preharvest
agroecosystem in Argentina to prevent fumonisin
contamination
M. Etcheverry 1, 2 , A. Nesci 1, 2 , P. Pereira 1,3 , M. Sartori 1,3
1 Laboratorio de Ecología Microbiana. Departamento de Microbiología e Inmunología, Facultad de
Ciencias Exactas Físico Químicas y Naturales. Universidad Nacional de Río Cuarto, Ruta Nacional N°
36 Km 601, Río Cuarto (5800), Córdoba, Argentina - 2 Members of the Research Career, Consejo
Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina - 3 Doctoral Fellow of
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
E-mail: metcheverry@exa.unrc.edu.ar
Biocontrol activity of Bacillusamyloliquefaciens, Microbacteriumoleovorans
against F. verticillioides colonization of field-grown maize and fumonisin
production in grains at harvest were investigated. Seed treatment during presowing
and spraying of maize ears during flowering were evaluated as inoculation
methods of selected agents. The impact of inoculation on F.verticillioides count in
maize roots and in grains at harvest level as well as on fumonisin content of the
grains was evaluated in field trials conducted under natural fungal infection and
also alter inoculation with different strains of F. verticillioides. Treatments effect on
maize growth and the diversity and activity of bacterial and fungal populatiotions
naturally associated with maize roots was also assessed. Additionaly, F
verticillioides count and fumonisin B1 content were significantly reduced in grains
of plants grown from B. amyloliquefaciens treated seeds. Studies on inoculum
production, physiological improvement and formulation process were assessed.
Cells of B. amyloliquefaciens grown in liquid media amended with glycerol
showed better tolerance at low aw and high survival under heat stress.
Furthermore, both biocontrol agents showed accumulation of betaine and ectoine
in cells of B. amyloliquefaciens and M. oleovorans can improve the tolerance of
both bacteria to water potential modifications and desiccation in the process of
freeze drying and production of formulated, which could improve bacterial growth
and survival under conditions of low water availability and also increase the
potential for biological control of F. verticillioides in field. MSB medium was select
for biomass production due to the high growth and survival after freeze-drying
process. Formulated were development of fresh cells and freeze-dried of
B.amyloliquefaciens and M. oleovorans. The efficacy of four stickers as seed
coating was studied, In field trial of maize, the pre-sowing application of freezedried
formulated B. amyloliquefaciens and M. oleovorans and paraffinic oil as
sticker, caused a decrease of fumonisin B1 in grain harvest treatments including
pre-sowing inoculation of F. verticillioides.
Keywords: biocontrol, Bacillus amyloliquefaciens, Microbacterium oleovorans,
Fumonisin B1
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