A Future Crop Biotechnology View of Sulfur and Selenium
- Muhammad Sayyar Khan and
- Rüdiger Hell
Sulfur is an essential nutrient for plants, animals, and humans. In plants, it also is required for the synthesis of compounds for defense against herbivores and pathogens. Optimized sulfur supply to plants is thus important for quality and yield of many crops. Breeding and biotechnology aim at the improvement of sulfur relations at several levels but most importantly in sulfur-rich seed storage proteins. Apart from lysine and some other amino acids, cysteine and especially methionine often limit the nutritional value of food and feed. Selenium is the uneven sister of sulfur, and although essential in human nutrition, it is potentially toxic at elevated concentrations. Phytoremediation of selenium-contaminated soils and biofortification of foods are two major goals of plant biotechnology. Because of their similar chemical and physical properties, sulfate and selenate are believed to share the initial route for uptake and assimilation. Recently, the regulation of some of the potentially health-promoting compounds of sulfur and selenium in the Brassicaceae family has received considerable interest. Improved crop production appears to be hampered by the joint pathway of uptake and assimilation followed by a bias between reduced sulfur- or selenium-containing secondary compounds, such as glucosinolates and methylselenocysteine, preventing a simultaneous increase of both metabolite groups. A comprehensive understanding of the key regulatory steps of sulfur and selenium metabolism is indispensible to this end.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2008. American Society of Agronomy, Crop Science Society of America, Soil Science Society of America, 5585 Guilford Road, Madison, WI 53711-5801, USA. Sulfur: A Missing Link between Soils, Crops, and Nutrition. Agronomy Monograph 50.