Work

Combination of selenium and molybdenum mitigates chromium toxicity in Nicotiana tabacum L. by regulating soil C, N, and P cycling

Year: 2026

Type: article

Abstract: Chromium (Cr), a heavy metal, has significant toxic effects on plant growth and development. The exogenous application of selenium (Se) and molybdenum (Mo) has been widely demonstrated to alleviate its toxicity and enhance plant adaptability under heavy metal stress. However, the role of soil microbiota and related metabolism in the mitigation of Cr toxicity by Se and Mo is not well understood. Therefore, this study was conducted to explore the impact of combined Se and Mo application on the microecological properties of Cr-contaminated soils. The findings showed that co-application of Se and Mo enhanced tobacco plant dry weight by 85.9% and decreased Cr concentration in roots by 59.6%. The combined application of Se–Mo enhanced the expression levels of amino acids, organic acids, carbohydrates and fatty acid analogs (PUFAs). Moreover, the relative abundance of bacteria ( Proteobacteria and Actinobacteriota ) involved in C, N, and P cycling in Cr-contaminated soils increased. In addition, the upregulation of functional genes associated with the C cycle ( mnp , abfA , sga , rbcL and pmoC ), N fixation ( nifH ), nitrification ( amoA ), and P cycle ( phoD ), as well as the downregulation of denitrification ( nirK1 and nirS2 ), promoted C, N, and P cycling in soil and ultimately mitigated Cr toxicity. The application of Se and Mo promoted the activation of carbon, nitrogen, and phosphorus nutrients by increasing soil pH, organic matter (SOM) content, and urease and sucrose activities, as well as a marked boost in alkaline phosphatase activity (SALP). Stimulating microbial activity and optimizing nutrient cycling, the combined application of Se and Mo alleviates Cr stress by modulating soil properties and directly regulating microbial functional genes. Our findings offer novel insights into the mechanisms through which Se and Mo alleviate Cr toxicity in contaminated soils.

Source: Industrial Crops and Products

DOI: 10.1016/j.indcrop.2026.122980