NanoSIMS analysis of arsenic and selenium in cereal grain

A - Papers appearing in refereed journals

Moore, K. L., Schroder, M., Lombi, E., Zhao, F-J., McGrath, S. P., Hawkesford, M. J., Shewry, P. R. and Grovenor, C. R. M. 2010. NanoSIMS analysis of arsenic and selenium in cereal grain. New Phytologist. 185 (2), pp. 434-445.

AuthorsMoore, K. L., Schroder, M., Lombi, E., Zhao, F-J., McGrath, S. P., Hawkesford, M. J., Shewry, P. R. and Grovenor, C. R. M.
Abstract

P>Cereals are an important source of selenium (Se) to humans and many people have inadequate intakes of this essential trace element. Conversely, arsenic (As) is toxic and may accumulate in rice grain at levels that pose a health risk. Knowledge of the localization of selenium and arsenic within the cereal grain will aid understanding of their deposition patterns and the impact of processes such as milling. High-resolution secondary ion mass spectrometry (NanoSIMS) was used to determine the localization of Se in wheat (Triticum aestivum) and As in rice (Oryza sativa). Combined synchrotron X-ray fluorescence (S-XRF) and NanoSIMS analysis utilized the strengths of both techniques. Selenium was concentrated in the protein surrounding the starch granules in the starchy endosperm cells and more homogeneously distributed in the aleurone cells but with Se-rich hotspots. Arsenic was concentrated in the subaleurone endosperm cells in association with the protein matrix rather than in the aleurone cells. NanoSIMS indicated that the high intensity of As identified in the S-XRF image was localized in micron-sized hotspots near the ovular vascular trace and nucellar projection. This is the first study showing subcellular localization in grain samples containing parts per million concentrations of Se and As. There is good quantitative agreement between NanoSIMS and S-XRF.

KeywordsPlant Sciences
Year of Publication2010
JournalNew Phytologist
Journal citation185 (2), pp. 434-445
Digital Object Identifier (DOI)doi:10.1111/j.1469-8137.2009.03071.x
PubMed ID19895416
Open accessPublished as non-open access
FunderEPSRC - Engineering and Physical Sciences Research Council
US Department of Energy - Basic Energy Sciences
NSERC
University of Washington
Simon Fraser University
Advanced Photon Source
US Department of Energy
Office of Science
Funder project or codeSEF
Centre for Crop Genetic Improvement (CGI)
ISSN0028646X
PublisherWiley
Grant IDGR/T19797
DE-AC02-06CH11357