Selenium alleviates cadmium toxicity by restricting its transfer and regulating starch anabolism genes expression

Cadmium (Cd) pollution adversely affects plant growth and development, leading to reductions in crop yields and posing a threat to human health. Selenium (Se) is an essential micronutrient for both humans and animals. Wheat, an important cereal crop, is particularly prone to accumulating Cd in polluted environments. However, there is a paucity of studies examining the mitigation mechanisms of Se on the photosynthetic systems of wheat leaves under Cd stress. In this study, the alleviating effect of Se on Cd toxicity in wheat was investigated. The results showed Se increased wheat biomass by 20 %-50 %, photosynthetic parameters by 26 %-55 %, chlorophyll content by 17 %-29 % and help to keep normal leaf structure under Cd stress. Se upregulated key starch anabolism genes TaAGPS1 , TaSUT2 , and TaSWEET15 expression level, and thus complemented soluble sugar content by 16 %-21 %, starch content by 15 %-59 % disturbed by Cd stress. Under Cd stress, Se decreased wheat shoot Cd content by 6 %-19 %, and increased shoot Fe, Mn, Zn content by 5–28 %, 23–58 %, 8–32 %, respectively. These results suggest that Se mitigates Cd stress in wheat by limiting Cd translocation to shoots and regulating the expression of key carbon metabolism genes. • Selenium restricts Cd translocation to shoot and increases Fe, Mn and Zn contents. • Selenium increases photosynthesis by maintaining normal leaf structure. • Selenium increases starch anabolism genes expression level and starch synthesis under Cd toxicity.