SURVEY AND AFLATOXIGENIC CHARACTERIZATION FOR ASPERGILLUS SECTION FLAVI FROM THREE MAIZE PRODUCTION REGIONS OF ARGENTINA

Abstract

Argentina is one of the main exporters of maize. Soil is the main source of inoculum for the species Aspergillus section Flavi determining grain colonization and the subsequent aflatoxin production. The objective of this study was to evaluate the Aspergillus section Flavi incidence in soil and corn kernels from different regions of Argentina and evaluate the sclerotial type and the aflatoxin B1 (AFB1) producing capacity. Maize kernels and maize soil samples were collected at harvest from the north of Argentina and from the center and south of the province of Córdoba. Analysis was performed by comparing the distribution of culturable fungal and Aspergillus section Flavi strains. The type of sclerotia and the production of aflatoxin B1 (AFB1) were evaluated. The Aspergillus section Flavi counts observed in soil samples from the southern region of Córdoba were similar than those observed in samples from the central region. Severity by Aspergillus section Flavi did not exceed 9% and 2.5% in southern and northern Córdoba. 75% of the strains from the northern region of Argentina produced L sclerotia while a 25% were not sclerotia producers and showed high levels of AFB1. The highest percentages of strains producing L sclerotia (95%) and the lowest number of S strains (5%) were isolated from the southern part of Córdoba. 61% of the strains from the central region produced L sclerotia while approximately 20% produced S sclerotia and the highest AFB1 levels. This study contributes to the knowledge of aflatoxigenic strains from three regions of Argentina and to the development of further aflatoxin control and prevention strategies.