Tracking Se Assimilation and Speciation through the Rice Plant - Nutrient Competition, Toxicity and Distribution

Alexandra K Nothstein; Elisabeth Eiche; Michael Riemann; Peter Nick; Lenny H E Winkel; Jörg Göttlicher; Ralph Steininger; Rita Brendel; Matthias von Brasch; Gabriele Konrad; Thomas Neumann

doi:10.1371/journal.pone.0152081

Tracking Se Assimilation and Speciation through the Rice Plant - Nutrient Competition, Toxicity and Distribution

PLoS One. 2016 Apr 26;11(4):e0152081. doi: 10.1371/journal.pone.0152081. eCollection 2016.

Authors

Affiliations

¹ Institute of Applied Geosciences (AGW), Karlsruhe Institute of Technology (KIT), Adenauerring 20b, D-76131 Karlsruhe, Germany.
² Molecular Cell Biology, Botanical Institute, and Center for Functional Nanostructures (CFN), Karlsruhe, Institute of Technology (KIT), Kaiserstraße 2, D-76131 Karlsruhe, Germany.
³ Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland.
⁴ Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Universitätsstraße 16, CH-8092 Zürich, Switzerland.
⁵ ANKA Synchrotron Radiation Facility, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany.

Abstract

Up to 1 billion people are affected by low intakes of the essential nutrient selenium (Se) due to low concentrations in crops. Biofortification of this micronutrient in plants is an attractive way of increasing dietary Se levels. We investigated a promising method of Se biofortification of rice seedlings, as rice is the primary staple for 3 billion people, but naturally contains low Se concentrations. We studied hydroponic Se uptake for 0-2500 ppb Se, potential phyto-toxicological effects of Se and the speciation of Se along the shoots and roots as a function of added Se species, concentrations and other nutrients supplied. We found that rice germinating directly in a Se environment increased plant-Se by factor 2-16, but that nutrient supplementation is required to prevent phyto-toxicity. XANES data showed that selenite uptake mainly resulted in the accumulation of organic Se in roots, but that selenate uptake resulted in accumulation of selenate in the higher part of the shoot, which is an essential requirement for Se to be transported to the grain. The amount of organic Se in the plant was positively correlated with applied Se concentration. Our results indicate that biofortification of seedlings with selenate is a successful method to increase Se levels in rice.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Biological Transport, Active
Germination
Humans
Hydroponics
Micronutrients / administration & dosage
Micronutrients / pharmacokinetics
Micronutrients / toxicity
Oryza / drug effects
Oryza / growth & development
Oryza / metabolism*
Plant Shoots / metabolism
Seedlings / metabolism
Selenic Acid / administration & dosage
Selenic Acid / pharmacokinetics
Selenic Acid / toxicity
Selenium / administration & dosage
Selenium / pharmacokinetics*
Selenium / toxicity

Substances

Micronutrients
Selenium
Selenic Acid

Grants and funding

This study, which was part of a PhD study, was funded for 2 years by a graduate student grant from the Landesgraduiertenföderung Baden- Würrtemberg through the Kalrsruhe Institute of Technology Council for Research and Promotion of Young Scientists (CRYS, KIT) for financial support via Dr. Monika Stelling’s YIG and the Helmholtz Graduate School GRACE (KIT). The third year of this PhD study was funded by a graduate student grant from the Graduate School of Climate and Environment at the Karlsruhe Institute of Technology. Lab material was made available through funding by the Young Investigator Group for Selenium Isotopes funded by the Karlsruhe Institute of Technology and the Graduate School for Climate and Environment at the Karlsruhe Institute for Technology. The authors acknowledge support by Deutsche Forschungsgemeinschaft and Open Access Publishing Fund of Karlsruhe Institute of Technology. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.