Mycotoxins in Vegetating Corn Plants from an Experimental Monoculture

This paper reports on studies that were conducted to characterize mycotoxin contamination of vege-tating corn (Zea mays L.) plants in the periods of leaf formation and tassel emergence. The early maturing hybrids Krasnodarskii 194 MV, Ladozhskii 175 MV, and Competence®, which are resistant to fungal diseases, were grown during the spring–summer period in the Moscow Oblast on a plot with sod-podzolic soil and with NPK 16:16:16 fertilizer application. For mycotoxicological analysis, the above-ground plant parts were sampled on a weekly basis starting from the third leaf stage (18 days after sowing). Seedling, leaf, and stem samples (in the total number of 172) were dried, homogenized, and extracted with a mixture of aceto-nitrile and water in the v : v ratio of 84 : 16 using 10 mL of mixture per 1 g of sample. Mycotoxin content was determined by indirect competitive ELISA in the extracts after diluting them 10-fold with phosphate-buffered saline, pH 7.5. T-2 toxin, deoxynivalenol, diacetoxyscirpenol, roridin A, sterigmatocystin, and PR-toxin were absent. Corn seedlings and leaves contained cyclopiazonic acid (CPA), emodin (EMO), mycophenolic acid (MPA), alternariol (AOL), ergot alkaloids (EA), and aflatoxin B₁ (AB₁), while a number of samples contained zearalenone (ZEN), ochratoxin A (OA), and citrinin (CIT) in concentrations ranging from 16 to 35 μg/kg. Group B fumonisins were found only in early seedlings. Stems were constantly contaminated with MPA, while EA and CIT were absent. Detection of AOL and EA remained stable in shoots and leaves of all hybrids during the change of development phases, as well as the average contents of CPA (about 100 μg/kg), AOL (from 17 to 27 μg/kg), EMO (35–58 μg/kg), MPA (28–41 μg/kg), EA (6–18 μg/kg), and AB₁ (2 μg/kg). In the stems of plants in the seventh–ninth leaf and tassel emerging phases, variation in CPA, EMO, AOL, AB₁, and OA detection was observed depending on the genotype.