Part I. Selenium Distribution, Bioavailability and Metabolism in Plants 1. Multi-Scale Factors and Processes Controlling Selenium Distributions in Soils 2. Biochemistry of Plant Selenium Uptake and Metabolism 3. Molecular Mechanisms of Selenium Responses and Resistance in Plants 4. Mechanisms of Plant Selenium Hyperaccumulation Part II. Selenium Metabolism in Non-plant Organisms - Influence on Se Fluxes in Ecosystems and Relevance for Human Health 5. Selenium and Algae: Accumulation, Tolerance Mechanisms and Dietary Perspectives 6. Bacteria versus Selenium: A View from the Inside Out 7. Selenium and the Plant Microbiome 8. Selenium Metabolism in Herbivores and Higher Trophic Levels Including Mammals Part III. Genetic, Evolutionary and Ecological Aspects of Plant Se Accumulation 9. The Genetics of Selenium Accumulation by Plants 10. Manipulating Selenium Metabolism in Plants: A Simple Twist of Metabolic Fate can Alter Selenium Tolerance and Accumulation 11. Ecology of Selenium in Plants 12. Evolutionary Aspects of Plant Selenium Accumulation Part IV. The Societal Relevance of Se for Human and Environmental Health: Biofortification and Phytoremediation 13. Overview of Selenium Deficiency and Toxicity Worldwide: Affected Areas, Selenium-Related Health Issues, and Case Studies 14. Selenium Biofortification 15. Effects of Selenium on Plant Metabolism and Implications for Crops and Consumers 16. Overview and Prospects of Selenium Phytoremediation Approaches
This book focuses on selenium (Se) metabolism in plants. It not only covers plant genetic, biochemical and physiological processes but places these in the context of Se movement in the food chain and the global environment, as well as discusses ecological and evolutionary significance. While Se is an essential micronutrient, it is toxic at high levels, and there is a narrow window between Se adequacy and toxicity. More than a billion people and their livestock in low-Se regions have been estimated to be affected by Se deficiency, which compromises the immune system, thyroid activity, male fertility and mental function. In high-Se areas, Se toxicity is a problem. Selenium-accumulating plants may be used to alleviate Se deficiency in consumers (biofortification), or to remove environmental Se pollution (phytoremediation), both covered extensively in this volume. Plant species genetically vary in Se uptake, metabolism and tolerance. Some plants native to seleniferous soils can even hyperaccumulate Se up to 1.5% of their dry weight. The book reviews the latest knowledge about the processes involved in Se uptake, metabolism, tolerance and (hyper)accumulation, as well as successful approaches to optimize Se accumulation and speciation via classical crop breeding and genetic engineering. Global processes that control Se distribution and movement are reviewed, as are associated deficiency and toxicity issues. Relevant for Se bioavailability and for Se movement in the food chain, Se metabolism is also reviewed in prokaryotes and in mammalian consumers, and the nutritional benefits of plant Se on consumers are discussed. The reader will learn about the profound ecological effects of plant Se on interactions with herbivores, pollinators, microbes and other plants, and the likely selection pressures that drive the evolution of Se hyperaccumulation.