Ameliorative effect of indole-3-acetic acid- and siderophore-producing Leclercia adecarboxylata MO1 on cucumber plants under zinc stress

This study investigated the plant growth-promoting effects of Leclercia adecarboxylata MO1 for Zn stress mitigation and plant growth improvement in Zn-contaminated soil. Results demonstrated that L. adecarboxylata MO1 produced siderophores that could solubilize Zn and silicate, had a tolerance to elevated levels of Zn supplementation (2 and 5 mM) in growth mediums, and produced significant amounts of indole-3-acetic acid (IAA). It was also found to promote plant growth under both control conditions and Zn toxicity (2 and 5 mM). Furthermore, L. adecarboxylata MO1 positively regulated physiochemical attributes by decreasing hydrogen peroxide (H₂O₂) and Zn uptake in both roots and shoots, improving antioxidant systems (e.g. catalase (CAT), peroxidase (POD), polyphenol peroxidase (PPO), superoxide anion (SOA), lipid peroxidation (MDA), and glutathione (GSH)), and reducing stress-responsive endogenous abscisic acid (ABA) and salicylic acid (SA) in plants grown under Zn toxicity of 2 and 5 mM, compared with non-inoculated plants.