Abstract:

      Selenium (Se) was discovered by Swedish chemist Jacob Berzelius (1779 -1848) on 1817 and  has become one of the most influential natural-occurring trace elements for humans, animals, and even plants. Till now, it is recognized that two Se-containing amino acids-selenomethionine (SeMet) and selenocysteine (SeCys) are involved in the regulation of two important enzymes families-glutathione peroxidases and thioredoxin reductases. These enzymes play important roles in human physiology, especially in protection from oxidative damage and regulation of intracellular redox state and thyroid hormone metabolism. However, low Se intakes partly resulting from vegetation produced on Se deficient  soils (usually <0.4 mg Se/kg) are more widespread than excessive Se in many countries, e.g., Finland, China, UK, Europe, Australia and New Zealand. Especially, the endemic diseases-Keshan Disease and Kaschin Beck Disease in Northeast China (Heilongjiang Province) were confirmed to derive from very low Se intake with less than 7 μg/d, while, selenosis caused by excessive intake of Se (occurred in Enshi, China) is characterized by loss of nails and hair in human and blind  staggers  in animals. Thus, Chinese scientists have proposed  safe Se intake ranges from 60~400 μg Se/d adult, which represent ranges already adapted by USA, Europe, Newzealand, Canada, Australia.

      In recent years, a new strategy of "Se biofortification" has been developed to increase Se accumulation in staple crops, and thereby improve Se intake and reduce Se deficiencies in humans. For this reason, more effective biofortification strategies could be achieved if plant breeders, molecular biologists, and agronomists collaborated to better understand the limiting factors of Se uptake, differences in Se accumulation and the biotransformation of Se into selenoamino acids within the plants. Thus, the Natural Biofortification Program (NBP) was proposed by the International Society for Selenium Research (ISSR) in 2017. We are calling for crop breeding scientists, soil scientists, agronomists, animal scientists and biologists to internationally cooperate on reducing the hidden hunger on Se.

      We have just finished celebrating Se 200 Anniversary International Conference on 13~17 August in Stockholm, Sweden, and more than 300 participants from more than 40 countries attended this conference, which included about 80 participants from China. Hence, this special issue on Se 200 anniversary in China is being published at an opportune time, and  will provide an interactive platform for multi-disciplinary Se researchers to share topics and achievements in China. I am very pleased to play the role as a  bridge-builder between Chinese Se researchers and international Se scientists via the International Society for Se Research (ISSR). I believe that  outstanding achievements will be attained in China in the near future via concerted efforts from Chinese Se scientists working independently and jointly with the international Se research community.