Antioxidant responses against aluminum metal stress in Geitlerinema amphibium

Abstract

In the current scenario, aluminum is one of the major metals that cause environmental pollution and has ill impact on organism health. As around 40% of bauxite deposits of India are available in Odisha, aluminum toxicity in the soil has impacted as an intimidating problem of Odisha. This aluminum metal pollution is regarded as a primary factor for limiting crop productivity in acidic soils of tropic and subtropic countries. The presence of a high degree of aluminum metal in the soil leads to loss of beneficial microflora, i.e., nitrogen-fixing cyanobacteria that play a key role in soil fertility. Hence, this investigation was performed on a filamentous non-heterocystous cyanobacterium Geitlerinema amphibium isolated from the aluminum-polluted sites, i.e., NALCO, Ash pond, Angul to uncover the defense mechanism of the strain exhibited under such stress. The strain was treated with different doses of AlCl3 (0–100 µM), and we observed redox imbalance leading to oxidative stress. Post-treatment of AlCl3, a remarkable decline in growth was evident with possible modifications in pigments associated with the phenomena. Further to combat against the stress under the redox environment, the organism activated antioxidant enzymes CAT, APX, GR, GPX, and SOD which were measured to identify the key responses involved in it. All the stress responsive enzymes were analyzed to demonstrate the interlink between the induction of stress and their detoxification through cellular response. The outcome of the work explored the multifaceted role of oxidative upset caused by AlCl3 pollutants and the cellular antioxidative strategies deployed by G. amphibium to nullify them.