Mycotoxicological analysis of the BMR-type sorghum-sudangrass hybrid during vegetation

High-yielding sorghum-sudangrass hybrids with reduced lignin content, obtained using the “brown-midrib gene 6” gene technology, are recommended and successfully used for silage, but their sanitary-relevant features are only beginning to be evaluated. This paper reports on contamination with microscopic fungi and mycotoxins of the plants of sorghumsudangrass hybrid of the ‘NutriTop Star’, which were collected from an experimental field (Russsian State Agrarian University – Moscow Timiryazev Agricultural Academy, Moscow region) during the period from tillering to the end of the stem elongation phase. The mycobiome was dominated by Alternaria fungi (68.8 %), with Fusarium (25.0 %) and Penicillium (12.5 %) taxa being less common, and Cladosporium and Aspergillus (6.3 %) being rare. The Alternaria isolates were predominantly A. tenuissima and in vitro biotests showed a high potential for the biosynthesis of alternariol. Enzyme immunoassay revealed the following in the leaves of plants collected in the "tillering" and "stem elongation" phases: alternariol (13–30 μg/kg), emodin (32–95 μg/kg), ochratoxin A (6–12 μg/kg) and mycophenolic acid in the stem elongation phase (19–64 μg/kg). The amounts of aflatoxin B1 (3–5 μg/kg) were close to the limit of detection, and the accumulation of cyclopiazonic acid and ergot alkaloids varied with the change of growth phases. In the stem parts of the plants, the detection of cyclopiazonic acid, ergot alkaloids, and emodin was rare. Analytes – T-2 toxin, deoxynivalenol, diacetoxyscirpenol, zearalenone, group B fumonisins, citrinin, sterigmatocystin, PR-toxin and roridin A were not detected. The information obtained is important for improving approaches to assessing the quality of sorghum feed.