Mechanisms of selenium hyperaccumulation in plants: A survey of molecular, biochemical and ecological cues

Publication date: Available online 4 April 2018Source: Biochimica et Biophysica Acta (BBA) - General SubjectsAuthor(s): Leonardo Warzea Lima, Elizabeth A.H. Pilon-Smits, Michela SchiavonAbstractBackgroundSelenium (Se) is a micronutrient required for many life forms, but toxic at higher concentration. Plants do not have a Se requirement, but can benefit from Se via enhanced antioxidant activity. Some plant species can accumulate Se to concentrations above 0.1% of dry weight and seem to possess mechanisms that distinguish Se from its analog sulfur (S). Research on these so-called Se hyperaccumulators aims to identify key genes for this remarkable trait and to understand ecological implications.Scope of reviewThis review gives a broad overview of the current knowledge about Se uptake and metabolism in plants, with a special emphasis on hypothesized mechanisms of Se hyperaccumulation. The role of Se in plant defense responses and the associated ecological implications are discussed.Major conclusionsHyperaccumulators have enhanced expression of S transport and assimilation genes, and may possess transporters with higher specificity for selenate over sulfate. Genes involved in antioxidant reactions and biotic stress resistance are also upregulated. Key regulators in these processes appear to be the growth regulators jasmonic acid, salicylic acid and ethylene. Hyperaccumulation may have evolved owing to associated ecological benefits, particularly protection against pathogens and he...
Source: Biochimica et Biophysica Acta (BBA) General Subjects - Category: Biochemistry Source Type: research