Fabaceae response to dimethoate insecticide application: investigation of germination, seedling growth and tolerance mechanisms

Context Pesticides are widely used to control crop diseases and pest infestations. However, their excessive and unregulated use poses considerable environmental challenges. Aims To evaluate the effects of dimethoate on the germination and seedling growth of Vicia faba, V. sativa, Trigonella foenum-greacum, and Medicago truncatula. Methods Physiological and biochemical changes were studied under different dimethoate concentrations (0, 0.4, 0.8 and 1.2 g L−1). Key results Results showed that dimethoate significantly inhibited growth in all species, especially at 1.2 g L−1 of dimethoate. This negative effect was accompanied by reactive oxygen species (ROS) accumulation and lipid peroxidation (malondialdehyde, MDA) induction. Different behaviors were shown among the studied species. M. truncatula was the most sensitive, exhibiting toxicity even at the lowest concentration. In contrast, T. foenum-graecum showed remarkable tolerance, maintaining better growth at the highest dose compared to the two others species. The results of statistical analyses, including Pearson’s correlation and principal component analysis, support the use of fenugreek as a tolerant cover crop. Conclusion T. foenum-graecum’s tolerance was associated with a lower reduction in total soluble sugars (25%) and a significant increase in antioxidant enzyme activity, particularly superoxide dismutase (70%). These adaptations are likely to help T. foenum-graecum cope with oxidative stress and maintain growth despite pesticide exposure. Implications The results offer valuable decision support for using T. foenum-graecum as a cover crop in the field when using dimethoate in pest control at grapevine and citrus fields.