Soil bacteria, genes, and metabolites stimulated during sulfur cycling and cadmium mobilization under sodium sulfate stress

• Published in: Environmental research Vol. 201; p. 111599
• Main Authors: Wang, Meng, Wang, Lifu, Shi, Huading, Liu, Yongbing, Chen, Shibao
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.10.2021
• Subjects: Functional genes; Sodium sulfate stress; Soil cadmium availability; Soil metabolites profile; Soil metabolites profile; Soil cadmium availability; Sodium sulfate stress; Functional genes
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2021.111599

Sodium sulfate stress is known to improve cadmium (Cd) mobilization in soil and microbial sulfur oxidation, Cd resistance, and the accumulation of stress tolerance-associated metabolites has been correlated with increased soil Cd availability and toxicity. In this study, aerobic soil microcosms with Cd-contamination were stimulated with sodium sulfate to investigate its effects on soil microbial community structure, functional genes, and associated metabolite profiles. Metagenomic analysis revealed that sulfur oxidizing and Cd-resistant bacteria carried gene clusters encoding sox, dsr, and sqr genes, and znt, czc, and cad genes, respectively. Exposure to sodium sulfate resulted in the reprogram of soil metabolites. In particular, intensification of sulfur metabolism triggered an up-regulation in the tricarboxylic acid (TCA) cycle, which promoted the secretion of carboxylic acids and their precursors by soil bacteria. The accumulation of organic acids induced in response to high sodium sulfate dosages potentially drove an observed increase in Cd mobility. Pseudomonas and Erythrobacter spp. exhibited a high capacity for adaptation to heavy metal- or sulfur-induced stress, evident by an increased abundance of genes and metabolites for sulfur cycling and Cd resistance. These results provide valuable insights towards understanding the microbial mechanisms of sulfur transformation and Cd dissolution under saline stress. •Na2SO4 enriched for S-oxidizing and Cd-resistant bacteria with functional genes.•The intense sulfur metabolism triggered the upregulation of the TCA cycle.•Pseudomonas and Erythrobacter spp. exhibited a capacity to adapt saline stress.•Both the responses potentially contributed to increased soil Cd mobility.