Underlying mechanisms responsible for restriction of uptake and translocation of heavy metals (metalloids) by selenium via root application in plants

•Co-precipitation of Se and HMs in soil is a key factor to reduce plant HM uptake.•Soil pH, Eh, water and microbes affect the ability of Se in reducing HM uptake.•Se affects HM uptake via altering root morphology which is affected by hormones.•Se doesn’t always stimulate more formation of and sequestration of HMs on Fe plaques.•Se downregulates genes encoding proteins responsible for Cd uptake.