A Tool Derived from the Vicia faba Micronucleus Assay, to Assess Genotoxicity, Cytotoxicity or Biostimulation of Novel Compounds Used in Agriculture

The increased use of biostimulants in conventional agriculture and organic farming requires the implementation of rapid tests to determine their effectiveness in enhancing plant growth and protection against abiotic stresses. However, their innocuity to plant health has rarely been demonstrated. We used the Vicia faba Micronucleus Assay, as described by the standard AFNOR EN ISO 29200(2020-05) to reveal biostimulant, genotoxic and cytotoxic effects of four commercialized wood-based products by comparing mitotic indices and micronucleus frequencies with respect to the controls. Neither genotoxicity, as measured by micronucleus frequency (MN), nor cytotoxicity, assessed by Mitotic index counts, was observed. Additionally, one of these stimulants (BHS®) conferred protective effects against contaminants (maleic hydrazide or lead nitrate). We describe that plotting micronuclei frequency against mitotic indices allows discrimination between cytotoxic/genotoxic effects from growth levels. Vicia faba experiments were successfully transposed to other agronomical important crops such as corn and sunflower. This technique can be valuable to industrials, to assess growth, potential cytoxicity and genotoxicity effects of any new biostimulant or organic.