Impact of Bacillus cereus SPB-10 on Growth Promotion of Wheat (Triticum aestivum L.) Under Arsenic-Contaminated Soil

Abstract

This study investigates the impact of bacteria on arsenic reduction in wheat plants, highlighting the potential of microbe-based eco-friendly strategies for plant growth. In the present study, bacterial isolate SPB-10 was survived at high concentration against both form of arsenic (As³⁺ and As⁵⁺). SPB-10 produced 5.2 g/L and 11.3 g/L of exo-polysaccharide at 20 ppm of As³⁺ and As⁵⁺, respectively, whereas qualitative examination revealed the highest siderophores ability. Other PGP attributes such as IAA production were recorded 52.12 mg/L and 95.82 mg/L, phosphate solubilization was 90.23 mg/L and 129 mg/L at 20 ppm of As³⁺ and As⁵⁺, respectively. Significant amount of CAT, APX, and Proline was also observed at 20 ppm of As³⁺ and As⁵⁺ in SPB-10. Isolate SPB-10 was molecularly identified as Bacillus cereus through 16S rRNA sequencing. After 42 days, wheat plants inoculated with SPB-10 had a 25% increase in shoot length and dry weight, and 26% rise in chlorophyll-a pigment under As⁵⁺ supplemented T4 treatment than control. Reducing sugar content was increased by 24% in T6-treated plants compared to control. Additionally, SPB-10 enhanced the content of essential nutrients (NPK), CAT, and APX in plant's-leaf under both As³⁺ and As⁵⁺ stressed conditions after 42 days. The study found that arsenic uptake in plant roots and shoots decreased in SPB-10-inoculated plants, with the maximum reduction observed in As⁵⁺ treated plants. Bio-concentration factor-BCF was reduced by 90.89% in SPB-10-inoculated treatment T4 after 42 days. This suggests that Bacillus cereus-SPB-10 may be beneficial for plant growth in arsenic-contaminated soil.