Mechanisms underlying the phytotoxicity and genotoxicity of aluminum and their alleviation strategies: A review. (September 2021)

• Record Type: Journal Article
• Authors: Chandra, Jipsi; Keshavkant, S.
• Is Part Of: Chemosphere. Volume 278(2021)
• Publication Date: 2021-09
• Subjects: Alleviation -- Nanoparticles -- Oxidative stress -- Metal toxicity -- Stress and metabolism -- Tolerance mechanisms; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.130384
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Aluminum (Al) is considered as a potential limiting factor for plant growth in acidic environment. At lower concentration, Al promotes plant growth by facilitating the phosphorous availability, while, at higher concentration, it causes rhizotoxicity by inhibiting the nutrient transportation system. Cellular membrane is identified as the first site of Al toxicity, which is consequent to Al-induced reactive oxygen species prompted lipid catabolism. Among all the soluble forms, the trivalent cationic form (Al 3+ ) of Al is most toxic. Though, the ability to ascribe Al-tolerance is very complex, exclusion is an extensively established process contributing to Al 3+ detoxification. Alteration in pH at root apex/rhizosphere, exudation of chelating agents, cell wall immobilization, and Al efflux have been recognized as probable methods for exclusion of Al, which is highly dependent on concentrations of organic acids, and plant species. Additionally, exogenous applications of boron, silicon, calcium, etc ., in Al-stressed plant species can form a conjugate with it, thereby reducing its bioavailability/toxicity. Moreover, nanoparticles (NPs) are emerging tools in agricultural sector, which are found to be relatively more effective in mitigation of metal stress compared to their bulk materials. This review exhibits the fundamental approaches of Al phytotoxicity and endows with a comprehensive knowledge of the cellular and metabolic processes underlying toxic impacts along with ameliorative efficiencies of various potential agents including NPs. Additionally, it also elucidates the molecular mechanisms, future research prospects and challenges in effective alleviation mechanisms for enhancing plant Al-tolerance, to improve the growth and yields of susceptible-species on acidic soil. Graphical abstract: Image 1 Highlights: Trivalent cationic form of Al is potential toxicants to plant in acidic environment. Al disturbs cell metabolism and redox homeostasis, leading to oxidative stress. Plants have various inherent defence strategies to circumvent Al toxicity. Modulation in gene expressions under Al stress is a key mechanism of its tolerance. Exogenously added elements and nanoparticles also act as toxicity ameliorant.