Plant seeds are often infected by fungi, either in the field or during storage. These fungi can cause plant diseases, and many can produce mycotoxins that are dangerous for humans and animals. Fungal infections are thus a serious threat, causing enormous agricultural and financial losses worldwide. Cold gas plasma (CGP) technology has advanced greatly in recent decades. It offers practical solutions in many areas, including microbial decontamination from the surface of seeds. In this work, we investigated the applicability of low-pressure oxygen CGP, obtained with a radio frequency generator, for fungal decontamination from the surface of common and Tartary buckwheat seeds. We were interested in: (i) how CGP affects: the frequency and diversity of naturally occurring fungi on buckwheat seeds, (ii) how the method of treatment with CGP (glow or afterglow) affects the fungal community of buckwheat seeds, (iii) whether the sensitivity to CGP is species-specific and (iv) how CGP treatment affects buckwheat seed germination. We found that as the treatment time with CGP increases, the infection rate, frequency and diversity of naturally occurring fungi on buckwheat seeds gradually decreases, whereby treatment in glow CGP mode is more effective than in afterglow. We demonstrated that the sensitivity of fungi to CGP treatment is species-specific. Fungi from the genus Fusarium, which have microconidia, proved to be the most resistant to CGP treatment. We also found that longer treatments with CGP had a very negative effect on the germination of buckwheat seeds, probably due to the etching of the outer layers of the seed and partly due to the thermal effects. This kind of treatment of buckwheat seeds with CGP would be suitable for treatment for food and feedstock but not for further sowing.
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