Impacts, causes and biofortification strategy of rice selenium deficiency based on publication collection

Selenium (Se) deficiency in rice will result in a Se hidden hunger threat to the general public's human health, particularly in areas where rice consumption is high. Nevertheless, the impact scope and coping strategies have not been given sufficient focus on a worldwide scale. In order to evaluate the impacts, causes and biofortification strategies of Se-deficient rice, this study collected data from the publications on three themes: market survey, field sampling and controlled experiments. According to the market survey, global rice Se concentrations were 0.079 mg/kg on mean and 0.062 mg/kg on median. East Asia has a human Se intake gap due to the region's high rice consumption and the lowest rice Se concentration in markets globally. Total Se concentrations in East Asian paddy soils were found to be adequate based on the field sampling. However, over 70 % of East Asian paddy fields were inadequate to yield rice that met the global mean for rice Se concentration. The Se-deficient rice was probably caused by widespread low Se bioavailability in East Asian paddy fields. There were two important factors influencing rice Se enrichment including root Se uptake and iron oxide in soils. Concentrating on these processes is beneficial to rice Se biofortification. Since Se is adequate in the paddy soils of East Asia. Rather of adding Se exogenously, activating the native Se in paddy soil is probably a more appropriate strategy for rice Se biofortification in East Asia. Meta-analysis revealed water management had the greatest impact on rice Se biofortification. The risks and solutions for rice Se deficiency were discussed in our farmland-to-table survey, which will be a valuable information in addressing the global challenge of Se hidden hunger. This study also provided new perspectives and their justifications, critically analyzing both present and future strategies to address Se hidden hunger.