Protection of Phaseolus vulgaris L. from Herbicide 2,4-D Results from Exposing Seeds to Humic Acid

Bean ( Phaseolus vulgaris L.) is the world’s most significant and basic legume crop for people diet. The intense use of the herbicides such as 2,4-dichlorophenoxyacetic acid (2,4-D) in bean planting areas can lead to a number of toxicological issues. To prevent such damages, humic acid (HA) may be used to increase plant development by improving nutrient uptake and to play a protecting role against stresses by regulating the antioxidative system of plants. Hence, the aim of the current study was to investigate the impacts of HA on DNA damage levels and DNA methylation changes against 2,4-D stress in the bean. HA treatments were applied to bean seedlings, and the 2,4-D was sprayed on the three-to-four-leaf stages at 2,4-D dose. We used random amplified polymorphic DNA (RAPD) for determining the changes in DNA damage and coupled restriction enzyme digestion-random amplification (CRED-RA) for DNA methylation changes. According to results, while the genomic template stability (GTS) decreased in the 2,4-D (5, 10, 20 and 40 mg/L) treatments, this value increased comparatively in the 2,4-D applied together with HA (0, 2, 4, 6, 8 and 10 mg/L) treatments. In CRED-RA patterns, as the HA doses were increased, there was generally a decrease in polymorphism rates (DNA methylation changes) caused by 2,4-D applications. Our results have clearly demonstrated that HA has a curative effect up to a level against genotoxic and DNA methylation changes caused by 2,4-D.