Cadmium (Cd) detoxification and activation of plant defense enzymes in wheat (Triticum aestivum) through the use of endophytic Bacillus thuringiensis and Salix alba root powder

Abstract

Cadmium (Cd) is a toxic heavy metal and a threat to the ecosystem therefore the current investigation was designed to use endophytic bacteria from the Salix alba roots and to investigate its plant growth promoting and Cd detoxification ability with and without Salix alba root powder. In a complete randomized design (CRD), the cadmium sulfate was applied at the rate of 20 mg/kg and 40 mg/kg soil. The Bacillus thuringiensis (Accession # MW979616) was identified from Salix alba roots. The combination of Bacillus thuringiensis inoculated seeds +0.5gm root powder showed significant increase in wheat shoot dry weight, root fresh weight, catalase, and ascorbate peroxidases by 457%, 223%, 105% and 74%, respectively. The application of Bacillus thuringiensis with Salix alba root powder boosted the plant growth and defense at higher concentrations of Cd. In another treatment with Bacillus thuringiensis inoculated seeds + CdSO4 40 mg/kg + 0.5gm root powder significantly increased the shoot fresh weight, root fresh weight, root dry weight, proline, sugar, superoxide dismutase, and peroxidase by 456%, 650%, 115%, 91%, 80%, 350%, and 250%, respectively with 80% reduction in plant Cd accumulation and increased bacterial population. Bacillus thuringiensis and Salix alba root powder can be useful for plant growth, Cd toxicity mitigation, accelerating bacterial activity in Cd-contaminated soil and uplifting the plant defense under heavy metal stress.