Determination of Mycotoxin Production of Fusarium Species in Genetically Modified Maize Varieties by Quantitative Flow Immunocytometry

Abstract

Levels of mycotoxins produced by Fusarium species in genetically modified (GM) and near-isogenic maize, were determined using multi-analyte, microbead-based flow immunocytometry with fluorescence detection, for the parallel quantitative determination of fumonisin B1, deoxynivalenol, zearalenone, T-2, ochratoxin A, and aflatoxin B1. Maize varieties included the genetic events MON 810 and DAS-59122-7, and their isogenic counterparts. Cobs were artificially infested by F. verticillioides and F. proliferatum conidia, and contained F. graminearum and F. sporotrichoides natural infestation. The production of fumonisin B1 and deoxynivalenol was substantially affected in GM maize lines: F. verticillioides, with the addition of F. graminearum and F. sporotrichoides, produced significantly lower levels of fumonisin B1 (~300 mg·kg^-1) in DAS-59122-7 than in its isogenic line (~580 mg·kg^-1), while F. proliferatum, in addition to F. graminearum and F. sporotrichoides, produced significantly higher levels of deoxynivalenol (~18 mg·kg^-1) in MON 810 than in its isogenic line (~5 mg·kg^-1). Fusarium verticillioides, with F. graminearum and F. sporotrichoides, produced lower amounts of deoxynivalenol and zearalenone than F. proliferatum, with F. graminearum and F. sporotrichoides. T-2 toxin production remained unchanged when considering the maize variety. The results demonstrate the utility of the Fungi-Plex™ quantitative flow immunocytometry method, applied for the high throughput parallel determination of the target mycotoxins.

Keywords: DAS-59122-7; MON 810; T-2; aflatoxin B1; deoxynivalenol; flow cytometry; fumonisin B1; immunoanalysis; maize; ochratoxin A; zearalenone.

Figure 1

Histogram of median fluorescence intensities (MFIs) detected in the Fungi-Plex™ multiplex flow cytometric determination for negative controls (white columns) and positive controls (black columns), as well as for the typical values of maize, of genetic events DAS 59122-7 (light grey columns) and MON 810 (dark grey columns) for mycotoxins fumonisin B1 (FB1), deoxynivalenol (DON), zearalenone (ZEA), T-2 toxin (T-2), ochratoxin A (OTA), and aflatoxin B1 (AB1).

Figure 2

Fumonisin B1 (FB1) content (mg·kg⁻¹) in maize ear cobs of GM and non-GM maize varieties infested by Fusarium species (F. proliferatum—artificial infestation, F. graminearum and F. sporotrichoides—natural background infestation and F. verticillioides—artificial infestation, F. graminearum and F. sporotrichoides—natural background infestation). Different alphabetical letters (a, b, ab) indicate statistical differences, p = 0.5.

Figure 3

Deoxynivalenol (DON) content (mg·kg⁻¹) in maize ear cob sample cobs of GM and non-GM maize varieties infested by Fusarium species (F. proliferatum—artificial infestation, F. graminearum and F. sporotrichoides—natural background infestation and F. verticillioides—artificial infestation, F. graminearum and F. sporotrichoides—natural background infestation). Different alphabetical letters (a, ab, bc) indicate statistical differences, p = 0.5.

Figure 4

Zearalenone (ZEA) content (μg·kg⁻¹) in maize ear cobs of GM and non-GM maize varieties infested by Fusarium species (F. proliferatum—artificial infestation, F. graminearum and F. sporotrichoides—natural background infestation and F. verticillioides—artificial infestation, F. graminearum and F. sporotrichoides—natural background infestation). Different alphabetical letters (a, b, ab) indicate statistical differences, p = 0.5.

Figure 5

T-2 toxin content (μg·kg⁻¹) in maize ear cobs of GM and non-GM maize varieties infested by Fusarium species (F. proliferatum—artificial infestation, F. graminearum and F. sporotrichoides—natural background infestation and F. verticillioides—artificial infestation, F. graminearum and F. sporotrichoides—natural background infestation).