Potential effects of Rhodococcus qingshengii strain PM1 on the bioremediation of selenium-contaminated soil and the assembly of its microbiome

Selenium is one of the essential micronutrients for living organisms, and both its deficiency and excessive intake have adverse effects on human health, with selenium intake exceeding 400 ug/day leading to selenosis. The dietary intake of selenium in the population depends to a certain extent on the amount of available selenium that enters the food chain from the soil. Therefore, selenium pollution zones are easily formed in soil environments, especially in selenium-rich areas, by weathering and leaching, as well as by high selenium-containing wastes generated by human production and life, which can affect the normal functioning of the ecosystems and jeopardise human health. Microorganisms play a crucial role in the biotransformation of selenium in nature by reducing the highly soluble and toxic selenite to the less soluble and toxic monomeric selenium, thus reducing the toxicity of selenite in the soil and improving the soil environment. However, insufficient understanding of the effects of selenite-degrading bacteria on soil microbial communities can negatively affect the remediation of selenium-contaminated soils. Therefore, we isolated a highly selenite-resistant strain, PM1, from high selenium zone soil and explored the potential effects on bioremediation of selenium-contaminated soil and its microbial community.