Cultivar differences in the biochemical and physiological responses of common beans to aluminum stress

Authors: TÓTH, BRIGITTA - University Of Debrecen; MOLOI, MAKAOENA - University Of The Free State; SZOKE, LÓRÁNT - University Of Debrecen; DANTER, MÁTYÁS - Vmware, Inc; Grusak, Michael

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2021
Publication Date: 10/3/2021
Citation: Tóth, B., Moloi, M.J., Szoke, L., Danter, M., Grusak, M.A. 2021. Cultivar differences in the biochemical and physiological responses of common beans to aluminum stress. Plants. 10(10):2097. https://doi.org/10.3390/plants10102097.
DOI: https://doi.org/10.3390/plants10102097

Interpretive Summary: Soil conditions leading to high levels of available aluminum are detrimental to plant growth. Some cultivars of certain crop plants are more tolerant to this aluminum stress, but information is limited on tolerance differences between cultivars. To identify common bean cultivars that perform better when challenged with high levels of aluminum, we analyzed various root and shoot traits in 25 bean cultivars, when roots were treated with or without available aluminum ions. Studies were performed hydroponically in liquid media so that aluminum concentrations could be controlled. We measured weight and length of roots, weights of shoots, and several functional traits of roots related to stress tolerance. Two bean cultivars, Arapaho and AC Island, were found to be highly tolerant to the imposed aluminum stress. These two cultivars could serve as parents in breeding programs to develop new cultivars with enhanced tolerance to high levels of soil aluminum.

Technical Abstract: Soil conditions leading to high levels of available aluminum are detrimental to plant growth, but data are limited on genotypic differences in tolerance to aluminum stress in some crops. In this study, various biochemical and physiological parameters were examined in roots and shoots of 25 common bean (Phaseolus vulgaris L.) cultivars (Pinto market class) under aluminum (Al) treatment. Plants were grown hydroponically using a simplified nutrient solution with or without 20 µM AlCl3. Reactive oxygen species (ROS), activities of the antioxidant enzymes superoxide dismutase (SOD) and guaiacol peroxidase (POD), as well as malondialdehyde (MDA) concentration, an indicator of lipid peroxidation, were measured to establish the effects of Al treatment on the plants. In addition, growth parameters such as shoot and root dry weight, root to shoot ratio, root elongation, and root volume changes were also investigated. Cultivar effect was significant for all the measured parameters, except for shoot dry weight. Inhibition of the root and shoot dry weight for selected common bean cultivars shows that the response of common bean to Al stress is genotype-specific. Additionally, Al-induced root elongation inhibition and root volume changes varied among the cultivars. Most cultivars had significantly higher SOD activity (20 of 25 cultivars) and POD activity (12 cultivars) under AlCl3 treatment compared to the controls. Positive significant correlation was observed between MDA and ROS, showing that Al stress induced the accumulation of ROS along with an increase in lipid peroxidation. Based on the results of this study, Arapaho and AC Island cultivars could potentially be used in future production of common beans under Al stress. Therefore, these two cultivars could also be included in Al tolerance breeding programs.