Mitigation of Copper Stress in Maize by Inoculation with Paenibacillus polymyxa and Bacillus circulans

Abstract

Copper (Cu) is a micronutrient that assumes a principal role in plant growth and development. However, its excess concentration in soil is imperiling crop productivity. Inoculation with different bacterial strains in cereals could modify growth traits, photosynthetic effectiveness, and generation of strong antioxidant defense systems to make them more tolerant of Cu stress. Therefore, a pot study was designed to test plant growth-promoting rhizobacteria (PGPR) including Paenibacillus polymyxa and Bacillus circulans to Cu exposed maize (Zea mays L.) plants. Increasing Cu (100 to 500 µM of CuSO4) concentration decreased growth traits, photosynthetic pigments, soluble sugars, phosphorous (P) and potassium (K) contents, and the activity of catalase (CAT) but increased proline and malondialdehyde (MDA) content, the activity of peroxidase (POD) and Cu ions at root and shoot level. Moreover, the bacterial treatment also modulated the antioxidant capability in stress-free plants. Nevertheless, inoculation with P. polymyxa and B. circulans alleviated Cu-induced growth, photosynthetic pigments and mineral nutrient (P and K) on one hand and regulating the pools of osmolytes and antioxidant enzymes, whilst simultaneously reducing MDA and Cu root and shoot contents. These improved activities of antioxidant enzymes and the regulation of osmolytes content elicited by the blend of bacterial inoculation would have retained the ability of maize plants to confer resilience to Cu stress. This study further affirms that the application of two specific bacterial strains to maize plants proved very effective to ameliorate the Cu toxicity.

Copper, cadmium and nickel pollution inhibit growth and promote ascorbate catabolism in cell cultures of Arabidopsis thaliana and Zea mays

“…We estimated the metal concentrations that led to almost 100% growth inhibition, and then examined various effects of these and 4-fold higher concentrations. Similar findings were reported by (Abdel Latef et al 2020), where increasing Cu 2+ (100 to 500 µM) concentration reduced growth traits and photosynthetic pigments in maize plants.…”

Seed priming with methyl jasmonate mitigates copper and cadmium toxicity by modifying biochemical attributes and antioxidants in Cajanus cajan

“…Our observations exposed that both Cu and Cd significantly enhanced proline accumulation during all the treatments, whilst AL-201 seedlings tended to build up the maximum proline contents at each Cu concentration. Same results were obtained by Noreen et al (2018) , and Abdel Latef et al (2020) who showed that plants grown under Cu stress increase proline content. Proline contributes as an osmoprotectant for the detoxification of ROS and protects the membrane ( Ghosh et al, 2021 ).…”

Physiological Responses of Salinized Fenugreek (Trigonellafoenum-graecum L.) Plants to Foliar Application of Salicylic Acid

“…Abiotic stresses have been documented as the chief threat to agricultural efficiency all over the world. Anthropogenic activities in the developmental era have intensified the degradation of the agricultural system and its productivity due to the foremost abiotic stresses, such as extreme temperatures, salinity, drought, nutrients (deficiency and excess), metals/metalloids, and UV radiation [ 1 , 2 , 3 , 4 ], which can potentially influence almost all plant metabolic processes and which may negatively affect 70% of crops’ yields [ 5 ]. One of these abiotic stresses is salinity, which threatens the agricultural system and affects all physiological processes, from seed germination to plant development, leading to reduced growth and yield [ 6 , 7 , 8 ].…”