Stable isotope tracing: A powerful tool for selenium speciation and metabolic studies in non-hyperaccumulator plants (ryegrass Lolium perenne L.)

Pamela Di Tullo (1) , A. Versini , Maïté Bueno (1) , Isabelle Le Hécho (1) , Y. Thiry (2) , P. Biron , M. Castrec-Rouelle , Florence Pannier (1)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
2 ANDRA - Agence Nationale pour la Gestion des Déchets Radioactifs

Selenium is both essential and toxic for mammals; the range between the two roles is narrow and not only dose-dependent but also related to the chemical species present in foodstuff. Unraveling the metabolism of Se in plants as a function of Se source may thus lead to ways to increase efficiency of fertilization procedures in selenium deficient regions. In this study, stable-isotope tracing was applied for the first time in plants to simultaneously monitor the bio-incorporation of two inorganic Se species commonly used as foodstuff enrichment sources. Occurrence and speciation of Se coming from different Se sources were investigated in root and leaf extracts of ryegrass (Lolium perenne L.), which had been co-exposed to two labeled Se species (77SeIV and 82SeVI). Although the plant absorbed similar amounts of Se when supplied in the form of selenite or selenate, the results evidenced marked differences in speciation and tissues allocation. Selenite was converted into organic forms incorporated mostly into high molecular weight compounds with limited translocation to leaves, whereas selenate was highly mobile being little assimilated into organic forms. Double-spike isotopic tracer methodology makes it possible to compare the metabolism of two species-specific Se sources simultaneously in a single experiment and to analyze Se behavior in not-hyperaccumulator plants, the ICP-MS sensitivity being improved by the use of enriched isotopes. © 2015 Springer-Verlag Berlin Heidelberg.

Mots clés: procedures; plant root; Stable isotope tracers; Species specifics; chemistry; selenium; plant leaf; evaluation study; Lolium; metabolism; Inductively coupled plasma mass spectrometry; Isotopes; Mass spectrometers; Physiology; Selenium compounds; High molecular weight compounds; HPLC ICP MS; Hyperaccumulator plant; Plants; Selenium speciation; Speciation; isotope; Plants (botany); transport at the cellular level; Biological Transport; Isotope Labeling; Plant Leaves; Plant Roots

Domaines: Chimie analytique; Sciences de l'environnement

Pamela Di Tullo, A. Versini, Maïté Bueno, Isabelle Le Hécho, Y. Thiry, et al.. Stable isotope tracing: A powerful tool for selenium speciation and metabolic studies in non-hyperaccumulator plants (ryegrass Lolium perenne L.). Analytical and Bioanalytical Chemistry, 2015, 407 (30), pp.9029-9042. ⟨10.1007/s00216-015-9069-4⟩. ⟨hal-01505718⟩